Background technology
PH test paper is applied to scientific research, industry, agricultural, environmental protection, medicine and field of food by wide model, in order to measure the pH value of liquids and gases.The reaction principle of pH is based on pH indicator method, at present, in general pH analysis test paper, contain methyl red [pH4.2 (red) ~ 6.2 (Huang)], bromcresol green [pH3.6 (Huang) ~ 5.4 (green)], Bromothymol blue [pH6.7 (Huang) ~ 7.5 (indigo plant)], the appropriate cooperation of acid base indicator of these mixing can reflect the range of variation of pH4.5 ~ 9.0.Yet, pH precision test paper precision on existing market is relatively poor, the error that general precision test paper pH value is measured is in ± 1 left and right, and it is easily subject to the impact of indoor environment, especially time, after test paper leaves test fluid, can change rapidly, if not rapid judgement, probably introduce larger error.
A kind of highly sensitive pH test paper and preparation method thereof (CN102519959A) is disclosed on Intellectual Property Right Bureau of the RPC website, the method is by adopting digital senior offset printing to substitute the method that standard colors version is printed in artificial serigraphy, solved human factor and caused that a same batch look version reproducibility is looked into, color and luster is inhomogeneous, and then affect the problem of test accuracy, and sensitivity and the accuracy of pH test paper itself are not well solved.And above-mentioned document is recorded, for guaranteeing that the caustic corrosion of pH body paper acid and alkali affects the quality of paper, improve the stability of pH test paper, water-based colouring stabilizer, cotton wood fibre mildewproof agent, specialties mildewproof agent in indicator formula, have been added, and the buffer neutralizer being formed by NaOH and phosphoric acid modulation, this not only makes production technology become complicated, and may when measuring Cucumber, affect the accuracy of test.
Summary of the invention
The technical problem to be solved in the present invention is the above-mentioned deficiency for prior art, and the preparation method of a kind of sensitivity and the accuracy pH precision test paper that all very high pH measurement range is 5.5-9.0 is provided.
For solving the problems of the technologies described above, technical scheme of the present invention is:
A preparation method for pH precision test paper, is characterized in that, it comprises the following steps:
Preparation indicator: by the yellow 198-202g of soap, malachite green 48-52g, acid lake blue 648-653g, bromophenol blue 1190-1210g, cresol red 124-128g, m-cresol purple 52-56g, bromcresol green 678-682g, is dissolved in 30% ethanol water of 700kg;
Dipping: the indicator preparing is poured in impregnator, the pH test paper body paper of reel successively enters impregnator through unreeling stand and dancing roll, adjust unreeling stand deflector roll and dancing roll, make body paper in tension and smooth state, body paper with the speed of 2.5-3.5m/s by the dipping tank on impregnator, indicator is uniformly coated on body paper, then, through rubber guide rollers extruding, enters drying unit;
Dry: under normal pressure, by vapours, dry, vapor (steam) temperature is 95-105 ℃, and the time is 1-2 minute.
The formula of described indicator is preferably: the yellow 199-201g of soap, malachite green 49-51g, acid lake blue 649-651g, bromophenol blue 1195-1205g, cresol red 125-127g, m-cresol purple 53-55g, bromcresol green 679-681g, is dissolved in 30% ethanol water of 700kg.
The formula of indicator is more preferably: the yellow 200g of soap, and malachite green 50g, acid lake blue 650g, bromophenol blue 1200g, cresol red 126g, m-cresol purple 54g, bromcresol green 680g, is dissolved in 30% ethanol water of 700kg.
Advantage of the present invention and beneficial effect:
(1) the pH precision test paper that preparation method of the present invention makes is highly sensitive, and error range is between ± 0.2.
(2) preparation method of pH precision test paper of the present invention, technique is simple, the method that adopts vapours to dry, and heating direct is to drying indicator gradually, enable more evenly, firmly, stably to invest on body paper, guaranteed the Stability and veracity of test paper test result.
(3) preparation method of pH precision test paper of the present invention, does not add any other material, has reduced the factor that may affect test value.
Embodiment
The invention is further illustrated by the following examples, but the present invention is not only confined to following examples.
Embodiment mono-
(1) preparation indicator: by the yellow 200g of soap, malachite green 50g, acid lake blue 650g, bromophenol blue 1200g, cresol red 126g, m-cresol purple 54g, bromcresol green 680g, is dissolved in 30% ethanol water of 700kg;
(2) dipping: the pH test paper body paper of reel successively enters impregnator through unreeling stand and dancing roll, adjust unreeling stand deflector roll and dancing roll, make body paper in tension and smooth state, body paper with the speed of 3m/s by the dipping tank on impregnator, indicator is uniformly coated on body paper, then through rubber guide rollers extruding, enter drying unit;
(3) dry: under normal pressure, by vapours, dry, vapor (steam) temperature is 100 ℃, and the time is 1.5 minutes;
(4) test: get a fritter test paper and be placed on and peel off on double dish, with the glass bar of clean dried, dip liquid drop to be measured in the middle part of test paper, observe the color after vary stable, contrast with standard color comparison card, color shows that pH is 6.0, is 6.0 by the pH value that pH meter records this solution simultaneously.
Embodiment bis-
(1) preparation indicator: by the yellow 198g of soap, malachite green 48g, acid lake blue 648g, bromophenol blue 1190g, cresol red 124g, m-cresol purple 52g, bromcresol green 678g, is dissolved in 30% ethanol water of 700kg;
(2) dipping: the pH test paper body paper of reel successively enters impregnator through unreeling stand and dancing roll, adjust unreeling stand deflector roll and dancing roll, make body paper in tension and smooth state, body paper with the speed of 2.5m/s by the dipping tank on impregnator, indicator is uniformly coated on body paper, then through rubber guide rollers extruding, enter drying unit;
(3) dry: under normal pressure, by vapours, dry, vapor (steam) temperature is 105 ℃, and the time is 1 minute;
(4) test: first with distilled water, test paper is wetting, be bonded at one end of glass bar, then deliver near the vessel port that fills gas to be measured, observe the variation of color, after stable, with standard color comparison card contrast, color demonstration pH is 7.0, is 7.0 by the pH value that pH meter records this gas simultaneously.
Embodiment tri-
(1) preparation indicator: by the yellow 202g of soap, malachite green 52g, acid lake blue 653g, bromophenol blue 1210g, cresol red 128g, m-cresol purple 56g, bromcresol green 682g, is dissolved in 30% ethanol water of 700kg;
(2) dipping: the pH test paper body paper of reel successively enters impregnator through unreeling stand and dancing roll, adjust unreeling stand deflector roll and dancing roll, make body paper in tension and smooth state, body paper with the speed of 3.5m/s by the dipping tank on impregnator, indicator is uniformly coated on body paper, then through rubber guide rollers extruding, enter drying unit;
(3) dry: under normal pressure, by vapours, dry, vapor (steam) temperature is 95 ℃, and the time is 2 minutes;
(4) test: get a fritter test paper on glass sheet, with the glass bar of clean dried, dip liquid drop to be measured in the middle part of test paper, observe the color after vary stable, contrast with standard color comparison card, color shows that pH is 8.0, is 8.0 by the pH value that pH meter records this solution simultaneously.
Embodiment tetra-
(1) preparation indicator: by the yellow 199g of soap, malachite green 49g, acid lake blue 649g, bromophenol blue 1195g, cresol red 125g, m-cresol purple 53g, bromcresol green 679g, is dissolved in 30% ethanol water of 700kg;
(2) dipping: the pH test paper body paper of reel successively enters impregnator through unreeling stand and dancing roll, adjust unreeling stand deflector roll and dancing roll, make body paper in tension and smooth state, body paper with the speed of 2.8m/s by the dipping tank on impregnator, indicator is uniformly coated on body paper, then through rubber guide rollers extruding, enter drying unit;
(3) dry: under normal pressure, by vapours, dry, vapor (steam) temperature is 102 ℃, and the time is 1.5 minutes;
(4) test: first with distilled water, test paper is wetting, be bonded at one end of glass bar, then deliver near the vessel port that fills gas to be measured, observe the variation of color, after stable, with standard color comparison card contrast, color demonstration pH is 8.5, is 8.5 by the pH value that pH meter records this gas simultaneously.
Embodiment five
(1) preparation indicator: by the yellow 201g of soap, malachite green 51g, acid lake blue 651g, bromophenol blue 1205g, cresol red 127g, m-cresol purple 55g, bromcresol green 681g, is dissolved in 30% ethanol water of 700kg;
(2) dipping: the pH test paper body paper of reel successively enters impregnator through unreeling stand and dancing roll, adjust unreeling stand deflector roll and dancing roll, make body paper in tension and smooth state, body paper with the speed of 3.2m/s by the dipping tank on impregnator, indicator is uniformly coated on body paper, then through rubber guide rollers extruding, enter drying unit;
(3) dry: under normal pressure, by vapours, dry, vapor (steam) temperature is 98 ℃, and the time is 2 minutes;
(4) test: get a fritter test paper on glass sheet, with the glass bar of clean dried, dip liquid drop to be measured in the middle part of test paper, observe the color after vary stable, contrast with standard color comparison card, color shows that pH is 9.0, is 9.0 by the pH value that pH meter records this solution simultaneously.