US20030166298A1 - Colorimetric artificial nose having an array of dyes and method for artificial olfaction - Google Patents

Abstract

The present invention involves an artificial nose comprising an array, the array comprising at least a first dye and a second dye deposited directly onto a single support in a predetermined pattern combination, the combination of dyes in the array having a distinct and direct spectral absorbance or reflectance response to distinct analytes comprising one or more parent analytes or their derivatives. In one embodiment, the invention further comprises an oxidizing source to partially oxidize at least one distinct parent analyte to at least one corresponding derivative analyte of said parent analyte, the array at least in part having a stronger distinct and direct absorbance or reflectance response to the derivative analyte than to the corresponding parent analyte.

Description

CONTINUING APPLICATION DATA
• This application is a Continuation-in-Part of U.S. application Ser. No. 09/705,329, filed on Nov. 3, 2000, which is a Continuation-in-Part of U.S. application Ser. No. 09/532,125, filed on Mar. 21, 2000, now U.S. Pat. No. 6,368,558.[0001]
• [0002] This invention was made with Government support under Contract Nos. HL25934 awarded by the National Institutes of Health & Contract No. DAAG55-97-1-2211 awarded by the Department of the Army. The Government has certain rights in the invention.
FIELD OF THE INVENTION
• The present invention relates to methods and apparatus for artificial olfaction, e.g., artificial noses, for the detection of odorants by a visual display.[0003]
BACKGROUND OF THE INVENTION
• There is a great need for olfactory or vapor-selective detectors (i.e., “artificial noses”) in a wide variety of applications. For example, there is a need for artificial noses that can detect low levels of odorants and/or where odorants may be harmful to humans, animals or plants. Artificial noses that can detect many different chemicals are desirable for personal dosimeters in order to detect the type and amount of odorants exposed to a human, the presence of chemical poisons or toxins, the spoilage in foods, the presence of flavorings, or the presence of vapor emitting items, such as plant materials, fruits and vegetables, e.g., at customs portals.[0004]
• Conventional artificial noses have severe limitations and disadvantages and are not considered generally useful for such purposes. Limitations and disadvantages of conventional artificial noses include their need for extensive signal transduction hardware, and their inability to selectively target metal-coordinating vapors and toxins. In addition, artificial noses which incorporate mass sensitive signal transduction or polar polymers as sensor elements are susceptible to interference by water vapor. This limitation is significant in that it can cause variable response of the detector with changes ambient humidity. See F. L. Dickert, O. Hayden, Zenkel, M. E. Anal. Chem. 71, 1338 (1999).[0005]
• Initial work in the field of artificial noses was conducted by Wilkens and Hatman in 1964, though the bulk of research done in this area has been carried out since the early 1980's. See, e.g., W. F. Wilkens, A. D. Hatman.[0006]Ann. NY Acad. Sci.,116, 608 (1964); K. Pursaud, G. H. Dodd.Nature,299, 352-355 (1982); and J. W. Gardner, P. N. Bartlett.Sensors and Actuators B,18-19, 211-220 (1994).
• Vapor-selective detectors or “artificial noses” are typically based upon the production of an interpretable signal or display upon exposure to a vapor emitting substance or odorant (hereinafter sometimes referred to as an “analyte”). More specifically, typical artificial noses are based upon selective chemical binding or an interface between a detecting compound of the artificial nose and an analyte or odorant, and then transforming that chemical binding into a signal or display, i.e., signal transduction.[0007]
• Polymer arrays having a single dye have been used for artificial noses. That is, a series of chemically-diverse polymers or polymer blends are chosen so that their composite response distinguishes a given odorant or analyte from others. Examples of polymer array vapor detectors, including conductive polymer and conductive polymer/carbon black composites, are discussed in: M. S. Freund, N. S. Lewis, Proc. Natl. Acad. Sci. U.S. Pat. No. 92,2652-2656 (1995); B. J. Doleman, R. D. Sanner, E. J. Severin, R. H. Grubbs, N. S. Lewis,[0008]Anal. Chem.70, 2560-2564 (1998); T. A. Dickinson, J. White, J. S. Kauer, D. R. Walt,Nature382, 697-700 (1996) (polymer array with optical detection); A. E. Hoyt, A. J. Ricco, H. C. Yang, R. M. Crooks,J. Am. Chem. Soc.117, 8672 (1995); and J. W. Grate, M. H. Abraham,Sensors andActuators B3, 85-111 (1991).
• Other interface materials include functionalized self-assembled monolayers (SAM), metal oxides, and dendrimers. Signal transduction is commonly achieved with mass sensitive piezoelectric substrates, surface acoustic wave (SAW) transducers, or conductive materials. Optical transducers (based on absorbance or luminescence) have also been examined. Examples of metal oxide, SAM, and dendrimer-based detectors are discussed in J. W. Gardner, H. V. Shurmer, P. Corcoran,[0009]Sensors andActuators B4, 117-121 (1991); J. W. Gardner, H. V. Shurmer, T. T. Tan,Sensors andActuators B6, 71-75 (1992); and R. M. Crooks, A. J. Ricco,Acc. Chem. Res.31, 219-227 (1998). These devices also use a single dye.
• Techniques have also been developed using a metalloporphyrin for optical detection of a specific, single gas such as oxygen or ammonia, and for vapor detection by chemically interactive layers on quartz crystal microbalances. See A. E. Baron, J. D. S. Danielson, M. Gouterman, J. R. Wan, J. B. Callis,[0010]Rev. Sci. Instrum.64, 3394-3402 (1993); J. Kavandi, et al.,Rev. Sci. Instrum.61, 3340-3347 (1990); W. Lee, et al.,J. Mater. Chem.3, 1031-1035 (1993); A. A. Vaughan, M. G. Baron, R. Narayanaswamy,Anal Comm.33, 393-396 (1996); J. A. J. Brunink, et al.,Anal. Chim. Acta325, 53-64 (1996); C. Di Natale, et al.,Sensors andActuators B44, 521-526 (1997); and C. Di Natale, et al.,Mat.Sci. Eng. C5, 209-215 (1998). However, these techniques either require extensive signal transduction hardware, or, as noted above, are limited to the detection of a specific, single gas. They are also subject to water vapor interference problems, as discussed previously.
• While typical systems to date have demonstrated some success in chemical vapor detection and differentiation, these systems have focused on the detection of non-metal binding or non-metal ligating solvent vapors, such as arenes, halocarbons and ketones. Detection of metal-ligating vapors (such as amines, thiols, and phosphines) has been much less explored. Further, while some single porphyrin based sensors have been used for detection of a single strong acid, there is a need for sensor devices that will detect a wide variety of vapors.[0011]
• To summarize, there are a number of limitations and drawbacks to typical artificial noses and single porphyrin based sensors. As noted above typical artificial noses are not designed for metal binding and metal ligating vapors, such as amines, thiols, and phosphines. Further, typical artificial noses require extensive signal transduction hardware, and are subject to interference from water vapor. As noted above, single porphyrin based sensors have been used for detection of a single strong acid, but cannot detect a wide variety of vapors. Thus, there is a need for new artificial noses and methods that overcome these and other limitations of prior artificial noses and single porphyrin based sensors and methods.[0012]
SUMMARY OF THE INVENTION
• The present invention comprises an array of dyes including at least a first dye and a second dye which in combination provide a spectral response distinct to an analyte or odorant. The dyes of the present invention produce a response in the spectrum range of about 200 nanometers to 2,000 nanometers, which includes the visible spectrum of light. It has now been discovered that an array of two or more dyes responds to a given ligating species with a unique color pattern spectrally and in a time dependent manner. Thus, dyes in the array of the present invention are capable of changing color in a distinct manner when exposed to any one analyte or odorant. The pattern of colors manifested by the multiple dyes is indicative of a specific or given analyte. In other words, the pattern of dye colors observed is indicative of a particular vapor or liquid species.[0013]
• In a preferred embodiment, the dyes of the array are porphyrins. In another preferred embodiment, the porphyrin dyes are metalloporphyrins. In a further preferred embodiment, the array will comprise ten to fifteen distinct metalloporphyrins in combination. Metalloporphyrins are preferable dyes in the present invention because they can coordinate metal-ligating vapors through open axial coordination sites, and they produce large spectral shifts upon binding of or interaction with metal-ligating vapors. In addition, porphyrins, metalloporphyrins, and many dyes show significant color changes upon changes in the polarity of their environment; this so-called solvatochromic effect will give net color changes even in the absence of direct bonding between the vapor molecules and the metal ions. Thus, metalloporphyrins produce intense and distinctive changes in coloration upon ligand binding with metal ligating vapors.[0014]
• The present invention provides a means for the detection or differentiation and quantitative measurement of a wide range of ligand vapors, such as amines, alcohols, and thiols. Further, the color data obtained using the arrays of the present innovation may be used to give a qualitative fingerprint of an analyte, or may be quantitatively analyzed to allow for automated pattern recognition and/or determination of analyte concentration. Because porphyrins also exhibit wavelength and intensity changes in their absorption bands with varying solvent polarity, weakly ligating vapors (e.g., arenes, halocarbons, or ketones) are also differentiable.[0015]
• Diversity within the metalloporphyrin array may be obtained by variation of the parent porphyrin, the porphyrin metal center, or the peripheral porphyrin substituents. The parent porphyrin is also referred to as a free base (“FB”) porphyrin, which has two central nitrogen atoms protonated (i.e., hydrogen cations bonded to two of the central pyrrole nitrogen atoms). A preferred parent porphyrin is depicted in FIG. 2A, with the substitution of a two hydrogen ion for the metal ion (depicted as “M”) in the center of the porphyrin. In FIG. 2A, TTP stands for 5,10,1 5,20-tetraphenylporphyrinate(-2).[0016]
• In accordance with the present invention, colorimetric difference maps can be generated by subtracting unexposed and exposed metalloporphyrin array images (obtained, for example, with a common flatbed scanner or inexpensive video or charge coupled device (“CCD”) detector) with image analysis software. This eliminates the need for extensive and expensive signal transduction hardware associated with previous techniques (e.g., piezoelectric or semiconductor sensors). By simply differencing images of the array before and after exposure to analytes, the present invention provides unique color change signatures for the analytes, for both qualitative recognition and quantitative analysis.[0017]
• Sensor plates which incorporate vapor sensitive combinations of dyes comprise an embodiment of the present invention which is economical, disposable, and can be utilized to provide qualitative and/or quantitative identification of an analyte. In accordance with the present invention, a catalog of arrays and the resultant visual pattern for each analyte can be coded and placed in a look-up table or book for future reference. Thus, the present invention includes a method of detecting an analyte comprising the steps of forming an array of at least a first dye and a second dye, subjecting the array to an analyte, inspecting the first and second dyes for a spectral response, and comparing the spectral response with a catalog of analyte spectral responses to identify the analyte.[0018]
• Because sensing is based upon either covalent interaction (i.e., ligation) or non-covalent solvation interactions between the analyte and the porphyrin array, a broad spectrum of chemical species is differentiable. While long response times (e.g., about 45 minutes) are observed at low analyte concentrations of about 1 ppm with reverse phase silica gel plates, use of impermeable solid supports (such as polymer- or glass-based micro-array plates) substantially increases the low-level response to less than 5 minutes.[0019]
• Thus, it is an object of the present invention to provide methods and devices for artificial olfaction, vapor-selective detectors or artificial noses for a wide variety of applications. It is another object of the present invention to provide methods of detection and artificial noses that can detect low levels of odorants and/or where odorants may be harmful to living human, animal or plant cells. It is also an object of the present invention to provide methods of olfactory detection and artificial noses that can detect and quantify many different chemicals for dosimeters that can detect chemical poisons or toxins, that can detect spoilage in foods, that can detect flavorings and additives, and that can detect plant materials, e.g., fruits and vegetables.[0020]
• Another object of the present invention is to provide for the detection of analytes using data analysis/pattern recognition techniques, including automated techniques.[0021]
• Another object of the invention is to provide an artificial nose comprising an array, the array comprising at least a first dye and a second dye deposited directly onto a single support in a predetermined pattern combination, the combination of the dyes in the array having a distinct and direct spectral absorbance or reflectance response to an analyte wherein the first dye and the second are selected from the group of dyes consisting of chemoresponsive dyes, and the second dye is distinct from the first dye. In one embodiment, the first dye is selected from the group consisting of porphyrin, chlorin, chlorophyll, phtahlocyanine, and salen and their metal complexes. In another embodiment, the second dye is selected from the group consisting of acid-base indicator dyes and solvatochromic dyes.[0022]
• Another object of the invention is to provide a method of detecting an analyte comprising the steps of: (a) forming an array of at least a first dye and a second dye deposited directly onto a single support in a predetermined pattern combination, the combination of the dyes in the array having a distinct and direct spectral absorbance or reflectance response to an analyte wherein the first dye and the second dye are selected from the group consisting of chemoresponsive dyes, and the second dye is distinct from the first dye, (b) subjecting the array to an analyte, (c) inspecting the array for a distinct and direct spectral absorbance or reflectance response, and (d) correlating the distinct and direct spectral response to the presence of the analyte. In one embodiment, the first dye is selected from the group consisting of porphyrin, chlorin, chlorophyll, phtahlocyanine, and salen and their metal complexes. In another embodiment, the second dye is selected from the group consisting of acid-base indicator dyes and solvatochromic dyes.[0023]
• Another object of the invention is to provide an artificial tongue comprising an array, the array comprising at least a first dye and a second dye deposited directly onto a single support in a predetermined pattern combination, the combination of the dyes in the array having a distinct and direct spectral absorbance or reflectance response to an analyte wherein the first dye and the second are selected from the group of dyes consisting of chemoresponsive dyes, and the second dye is distinct from the first dye. In one embodiment, the first dye is selected from the group consisting of porphyrin, chlorin, chlorophyll, phtahlocyanine, and salen and their metal complexes. In another embodiment, the second dye is selected from the group consisting of acid-base indicator dyes and solvatochromic dyes.[0024]
• Another object of the invention is to provide an artificial nose comprising an array, the array comprising at least a first dye and a second dye deposited directly onto a single support in a predetermined pattern combination, the combination of dyes in the array having a distinct and direct spectral absorbance or reflectance response to distinct analytes comprising one or more parent analytes or their derivatives, and an oxidizing source to partially oxidize at lest one distinct parent analyte to at least one corresponding derivative analyte of said parent analyte, the array at least in part having a stronger distinct and direct absorbance or reflectance response to the derivative analyte than to the corresponding parent analyte[0025]
BRIEF DESCRIPTION OF THE DRAWINGS
• The file of this patent contains at least one drawing executed in color. Copies of this patent with color drawing(s) will be provided by the Patent and Trademark Office upon request and payment of the necessary fee.[0026]
• FIG. 1 illustrates an embodiment of the optical sensing plate of the present invention using a first elution in the y axis and a second elution in the x axis of the plate. In this embodiment the first elution R-OH/hexane and the second elution is R-SH/hexane.[0027]
• FIG. 2A illustrates an embodiment of the invention using metalloporphyrins as the sensing dyes.[0028]
• FIG. 2B illustrates an embodiment of the invention using metalloporphyrins as the sensing dyes.[0029]
• FIG. 3A illustrates a vapor exposure apparatus for demonstration of the present invention.[0030]
• FIG. 3B illustrates a vapor exposure apparatus for demonstration of the present invention.[0031]
• FIG. 4 illustrates the color change profile in a metalloporphyrin array of FIG. 2 when used in the vapor exposure apparatus of FIG. 3A to detect n-butylamine. Metalloporphyrins were immobilized on reverse phase silica gel plates.[0032]
• FIG. 5 illustrates a comparison of color changes at saturation for a wide range of analytes. Each analyte was delivered to the array as a nitrogen stream saturated with the analyte vapor at 20° C. DMF stands for dimethylformamide; THF stands for tetrahydrofuran.[0033]
• FIG. 6 illustrates two component saturation responses of mixtures of 2-methylpyridine and trimethylphosphite. Vapor mixtures were obtained by mixing two analyte-saturated N[0034]₂streams at variable flow ratios.
• FIG. 7 illustrates a comparison of Zn(TPP) spectral shifts upon exposure to ethanol and pyridine (py) in methylene chloride solution (A) and on the reverse phase support (B).[0035]
• FIG. 8 illustrates another embodiment of the present invention, and more particularly, an small array comprising microwells built into a wearable detector which also contains a portable light source and a light detector, such as a charge-coupled device (CCD) or photodiode array.[0036]
• FIG. 9 illustrates another embodiment of the present invention, and more particularly, a microwell porphyrin array wellplate constructed from polydimethylsiloxane (PDMS).[0037]
• FIG. 10 illustrates another embodiment of the present invention, and more particularly, a microplate containing machined teflon posts, upon which the porphyrin array is immobilized in a polymer matrix (polystyrene/dibutylphthalate).[0038]
• FIG. 11 illustrates another embodiment of the present invention, showing a microplate of the type shown in FIG. 10, consisting of a minimized array of four metalloporphyrins, showing the color profile changes for n-octylamine, dodecanethiol, and tri-n-butylphosphine, each at 1.8 ppm.[0039]
• FIG. 12 illustrates the immunity of the present invention to interference from water vapor.[0040]
• FIG. 13 illustrates the synthesis of siloxyl-substituted bis-pocket porphyrins in accordance with the present invention.[0041]
• FIGS. 14[0042]a,14b, and14cillustrate differences in K_eqfor various porphyrins.
• FIG. 15 illustrates molecular models of Zn(Si[0043]₆PP) (left column) and Zn(Si₈PP) (right column).
• FIG. 16 illustrates an array containing illustrative examples of porphyrin, metalloporphyrin, acid-base indicator, and solvatochromatic dyes.[0044]
• FIG. 17 illustrates the response of the array described in FIG. 16 to acid vapors, specifically formic acid, acetic acid, iso-valeric acid, and 3-methyl-2-hexenoic acid.[0045]
• FIG. 18 illustrates a preferred array containing illustrative examples of porphyrin, metalloporphyrin, acid-base indicator, and solvatochromatic dyes.[0046]
• FIG. 19 illustrates the response of the array described in FIG. 18 to acetone.[0047]
• FIG. 20 illustrates a vapor exposure apparatus shown in FIG. 3B, further having a partial oxidation cartridge to provide increased sensitivity to analytes.[0048]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
• Production of the Sensor Plate of the Present Invention[0049]
• A[0050]sensor plate10 fabricated in accordance with the present invention is shown in FIG. 1.Sensor plate10 comprises a two-dimensionally spatially resolvedarray12 of various sensing elements ordyes14 capable of changing color upon interaction (e.g., binding, pi-pi complexation, or polarity induced shifts in color). As shown in FIG. 1, a library ofsuch dyes14 can be given spatial resolution by two-dimensional chromatography or by direct deposition, including, but not limited to, ink-jet printing, micropipette spotting, screen printing, or stamping. In FIG. 1,metalloporphyrin mixture6 is placed atorigin7. Next, themetalloporphyrin mixture6 is eluted through a silica gel or reversed-phase silica gel5 insensor plate10, and the metalloporphyrins are spatially resolved from each other and immobilized insilica gel5 as depicted by the oval andcircular shapes4 as shown in FIG. 1.Sensor plate10 can be made from any suitable material or materials, including but not limited to, chromatography plates, paper, filter papers, porous membranes, or properly machined polymers, glasses, or metals.
• FIG. 1 also illustrates an embodiment of the optical sensing plate of the present invention using a[0051]first elution8 in the y axis and asecond elution9 in the x axis ofsensor plate10. In this embodiment, thefirst elution8 is R—OH/hexane and thesecond elution9 is R—SH/hexane. The order of the first and second elutions can be reversed. The first and second elutions are used to spatially resolve themetalloporphyrin mixture6 insilica gel5. As shown in FIG. 1, the upperleft hand quadrant3 is characterized by metalloporphyrins that are “hard” selective, i.e., having a metal center having a high chemical hardness, i.e., a high charge density. As shown in FIG. 1, the lowerright hand quadrant2 is characterized by metalloporphyrins that are “soft” selective, i.e., having a metal center having a low chemical hardness, i.e., a low charge density. In accordance with the present invention, the array can be a spatially resolved collection of dyes, and more particularly a spatially resolved combinatorial family of dyes.
• In accordance with the present invention, a porphyrin-metalloporphyrin sensor plate was prepared and then used to detect various odorants. More specifically, solutions of various metalated tetraphenylporphyrins in either methylene chloride or chlorobenzene were spotted in 1 μL aliquots onto two carbon (“C2”, i.e, ethyl-capped) reverse phase silica thin layer chromatography plates (Product No. 4809-800, by Whatman, Inc., Clifton, N.J.) to yield the[0052]sensor array16 seen in FIG. 2B. As shown in FIG. 2B and summarized in Table 1 below, the dyes have the following colors (the exact colors depend, among other things, upon scanner settings).

  TABLE 1
  (Summarizing Colors of Dyes in FIG. 2B)

  Sn4+ - Green	Co3+ - Red	Cr3+ - Deep Green
  Mn3+ - Green	Fe3+ - Dark Red	Co2+ - Red
  Cu2+ - Red	Ru2+ - Light Yellow	Zn2+ - Greenish Red
  Ag2+ -Red	2H+(Free Base “FB”) — Red

• A[0053]metalloporphyrin15, sometimes referred to as M(TPP), of the present invention is depicted in FIG. 2A. FIG. 2A also depicts various metals of themetalloporphyrins15 of the present invention, and corresponding metal ion charge to radius ratio (i.e., Z/r Ratio) in reciprocal angstroms. The Z/r Ratio should preferably span a wide range in order to target a wide range of metal ligating analytes. These metalloporphyrins have excellent chemical stability on the solid support and most have well-studied solution ligation chemistry. Reverse phase silica was chosen as a non-interacting dispersion medium for themetalloporphyrin array16 depicted in FIG. 2B, as well as a suitable surface for diffuse reflectance spectral measurements. More importantly, the reverse phase silica presents a hydrophobic interface, which virtually eliminates interference from ambient water vapor. After spotting,sensor plates18 like the one depicted in FIG. 2B were dried under vacuum at 50° C. for 1 hour prior to use. Thus, immobilization of the metalloporphyrins on a reverse phase silica support is obtained. While ten (10) different metalloporphyrins are shown in FIG. 2A, those of skill in the art will recognize that many other metalloporphyrins are useful in accordance with the present invention. Those of skill in the art will further recognize that in accordance with the broad teachings of the present invention, any dyes capable of changing color upon interacting with an analyte, both containing and not containing metal ions, are useful in the array of the present invention.
• Colorimetric Analysis Using the Sensor Plate[0054]
• For the detection and analysis of odorants in accordance with the present invention, one needs to monitor the absorbance of the sensor plate at one or more wavelengths in a spatially resolved fashion. This can be accomplished with an imaging spectrophotometer, a simple flatbed scanner (e.g. a[0055]Hewlett Packard Scanjet 3c), or an inexpensive video or CCD camera.
• FIG. 3A illustrates a[0056]vapor exposure apparatus19 of the present invention. FIG. 3B illustrates top and side views ofbottom piece21 and a top view oftop piece21′ of a vaporexposure flow cell20 of the present invention. In an embodiment of the present invention for purposes of demonstration, eachsensor plate18 was placed inside of a stainlesssteel flow cell20 equipped with aquartz window22 as shown in FIGS. 3A and 3B. Scanning of thesensor plate18 was done on a commercially available flatbed scanner24 (Hewlett Packard Scanjet 3c) at 200 dpi resolution, in full color mode. Following an initial scan, a control run with a first purenitrogen flow stream26 was performed. Thearray16 ofplate18 was then exposed to a secondnitrogen flow stream28 saturated with aliquid analyte30 of interest. As shown in FIG. 3A, thenitrogen flow stream28 saturated withliquid analyte30 results in a saturatedvapor32. Saturatedvapor32, containing theanalyte30 of interest were generated by flowingnitrogen flow stream28 at 0.47 L/min. through the neatliquid analyte30 in a water-jacketed, glass frittedbubbler34. Vapor pressures were controlled by regulating thebubbler34 temperature. As shown in FIG. 3B,vapor channels23 permit vapor flow tosensor plate18.
EXAMPLE 1
• Scanning at different time intervals and subtracting the red, green and blue (“RGB”) values of the new images from those of the original scan yields a color change profile. This is shown for n-butylamine in FIG. 4, in which color change profiles of the[0057]metalloporphyrin sensor array16 as a function of exposure time to n-butylamine vapor. Subtraction of the initial scan from a scan after 5 min. of N₂exposure was used as a control, giving a black response, as shown. 9.3% n-butylamine in N₂was then passed over the array and scans made after exposure for 30 s, 5 min., and 15 min. The red, green and blue (“RGB”) mode images were subtracted (absolute value) to produce the color change profiles illustrated. Virtually all porphyrins are saturated after 30 seconds of exposure, yielding a color fingerprint unique for each class of analytes, which is illustrated in FIG. 4.
• More specifically, subtraction of the[0058]initial scan40 from a scan after 5 min. of N₂exposure was used as a control, giving a black response, as shown in FIG. 4. A nitrogen flow stream containing 0.093% n-butylamine was then passed over thearray16 and scans42,44, and46 were made after exposure for 30 seconds, 5 minutes, and 15 minutes, respectively. The RGB mode images were subtracted (absolute value) using Adobe Photoshop™ (which comprises standard image analyzing software), with contrast enhancement by expanding the pixel range (a 32 value range was expanded to 256 each for the R, G, and B values). Subtraction of exposed and unexposed images gives color change patterns that vary in hue and intensity. Because differentiation is provided by an array of detectors, the system has parallels the mammalian olfactory system. As shown in FIG. 4 and summarized in Table 2 below, the dyes have the following colors inscans42,44, and46.

  TABLE 2
  (Summarizing Colors of Dyes in FIG. 4, Scans 42, 44, and 46)

  Sn4+ - No Change	Co3+ - Green	Cr3+ - Green
  Mn3+ - No Change	Fe3+ - Red	Co2+ - Faint Green
  Cu2+ - No Change	Ru2+ - No Change	Zn2+ - Light Green
  Ag2+ -No Change	2H+(Free Base “FB”) —
  	Light Blue

• As summarized in Table 3 below, for the[0059]TTP array 16 depicted on the left-hand side of FIG. 4, the dyes have the following colors.

  TABLE 3
  Sn4+ - Greenish Yellow	Co3+ - Red	Cr3+ - Yellow with Dark Red
  		Center
  Mn3+ - Greenish Yellow	Fe3+ - Dark Red	Co2+ - Red
  Cu2+ - Red	Ru2+ - Light Yellow	Zn2+ - Red
  Ag2+ -Red	2H+(Free Base “FB”) — Red

EXAMPLE 2
• Visible spectral shifts and absorption intensity differences occur upon ligation of the metal center, leading to readily observable color changes. As is well known to those with skill in the art, the magnitude of spectral shift correlates with the polarizability of the ligand; hence, there exists an electronic basis for analyte distinction. Using metal centers that span a range of chemical hardness and ligand binding affinity, a wide range of volatile analytes (including soft ligands, such as thiols, and harder ligands, such as amines) are differentiable. Because porphyrins have been shown to exhibit wavelength and intensity changes in their absorption bands with varying solvent polarity, it is contemplated that the methods and apparatus of the present invention can be used to calorimetrically distinguish among a series of weakly ligating solvent vapors (e.g., arenes, halocarbons, or ketones), as shown for example in FIG. 5.[0060]
• A comparison of color changes at saturation for a wide range of analytes is shown in FIG. 5. Each analyte is identified under the[0061]colored array16 that identifies each analyte. ). DMF stands for the analyte dimethylformamide, and THF stands for the analyte tetrahydrofuran. As shown in FIG. 5 and summarized in Table 4 below, the colors of each dye in response to a particular analyte are as follows.

  TABLE 4
  Analyte: DMF

  Sn4+ - No Change	Co3+ - Green	Cr3+ - No Change
  Mn3+ - No Change	Fe3+ - No Change	Co2+ - No Change
  Cu2+ - Blue	Ru2+ - No Change	Zn2+ - No Change
  Ag2+ - No Change	2H+(Free Base “FB”) — Blue

  Analyte: Ethanol

  Sn4+ - Dark Blue	Co3+ - No Change	Cr3+ - Red
  Mn3+ - No Change	Fe3+ - No Change	Co2+ - No Change
  Cu2+ - No Change	Ru2+ - No Change	Zn2+ - Blue
  Ag2+ - No Change	2H+(Free Base “FB”) - No
  	Change

  Analyte: Pyridine

  Sn4+ - No Change	Co3+ - Green	Cr3+ - Dark Green
  Mn3+ - No Change	Fe3+ - No Change	Co2+ - No Change
  Cu2+ - No Change	Ru2+ - No Change	Zn2+ - Green
  Ag2+ - No Change	2H+(Free Base “FB”) — Blue

  Analyte: Hexylamine

  Sn4+ - No Change	Co3+ - Dark Green	Cr3+ - Green
  Mn3+ - No Change	Fe3+ - Red	Co2+ - No Change
  Cu2+ - Blue	Ru2+ - No Change	Zn2+ - Green
  Ag2+ - Dark Blue	2H+(Free Base “FB”) — Blue

  Analyte: Acetonitrile

  Sn4+ - Blue	Co3+ - Dark Green	Cr3+ - No Change
  Mn3+ - Yellow	Fe3+ - Dark Green	Co2+ - No Change
  Cu2+ - Blue	Ru2+ - Blue (faint dot)	Zn2+ - Blue
  Ag2+ - No Change	2H+(Free Base “FB”) — Blue

  Analyte: Acetone

  Sn4+ - No Change	Co3+ - No Change	Cr3+ - Red (small dot)
  Mn3+ - No Change	Fe3+ - No Change	Co2+ - No Change
  Cu2+ - Dark Blue	Ru2+ - No Change	Zn2+ - Dark Blue
  Ag2+ - No Change	2H+(Free Base “FB”) — Blue

  Analyte: THF

  Sn4+ - Dark Blue	Co3+ - Green	Cr3+ - Red
  Mn3+ - Blue (small dot)	Fe3+ - Dark Green	Co2+ - No Change
  Cu2+ - Blue	Ru2+ - No Change	Zn2+ - Blue
  Ag2+ - No Change	2H+(Free Base “FB”) — Blue

  Analyte: CH2Cl2

  Sn4+ - Dark Blue	Co3+ - No Change	Cr3+ - No Change
  Mn3+ - Yellow and Red (small	Fe3+ - No Change	Co2+ - No Change
  dot)
  Cu2+ - Dark Blue	Ru2+ - No Change	Zn2+ - No Change
  Ag2+ - No Change	2H+(Free Base “FB”) — Blue

  Analyte: CHCl3

  Sn4+ - Dark Blue	Co3+ - Dark Green	Cr3+ - Yellow (circle)
  Mn3+ - Yellow	Fe3+ - Dark Green (very faint)	Co2+ - No Change
  Cu2+ - Dark Blue (very faint)	Ru2+ - No Change	Zn2+ - Blue
  Ag2+ - Blue (very faint)	2H+(Free Base “FB”) — Blue

  Analyte: P(OC2H5)3

  Sn4+ - No Change	Co3+ - Yellow	Cr3+ - Dark Green
  Mn3+ - No Change	Fe3+ - Dark Green (very faint)	Co2+ - Greenish Yellow
  Cu2+ - Dark Blue (faint)	Ru2+ - No Change	Zn2+ - Greenish Blue
  Ag2+ - Blue (very faint)	2H+(Free Base “FB”) — Blue

  Analyte: P(C4H9)3

  Sn4+ - No Change	Co3+ - Yellow and Red	Cr3+ - Deep Red
  Mn3+ - No Change	Fe3+ - Dark Green (faint)	Co2+ - Red (with some yellow)
  Cu2+ - No Change	Ru2+ - Dark Blue	Zn2+ - Yellow
  Ag2+ - No Change	2H+(Free Base “FB”) — No
  	Change

  Analyte: C6H13SH

  Sn4+ - Green	Co3+ - No Change	Cr3+ - Yellow circle
  		surrounded by greenish blue
  		circle
  Mn3+ - Yellow	Fe3+ - Dark Green	Co2+ - No Change
  Cu2+ - Dark Blue (faint)	Ru2+ - No Change	Zn2+ - Green
  Ag2+ - Blue (very faint)	2H+(Free Base “FB”) — Blue

  Analyte: (C3H7)2S

  Sn4+ - Dark Blue (faint)	Co3+ - Deep Green	Cr3+ - Green
  Mn3+ - No Change	Fe3+ - Dark Green	Co2+ - Dark Green (very faint)
  Cu2+ - Dark Blue (faint)	Ru2+ - Green	Zn2+ - Green
  Ag2+ - Blue (very faint)	2H+(Free Base “FB”) — Blue

  Analyte: Benzene

  Sn4+ - No Change	Co3+ - Green	Cr3+ - Yellow (very faint)
  Mn3+ - Yellow (some green)	Fe3+ - Dark Green	Co2+ - No Change
  Cu2+ - No Change	Ru2+ - No Change	Zn2+ - Dark Green
  Ag2+ - No Change	2H+(Free Base “FB”) — Blue

• The degree of ligand softness (roughly their polarizability) increases from left to right, top to bottom as shown in FIG. 1. Each analyte is easily distinguished from the others, and there are family resemblances among chemically similar species (e.g., pyridine and n-hexylamine). Analyte distinction originates both in the metal-specific ligation affinities and in their specific, unique color changes upon ligation. Each analyte was delivered to the array as a nitrogen stream saturated with the analyte vapor at 20° C. (to ensure complete saturation, 30 min. exposures to vapor were used. Although these fingerprints were obtained by exposure to saturated vapors (thousands of ppm), unique patterns can be identified at much lower concentrations.[0062]
• The[0063]metalloporphyrin array16 has been used to quantify single analytes and to identify vapor mixtures. Because the images' color channel data (i.e., RGB values) vary linearly with porphyrin concentration, we were able to quantify single porphyrin responses to different analytes. Color channel data were collected for individual spots and plotted, for example, as the quantity (R_plt−R_spt)/(R_plt), where R_pltwas the red channel value for the initial silica surface and R_sptthe average value for the spot. For example, Fe(TFPP)(Cl) responded linearly to octylamine between 0 and 1.5 ppm. Other porphyrins showed linear response ranges that varied with ligand affinity (i.e., equilibrium constant).
EXAMPLE 3
• The array of the present invention has demonstrated interpretable and reversible responses even to analyte mixtures of strong ligands, such as pyridines and phosphites, as is shown in FIG. 6. Color change patterns for the mixtures are distinct from either of the neat vapors. Good reversibility was demonstrated for this analyte pair as the vapor mixtures were cycled between the neat analyte extremes, as shown in FIG. 6, which shows the two component saturation responses to mixtures of 2-methylpyridine (“2MEPY”) and trimethylphosphite (“TMP”). Vapor mixtures were obtained by mixing the analyte-saturated N[0064]₂streams at variable flow ratios. A single plate was first exposed to pure trimethylphosphite vapor in N₂(Scan A), followed by increasing mole fractions of 2-methylpyridine up to pure 2-methylpyridine vapor (Scan C), followed by decreasing mole fractions of 2-methylpyridine back to pure trimethylphosphite vapor. In both directions, scans were taken at the same mole fraction trimethylphosphite and showed excellent reversibility; scans at mole fractions at 67% trimethylphosphite (χ_tmp=0.67, Scans B and D) and of their difference map are shown (Scan E). Response curves for the individual porphyrins allow for quantification of the mixture composition. The colors of each dye upon exposure to the analytes TMP and 2MEPY are shown in FIG. 6 and are summarized in Table 5 below.

  TABLE 5
  Scan A, Analyte: Neat TMP

  Sn4+ - Dark Blue	Co3+ - Yellow	Cr3+ - No Change
  Mn3+ - Yellow with red center	Fe3+ - Dark Green	Co2+ - Greenish Yellow
  Cu2+ - Dark Blue	Ru2+ - No Change	Zn2+ - Blue
  Ag2+ - Green (very faint)	2H+(Free Base “FB”) —
  	Reddish Blue

  Scan B, Analyte: TMP,xTMP= 0.67

  Sn4+ - Blue	Co3+ - Green	Cr3+ - Green (small dot)
  Mn3+ - Yellow and Green	Fe3+ - Green and Yellow	Co2+ - Green with red center
  Cu2+ - Dark Blue	Ru2+ - Purple (very faint)	Zn2+ - Blue
  Ag2+ - Greenish Blue	2H+(Free Base “FB”) —
  	Reddish Blue

  Scan C, Analyte: Neat 2MEPY

  Sn4+ - Blue	Co3+ - Green	Cr3+ - No Change
  Mn3+ - Yellow and Green with	Fe3+ - Red with some Yellow	Co2+ - Green
  Red center
  Cu2+ - Dark Blue	Ru2+ - Deep Blue	Zn2+ - Green with some Blue
  Ag2+ - Green with some Blue	2H+(Free Base “FB”) —
  	Reddish Blue

  Scan D, Analyte: TMP,xTMP= 0.67

  Sn4+ - Blue	Co3+ - Green	Cr3+ - No Change
  Mn3+ - Yellow and Green	Fe3+ - Green and Yellow	Co2+ - Green
  Cu2+ - Dark Blue	Ru2+ - Purple (very faint)	Zn2+ - Blue
  Ag2+ - Greenish Blue (very	2H+(Free Base “FB”) —
  faint)	Reddish Blue

  Scan E

  Sn4+ - No Change	Co3+ - No Change	Cr3+ - No Change
  Mn3+ - No Change	Fe3+ - No Change	Co2+ - No Change
  Cu2+ - Blue (very faint)	Ru2+ - Blue (small dot)	Zn2+ - No Change
  Ag2+ - Blue (very faint)	2H+(Free Base “FB”) — Green

EXAMPLE 4
• In an effort to understand the origin of the color changes upon vapor exposure, diffuse reflectance spectra were obtained for single porphyrin spots before and after exposure to analyte vapors. Porphyrin solutions were spotted in 50 L aliquots onto a plate and allowed to dry under vacuum at 50° C. Diffuse reflectance spectra of the plate were then taken using a UV-visible spectrophotometer equipped with an integrating sphere. Unique spectral shifts were observed upon analyte exposure, which correlated well with those seen from solution ligation. For example, Zn(TPP) exposure to ethanol and pyridine gave unique shifts which were very similar to those resulting from ligand exposure in solution. FIG. 7 shows a comparison of Zn(TPP) spectral shifts upon exposure to ethanol and pyridine (py) in methylene chloride solution (A) and on the reverse phase support (B). In both A and B, the bands correspond, from left to right, to Zn(TPP), Zn(TPP)(C[0065]₂H₅OH), and Zn(TPP)(py), respectively. Solution spectra (A) were collected using a Hitachi U-3300 spectrophotometer; Zn(TPP), C₂H₅OH, and py concentrations were approximately 2 μM, 170 mM, and 200 μM, respectively. Diffuse reflectance spectra (B) were obtained with an integrating sphere attachment before exposure to analytes, after exposure to ethanol vapor in N₂, and after exposure to pyridine vapor in N₂for 30 min. each using the flow cell.
• Improvement to Low Concentration Response[0066]
• Color changes at levels as low as 460 ppb have been observed for octylamine vapor, albeit with slow response times due to the high surface area of the silica on the[0067]plate18. The surface area of C2 plates is ≈350 m²/gram. Removal of excess silica gel surrounding the porphyrin spots from theplate 18 led to substantial improvements in response time for exposures to trace levels of octylamine. Because the high surface area of the reverse phase silica surface is primarily responsible for the increased response time, other means of solid support or film formation can be used to improve low concentration response.
• Further, the present invention contemplates miniaturization of the array using small wells 60 (<1 mm), for example in glass, quartz, or polymers, to hold metalloporphyrin or other dyes as thin films, which are deposited as a solution, by liquid droplet dispersion (e.g., airbrush or inkjet), or deposited as a solution of polymer with metalloporphyrin.[0068]
• These embodiments are depicted in FIGS. 8, 9, and[0069]10. FIG. 8 illustrates the interfacing of amicroplate60 into an assembly consisting of aCCD70, amicroplate72 and alight source74. FIG. 9 illustrates another embodiment of the present invention, and more particularly, a microwellporphyrin array weliplate80 constructed from polydimethylsiloxane (PDMS). The colors of the dyes shown in FIG. 9 are summarized below in Table 6.

  TABLE 6
  Sn4+ - Dark Red	Co3+ - Dark Red	Cr3+ - Dark Green
  Mn3+ - Green	Fe3+ - Dark Red	Co2+ - Yellowish Green
  Cu2+ - Deep Red	Ru2+ - Dark Red	Zn2+ - Red with some
  		Yellow
  Ag2+ -Red	2H+(Free Base “FB”) —
  	Red

• FIG. 10 demonstrates deposition of metalloporphyrin/polymer (polystyrene/dibutylphthalate) solutions upon a plate, which includes a series of micro-machined Teflon® posts[0070]100 having the same basic position relative to each other as shown in FIG. 2A and FIG. 2B. The colors for the dyes in the middle of FIG. 10 are summarized in Table 7 below.

  TABLE 7
  Sn4+ - Yellow	Co3+ - Orange	Cr3+ - Yellow
  Mn3+ - Yellow	Fe3+ - Orange	Co2+ - Orange
  Cu2+ - Orange	Ru2+ - Dark Yellow	Zn2+ - Orange
  Ag2+ -Orange	2H+(Free Base “FB”) — Red

• The colors for the dyes on the right hand side of FIG. 10 are summarized in Table 8 below.[0071]

  TABLE 8
  Sn4+ - No Change	Co3+ - Green	Cr3+ - Red
  Mn3+ - Blue	Fe3+ - Red	Co2+ - Red, Green, Blue, and
  		Yellow
  Cu2+ - Green with some Blue	Ru2+ - Blue (very faint)	Zn2+ - Yellow with some Red
  Ag2+ - Green with someBlue	2H+(Free Base “FB”) — Green
  	with some Blue

EXAMPLE 5
• FIG. 11 shows the color profile changes from a microplate of the type shown in FIG. 10. The microplate, consisting of a minimized array of four metalloporphyrins, i.e., Sn(TPP)(CL[0072]₂), Co(TPP)(Cl), Zn(TPP), Fe(TFPP)(Cl), clockwise from the upper left (where TFPP stands for 5,10,15,20-tetrakis(pentafluorophenyl)porphyrinate). The color profile changes are shown in FIG. 11 after exposure to low levels of n-octylamine, dodecanethiol (C₁₂H₂₅SH), and tri-n-butylphosphine (P(C₄H₉)₃), each at 1.8 ppm, which is summarized in Table 9 below.

  TABLE 9
  Dyes on Teflon ®

  Sn — Dark Yellow	Co — Red
  Zn — Red	Fe — Orange with Red outline

  Dyes exposed to n-octylamine

  Sn — No Change	Co — Green (very faint)
  Zn — Red	Fe — Green

  Dyes exposed to C12H25SH

  Sn — Red	Co — Green with some red, yellow and blue
  	(faint)
  Zn — Red with some green and yellow	Fe — Blue (very faint)

  Dyes exposed to P(C4H9)3

  Sn — No Change	Co — Yellow with red center and some red periphery
  Zn — Green	Fe — Yellow with some Green and Blue

• The low ppm levels of octylamine, an analyte of interest, were generated from temperature-regulated octylamine/dodecane solutions with the assumption of solution ideality. The dodecane acts as a diluent to lower the level of octylamine vapor pressure for the purposes of this demonstration of the invention.[0073]
EXAMPLE 6
• FIG. 12 illustrates the immunity of the present invention to interference from water vapor. The hydrophobicity of the reverse phase support greatly any possible effects from varying water vapor in the atmosphere to be tested. For instance, as shown in FIG. 12, a color fingerprint generated from exposure of the array to n-hexylamine (0.86% in N[0074]₂) was identical to that for n-hexylamine spiked heavily with water vapor (1.2% H₂O, 0.48% hexylamine in N₂). Seescans120,122 and124. The ability to easily detect species in the presence of a large water background represents a substantial advantage over mass-sensitive sensing techniques or methodologies that employ polar polymers as part of the sensor array. The color patterns shown in FIG. 12 are summarized in Table 10 below.

  TABLE 10
  Scan 120

  Sn4+ - No Change	Co3+ - Green	Cr3+ - Green
  Mn3+ - No Change	Fe3+ - Red	Co2+ - No Change
  Cu2+ - No Change	Ru2+ - No Change	Zn2+ - Green
  Ag2+ -No Change	2H+(Free Base “FB”) —Dark
  	Blue

  Scan

  122

  Sn4+ - No Change	Co3+ - Green	Cr3+ - Green
  Mn3+ - No Change	Fe3+ - Red	Co2+ - No Change
  Cu2+ - No Change	Ru2+ - Green (small dot)	Zn2+ - Green
  Ag2+ -No Change	2H+(Free Base “FB”) —Dark
  	Blue

  Scan

  124

  Sn4+ - Bluish Circle	Co3+ - Bluish Circle	Cr3+ - Bluish Circle

• [0075]

  Sn4+ - Bluish Circle	Co3+ - Bluish Circle	Cr3+ - Bluish Circle
  Mn3+ - Bluish Circle	Fe3+ - Bluish Circle	Co2+ - Bluish Circle
  Cu2+ - Bluish Circle	Ru2+ - Bluish Circle	Zn2+ - Bluish Circle
  Ag2+ -Bluish Circle	2H+(Free Base “FB”) — Bluish Circle

• Additional Features of the Preferred Embodiments of the Invention[0076]
• Having demonstrated electronic differentiation, an important further goal is the shape-selective distinction of analytes (e.g., n-hexylamine vs. cyclohexylamine). Functionalized metalloporphyrins that limit steric access to the metal ion are candidates for such differentiation. For instance, we have been able to control ligation of various nitrogenous ligands to dendrimer-metalloporphyrins and induce selectivities over a range of more than 10[0077]⁴. As an initial attempt toward shape-selective detection, we employed the slightly-hindered tetrakis(2,4,6-trimethoxyphenyl)porphyrins (TTMPP) in our sensing array. With these porphyrins, fingerprints for t-butylamine and n-butylamine showed subtle distinctions, as did those for cyclohexylamine and n-hexylamine. Using more hindered metalloporphyrins, it is contemplated that the present invention can provide greater visual differentiation. Such porphyrins include those whose periphery is decorated with dendrimer, siloxyl, phenyl, t-butyl and other bulky substituents, providing sterically constrained pockets on at least one face (and preferably both) of the porphyrin.
• In a similar fashion, it is contemplated that the sensor plates of the present invention can be used for the detection of analytes in liquids or solutions, or solids. A device that detects an analyte in a liquid or solution or solid can be referred to as an artificial tongue. Proper choice of the metal complexes and the solid support must preclude their dissolution into the solution to be analyzed. It is preferred that the surface support repel any carrier solvent to promote the detection of trace analytes in solution; for example, for analysis of aqueous solutions, reverse phase silica has advantages as a support since it will not be wetted directly by water.[0078]
• Alternative sensors in accordance with the present invention may include any other dyes or metal complexes with intense absorbance in the ultraviolet, visible, or near infrared spectra that show a color change upon exposure to analytes. These alternative sensors include, but are not limited to, a variety of macrocycles and non-macrocycles such as chlorins and chlorophylls, phthalocyanines and metallophthalocyanines, salen-type compounds and their metal complexes, or other metal-containing dyes.[0079]
• The present invention can be used to detect a wide variety of analytes regardless of physical form of the analytes. That is, the present invention can be used to detect any vapor emitting substance, including liquid, solid, or gaseous forms, and even when mixed with other vapor emitting substances, such solution mixtures of substances.[0080]
• The present invention can be used in combinatorial libraries of metalloporphyrins for shape selective detection of substrates where the substituents on the periphery of the macrocycle or the metal bound by the porphyrin are created and then physically dispersed in two dimensions by (partial) chromatographic or electrophoretic separation.[0081]
• The present invention can be used with chiral substituents on the periphery of the macrocycle for identification of chiral substrates, including but not limited to drugs, natural products, blood or bodily fluid components.[0082]
• The present invention can be used for analysis of biological entities based on the surface proteins, oligosacharides, antigens, etc., that interact with the metalloporphyrin array sensors of the present invention. Further, the sensors of the present invention can be used for specific recognition of individual species of bacteria or viruses.[0083]
• The present invention can be used for analysis of nucleic acid sequences based on sequence specific the surface interactions with the metalloporphyrin array sensors. The sensors of the present invention can be used for specific recognition of individual sequences of nucleic acids. Substituents on the porphyrins that would be particularly useful in this regard are known DNA intercalating molecules and nucleic acid oligomers.[0084]
• The present invention can be used with ordinary flat bed scanners, as well as portable miniaturized detectors, such as CCD detectors with microarrays of dyes such as metalloporphyrins.[0085]
• The present invention can be used for improved sensitivity, automation of pattern recognition of liquids and solutions, and analysis of biological and biochemical samples.[0086]
• Superstructure Bonded to the Periphery of the Porphyrin[0087]
• The present invention includes modified porphyrins that have a super structure bonded to the periphery of the porphyrin. A super structure bonded to the periphery of the porphyrin in accordance with the present invention includes any additional structural element or chemical structure built at the edge of the porphyrin and bonded thereto.[0088]
• The super structures can include any structural element or chemical structure characterized in having a certain selectivity. Those of skill in the art will recognize that the super structures of the present invention include structures that are shape selective, polarity selective, inantio selective, regio selective, hydrogen bonding selective, and acid-base selective. This structures can include siloxyl-substituted substituents, nonsiloxyl-substituted substituents and nonsiloxyl-substituted substituents, including but not limited to aryl substituents, alkyl substituents, and organic, organometallic, and inorganic functional group substituents.[0089]
• Superstructure Bis-Pocket Porphyrins[0090]
• A number of modified porphyrins have been synthesized to mimic various aspects of the enzymatic functions of heme proteins, especially oxygen binding (myoglobin and hemoglobin) and substrate oxidation (cytochrome P-450). See Suslick, K. S.; Reinert, T. J. J. Chem. Ed. 1985, 62, 974; Collman, J. P.; Zhang, X.; Lee, V. J.; Uffelman, E. S.; Brauman, J. I. Science 1993, 261, 1404; Collman, J. P.; Zhang, X. in Comprehensive Supramolecular Chemistry; Atwood, J. L.; Davies, J. E. D.; MacNicol, D. D.; Vogtel, F. Eds.; Pergamon: New York, 1996; vol. 5, pp. 1-32; Suslick, K. S.; van Deusen-Jeffries, S. in Comprehensive Supramolecular Chemistry; Atwood, J. L.; Davies, J. E. D.; MacNicol, D. D.; Vogtel, F. Eds.; Pergamon: New York, 1996; vol.5, pp. 141-170; Suslick, K. S. in Activation and Functionalization of Alkanes; Hill, C. L., ed.; Wiley & Sons: New York, 1989; pp. 219-241. The notable property of many heme proteins is their remarkable substrate selectivity; the development of highly regioselective synthetic catalysts, however, is still at an early stage. Discrimination of one site on a molecule from another and distinguishing among many similar molecules presents a difficult and important challenge to both industrial and biological chemistry. See Metalloporphyrins in Catalytic Oxidations; Sheldon, R. A. Ed. Marcel Dekker: New York, 1994). Although the axial ligation properties of simple synthetic metalloporphyrins are well documented in literature, see Bampos, N.; Marvaud, V.; Sanders, J. K. M. Chem. Eur. J. 1998, 4, 325; Stibrany, R. T.; Vasudevan, J.; Knapp, S.; Potenza, J. A.; Emge, T.; Schugar, H. J. J. Am. Chem. Soc. 1996, 118, 3980, size and shape control of ligation to peripherally modified metalloporphyrins has been largely unexplored, with few notable exceptions, where only limited selectivities have been observed. See Bhyrappa, P.; Vaijayanthimala, G.; Suslick, K. S. J. Am. Chem. Soc. 1999, 121, 262; Imai, H.; Nakagawa, S.; Kyuno, E. J. Am. Chem. Soc. 1992, 114, 6719.[0091]
• The present invention includes the synthesis, characterization and remarkable shape-selective ligation of silylether-metalloporphyrin scaffolds derived from the reaction of 5,10,15,20-tetrakis(2′,6′-dihydroxyphenyl)porphyrinatozinc(II) with t-butyldimethylsilyl chloride, whereby the two faces of the Zn(II) porphyrin were protected with six, seven, or eight siloxyl groups. This results in a set of three porphyrins of nearly similar electronics but with different steric encumbrance around central metal atom present in the porphyrin. Ligation to Zn by classes of different sized ligands reveal shape selectivities as large as 10[0092]⁷.
• A family of siloxyl-substituted bis-pocket porphyrins were prepared according to the scheme of FIG. 13. The abbreviations of the porhyrins that can be made in accordance with the scheme shown in FIG. 13 are as follows:[0093]
• Zn(TPP), 5,10,15,20-tetraphenylporphyrinatozinc(II);[0094]
• Zn[(OH)[0095]₆PP], 5-phenyl-10,15,20-tris(2/,6/-dihydroxyphenyl)porphyrinatozinc(II);
• Zn[(OH)[0096]₈PP], 5,10,15,20-tetrakis(2/,6/-dihydroxyphenyl)porphyrinatozinc(II);
• Zn(Si[0097]₆PP), 5(phenyl)-10,15,20-trikis(2/,6/-disilyloxyphenyl)porphyrinatozinc(II);
• Zn(Si[0098]₇OHPP), 5,10,15-trikis(2/,6/-disilyloxyphenyl)-20-(2/-hydroxy-6/-silyloxyphenyl)porphyrinatozinc(II);
• Zn(Si8PP), 5,10,15,20-tetrakis(2/,6/-disilyloxyphenyl)porphyrinatozinc(II). The synthesis of Zn[(OH)[0099]₆PP], Zn(Si₆PP), and Zn(Si8PP) is detailed below. Zn[(OH)₆PP] and Zn[(OH)₈PP] were obtained (see Bhyrappa, P.; Vaijayanthimala, G.; Suslick, K. S. J. Am. Chem. Soc. 1999, 121, 262) from demethylation (see Momenteau, M.; Mispelter, J.; Loock, B.; Bisagni, E. J. Chem. Soc. Perkin Trans. 1, 1983, 189) of corresponding free base methoxy compounds followed by zinc(II) insertion. The methoxy porphyrins were synthesized by acid catalysed condensation of pyrrole with respective benzaldehydes following Lindsey procedures. See Lindsey, J. S.; Wagner, R. W. J. Org. Chem. 1989, 54, 828. Metalation was done in methanol with Zn(O₂CCH₃)₂. The t-butyldimethylsilyl groups were incorporated into the metalloporphyrin by stirring a DMF solution of hydroxyporphyrin complex with TBDMSiCl (i.e., t-butyldimethylsilyl chloride) in presence of imidazole. See Corey, E. J; Venkateswarlu, A. J. Am. Chem. Soc. 1972, 94, 6190. The octa (Zn(Si₈PP)), hepta (Zn(Si₇OHPP)), and hexa (Zn(Si₆PP)) silylether porphyrins were obtained from Zn[(OH)gPP] and Zn[(OH)₆PP], respectively. The compounds were purified by silica gel column chromatography and fully characterized by UV-Visible,¹H-NMR, HPLC, and MALDI-TOF MS.
• The size and shape selectivities of the binding sites of these bis-pocket Zn silylether porphyrins were probed using the axial ligation of various nitrogenous bases of different shapes and sizes in toluene at 25° C. Zn(II) porphyrins were chosen because, in solution, they generally bind only a single axial ligand. Successive addition of ligand to the porphyrin solutions caused a red-shift of the Soret band typical of coordination to zinc porphyrin complexes. There is no evidence from the electronic spectra of these porphyrins for significant distortions of the electronic structure of the porphyrin. The binding constants (K[0100]_eq) and binding composition (always 1:1) were evaluated using standard procedures. See Collman, J. P.; Brauman, J. I.; Doxsee, K. M.; Halbert, T. R.; Hayes, S. E.; Suslick, K. S. J. Am. Chem. Soc. 1978, 100,2761; Suslick, K. S.; Fox, M. M.; Reinert, T. J. Am. Chem. Soc. 1984, 106, 4522. The Kq values of the silylether porphyrins with nitrogenous bases of different classes are compared with the sterically undemanding Zn(TPP) in FIGS. 14a,14b, and14c. It is worth noting the parallel between shape selectivity in these equilibrium measurements and prior kinetically-controlled epoxidation and hydroxylation. See Collman, J. P.; Zhang, X. in Comprehensive Supramolecular Chemistry; Atwood, J. L.; Davies, J. E. D.; MacNicol, D. D.; Vogtel, F. Eds.; Pergamon: New York, 1996; vol. 5, pp. 1-32; Suslick, K. S.; van Deusen-Jeffries, S. in Comprehensive Supramolecular Chemistry; Atwood, J. L.; Davies, J. E. D.; MacNicol, D. D.; Vogtel, F. Eds.; Pergamon: New York, 1996; vol. 5, pp. 141-170; Suslick, K. S. in Activation and FunctionalizationofAlkanes; Hill, C. L., ed.; Wiley& Sons: New York, 1989; pp.219-241; Bhyrappa, P.; Young, J.K.; Moore, J.S.; Suslick, K. S. J. Am. Chem. Soc., 1996,118,5708-5711. Suslick, K. S.; Cook, B. R. J. Chem. Soc., Chem. Comm. 1987, 200-202; Cook, B. R.; Reinert, T. J.; Suslick, K. S. J. Am. Chem. Soc. 1986, 108, 7281-7286; Suslick, K. S.; Cook, B. R.; Fox, M. M. J. Chem. Soc., Chem. Commun. 1985, 580-582. The selectivity for equilibrated ligation appears to be substantially larger than for irreversible oxidations of similarly shaped substrates.
• The binding constants of silylether porphyrins are remarkably sensitive to the shape and size of the substrates relative to Zn(TPP). See FIGS. 14[0101]a,14b, and14c. The binding constants of different amines could be controlled over a range of 10¹to 10⁷relative to Zn(TPP). It is believed that these selectivities originate from strong steric repulsions created by the methyl groups of the t-butyldimethylsiloxyl substituents. The steric congestion caused by these bulky silylether groups is pronounced even for linear amines and small cyclic amines (e.g., azetidine and pyrrolidine).
• There are very large differences in K[0102]_eqfor porphyrins having three versus four silylether groups on each face (e.g., hexa- vs. octa-silylether porphyrins), as expected based on obvious steric arguments (see FIGS. 14a,14b, and14c). Even between the hexa-over hepta-silylether porphyrins, however, there are still substantial differences in binding behavior. It is believed that this is probably due to doming of the macrocycle in the hexa- and hepta-silylether porphyrins, which lessens the steric constraint relative to the octasilylether porphyrin. Such doming will be especially important in porphyrins whose two faces are not identical. The free hydroxy functionality of the hepta-silylether may play a role in binding of bi-functionalized ligands (e.g., free amino acids); for the simple amines presented here, however, we have no evidence of any special effects.
• These silylether porphyrins showed remarkable selectivities for normal, linear amines over their cyclic analogues. For a series of linear amines (n-propylamine through n-decylamine), K[0103]_eqwere very similar for each of the silylether porphyrins. In comparison, the relative K_eqfor linear versus cyclic primary amines (FIG. 14a, n-butylamine vs. cyclohexylamine) were significantly different: K_eq^linear/K_eq^cyclicranges from 1 to 23 to 115 to >200 for Zn(TPP), Zn(Si₆PP), Zn(Si₇OHPP), and Zn(SigPP), respectively. The ability to discriminate between linear and cyclic compounds is thus established.
• A series of cyclic 2° amines (FIG. 14[0104]b) demonstrate the remarkable size and shape selectivities of this family of bis-pocket porphyrins. Whereas the binding constants to Zn(TPP) with those amines are virtually similar. In contrast, the K_eqvalues for silylether porphyrins strongly depend on the ring size and its peripheral substituents. The effect of these shape-selective binding sites is clear, even for compact aromatic ligands with non-ortho methyl substituents (FIG. 14c).
• The molecular structures of these silylether porphyrins explains their ligation selectivity. The x-ray single crystal structure of Zn(Si[0105]₈PP) has been solved in the triclinic P lbar space group. See Single crystal x-ray structure of Zn(Si8PP) shown in FIG. 15. As shown in FIG. 15, Zn(Si₆PP) (energy minimized molecular model) and Zn(Si₈PP) (single crystal x-ray structure) have dramatically different binding pockets. In the octasilylether porphyrin, the top access on both faces of the porphyrin is very tightly controlled by the siloxyl pocket. In contrast, the metal center of the hexasilylether porphyrin is considerably more exposed for ligation.
• FIG. 15 illustrates molecular models of Zn(Si[0106]₆PP) (left column) and Zn(Si₈PP) (right column). The pairs of images from top to bottom are cylinder side-views, side-views, and top-views, respectively; space filling shown at 70% van der Waals radii; with the porphyrin carbon atoms shown in purple, oxygen atoms shown in red, silicon atoms in green, and Zn in dark red. The x-ray single crystal structure of Zn(Si8PP) is shown; for Zn(Si₆PP), an energy-minimized structure was obtained usingCerius 2 from MSI.
• In summary, a series of bis-pocket siloxyl metalloporphyrin complexes were prepared with sterically restrictive binding pockets on both faces of the macrocycle. Ligation to Zn by various nitrogenous bases of different sizes and shapes were investigated. Shape selectivities as large as 10[0107]⁷were found, compared to unhindered metalloporphyrins. Fine-tuning of ligation properties of these porphyrins was also possible using pockets of varying steric demands. The shape selectivities shown here rival or surpass those of any biological system.
• Examples of Synthesis of Super Structures[0108]
• Synthesis of 5-phenyl-10,15,20-tris(2/,6/-dihydroxy-phenyl)-porphyrinatozinc(II), Zn[(OH)[0109]₆PP]:
• The free base 5-phenyl-10,1 5,20-tris(2/,6/-dimethoxyphenyl)-porphyrin was synthesized by Lewis acid catalyzed condensation of 2,6-dimethoxybezaldehyde and benzaldehyde with pyrrole (3:1:4 mole ratio) following the Lindsey procedure. See Lindsey, J. S.; Wagner, R. W. J. Org. Chem. 1989, 54, 828. The mixture of products thus formed was purified by silica gel column chromatography (if necessary, using CH[0110]₂Cl₂as eluant). The isolated yield of the desired product was found to be 7% (wrt pyrrole used). The corresponding hydroxyporphyrins were obtained by demethylation with pyridine hydrochloride. See Momenteau, M.; Mispelter, J.; Loock, B.; Bisagni, E. J. Chem. Soc. Perkin Trans. 1, 1983, 189. After typical work-up known to those skilled in the art, the crude compound was purified by silica gel column chromatography using ethylacetate as eluant. The first fraction was Zn[(OH)₆PP], which was collected and the solvent was removed. The yield of the product was 90% (based on starting hydroxyporphryin).¹H NMR of H₂[(OH)₆PP] in acetone-d₆(pPm): 8.96-8.79 (m, 8H, b-pyrrole H), 8.24 (m, 2H, o-H 5-Phenyl), 8.07 and 8.02 (2s, 6H, —OH), 7.83 (m, 3H, m,p-H 5-Phenyl), 7.50 (t, 3H, p-H hydroxyphenyl), 6.90 (d, 6H, m-H hydroxyphenyl), −2.69 (s, 2H, imino-H). Elemental analysis, calcd. for C₄₄H₃₀O₆N₄.H₂O: C=72.5, H=4.4 and N=7.7%. Found C=72.7, H=4.4 and N=7.4%. The compound showed molecular ion peak at 711 (m/z calcd. for C₄₄H₃₀O₆N₄=710) in FAB-MS.
• The Zn derivative was obtain by stirring methanol solution of H[0111]₂[(OH)₆PP] with excess Zn(O₂CCH₃)₂2H₂O for 1 hour. Methanol was evaporated to dryness and the residue was dissolved in ethylacetate, washed with water, and the organic layer passed through anhyd. Na₂SO₄. The concentrated ethylacetate solution was passed through a silica gel column and the first band was collected as the desired product. The yield of the product was nearly quantitative.¹H NMR of Zn(OH)₆PP in acetone-d₆(ppm): 8.95-8.79 (m, 8H, b-pyrrole H), 8.22 (m, 2H, o-H 5-Phenyl), 7.79 (m, 3H, m,p-H 5-Phenyl), 7.75 and 7.65 (2s, 6H, —OH), 7.48 (t, 3H, p-H hydroxyphenyl), 6.88 (d, 6H, m-H hydroxyphenyl). Elemental analysis, calcd. for ZnC₄₄H₂₈O₆N₄.H₂O: C=66.7, H=3.8, N=7.1 and Zn=8.3%. Found C=66.4, H=3.8, N=6.7 and Zn=8.2%. The compound showed molecular ion peak at 774 (m/z calcd. for ZnC₄₄H₂₈O₆N₄=773) in FAB-MS.
• Synthesis of 5-phenyl-10,15,20-tris(2/,[0112]⁶/-disilyloxyphenyl)-porphyrinatozinc(II), Zn(Si₆PP):
• The hexasilylether porphyrin was synthesized by stirring a DMF solution of 5-phenyl-10,15,20-tris(2/,6/-dihydroxyphenyl)-porphyrinatozinc(II) (100 mg, 0.13 mmol) with t-butyldimethyl silylchloride (1.18 g, 7.8 mmol) in presence of imidazole (1.2 g, 17.9 mmol) at 60° C. for 24 h under nitrogen. After this period the reaction mixture was washed with water and extracted in CHCl[0113]₃. The organic layer was dried over anhyd. Na₂SO₄. The crude reaction mixture was loaded on a short silica gel column and eluted with mixture of CHCl₃/petether (1:1, v/v) to get rid of unreacted starting material and lower silylated products. The desired compound was further purified by running another silica gel column chromatography using mixture of CHCl₃/petether (1:3, v/v) as eluant. The yield of the product was 60% based on starting hydroxyporphyrin.
• [0114]¹H NMR in chloroform-d (ppm): 8.94-8.82 (m, 8H, b-pyrrole H), 8.20 (m, 2H, o-H 5-Phenyl), 7.74 (m, 3H, m,p-H 5-Phenyl), 7.49 (t, 3H, p-H hydroxyphenyl), 6.91 (t, 6H, m-H hydroxyphenyl), −0.02 and −0.34 (2s, 54H, t-butyl H), −0.43, −0.78 and −1.01 (3s, 36H, methyl H).
• Elemental analysis, calcd. for ZnC[0115]₈₀H₁₁₂O₆N₄Si₆: C=65.8, H=7.7, N=3.8, Si=11.5 and Zn=4.5%. Found C=65.5, H=7.7, N=3.8, Si=11.2 and Zn=4.4%. The low resolution MALDI-TOF mass spectrum showed molecular ion peak at 1457 (m/z calcd. for ZnC₈₀H₁₁₂O₆N₄Si₆=1458).
• Synthesis of 5,10,15-tris(2/,6/-disilyoxyphenyl)-20-(2/-hydr-oxy-6/-silyloxyphenyl)porphyrinatozinc(II), [Zn(Si[0116]₇OHPP)], and 5,10,15,20-tetrakis(2/,6/-disilyloxyphenyl)porphy-rinato-zinc(II), [Zn(Si₈PP)]:
• The synthesis of[0117]precursor porphyrin 5,10,15,20-tetrakis-(2/,6/-dihydroxyphenyl)porphyrin and its Zn derivative was accomplished as reported earlier. See Bhyrappa, P.; Vaijayanthimala, G.; Suslick, K. S. J. Am. Chem. Soc. 1999,121,262. The hepta- and octa-silylether porphyrins were synthesized by stirring DMF solution of 5,10,15,20-tetrakis(2/,6/-dihydroxyphenyl)porphyrinatozinc(II) (100 mg, 0.12 mmol) with t-butyldimethyl silylchloride (1.45 g, 9.6 mmol) in presence of imidazole (1.50 g, 22.1 mmol) at 60° C. for 24 h under nitrogen. After usual work-up the mixture of crude products were loaded on a silica gel column and eluted with mixture of CHCl₃/pet. ether (1: 1, v/v) to remove unreacted starting material and lower silylated products. The major product isolated from this column is a mixture of hepta- and octa-silylated porphyrins. The mixture thus obtained was further purified by another silica gel column chromatography using mixture of CHCl₃/pet. ether (1:3, v/v) as eluant. The first two bands were isolated as octa- and hepta-silylether porphyrin at 45% and 30% yield, respectively. Both the compounds were characterized by UV-Visible,¹H NMR and MALDI-TOF spectroscopic techniques. The homogeneity of the sample was verified by HPLC.
• For Zn(Si[0118]₇OHPP),¹HNMR in chloroform-d (ppm): 8.91 (m, 8H, b-pyrrole H), 7.50 (m, 4H, p-H), 7.01-6.81 (m, 8H, m-H), 0.11 to −0.03 (12s, 105H, t-butyl and methyl H). Elemental analysis, caled. for ZnC₈₆H₁₂₆O₈N₄Si₇: C=64.3, H=7.8, N=3.5, Si=12.3 and Zn=4.1%. Found C=63.6, H=8.1, N=3.5, Si=12.1 and Zn=3.9%. The low resolution MALDI-TOF mass spectrum showed molecular ion peak at 1604 (m/z calcd. for ZnC₈₆H₁₂₆O₈N₄Si₇=1604).
• For Zn(Si[0119]₈PP),¹H NMR in chloroform-d (ppm): 8.89 (s, 8H, b-pyrrole H), 7.49 (t, 4H, p-H), 6.92 (d, 8H, m-H), 0.09 (s, 72H, t-butyl H), −1.01 (s, 48H, methyl H). Elemental analysis, calcd. for ZnC₉₂H₁₄₀O₈N₄Si₈: C=64.2, H=8.1, N=3.3, Si=13.1 and Zn=3.8%. Found C=63.5, H=8.4, N=3.3, Si=12.8 and Zn=4.0%. The low resolution MALDI-TOF mass spectrum showed molecular ion peak at 1719 (m/z calcd. for ZnC₉₂H₁₄₀O₈N₄Si₈=1718).
• Additional Features of the Preferred Embodiments of the Invention[0120]
• Having demonstrated electronic differentiation and shape-selective distinction of analytes that bind to metal ions in metallodyes, an important further goal is the differentiation of analytes that do not bind or bind only weakly to metal ions. Such analytes include acidic compounds, such as carboxylic acids, and certain organic compounds lacking ligatable functionality, such as simple alkanes, arenes, some alkenes and alkynes (especially if sterically hindered), and molecules sterically hindered as to preclude effective ligation. One approach that has been developed to achieve this goal in accordance with the present invention is to include in the sensor array other chemoresponsive dyes, including pH sensitive dyes (i.e., pH indicator or acid-base indicator dyes that change color upon exposure to acids or bases), and/or solvatochromic dyes (i.e., dyes that change color depending upon the local polarity of their micro-environment).[0121]
• It has been discovered that the addition of pH sensitive dyes and solvatochromic dyes to other arrays containing metalloporphyrins as described above expands the range of analytes to which the arrays are sensitive, improves sensitivities to some analytes, and increases the ability to discriminate between analytes.[0122]
• The present invention includes an artificial nose comprising an array, the array comprising at least a first dye and a second dye deposited directly onto a single support in a predetermined pattern combination, the combination of the dyes in the array having a distinct and direct spectral absorbance or reflectance response to an analyte wherein the first dye and the second dye are selected from the group consisting of chemoresponsive dyes, and the second dye is distinct from the first dye. In a preferred embodiment, the first dye is selected from the group consisting of porphyrin, chlorin, chlorophyll, phtahlocyanine, and salen and their metal complexes. In another preferred embodiment, the second dye is selected from the group of dyes consisting of acid-base indicator dyes and solvatochromic dyes.[0123]
• The present invention includes a method of detecting an analyte comprising the steps of: (a) forming an array of at least a first dye and a second dye deposited directly onto a single support in a predetermined pattern combination, the combination of the dyes in the array having a distinct and direct spectral absorbance or reflectance response to an analyte wherein the first dye and the second dye are selected from the group consisting of chemoresponsive dyes, and the second dye is distinct from the first dye; (b) subjecting the array to an analyte; (c) inspecting the array for a distinct and direct spectral absorbance or reflectance response; and (d) correlating the distinct and direct spectral response to the presence of the analyte. In a preferred method, the first dye is selected from the group consisting of porphyrin, chlorin, chlorophyll, phtahlocyanine, and salen and their metal complexes. In another preferred method, the second dye is selected from the group of acid-base indicator dyes and solvatochromic dyes.[0124]
• The present invention includes an artificial tongue comprising an array, the array comprising at least a first dye and a second dye deposited directly onto a single support in a predetermined pattern combination, the combination of the dyes in the array having a distinct and direct spectral absorbance or reflectance response to an analyte wherein the first dye and the second dye are selected from the group consisting of chemoresponsive dyes, and the second dye is distinct from the first dye. In a preferred embodiment, the first dye is selected from the group consisting of porphyrin, chlorin, chlorophyll, phtahlocyanine, and salen and their metal complexes. In another preferred embodiment, the second dye is selected from the group of dyes consisting of acid-base indicator dyes and solvatochromic dyes.[0125]
• Chemoresponsive dyes are those dyes that change color, in either reflected or absorbed light, upon changes in their chemical environment. Three general classes of chemoresponsive dyes are (1) Lewis acid/base dyes, (2) pH indicator dyes, and (3) solvatochromic dyes.[0126]
• Lewis acid/base dyes are those dyes that contain a Lewis acidic or basic center (where a Lewis acid is an electron pair acceptor and a Lewis base is an electron pair donor) and change color in response to changes in the Lewis acidity or basicity of their environment. A specific set of Lewis acid/base dyes includes dyes such as porphyrin, chlorin, chlorophyll, phtahlocyanine, and salen and their metal complexes.[0127]
• pH indicator or acid-base indicator dyes are those that change color in response to changes in the proton acidity or basicity (also called Bronsted acidity or basicity) of their environment. A specific set of pH indicator dyes include Chlorphenol Red, Bromocresol Green, Bromocresol Purple, Bromothymol Blue, Phenol Red, Thymol Blue, Cresol Red, Alizarin, Mordant Orange, Methyl Orange, Methyl Red, Congo Red, Victoria Blue B, Eosin Blue, Fat Brown B, Benzopurpurin 4B, Phloxine B, Orange G, Metanil Yellow, Naphthol Green B, Methylene Blue, Safranine O, Methylene Violet 3RAX, Sudan Orange G, Morin Hydrate, Neutral Red, Disperse Orange 25, Rosolic Acid, Fat Brown RR, Cyanidin chloride, 3,6-Acridineamine, 6′-Butoxy-2,6-diamino-3,3′-azodipyridine, para-Rosaniline Base, Acridine Orange Base, Crystal Violet, and Malachite Green Carbinol Base.[0128]
• Solvatochromic dyes are those that change color in response to changes in the general polarity of their environment, primarily through strong dipole-dipole interactions. To some extent, all dyes inherently are solvatochromic, although some are much more responsive than others. A specific set of highly responsive solvatochromic dyes include Reichardt's Dye and Nile Red.[0129]
• It has been discovered that the following pH indicator (i.e., acid-base indicator) dyes and solvatochromic dyes are useful to expand the range of analytes to which the arrays containing metalloporphyrins are sensitive, improve sensitivities to some analytes, and increase the ability to discriminate between analytes. Those skilled in the art will recognize that other modifications and variations in the choice of such auxiliary dyes may be made in addition to those described and illustrated herein without departing from the spirit and scope of the present invention. Accordingly, the choice of dyes described and illustrated herein should be understood to be illustrative only and not limiting upon the scope of the present invention.[0130]
• Chlorphenol Red[0131]
• Molecular Formula: Cl[0132]₉H₁₂Cl₂O₅S
• Molecular Weight: 423.28[0133]
• CAS: 4430-20-0[0134]
• Transition interval: pH 4.8 (yellow) to pH 6.7 (violet)[0135]
• Bromocresol Green[0136]
• Synonyms: 3′,3″,5′,5″Tetrabromo-m-cresolsulfonphthalein; Bromcresol Green[0137]
• Molecular Formula: C[0138]₂₁H₁₄Br₄O₅S
• Molecular Weight: 698.04[0139]
• CAS: 76-60-8[0140]
• pH=3.8 yellow[0141]
• =5.4 blue[0142]
• Bromocresol Purple[0143]
• Synonyms: 5′,5″ dibromo-m-cresolsulfonphthalein; Bromcresol Purple[0144]
• Molecular Formula: C[0145]₂₁H₁₆Br₂O₅S
• Molecular Weight: 698.04[0146]
• CAS:1 15-40-2[0147]
• pH=5.2 yellow[0148]
• =6.8 blue[0149]
• Bromothymol Blue[0150]
• Synonyms: 3′,3″-Dibromothymolsulfonphthalein; Bromthymol Blue[0151]
• Molecular Formula: C[0152]₂₇H₂₈Br₂O₅S
• Molecular Weight: 624.41[0153]
• CAS: 76-59-5[0154]
• pH=6.0 yellow[0155]
• =7.6 blue[0156]
• Phenol Red[0157]
• Synonyms: Phenolsulfonphthalein[0158]
• Molecular Formula: C[0159]₁₉H₁₄O₅S
• Molecular Weight: 354.38[0160]
• CAS: 143-74-8[0161]
• pH=6.8 yellow[0162]
• =8.2 red[0163]
• Thymol Blue[0164]
• Synonyms: Thymolsulfonphthalein[0165]
• Molecular Formula: C[0166]₂₇H₃₀O₅S
• Molecular Weight: 466.60[0167]
• CAS: 76-61-9[0168]
• pH=1.2 red[0169]
• =2.8 yellow[0170]
• =8 yellow[0171]
• =9.2 blue[0172]
• Cresol Red[0173]
• Synonyms: Phenol, 4,4′-(1,1-dioxido-3H-2,1-benzoxathiol-3-ylidene)bis[2-methyl-(9CI)][0174]
• Molecular Formula: C[0175]₂₁H₁₈O₅S
• Molecular Weight: 382.43[0176]
• CAS: 1733-12-6[0177]
• pH 1.8 (orange) to pH 2.0 (yellow); Transition interval (alkaline): pH 7.0 (yellow) to pH 8.8 (violet)[0178]
• Alizarin[0179]
• Synonyms: 1,2-Dihydroxyanthraquinone, 9,10-Anthracenedione, 1,2-dihydroxy-(9CI)[0180]
• Molecular Formula: C[0181]₁₄H₈O₄
• Molecular Weight: 240.22[0182]
• CAS: 72-48-0[0183]
• pH=5.5 yellow[0184]
• =6.8 red[0185]
• =10.1 red[0186]
• =12.1 violet[0187]
• [0188]Mordant Orange 1
• Synonyms: Alizarin Yellow R, C.I. 14030, 5-(4-nitrophenylazo)salicylic acid[0189]
• Molecular Formula: C[0190]₁₃H₉N₃O₅
• Molecular Weight: 287.23[0191]
• CAS: 2243-76-7[0192]
• Methyl Orange[0193]
• Synonyms: 4-(p-[Dimethylamino]phenylazo)benzenesulfonic acid, sodium salt[0194]
• Acid Orange 52[0195]
• Molecular Formula: C[0196]₁₄Hl₄N₃O₃SNa
• Molecular Weight: 327.3[0197]
• pH 3.0 (pink)-pH 4.4 (yellow)[0198]
• Methyl Red[0199]
• Synonyms: 4-Dimethylaminoazobenzene-2′carboxylicacid; 2-(4-Dimethylaminophenylazo)-benzoic acid[0200]
• Molecular Formula: C[0201]₁₅H₁₅N₃O₂
• Molecular Weight: 269.31[0202]
• CAS: 493-52-7[0203]
• pH=4.2 pink[0204]
• =6.2 yellow[0205]
• Reichardt's Dye[0206]
• Synonyms: [2,6-diphenyl-4-(2,4,6-triphenylpyridinio)phenolate][0207]
• Molecular Formula: C[0208]₄₁H₂₉NO
• Molecular Weight: 551.69[0209]
• CAS: 10081-39-7[0210]
• Nile Red[0211]
• Synonyms: 5H-Benzo[a]phenoxazin-5-one, 9-(diethylamino)-(7CI, 8CI, 9CI), 9-(Diethylamino)-5H-benzo[a]phenoxazin-5-one; Nile Blue A oxazone[0212]
• Molecular Formula: C[0213]₂₀H₁₈N₂O₂
• Molecular Weight: 318.38[0214]
• CAS: 7385-67-3[0215]
• Congo Red[0216]
• Molecular Formula: C[0217]₃₂H₂₄N₆O₆S2 Na₂
• Molecular Weight: 696.67[0218]
• CAS: 573-58-0[0219]
• pH range: blue 3.1-4.9 red[0220]
• Victoria Blue B[0221]
• Synonyms:[0222]Basic Blue 26, C.I. 44045
• Molecular Formula: C[0223]₃₃H₃₂ClN₃
• Molecular Weight: 506.10[0224]
• CAS: 2580-56-5[0225]
• Eosin Blue[0226]
• Synonyms: (Acid Red 91, C.I. 45400, 4′,5′-dibromo-2′,7′-dinitrofluorescein, disodium salt)[0227]
• Molecular Formula: C[0228]₂₀H₈Br₂N₂O₉
• Molecular Weight: 624.08[0229]
• CAS: 548-24-3[0230]
• Fat Brown B[0231]
• Synonyms: Solvent red 3[0232]
• Molecular Formula: C[0233]₁₈H₁₆N₂O₂
• Molecular Weight: 292.3[0234]
• CAS: 6535-42-8[0235]
• Benzopurpurin 4B[0236]
• Synonyms: (C.I. 23500, Direct Red 2)[0237]
• Molecular Formula: C[0238]₃₄H₂₈N₆O₆S₂
• Molecular Weight: 724.73[0239]
• CAS: 992-59-6[0240]
• pH range: violet 1.2-3.8 yellow[0241]
• Phloxine B[0242]
• Molecular Formula: C[0243]₂₀H₄Br₄Cl₄O₅
• CAS: 18472-87-2[0244]
• pH range: colorless 2.1-4.1 pink[0245]
• Orange G[0246]
• Synonyms: 1-Phenylazo-2-naphthol-6,8-disulfonic acid disodium salt[0247]
• Molecular Formula: C[0248]₁₆H₁₀N₂Na₂O₇S₂
• Molecular Weight: 452.[0249]
• pH range: yellow 11.5-14.0 pink[0250]
• Metanil Yellow[0251]
• Synonyms: (Acid Yellow 36, C.I. 13065)[0252]
• Molecular Formula: C[0253]₁₈H₁₅N₃O₃S Na
• Molecular Weight: 375.38[0254]
• CAS: 587-98-4[0255]
• pH 1.5 (red) to pH 2.7 (yellow)[0256]
• Naphthol Green B[0257]
• Synonyms: ([0258]Acid Green 1, C.I. 10020)
• Molecular Formula: C[0259]₁₀H₇NO₅S
• Molecular Weight: 878.47[0260]
• CAS: 19381-50-1[0261]
• Methylene Blue[0262]
• Synonyms: ([0263]Basic Blue 9, C.I. 52015)
• Molecular Formula: C[0264]₁₆H₁₈ClN₃S
• Molecular Weight: 373.90[0265]
• CAS: 7220-79-3[0266]
• Safranine O[0267]
• Synonyms: (C.I. 50240, 3,7-diamino-2,8-dimethyl-5-phenylphenazinium chloride)[0268]
• Molecular Formula: C[0269]₂₀H₁₉ClN₄
• Molecular Weight: 350.85[0270]
• CAS: 477-73-6[0271]
• Methylene Violet 3RAX[0272]
• Synonyms: [3-amino-7-(diethylamino)-5-phenylphenazinium chloride, C.I. 50206, N,N-diethylphenosafranine][0273]
• Molecular Formula: C[0274]₂₂H₂₃ClN₄
• Molecular Weight: 378.91[0275]
• CAS: 4569-86-2[0276]
• Sudan Orange G[0277]
• Synonyms: [C.I. 11920, 4-(phenylazo)resorcinol, Solvent Orange 1][0278]
• Molecular Formula: C[0279]₆H₅N═NC₆H₃-1,3-(OH)₂
• Molecular Weight: 214.22[0280]
• CAS: 2051-85-6[0281]
• Morin Hydrate[0282]
• Synonyms: (2′,3,4′,5,7-pentahydroxyflavone)[0283]
• Molecular Formula: C[0284]₁₅H₁₀O₇
• Molecular Weight: 302.24[0285]
• Neutral Red[0286]
• Molecular Formula: C[0287]₁₅H₁₆N₄.HCl
• Molecular Weight: 288.78[0288]
• CAS: 553-24-2[0289]
• pH=6.8 red[0290]
• =8.0 yellow[0291]
• Disperse Orange 25[0292]
• Molecular Formula: C[0293]₁₇H₁₇N₅O₂
• Molecular Weight: 323.36[0294]
• CAS: 31482-56-1[0295]
• Rosolic Acid[0296]
• Molecular Formula: C[0297]₂₀H₁₆O₃
• Molecular Weight: 290.32[0298]
• CAS: 603-45-2[0299]
• pH=5.0 yellow[0300]
• =6.8 pink[0301]
• Fat Brown RR[0302]
• Molecular Formula: C[0303]₁₆H₁₄N₄
• Molecular Weight: 262.32[0304]
• CAS: 6416-57-5[0305]
• Cyanidin Chloride[0306]
• Molecular Formula: C15H11O6.Cl[0307]
• Molecular Weight: 322.7[0308]
• CAS: 528-58-5[0309]
• 3,6-Acridineamine[0310]
• Molecular Formula: C[0311]₁₃H₁₁N₃
• Molecular Weight: 209.25[0312]
• CAS Number: 92-62-6[0313]
• 6′-Butoxy-2,6-diamino-3,3′-azodipyridine[0314]
• Synonym: Azodipyridine[0315]
• Molecular Formula: C[0316]₁₄H₁₈N₆O
• Molecular Weight: 286.34[0317]
• CAS: 617-19-6[0318]
• para-Rosaniline Base[0319]
• Synonym: Rosaniline[0320]
• Molecular Formula: C[0321]₁₉H₁₉N₃O
• Molecular Weight: 305.4[0322]
• CAS: 25620-78-4[0323]
• Acridine Orange Base[0324]
• Molecular Formula: C[0325]₁₇H₁₉N₃
• Molecular Weight: 265.36[0326]
• CAS: 494-38-2[0327]
• Crystal Violet[0328]
• Molecular Formula: C[0329]₂₅H₃₀N₃Cl
• Molecular Weight: 407.99[0330]
• CAS: 548-62-9[0331]
• pH=0 yellow[0332]
• =1.8 blue[0333]
• Malachite Green Carbinol Base[0334]
• Molecular Formula: C[0335]₂₃H₂₆N₂O
• Molecular Weight: 346.48[0336]
• CAS: 510-13-4[0337]
• pH=0.2 yellow[0338]
• =1.8 blue-green[0339]
• In a preferred embodiment, a low volatility liquid, e.g., a plasticizer, is used in an array of the present invention to keep the dyes in the array from crystallizing and to enhance then response of the array to an analyte. Examples of suitable low volatility liquids include, but are not limited to DOW CORNING 704 silicone diffusion pump fluid (Molecular Weight: 484.82, Density: 1.070, CAS Number: 3982-82-9), and diundecyl phthalate (Molecular Weight: 474.73, Density: 0.950, CAS Number: 3648-20-2, Formula: C[0340]₃₀H₅₀O₄, Boiling Point (° C.): 523 at 760 torr), dibutyl phthalate (Molecular Weight: 278.4, Density: 1.048, CAS Number: 84-74-2, Formula: C₁₆H₂₂O₄, Boiling Point (° C.): 340 at 760 torr), diisopropyl phthalate (Molecular Weight: 250.3, Density: 1.063, CAS Number: 605-45-8, Formula: C₁₄H₁₈O₄), squalane (Molecular Weight: 422.83, Density: 0.810, CAS Number: 111-01-3, Formula: C₃₀H₆₂, Boiling Point (° C.): 176 at 0.05 torr), triethylene glycol dimethyl ether (synonym: Trigluyme, Molecular Weight: 178.23, Density: 0.986, CAS Number: 112-49-2, Formula: C₈H₁₈O₄, Boiling Point (° C.): 216 at 760 torr), and tetraethlyene glycol dimethyl ether (synonym: Tetraglyme, (Molecular Weight: 222.28, Density: 1.009, CAS Number: 143-24-8, Formula: C₁₀H₂₂O₅, Boiling Point (° C.): 275-276at 760 torr).
• FIG. 16 illustrates an array containing illustrative examples of porphyrin, metalloporphyrin, acid-base indicator, and solvatochromatic dyes. Typical sizes can range from 0.5 mm to 2 cm on a side. Linear, hexagonal, or rectangular arrays are also easily used. From left to right and top to bottom the identities and colors of the dyes used in the illustrative example of FIG. 16 are listed in Table 11 as follows (the exact colors depend, among other things, upon scanner settings).[0341]

  TABLE 11
  (Summarizing the Dyes and Colors in FIG. 16, i.e., “Dye - Color”)

  SnTPPCl2-	CoTPP -	CrTPPCl -	MnTPPCl -	FeTPPCl - Light	CuTPP -
  Light Green	Peach	Green	Green	Brownish Green	Salmon
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP - Salmon	FeTFPPCl -
  Salmon	Pink	Tan	Pink		Olive
  ZnSi6PP -	ZnSi7OHPP -	ZnSi8PP -	H2TPP -	H2FPP - Light	Alizarin basic -
  Pink	Deep Pink	Pink	Carmel	Brown	Violet
  Me Red -	BCP - Dark	BCPbasic -	BTB - Dark	BTB basic - Blue	Ph Red basic -
  Orange	Green	Blue	Yellow		Lavender
  Nile Red -	BCG - Blue	BCG basic -	CresRed -	CresRed basic -	CP Red -
  Violet		Blue	Brownish	Purple	Purple
  			Purple
  R Dye -	TB - Yellow	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Light Blue		Greenish	Yellow	Orangish Brown	Bluish
  		Gray			Purple

• FIG. 17 illustrates the response of the array described in FIG. 16 to acid vapors, specifically formic acid, acetic acid, iso-valeric acid, and 3-methyl-2-hexenoic acid. As shown in FIG. 17 and summarized in Table 12 below, the color changes of each dye in response to a particular analyte are shown as color difference maps, as follows (the exact colors depend, among others things, upon scanner settings). The color changes are derived simply by comparing the before exposure and after exposure colors and subtracting the two images (i.e., the absolute value of the difference of the red values becomes the new red value in the color difference map; etc. for green values and blue values). If there is no change in the red, green, and blue color values of a dye in the after-exposure image, then the color difference map will show black (i.e., red value =green value =blue value =0).[0342]

  TABLE 12
  (Summarizing the Dyes and Color Changes in FIG. 17, i.e. “Dye - Difference
  Map Color”)
  (Analyte: Formic Acid 140 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl	MnTPPCl	FeTPPCl -	CuTPP -
  Black	Black (no	Black	Black	Faint Blue	Black (no
  (no	change)	(no	(no	Periphery	change)
  change)		change)	change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPCl -
  Black (no	Black (no	Black	Black (no	Black (no	Black (no
  change)	change)	(no	change)	change)	change)
  		change)
  ZnSi6PP -	ZnSi7OHPP -	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Dark Blue
  change)	change)	change)	change)	change)
  Me Red -	BCP -	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no	Yellow	White	Black (no	Red	Green
  change)			change)	Periphery
  				w/Yellow
  				Center
  Nile Red -	BCG -	BCG	CresRed -	CresRed	CP Red -
  Black (no	Black (no	basic -	Black (no	basic - Light	Black (no
  change)	change)	Dark	change)	Green	change)
  		Purple
  R Dye -	TB - Black	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	(no change)	Black (no	Green and	Dark	Yellow
  change)		change)	Purple	Purple	Periphery and
  					Purple center

  (Analyte: Formic Acid 210 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl	FeTPPCl -	CuTPP - Black
  Black	Black (no	Black (no	Black (no	Black (no	(no change)
  (no	change)	change)	change)	change)
  change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP - Black	FeTFPPCl -
  Black (no	Black (no	Black (no	Black (no	(no change)	Black (no
  change)	change)	change)	change)		change)
  ZnSi6PP -	ZnSi7OH	ZnSi8PP -	H2TPP -	H2FPP - Black	Alizarin basic -
  Black (no	PP -	Black (no	Black (no	(no change)	Black (no
  change)	Black (no	change)	change)		change)
  	change)
  Me Red -	BCP -	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no	Red	Yellow	Black (no	Red	Green
  change)		Periphery and	change)
  		Red Center
  Nile Red -	BCG -	BCG basic -	CresRed -	CresRed basic -	CP Red - Black
  Black (no	Black (no	Red periphery	Black (no	Green	(no change)
  change)	change)		change)
  R Dye -	TB -	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Yellow
  change)	change)	change)	change)	change)	Periphery and
  					Purple Center

  (Analyte: Formic Acid 340 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl -	FeTPPCl -	CuTPP - Black
  Black	Black (no	Black (no	Black (no	Black (no	(no change)
  (no	change)	change)	change)	change)
  change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPCl - Black
  Black (no	Black (no	Black (no	Black (no	Black (no	(no change)
  change)	change)	change)	change)	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Green and Purple
  change)	change)	change)	change)	change)
  Me Red -	BCP -	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no	Yellow	White	Black (no	Yellow	Green
  change)			change)
  Nile Red -	BCG - Red	BCG basic -	CresRed -	CresRed	CP Red - Green
  Black (no		Red and	Black (no	basic - Light
  change)		Purple	change)	Green
  R Dye -	TB - Black	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	(no change)	Black (no	Blue	Purple	White
  change)		change)

  (Analyte: Formic Acid 680 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl	FeTPPCl -	CuTPP - Black (no
  Black	Black (no	Black (no	Black (no	Black (no	change)
  (no	change)	change)	change)	change)
  change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPCl - Black
  Black (no	Black (no	Black (no	Black (no	Black (no	(no change)
  change)	change)	change)	change)	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Green and Purple
  change)	change)	change)	change)	change)
  Me Red -	BCP -	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no	Yellow	White	Black (no	Red	Green
  change)			change)	Periphery
  				and Yellow
  				Center
  Nile Red -	BCG Red	BCG	CresRed -	CresRed	CP Red - Black
  Black	and Purple	basic - Red	Black (no	basic - Green	(no change)
  (no		and Purple	change)
  change)
  R Dye -	TB - Black	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	(no change)	Black (no	Light blue	Purple	White
  change)		change)

  (Analyte: Acetic Acid 170 ppb)

  SnTPPCl2 -	CoTPP - Black	CrTPPCl -	MnTPPCl	FeTPPCl -	CuTPP -
  Black	(no change)	Black (no	Black (no	Black (no	Black (no
  (no		change)	change)	change)	change)
  change)
  AgTPP -	NiTPP - Black	InTPPCL -	IrTPPCl -	ZnTPP - Black	FeTFPPCl -
  Black (no	(no change)	Black (no	Black (no	(no change)	Black (no
  change)		change)	change)		change)
  ZnSi6PP -	ZnSi7OHPP -	ZnSi8PP -	H2TPP -	H2FPP - Black	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	(no change)	Black (no
  change)	change)	change)	change)		change)
  Me Red -	BCP - Red	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no		Orange	Black (no	Red	Black (no
  change)			change)		change)
  Nile Red -	BCG - Purple	BCG basic -	CresRed -	CresRed basic -	CP Red. -
  Black (no	and Orange	Purple	Black (no	Black (no	Black (no
  change)		Orange	change)	change)	change)
  R Dye -	TB - Black (no	TB basic -	MeOr -	MeOr basic -	CP Red
  Black (no	change)	Black (no	Black (no	Black (no	basic - Black
  change)		change)	change)	change)	(no change)

  (Analyte: Acetic Acid 250 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl -	FeTPPCl -	CuTPP - Black (no
  Black	Black (no	Black (no	Black (no	Black (no	change)
  (no	change)	change)	change)	change)
  change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPCl - Black
  Black (no	Black (no	Black (no	Black (no	Black (no	(no change)
  change)	change)	change)	change)	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Black (no change)
  change)	change)	change)	change)	change)
  Me Red -	BCP -	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no	Yellow with	Red	Black (no	Red	Green
  change)	Red Center		change)
  Nile Red -	BCG -	BCG basic -	CresRed -	CresRed	CP Red - Black
  Black (no	Orange	Red and	Black (no	basic -	(no change)
  change)		Purple	change)	Black (no
  				change)
  R Dye -	TB - Black	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	(no change)	Black (no	Black (no	Black (no	White
  change)		change)	change)	change)

  (Analyte: Acetic Acid 340 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl -	FeTPPCl -	CuTPP - Black (no
  Black	Black (no	Black (no	Black (no	Black (no	change)
  (no	change)	change)	change)	change)
  change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPCl - Black
  Black (no	Black (no	Black (no	Black (no	Black (no	(no change)
  change)	change)	change)	change)	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Black (no change)
  change)	change)	change)	change)	change)
  Me Red -	BCP -	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no	Yellow	Yellow	Black (no	Ornage	Green
  change)			change)
  Nile Red -	BCG -	BCG basic -	CresRed -	CresRed	CP Red - Black
  Black (no	Faint	Purple	Black (no	basic -	(no change)
  change)	Orange and		change)	Green
  	Purple
  R Dye -	TB - Black	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	(no change)	Black (no	Black (no	Black (no	White
  change)		change)	change)	change)

  (Analyte: Acetic Acid 650 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl - n	FeTPPCl -	CuTPP - Black (no
  Black	Black (no	Black (no	Black (no	Black (no	change)
  (no	change)	change)	change)	change)
  change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPCl - Black
  Black (no	Black (no	Black (no	Black (no	Black (no	(no change)
  change)	change)	change)	change)	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Faint Green
  change)	change)	change)	change)	change)
  Me Red -	BCP -	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no	Yellow and	Faint	Orange	Yellow	Green
  change)	Orange)	Yellow
  Nile Red -	BCG -	BCG basic -	CresRed -	CresRed	CP Red - Faint
  Black (no	Black (no	Purple	Black (no	basic -	Green
  change)	change)		change)	White
  R Dye -	TB - Black	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	(no change)	Black (no	Black (no	Green	White
  change)		change)	change)

  (Analyte: Iso-Valeric Acid 280 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl -	FeTPPCl -	CuTPP - Black (no
  Black	Black (no	Black (no	Black (no	Black (no	change)
  (no	change)	change)	change)	change)
  change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPC - Black
  Black (no	Black (no	Black (no	Black (no	Black (no	(no change)
  change)	change)	change)	change)	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Black (no change)
  change)	change)	change)	change)	change)
  Me Red -	BCP - Red	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no	Black (no	Faint Red	Black (no	Orange	Orange
  change)	change)		change)
  Nile Red -	BCG -	BCG basic -	CresRed -	CresRed	CP Red - Black
  Black (no	Faint Purple	Red	Black (no	basic - Dark	(no change)
  change)	Periphery	Periphery	change)	Green
  R Dye -	TB - Red	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	and Purple	Red	Green	Green	Green Periphery
  change)	Periphery	Periphery	Center	Periphery

  (Analyte: Iso-Valeric 420 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl -	FeTPPCl -	CuTPP - Black (no
  Black	Black (no	Black (no	Black (no	Black (no	change)
  (no	change)	change)	change)	change)
  change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPCl - Black
  Black (no	Black (no	Black (no	Black (no	Black (no	(no change)
  change)	change)	change)	change)	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Black (no change)
  change)	change)	change)	change)	change)
  Me Red -	BCP - Red	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no		Faint	Black (no	Orange and	Faint Orange and
  change)		Green and	change)	Yellow	Green
  		orange
  Nile Red -	BCG -	BCG basic -	CresRed -	CresRed	CP Red - Black
  Black (no	Orange	Orange	Black (no	basic -	(no change)
  change)		Periphery	change	Green
  R Dye -	TB - Black	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	(no change)	Black (no	Green	Green	Green
  change)		change)

  (Analyte: Iso-Valeric Acid 850 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl -	FeTPPCl -	CuTPP - Black
  Faint	Faint Purple	Faint	Faint Purple	Faint Purple	(no change)
  blue		Purple
  AgTPP -	NiTPP -	InTPPCL -	IrTPPC1 -	ZnTPP -	FeTFPPCl - Black
  Faint Blue	Black (no	Faint Pink	Black (no	Black (no	(no change)
  	change)		change)	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Faint Blue	Faint Blue	Black (no	Faint Blue	Black (no	Black (no change)
  		change)		change)
  Me Red -	BCP - White	BCP basic -	BTB - Blue	BTB basic -	Ph Red basic -
  Black (no	and Red	Yellow	and Red	Red and	Yellow and Red
  change)		and Red		Yellow
  Nile Red -	BCG - White,	BCG basic -	CresRed -	CresRed	CP Red - Faint
  Black (no	Red and Blue	White	Purple	basic -	Orange
  change)		and Red	Periphery	Light Green
  R Dye -	TB - Light	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Faint Red	Blue	Purple	Green and	Light	Light Green
  	Periphery	Periphery	Blue	Green
  		and Red
  		Center

  (Analyte: Iso-Valeric Acid 1700 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl -	FeTPPCl -	CuTPP - Black (no
  Black	Black (no	Black (no	Black (no	Black (no	change)
  (no	change)	change)	change)	change)
  change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPCl - Black
  Black (no	Black (no	Black (no	Black (no	Black (no	(no change)
  change)	change)	change)	change)	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Faint Purple
  change)	change)	change)	change)	change)
  Me Red -	BCP - Red	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no		White	Black (no	White	White and Purple
  change)			change)
  Nile Red -	BCG - Red	BCG basic -	CresRed -	CresRed	CP Red - Black
  Black	and Purple	White,	Black (no	basic -	(no change)
  (no		Red, and	change)	White
  change)		Purple
  R Dye -	TB - Black	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	(no change)	Faint Red	Black (no	Faint	Green
  change)			change)	Green

  (Analyte: 3-Methyl-2-hexenoic Acid 12 ppb)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl -	FeTPPCl -	CuTPP - Black (no
  Black	Black (no	Black (no	Black (no	Black (no	change)
  (no	change)	change)	change)	change)
  change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPCl - Black
  Black (no	Black (no	Black (no	Black (no	Black (no	(no change)
  change)	change)	change)	change)	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Black (no	Black (no	Black (no	Black (no	Black (no change)
  change)	change)	change)	change)	change)
  Me Red -	BCP - Faint	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Black (no	Purple	White	Black (no	Red	Purple and Green
  change)		and Purple	change)
  Nile Red -	BCG -	BCG basic -	CresRed -	CresRed	CP Red - Black
  Black (no	Faint Red	Faint	Black (no	basic - Light	(no change)
  change)	and Purple	White and	change)	Blue and
  		Purple		Green
  R Dye -	TB - Black	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Black (no	(no change)	Black (no	Black (no	Blue and	Green
  change)		change)	change)	Green

• FIG. 18 illustrates a preferred array containing illustrative examples of porphyrin, metalloporphyrin, acid-base indicator, and solvatochromatic dyes. Typical sizes of the array can range from 0.5 mm to 2 cm on a side. Linear, hexagonal or rectangular arrays are also easily used. From left to right and top to bottom the identities and colors of the dyes used in the illustrative example of FIG. 18 are listed in Table 13 as follows (the exact colors depend, among other things, upon scanner setting).[0343]

  TABLE 13
  (Summarizing the Dyes and Colors in FIG. 18, i.e., “Dye - Color”)

  SnTPPCl2-	CoTPP - Tan	CrTPPCl - Green	MnTPPCl -	FeTPPCl - Light	CuTPP -
  Light Green		with Dark Green	Green	Green	Light Pink
  		Center
  Zn(C3F7)4P -	ZnF2PP -	InTPPCl -	ZnTMP -	ZnTPP -	FeTFPPCl -
  Gray	Light Pink	Reddish Beige	Pink	Salmon	Beige
  ZnSi6PP -	ZnSi7OHPP -	ZnSi8PP - Light	H2TPP -	H2FPP -	Neutral Red
  Pink	Pink	Pink	Light	Greenish Yellow	Pink with
  			Reddish		Brown
  			Beige		Center
  Methyl Red -	Disperse	Rosolic Acid -	Fat Brown	Cyanidin	Metanil
  Orange	Orange 25 -	Red	RR - Dark	Chloride -	Yellow -
  	Pinkish			Reddish Brown	Light
  	Orange				Yellow
  Nile Red -	Mordant	3,6-Acridineamine	Bromocresol	Azodipyridine -	Rosaniline -
  				Yellow
  Light Purple	Orange 1 -	Yellow	Green -		Pink
  	Light Yellow		Dark Yellow
  Reichardt's	Acridine	Crystal Violet -	Thymol Blue	Congo Red -	Malachite
  Dye - Teal	Orange	Dark Blue	Purple	Dark Red	Green
  	Base -				Carbinol
  	Yellow				base - Light
  					Blue

• where[0344]
• SnTPPCl[0345]₂is 5,10,15,20-Tetraphenyl-21H,23H-porphine tin(IV) dichloride
• Molecular Formula: C[0346]₄₄H₂₈SnCl₂N₄
• Molecular Weight: 802[0347]
• CAS: 26334-85-0;[0348]
• CoTPP is 5,10,15,20-Tetraphenyl-21H,23H-porphine cobalt(II)[0349]
• Molecular Formula: C[0350]₄₄H₂₈CoN₄
• Molecular Weight: 671[0351]
• CAS: 14172-90-8;[0352]
• CrTPPCl is 5,10,15,20-Tetraphenyl-21H,23H-porphine chromium(III) chloride[0353]
• Molecular Formula: C[0354]₄₄H₂₈CrClN₄
• Molecular Weight: 700[0355]
• CAS: 28110-70-5;[0356]
• MnTPPCl is 5,10,15,20-Tetraphenyl-21H,23H-porphine manganese(III) chloride[0357]
• Molecular Formula: C[0358]₄₄H₂₈ClMnN₄
• Molecular Weight: 703[0359]
• CAS: 32195-55-4;[0360]
• FeTPPCl is 5,10,15,20-Tetraphenyl-21H,23H-porphine iron(III) chloride[0361]
• Molecular Formula: C[0362]₄₄H₂₈ClFeN₄
• Molecular Weight: 704[0363]
• CAS: 16456-81-8;[0364]
• CuTPP is 5,10,15,20-Tetraphenyl-21H,23H-porphine copper(II)[0365]
• Molecular Formula: C[0366]₄₄H₂₈CuN₄
• Molecular Weight: 676[0367]
• CAS: 14172-91-9;[0368]
• Zn(C[0369]₃F₇)₄P is meso tetra(heptafluoropropyl)porphine zinc(II)
• Molecular Formula: C[0370]₃₂H₈ZnF₂₈N₄
• Molecular Weight: 1044;[0371]
• ZnF[0372]₂PP is 5,10,15,20-Tetrakis(2,6-difluorophenyl)-21H,23H-porphine zinc(II)
• Molecular Formula: C44H[0373]₂₀F₈N₄Zn
• Molecular Weight: 820;[0374]
• InTPPCl is 5,10,15,20-Tetraphenyl-21H,23H-porphine indium(III) chloride[0375]
• Molecular Formula: C[0376]₄₄H₂₈ClInN₄
• Molecular Weight: 763;[0377]
• ZnTMP is 5,10,15,20-Tetrakis(2,4,6-trimethylphenyl)-21H,23H-porphine zinc(II)[0378]
• Molecular Formula: C[0379]₅₆H₅₂N₄Zn
• Molecular Weight: 846[0380]
• CAS: 104025-54-9;[0381]
• ZnTPP is 5,10,15,20-Tetraphenyl-21H,23H-porphine zinc(II)[0382]
• Molecular Formula: C[0383]₄₄H₂8N₄Zn
• Molecular Weight: 678[0384]
• CAS: 14074-80-7;[0385]
• FeTFPPCl is 5,10,15,20-Tetrakis(pentafluorophenyl)-21H,23H-porphine iron(III) chloride[0386]
• Molecular Formula: C[0387]₄₄H₈CIF₂₀FeN₄
• Molecular Weight: 1063.85[0388]
• CAS: 36965-71-6;[0389]
• ZnSi[0390]₆PP is 5(phenyl)-10,15,20-trikis(2 ,6-disilyloxyphenyl)porphyrinatozinc(II)
• Molecular Formula: ZnC[0391]₈₀H₁₁₂O₆N₄Si₆
• Molecular Weight: 1458;[0392]
• ZnSi[0393]₇OHPP is 5,10,15-trikis(2′,6′-disilyloxyphenyl)-20-(2/-hydroxy-6/-silyloxyphenyl)porphyrinatozinc(II)
• Molecular Formula: ZnC[0394]₈₆H₁₂₆O₈N₄Si₇
• Molecular Weight: 1604;[0395]
• ZnSi[0396]₈PP is 5,10,15,20-tetrakis(2/,6/-disilyloxyphenyl)porphyrinatozinc(II)
• Molecular Formula: ZnC[0397]₉₂H₁₄₀O₈N₄Si₈
• Molecular Weight: 1718;[0398]
• H[0399]₂TPP is 5,10,15,20-Tetraphenyl-21H,23H-porphine
• Molecular Formula: C[0400]₄₄H₃₀N₄
• Molecular Weight: 614.75[0401]
• CAS: 917-23-7;[0402]
• H[0403]₂FPP is 5,10,15,20-Tetrakis(pentafluorophenyl)-21H,23H-porphine
• Molecular Formula: C[0404]₄₄H₁₀F₂ON₄
• Molecular Weight: 974.57[0405]
• CAS: 25440-14-6;[0406]
• Azodipyridine is 6′-Butoxy-2,6-diamino-3,3′-azodipyridine[0407]
• Molecular Formula: C[0408]₁₄H₁₈N₆O
• Molecular Weight: 286.34[0409]
• CAS: 617-19-6;[0410]
• Rosaniline is Para-Rosaniline Base[0411]
• Molecular Formula: C[0412]₁₉H₁₉N₃O
• Molecular Weight: 305.4[0413]
• CAS: 25620-78-4[0414]
• FIG. 19 illustrates the response of the array described in FIG. 18 to acetone. As shown in FIG. 18 and summarized in Table 14 below, the color changes of each dye in response to aceteone are as follows (the exact colors depend, among other things, upon scanner settings). The color changes are derived simply by comparing the before exposure and after exposure colors and subtracting the two images (i.e., the absolute value of the difference of the red values becomes the new red value in the color difference map; etc. for green values and blue values). If there is no change in the red, green, and blue color values of a dye in the after-exposure image, then the color difference map will show black (i.e., red value =green value =blue value =0).[0415]

  TABLE 14
  (Summarizing the Dyes and Colors in FIG. 19, i.e., “Dye - Color”)

  SnTPPCl2 -	CoTPP -	CrTPPCl -	MnTPPCl	FeTPPCl -	CuTPP - Black
  Reddish	Lavender	Gray	Pink	Black (no	(no change)
  Brown				change)
  AgTPP -	NiTPP -	InTPPCL -	IrTPPCl -	ZnTPP -	FeTFPPCl - Dark
  White	Light Teal	Blue	Light	Black (no	Dark Cobalt
  			Green	change)
  ZnSi6PP -	ZnSi7OHPP	ZnSi8PP -	H2TPP -	H2FPP -	Alizarin basic -
  Black (no	Aqua	Dark Teal	Green	White	Dark Purple
  change)				Periphery
  				and Blue
  				Center
  Me Red -	BCP -	BCP basic -	BTB -	BTB basic -	Ph Red basic -
  Dark Blue	Green	Light	Light	Dark Blue	Royal Blue
  		Green	Green
  Nile Red -	BCG - Tan	BCG basic -	CresRed -	CresRed	CP Red - Gold
  Olive		Black (no	Dark Pink	basic - Blue
  		change)
  R Dye -	TB - Brown	TB basic -	MeOr -	MeOr basic -	CP Red basic -
  Light		Green	Light	Dark Blue	Black (no change)
  Pink			Green

• Partial Oxidation[0416]
• Having demonstrated electronic differentiation and shape-selective distinction of analytes that bind to metal ions in metallodyes and of acidic or basic analytes that effect other chemoresponsive dyes (e.g., pH sensitive dyes and solvatochromic dyes), there are further embodiments of the present invention that provide for the differentiation of analytes that do not bind or bind only weakly to metal ions. Such analytes include certain organic compounds lacking ligatable functionality, such as simple alkanes, arenes, alkenes and alkynes (especially if sterically hindered), and molecules sterically hindered as to preclude effective ligation.[0417]
• By partially oxidizing (partial meaning oxidation that does not convert all of the carbon atoms of the analytes completely to carbon dioxide) such parent analytes, new mixtures of derivative analytes are formed that provide a unique analytical fingerprint for the presence of the parent analytes. The partial oxidation of such parent analytes to mixtures of alcohols, aldehydes, ketones, carboxylic acids, including small carboxylic acids (e.g., formic, acetic, propionic), carbon monoxide, and carbon dioxide can be easily accomplished, thus effecting the chemical conversion of weakly-responsive organic compounds to more volatile organic compounds. These more volatile organic compounds have a stronger interaction(s) with the array of the present invention, and thus provide stronger responses, than do the parent analytes with the array of the present invention. Preferably, for example, after partial oxidation of a parent analyte, the derivative analyte(s) may have stronger ligation, acid-base (including Lewis and/or Br?nsted acids and bases), hydrogen bonding, and/or dipolar interactions with an array of the present invention than does the parent analyte. For example, hexane can be partially oxidized to derivative analytes such as hexanoic acid, hexanol, hexanal, and C[0418]₆-ketones.
• Thus, a table or database of fingerprints of analytes can be made in accordance with the present invention by subjecting known analytes to partial oxidation pursuant to a certain protocol, and then observing and recording the absorbance or reflectance response an the above-described array to the partially oxidized known analytes. Later, an unknown analyte can be subjected to the same protocol of partial oxidation, and the resulting absorbance or reflectance response or the array to the partially oxidized unknown analyte can be matched with the corresponding fingerprint in the table or database of fingerprints. For example, a known source of hexane can be partially oxidized pursuant to a certain protocol, and the fingerprint of the resulting analyte can be observed and recorded. An unknown analyte can then be partially oxidized pursuant to the same protocol, and if the fingerprint of the resulting analyte matches that of hexane, then the unknown analyte will have been identified as hexane.[0419]
• In one embodiment, an above-described array is first subjected to an unknown analyte that has not been partially oxidized. Should the array have no response or a weak response to the unknown analyte such that the unknown analyte cannot be determined, then the unknown analyte can be subjected to a particular partial oxidation protocol to form at least one derivative analyte corresponding to the unknown analyte. The array can then be subjected to the at least one derivative analyte and inspected for a direct and distinct spectral absorbance or reflectance response corresponding to the derivative analyte. The response or fingerprint can then be matched with the corresponding response or fingerprint of a known analyte that had been subjected to the same particular partial oxidation protocol, and thus the unknown analyte can be identified.[0420]
• For partial oxidation of the parent analyte to occur, an oxidizing source must react with the parent analyte. The oxidizing source can be any suitable source of oxygen gas (e.g., as a component of air), or other oxidant or oxidizing agent (e.g., hydrogen peroxide, hypochlorite, chlorine dioxide, chlorine or other bleaching agents). To achieve partial oxidation of the parent analyte, the oxidizing source must be present in a range of concentration or amount sufficient to result in forming a derivative analyte that has a stronger response with at least part of the array of the present invention than the parent analyte, but below that needed to fully oxidize the parent analyte completely to carbon dioxide.[0421]
• In one embodiment, the incoming gas to be analyzed is brought into contact with an oxidizing source. For example, the incoming gas having a parent analyte can be passed through a column or cartridge comprising a heterogeneous oxidation catalyst. The outgoing gas coming out of the column or cartridge will comprise at least one derivative analyte that is then exposed to a dye array previously described above. The time of transit (so-called “residence time” of the analyte gas) over or through the bed of oxidation catalyst can be adjusted by the flow rate or the physical length of the catalyst bed so as to optimize the partial oxidation of the parent analyte(s).[0422]
• The extent of oxidation can also be adjusted by the concentration of the oxidant in the analyte gas or liquid (e.g., by adding O[0423]₂or hydrogen peroxide). Suitable oxidation catalysts are of many potential types, including but not limited to noble metals (e.g., Pt or Pd) or their oxides, early transition metal oxides (e.g., V₂O₅), and metal-containing microporous zeolites. Such oxidation catalysts can be used either in substantially pure form or supported on various high surface area supports, such as silica, alumina, charcoal, or diamtomaceous earth among others.
• If an oxidation catalyst is used, the extent of oxidation can also be adjusted by the temperature at which the catalyst is kept, such as a range that includes 100 K to 1000 K. An embodiment may often utilize a catalyst of sufficient activity and concentration to permit its effective use at room temperature.[0424]
• FIG. 20 illustrates an embodiment of a vapor exposure apparatus of the present invention. The basic difference between the embodiment shown in FIG. 3B is that the embodiment shown in FIG. 20 further includes a[0425]partial oxidation cartridge200 having asuitable oxidation catalyst202. Partial oxidation of the incoming gas or parent analyte204 usingoxidation catalyst202 can be used to provide increased sensitivities to analytes. More specifically, theoxidation catalyst202 ofpartial oxidation cartridge200 can used in accordance with the present invention to provide increased sensitivities to analytes that do not have significant acidic or basic functionality, including alkanes, arenes, alkenes and alkynes (especially if sterically hindered), and molecules sterically hindered as to preclude effective ligation.
• FIG. 20 illustrates top and side views of[0426]bottom piece21 and a top view oftop piece21′ of a vaporexposure flow cell20 of the present invention. In the embodiment shown in FIG. 20, for purposes of demonstration, asensor plate18 havingarray16 is placed inside of aflow cell20 equipped with aquartz window22. In a preferred embodiment, flowcell20 is made from stainless steel.Inlet23 for the analyte vapor includespartial oxidation cartridge200. Preferably,cartridge200 is packed with a solid or solid-supportedoxidation catalyst202 optimized for partial oxidation of the incoming analyte.Cartridge200 can be thermostated above or below room temperature as needed to optimize the partial oxidation of incoming analyte.Outlet23′ permits vapor flow out fromsensor plate18. In accordance with this embodiment, incoming gas or parent analyte204 is partially oxidized as it is passed throughcartridge200, and the partially oxidized gas206, which now contains at least one derivative analyte, flows intocontact array16 ofsensor plate18, and then exits from outlet23.′
• In accordance with the present invention, a table of responses of the array(s) described herein to a plurality of distinct known analytes can be prepared and used identify an unknown analytes at a later time.[0427]
• The present invention provides methods for detection. In one embodiment, a method (I) of detecting at least one parent analyte comprises the steps of (a) forming an array by depositing at least a first dye and a second dye directly onto a single support in a predetermined patter combination, the combination of dyes in the array having a distinct and direct spectral or reflectance response to distinct analytes comprising one or more parent analytes or their derivatives, (b) partially oxidizing at least one parent analyte to form at least one derivative analyte corresponding to said parent analyte, (c) subjecting the array to the at least one derivative analyte, and (d) inspecting the first dye and the second dye for a direct and distinct spectral response corresponding to the derivative analyte.[0428]
• In another embodiment, a method (II) of detecting at least one unknown parent analyte comprises the steps of[0429]
• (a) forming an array by depositing at least a first dye and a second dye directly onto a single support in a predetermined pattern combination, the combination of dyes in the array having a distinct and direct spectral absorbance or reflectance response to distinct analytes comprising one or more parent analytes or their derivatives,[0430]
• (b) partially oxidizing at least one known parent analyte pursuant to a certain protocol to form at least one derivative analyte corresponding to said known parent analyte,[0431]
• (c) subjecting the array to the at least one derivative analyte corresponding to said known parent analyte,[0432]
• (d) inspecting the array for a direct and distinct spectral response to the derivative analyte corresponding to said known analyte,[0433]
• (e) forming an array identical to the array formed in step (a) by repeating step (a) or returning the array in step (a) to its condition prior to step (c),[0434]
• (f) partially oxidizing at least one unknown parent analyte pursuant to the certain protocol to form at least one derivative analyte corresponding to said unknown parent analyte,[0435]
• (g) subjecting the array formed in step (e) to the at least one derivative analyte corresponding to said unknown parent analyte,[0436]
• (h) inspecting the array after step (g) for a direct and distinct spectral response to the derivative analyte corresponding to said unknown parent analyte, and[0437]
• (i) determining after step (h) whether the direct and distinct spectral response of the array to the derivative analyte corresponding to the unknown parent analyte matches the direct and distinct spectral response of the array to the derivative analyte corresponding to the known parent analyte in step (d).[0438]
• The method (II) of the above paragraph can further comprise the step of subjecting the array formed in step (e) to the at least one unknown parent analyte prior to step (f) and determining whether the array formed in step (e) has a response insufficient to detect the unknown parent analyte prior to proceeding to step (f). The method (II) can further comprise the step of subjecting the array formed in step (a) to the at least one known parent analyte prior to step (b) and determining whether the array formed in step (a) has a response insufficient to detect the unknown parent analyte prior to proceeding to step (b).[0439]
• The present invention provides a method (III) of making a table of responses of an array to a plurality of distinct analytes comprising the steps of[0440]
• (a) forming an array by depositing at least a first die and a second dye directly onto a single support in a predetermined pattern combination, the combination of dyes in the array having a distinct and direct spectral absorbance or reflectance response to distinct analytes comprising one or more parent analytes or their derivatives,[0441]
• (b) subjecting the array to at least one known parent analyte,[0442]
• (c) inspecting the distinct and direct absorbance or reflectance response that exists of the array to the at least one known parent analyte,[0443]
• (d) if no distinct and direct absorbance or reflectance response exists of the array to the at least one known parent analyte, then partially oxidizing the at least one known parent analyte pursuant to a certain protocol to form at least one derivative analyte corresponding to said known parent analyte,[0444]
• (e) subjecting the array to the at least one derivative analyte corresponding to said known parent analyte,[0445]
• (f) inspecting the array for a direct and distinct spectral response to the derivative analyte corresponding to said known analyte,[0446]
• (g) forming an array identical to the array formed in step (a) by repeating step (a) or returning the array in step (a) to its condition prior to step (b),[0447]
• (h) subjecting the array formed in step (g) to at least one unknown parent analyte to determine whether the array has a response sufficient to detect the unknown parent analyte,[0448]
• (i) if after step (h) the array has a response sufficient to detect the unknown parent analyte, then determining whether the response matches the response of a known patent analyte in step (c),[0449]
• (j) if after step (h) the array does not have a response sufficient to detect the unknown parent analyte, then partially oxidizing the at least one unknown parent analyte pursuant to the certain protocol to form at least one derivative analyte corresponding to said unknown parent analyte,[0450]
• (k) subjecting the array after step (j) to the at least one derivative analyte corresponding to said unknown parent analyte,[0451]
• (l) inspecting the array after step (k) for a direct and distinct spectral response corresponding to the derivative analyte corresponding to said unknown parent analyte, and[0452]
• (m) determining after step (l) whether the direct and distinct spectral response of the array to the derivative analyte corresponding to the unknown parent analyte matches the direct and distinct spectral response of the array to the derivative analyte corresponding to the known parent analyte in step (f).[0453]
• Many modifications and variations may be made in the techniques and structures described and illustrated herein without departing from the spirit and scope of the present invention. Accordingly, the techniques and structures described and illustrated herein should be understood to be illustrative only and not limiting upon the scope of the present invention.[0454]

Claims (30)

What is claimed is:

1. An artificial nose comprising an array, the array comprising at least a first dye and a second dye deposited directly onto a single support in a predetermined pattern combination, the combination of dyes in the array having a distinct and direct spectral absorbance or reflectance response to distinct analytes comprising one or more parent analytes or their derivatives, and an oxidizing source to partially oxidize at least one distinct parent analyte to at least one corresponding derivative analyte of said parent analyte, the array at least in part having a stronger distinct and direct absorbance or reflectance response to the derivative analyte than to the corresponding parent analyte.

2. The artificial nose ofclaim 1, wherein the at least one distinct parent analyte is from the group consisting of organic compounds lacking ligatable functionality and molecules sterically hindered as to preclude effective ligation, acid-base interaction functionality, hydrogen-base interaction functionality, and dipolar interaction functionality.

3. The artificial nose ofclaim 1, wherein the at least one corresponding derivative analyte has a stronger interaction with at least part of the array than its corresponding parent analyte.

4. The artificial nose ofclaim 3, wherein the stronger interaction is from the group consisting of ligation interaction, acid-base interaction, hydrogen-base interaction, and dipolar interaction.

5. The artificial nose ofclaim 1, wherein the oxidizing source comprises an oxidation catalyst.

6. The artificial nose ofclaim 5, wherein the oxidation catalyst from the group consisting of noble metals, noble metal oxides, early transition metals oxides and metal-containing microporous zeolites.

7. The artificial nose ofclaim 5, wherein the oxidation catalyst is contained in a cartridge.

8. The artificial nose ofclaim 1, wherein the oxidizing source is from the group consisting of substantially pure oxygen, air, hydrogen peroxide, hypochlorite, chlorine dioxide, chlorine or other bleaching agents.

9. The artificial nose ofclaim 5, wherein the oxidation catalyst is from the group consisting of platinum, palladium, and vanadium oxide.

10. The artificial nose ofclaim 5, wherein the partial oxidation of the at least one distinct analyte is conducted in a temperature range of between 100 K and 1000 K.

11. The artificial nose ofclaim 1, wherein the at least one derivative analyte is from the group consisting of alcohols, aldehydes, ketones, carboxylic acids, carbon monoxide, and carbon dioxide.

12. A method of detecting at least one parent analyte comprising the steps of (a) forming an array by depositing at least a first dye and a second dye directly onto a single support in a predetermined patter combination, the combination of dyes in the array having a distinct and direct spectral or reflectance response to distinct analytes comprising one or more parent analytes or their derivatives, (b) partially oxidizing the at least one parent analyte to form at least one derivative analyte corresponding to said parent analyte, (c) subjecting the array to the at least one derivative analyte, and (d) inspecting the first dye and the second dye for a direct and distinct spectral response corresponding to the derivative analyte.

13. A method of detecting at least one unknown parent analyte comprising the steps of

(a) forming an array by depositing at least a first dye and a second dye directly onto a single support in a predetermined pattern combination, the combination of dyes in the array having a distinct and direct spectral absorbance or reflectance response to distinct analytes comprising one or more parent analytes or their derivatives,

(b) partially oxidizing at least one known parent analyte pursuant to a certain protocol to form at least one derivative analyte corresponding to said known parent analyte,

(c) subjecting the array to the at least one derivative analyte corresponding to said known parent analyte,

(d) inspecting the array for a direct and distinct spectral response to the derivative analyte corresponding to said known analyte,

(e) forming an array identical to the array formed in step (a) by repeating step (a) or returning the array in step (a) to its condition prior to step (c),

(f) partially oxidizing at least one unknown parent analyte pursuant to the certain protocol to form at least one derivative analyte corresponding to said unknown parent analyte,

(g) subjecting the array formed in step (e) to the at least one derivative analyte corresponding to said unknown parent analyte,

(h) inspecting the array after step (g) for a direct and distinct spectral response to the derivative analyte corresponding to said unknown parent analyte, and

(i) determining after step (h) whether the direct and distinct spectral response of the array to the derivative analyte corresponding to the unknown parent analyte matches the direct and distinct spectral response of the array to the derivative analyte corresponding to the known parent analyte in step (d).

14. The method ofclaim 13 further comprising the step of subjecting the array formed in step (e) to the at least one unknown parent analyte prior to step (f) and determining whether the array formed in step (e) has a response insufficient to detect the unknown parent analyte prior to proceeding to step (f).

15. The method ofclaim 13 further comprising the step of subjecting the array formed in step (a) to the at least one known parent analyte prior to step (b) and determining whether the array formed in step (a) has a response insufficient to detect the unknown parent analyte prior to proceeding to step (b).

16. A table of responses of the array of the artificial nose ofclaim 1 to a plurality of distinct analytes.

17. A method of making a table of responses of an array to a plurality of distinct analytes comprising the steps of

(a) forming an array by depositing at least a first die and a second dye directly onto a single support in a predetermined pattern combination, the combination of dyes in the array having a distinct and direct spectral absorbance or reflectance response to distinct analytes comprising one or more parent analytes or their derivatives,

(b) subjecting the array to at least one known parent analyte,

(c) inspecting the distinct and direct absorbance or reflectance response that exists of the array to the known parent analyte,

(d) if no distinct and direct absorbance or reflectance response exists of the array to the at least one known parent analyte, then partially oxidizing the at least one known parent analyte pursuant to a certain protocol to form at least one derivative analyte corresponding to said known parent analyte,

(e) subjecting the array to the at least one derivative analyte corresponding to said known parent analyte,

(f) inspecting the array for a direct and distinct spectral response to the derivative analyte corresponding to said known analyte,

(g) forming an array identical to the array formed in step (a) by repeating step (a) or returning the array in step (a) to its condition prior to step (b),

(h) subjecting the array formed in step (g) to at least one unknown parent analyte to determine whether the array has a response sufficient to detect the unknown parent analyte,

(i) if after step (h) the array has a response sufficient to detect the unknown parent analyte, then determining whether the response matches the response of a known patent analyte in step (c),

(j) if after step (h) the array does not have a response sufficient to detect the unknown parent analyte, then partially oxidizing the at least one unknown parent analyte pursuant to the certain protocol to form at least one derivative analyte corresponding to said unknown parent analyte,

(k) subjecting the array after step 0) to the at least one derivative analyte corresponding to said unknown parent analyte,

(l) inspecting the array after step (k) for a direct and distinct spectral response corresponding to the derivative analyte corresponding to said unknown parent analyte, and

(m) determining after step (1) whether the direct and distinct spectral response of the array to the derivative analyte corresponding to the unknown parent analyte matches the direct and distinct spectral response of the array to the derivative analyte corresponding to the known parent analyte in step (f).

18. The method ofclaim 12 further comprising the step of forming a table of responses of the array to a plurality of distinct analytes.

19. An artificial tongue comprising an array, the array comprising at least a first dye and a second dye deposited directly onto a single support in a predetermined pattern combination, the combination of dyes in the array having a distinct and direct spectral absorbance or reflectance response to distinct analytes comprising one or more parent analytes or their derivatives, wherein the one or more parent analytes or their derivatives are in solution or liquid analytes, or analytes in a solid or solid analytes, and an oxidizing source to partially oxidize at least one distinct parent analyte to at least one corresponding derivative analyte of said parent analyte, the array at least in part having a stronger distinct and direct absorbance or reflectance response to the derivative analyte than to the corresponding parent analyte.

20. The artificial tongue ofclaim 19, wherein the at least one distinct parent analyte is from the group consisting of organic compounds lacking ligatable functionality and molecules sterically hindered as to preclude effective ligation, acid-base interaction functionality, hydrogen-base interaction functionality, and dipolar interaction functionality.

21. The artificial tongue ofclaim 19, wherein the at least one corresponding derivative analyte has a stronger interaction with at least part of the array than its corresponding parent analyte.

22. The artificial tongue ofclaim 21, wherein the stronger interaction is from the group consisting of ligation interaction, acid-base interaction, hydrogen-base interaction, and dipolar interaction.

23. The artificial tongue ofclaim 19, wherein the oxidizing source comprises an oxidation catalyst.

24. The artificial tongue ofclaim 23, wherein the oxidation catalyst from the group consisting of noble metals, noble metal oxides, early transition metals oxides and metal-containing microporous zeolites.

25. The artificial tongue ofclaim 23, wherein the oxidation catalyst is contained in a cartridge.

26. The artificial tongue ofclaim 19, wherein the oxidizing source is from the group consisting of substantially pure oxygen, air, hydrogen peroxide, hypochlorite, chlorine dioxide, chlorine or other bleaching agents.

27. The artificial tongue ofclaim 23, wherein the oxidation catalyst is from the group consisting of platinum, palladium, and vanadium oxide.

28. The artificial tongue ofclaim 23, wherein the partial oxidation of the at least one distinct analyte is conducted in a temperature range of between 100 K and 1000 K.

29. The artificial tongue ofclaim 19, wherein the at least one derivative analyte is from the group consisting of alcohols, aldehydes, ketones, carboxylic acids, carbon monoxide, and carbon dioxide.

30. A table of responses of the array of the artificial tongue ofclaim 19 to a plurality of distinct analytes.

Images