Chemical dropping electrode and method for monitoring pH value in solution

A dripping electrode and chemical technology, applied in the field of electrochemistry, can solve the problems of long-term environmental impact on the health of operators, inability to reuse, highly toxic metal mercury, etc., to avoid electrode contamination, easy calculation, and good stability Effect

Inactive Publication Date: 2010-01-06
SHANGHAI JIAO TONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the commonly used liquid phase electrode mercury drop electrode has fatal disadvantages: the electrode process that can be realized on the electrode is limited, metal mercury is highly toxic, and has a great impact on the environment and the health of long-term operators
[0005] After searching the literature of the prior art, it is found that the Chinese patent application publication CN1321885 (publication date: 2001.11.14) describes the following content, a modified platinum electrode is used as the working electrode, and a silver / silver chloride electrode is used as the reference electrode. Specific electrode, using platinum wire electrode as the counter electrode, using this three-phase electrode system to calculate the Gibbs free energy of lithium ions, sodium ions, potassium ions and other strongly hydrophilic ions migrating between the water / oil interface, that is, liquid / liquid Theoretical research on the physical and chemical properties of the interface. The preparation of this modified working electrode is cumbersome and cannot be reused. It does not have the prospect of practical application in environmental monitoring.

Method used

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  • Chemical dropping electrode and method for monitoring pH value in solution

Examples

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Effect test

Embodiment 1

[0020] Influence of Ionic Liquid Concentration in Organic Phase on pH Detection

[0021] Prepare 0.01mol.L -1 Lithium chloride solution 20mL, use hydrochloric acid and sodium hydroxide to adjust the pH of the lithium chloride solution to 2; place the three-phase electrode on the electrode holder, use a syringe to draw the solution containing different concentrations of 1-n-butyl 3-methylimidazole hexafluoro Phosphate 1,2-dichloroethane, control the droplet size at the top of the glass dropper to 11.11 μL, use the square wave method to scan within -1 ~ 1V, the results are shown in Table 1. With the increase of the concentration of the ionic liquid, the peak current of the hydrogen ion also increases under the condition of the same pH value, so the concentration of the ionic liquid is fixed in the process of measuring the pH.

[0022] Table 1

[0023] Ionic liquid concentration / mol.L -1

Embodiment 2

[0025] Peak current obtained at different pH values

[0026] Prepare 0.01mol.L -1 Lithium chloride solution 20mL, use hydrochloric acid and sodium hydroxide to adjust to different pH as the solution to be tested; place the three-phase electrode on the electrode holder, use a syringe to draw 1.25mol.L -1 1,2-dichloroethane of 1-n-butyl 3-methylimidazolium hexafluorophosphate, control the droplet size at the top of the glass dropper to 11.11 μL, and use the square wave method to carry out within -1 ~ 1V The scan results are shown in Table 2. As the pH value increases, the peak current has a linear relationship with the pH, so under a certain background, the pH of the solution can be obtained through the magnitude of the peak current in the solution.

[0027] Table 2

[0028] pH

Embodiment 3

[0030] Influence of droplet size on the detection effect of pH value

[0031] Prepare 0.01mol.L -1 Lithium chloride solution 20mL, use hydrochloric acid and sodium hydroxide to adjust the pH to 2.5 as the solution to be tested; place the three-phase electrode on the electrode holder, and use a syringe to draw 1.25mol.L -1 1,2-dichloroethane of 1-n-butyl 3-methylimidazolium hexafluorophosphate, control the droplet at the top of the glass dropper to be of different sizes, use the square wave method to scan within -1 ~ 1V , the results are shown in Table 3. During the scanning process, the droplet size of the working electrode will also affect the magnitude of the peak current, so the size of the working electrode must be fixed during the measurement of pH.

[0032] table 3

[0033] Droplet size / μL

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Abstract

The invention relates to a chemical dropping electrode and a method for monitoring a pH value in solution in the field of environmental monitoring. The electrode comprises a flowing syringe, a stainless steel joint, a glass burette, a conductive wire, a liquid storing groove, a Pt pole, an Ag / AgCl pole and a pole frame, wherein the flowing syringe is connected with the glass burette by the stainless steel joint; the conductive wire is inserted into the glass burette; one end of the conductive wire is connected to the stainless steel joint, and the other end of the conductive wire is in tangent with an outlet of the glass burette; the glass burette, the Pt pole and the Ag / AgCl pole are positioned on the pole frame; and the pole frame is arranged on the liquid storing groove. The method for monitoring a pH value by the electrode comprises the following steps: absorbing 1, 2-dichloroethane into the flowing syringe; controlling the amount of liquid drop at the top end of the glass burette; and detecting the pH value. The invention has simple and convenient operation and high stability and sensitivity.

Description

technical field [0001] The invention relates to an electrode and a monitoring method in the field of electrochemical technology, in particular to a chemical dripping electrode and a method for monitoring the pH value in a solution. technical background [0002] The commonly used pH measurement sensors in the laboratory mainly use glass electrodes. During the use of this solid-phase electrode, due to its low mechanical strength, it is easily broken, and the glass capillary pores in sensitive parts are easy to be polluted and blocked, and the attenuation and aging resistance cycle is short. . The surface of the electrode or membrane is easily contaminated by the analyte, resulting in poor reproducibility of the test results, and the situation is even less optimistic when used for online monitoring. In the process of pH monitoring, people also tried to improve the test results by means of ultrasonic cleaning and mechanical removal, but the effect was still not completely impro...

Claims

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Application Information

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IPC IPC(8): G01N27/403G01N27/48
Inventor 舒菲菲贾金平谢少艾王亚林王珺
Owner SHANGHAI JIAO TONG UNIV
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