CN101042365A - Dissolved oxygen electrochemical sensor - Google Patents

Abstract

Translated fromChinese

一种溶解氧电化学传感器，采用丝网印刷技术在Al₂O₃陶瓷基板上制成叉指金电极、叉指Pt电极、Ag/AgCl电极、以及相应的金焊盘，将聚苯乙烯溶液滴加在叉指金电极和叉指Pt电极上用甩胶机旋涂，经紫外光照射12小时固化形成感测薄膜，膜厚为200～300nm，除感测薄膜及Ag/AgCl电极以外的区域用绝缘胶覆盖形成绝缘层，金焊盘上涂敷环氧树脂。同现有技术比较，本发明具有如下突出的优点：本溶解氧电化学传感器具有更长的寿命，更高的灵敏度，良好的稳定性，制作简单，成本低廉。

An electrochemical sensor for dissolved oxygen, using screen printing technology to make interdigitated gold electrodes, interdigitated Pt electrodes, Ag/AgCl electrodes, and corresponding gold pads on Al₂ O₃ ceramic substrates, polystyrene solution Add it dropwise on the interdigitated gold electrode and the interdigitated Pt electrode, spin-coat it with a glue spinner, and cure it by ultraviolet light for 12 hours to form a sensing film with a film thickness of 200-300nm. Except for the sensing film and Ag/AgCl electrode The area is covered with insulating glue to form an insulating layer, and epoxy resin is coated on the gold pad. Compared with the prior art, the present invention has the following outstanding advantages: the dissolved oxygen electrochemical sensor has longer life, higher sensitivity, good stability, simple manufacture and low cost.

Description

A kind of dissolved oxygen electrochemical sensor

Technical field

The present invention relates to a kind of electrochemical sensor, particularly a kind of dissolved oxygen electrochemical sensor.

Background technology

Because the fast development of industry causes pollution of waterhead serious day by day in recent years, the water source quality utmost point need be controlled.For the monitoring of water source quality, general all with the index of the dissolved oxygen DO in the water as the contaminated degree of water quality.If the dissolved oxygen DO height in the water represents that then this water quality is preferable; Otherwise,, represent that then the contaminated degree of this water quality is serious if the dissolved oxygen DO in the water is very low.

The measurement of oxygen in water mainly relies on dissolved oxygen sensor to finish.Dissolved oxygen sensor as far back as 1956 promptly by Clark[1] develop, its structure is the film coated electrode, liquid electrolyte is separated with tested solution with electrode, and for a long time electrode is contacted with liquid electrolyte, membraneous material selects for use oxygen to see through, the tygon that stops other material to pass through simultaneously.High oxygen permeability membraneous material commonly used also comprises [2] such as polytetrafluoroethylene PTFE, polyvinylchloride, silica gel.The action principle of dissolved oxygen sensor is: when oxygen is dissolved in the liquid electrolyte by the optional membrane, carry out electrochemical reaction with electrode surface, convert oxygen concentration to electric current or electric potential signal, signal is output after amplifier strengthens.

Dissolved oxygen sensor development so far, its technology is comparatively ripe, but still has some shortcomings to break through, the life problems of sensor when containing in the high-concentration chlorine ion solution.As when being used for the seawater dissolved oxygen DO and detecting, because the existence of chlorion, corrosion phenomenon can take place in sensor electrode behind the impressed voltage, so still there is not the desirable dissolved oxygen sensor that seawater pollution detects that can be used for so far.

Dissolved oxygen sensor mostly adopts the method [3,4,5] of macromolecule membrane coated electrodes such as cellulose acetate, PTFE and PVC at present; The shortcoming of cellulose acetate is to apply continuously voltage carries out in the dissolved oxygen sensing process, and this macromolecule membrane can be stopped up by the calcium ion in the water, causes sensor to have only 12 hours serviceable life; The dissolved oxygen sensor of PTFE film coated electrode preparation has only 24 hours serviceable life; Though the PVC film can reduce the calcium ion blocking problem, serviceable life was above 72 hours, but really have the restriction of PVC anti-storage time (shelf life), and when being used for that general river dissolved oxygen DO carried out actual measurement, the metallic ion deposition problems more will be a big hidden danger.In addition, corrosion reaction under wet environment, behind the impressed voltage, also can take place on the electrode in working electrode and be with a kind of metal material to electrode in the said method.

Summary of the invention

The object of the present invention is to provide a kind of dissolved oxygen electrochemical sensor, cover screen printing electrode with the polystyrene macromolecule membrane, working electrode with electrode is used different metal materials, can avoid chlorion in the solution, when metallic ion exists, cause the generation of electrode corrosion reaction behind the impressed voltage; Working electrode and electrode adopted interdigital electrode version can improve the response current rate of diffusion, strengthens the sensitivity of sensor.

A kind of dissolved oxygen electrochemical sensor comprises Al₂O₃Ceramic substrate,interdigital gold electrode 2 as working electrode, asinterdigital Pt electrode 3 to electrode, Ag/AgCl electrode 4 as contrast electrode, and correspondinggold solder dish 5a, 5b, 5c, cover thesensing film 6 oninterdigital gold electrode 2 and theinterdigital Pt electrode 3, it is characterized in that:interdigital gold electrode 2,interdigital Pt electrode 3, Ag/AgCl electrode 4 and correspondinggold solder dish 5a, 5b, 5c are at Al with screen printing technique₂O₃Make on theceramic substrate 1,sensing film 6 is dripped oninterdigital gold electrode 2 andinterdigital Pt electrode 3 with the photoresist spinner spin coating by polystyrene solution after UV-irradiation solidify to form in 12 hours, substrate is provided with one with insulating gel covered dielectric layer 7,gold solder dish 5a, the last coating of 5b, 5c epoxide resin AB glue;Sensing film 6 thickness are 200～300nm.

With prior art relatively, the present invention has following outstanding advantage: 1) the present invention covers the screen printing electrode surface with the polystyrene macromolecule membrane, electrode can be completely cut off with wet environment, when having chlorion or metallic ion in the solution, can avoid electrode corrosion behind the impressed voltage, reach 120 hours serviceable life; 2) working electrode with electrode is adopted different metal materials, further be reduced in the generation of wet environment bottom electrode corrosion reaction; 3) working electrode and electrode adopted interdigital electrode version improves the response current rate of diffusion, and sensor highly sensitive in 4～20ppm dissolved oxygen concentration scope, presents the good linear relation, and sensitivity is-6.05 μ A/ppm; 4) adopt at Al₂O₃Silk-screen electrode preparation dissolved oxygen electrochemical sensor on the ceramic substrate, microminiaturization is made simple, with low cost.

Description of drawings

Fig. 1 is the electrode structural chart of dissolved oxygen electrochemical sensor of the present invention.

Fig. 2 is the structural representation of dissolved oxygen electrochemical sensor of the present invention.

Fig. 3 is the current-responsive figure of this dissolved oxygen electrochemical sensor to dissolved oxygen concentration, and horizontal ordinate is a dissolved oxygen concentration, and ordinate is a response current intensity.

Embodiment

Embodiment 1:

A kind of dissolved oxygen electrochemical sensor,interdigital gold electrode 2,interdigital Pt electrode 3, Ag/AgCl electrode 4 and correspondinggold solder dish 5a, 5b, 5c are at Al with screen printing technique₂O₃Make on theceramic substrate 1, the width ofinterdigital gold electrode 2 andinterdigital Pt electrode 3, spacing are 0.5mm, the length of Ag/AgCl electrode 4 is 10mm,sensing film 6 is dripped oninterdigital gold electrode 2 andinterdigital Pt electrode 3 with the photoresist spinner spin coating after UV-irradiation solidify to form in 12 hours by polystyrene solution, and the area ofsensing film 6 is 25.25mm², substrate is provided with one with insulating gel covered dielectric layer 7,gold solder dish 5a, the last coating of 5b, 5c epoxide resin AB glue; Sensingfilm 6 thickness are 200～300nm.As shown in Figure 1 and Figure 2.

At 1atm, temperature is under 25 ℃ the situation, be that dissolved oxygen content in 3% the sodium-chloride water solution is tested to mass concentration: at first in solution, fed nitrogen 25 minutes, compel the oxygen in the clean solution, feed a certain amount of oxygen then, oxygen concentration in the solution is 4ppm, use dissolved oxygen electrochemical sensor of the present invention, applying current potential is-0.6V (vs.Ag/AgCl), record corresponding response current value, like this process successively in the test solution dissolved oxygen concentration be respectively 6ppm, 8ppm, 10ppm, 12ppm, 14ppm, 16ppm, 18ppm, response current during 20ppm, obtain different dissolved oxygen concentration and sensor response current strength relationship, as shown in Figure 3.

In 4～20ppm dissolved oxygen concentration scope, present the good linear relation, transducer sensitivity is-6.05 μ A/ppm, is limited to 4ppm under detecting.

Use dissolved oxygen electrochemical sensor of the present invention, be continuously applied-0.6V (vs.Ag/AgCl) current potential and reach 120 hours, the dissolved oxygen content that to mass concentration is the 8ppm concentration in 3% the sodium-chloride water solution carries out follow-on test, response current remains on same stationary value, obviously corrosion does not take place in electrode, and sensor has the very long life-span.

List of references

1.Clark?L?C，Monitor?and?control?of?blood?and?tissue?oxygen?tension，Trans.Am.Soc.Artificial?Intern，1956，2：41～49

2.Hitchmam?M?L，Measurement?of?Dissolved?Oxygen，John?Wiley?&Sons，Inc.New?York，1978

3.Glasspool，W.V.and?Atkinson，J.K.，A?screen-printed?amperometric?dissolved?oxygensensor?utilising?an?immobilised?electrolyte?gel?and?membrane，Sensors?and?Actuators?B，1998，48：308～317

4.Atkinson?J?K，Glasspool?W?V，An?investigation?of?the?factors?influencing?stabilityin?continuously-powered?screen-printed?amperometric?dissolved?oxygen?sensors，Microelectronics?Internationa，2001，18(2)：26～30

5.Atkinson?J?K，Glasspool?W?V，An?evaluation?of?the?characteristics?of?membranematerials?suitable?for?the?batch?fabrication?of?dissolved?oxygen?sensors，MicroelectronicsInternationa，2003，20(2)：32～40。

Claims (2)

Translated fromChinese

1.一种溶解氧电化学传感器，包括Al₂O₃陶瓷基板(1)，作为工作电极的叉指金电极(2)，作为对电极的叉指Pt电极(3)，作为参比电极的Ag/AgCl电极(4)，以及相应的金焊盘(5a，5b，5c)，覆盖在叉指金电极(2)和叉指Pt电极(3)上的感测薄膜(6)，其特征在于：叉指金电极(2)、叉指Pt电极(3)、Ag/AgCl电极(4)以及相应的金焊盘(5a，5b，5c)是用丝网印刷技术在Al₂O₃陶瓷基板(1)上制成的，感测薄膜(6)由聚苯乙烯溶液滴加在叉指金电极(2)和叉指Pt电极(3)上用甩胶机旋涂后经紫外光照射12小时固化形成，基板上设有一个用绝缘胶覆盖的绝缘层(7)，金焊盘(5a，5b，5c)上涂敷环氧树脂AB胶。1. An electrochemical sensor for dissolved oxygen, comprising Al₂ O₃ ceramic substrate (1), as the interdigitated gold electrode (2) of working electrode, as the interdigitated Pt electrode (3) of counter electrode, as the interdigitated Pt electrode (3) of reference electrode Ag/AgCl electrodes (4), and corresponding gold pads (5a, 5b, 5c), cover the sensing film (6) on the interdigitated gold electrode (2) and the interdigitated Pt electrode (3), its characteristic In that: interdigitated gold electrodes (2), interdigitated Pt electrodes (3), Ag/AgCl electrodes (4) and corresponding gold pads (5a, 5b, 5c) are printed on Al₂ O₃ ceramics by screen printing technology Made on the substrate (1), the sensing film (6) is dripped with polystyrene solution on the interdigitated gold electrode (2) and the interdigitated Pt electrode (3), spin-coated with a glue spinner and then irradiated with ultraviolet light After 12 hours of curing, an insulating layer (7) covered with insulating glue is provided on the substrate, and epoxy resin AB glue is coated on the gold pads (5a, 5b, 5c).2.根据权利要求1所述的溶解氧电化学传感器，其特征在于：感测薄膜(6)厚度为200～300nm。2. The dissolved oxygen electrochemical sensor according to claim 1, characterized in that the thickness of the sensing film (6) is 200-300 nm.

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