Trace dissolving oxygen electrochemical sensor

Abstract

An electrochemical transducer of dissolved oxygen in trace amount is prepared as having positive electrode prepared in form of round tube, jacketing top and bottom end of positive electrode on shell with its built - in fixing base being set on connection body, setting negative electrode at head of connection body and contacting negative electrode internal surface to temperature transducer in connection body, setting electrolyte containing cavity between positive electrode and shell and oxygen permeating film at bottom end of shell, contacting oxygen permeating film internal surface with negative electrode and closed electrolyte.

Description

technical field [0001] The invention relates to the field of electrochemistry, and is an electrochemical sensor for trace dissolved oxygen. Background technique [0002] The detection of trace dissolved oxygen is often used in the detection of special water quality. For example, the boiler feed water of thermal power plants and nuclear power plants is desalted and deoxygenated water. The content of dissolved oxygen is generally below 7μg / L, otherwise it will accelerate the boiler wall. oxidation corrosion. Such a low content of dissolved oxygen produces a very weak electrical signal in the sensor, typically 10 -10 a. [0003] The main defect of the existing ordinary dissolved oxygen electrochemical sensor is that although the cathode also uses inert metal materials such as gold, the purity of the material is not enough, and other metal impurities contained will electrochemically react with the anode in the electrolyte, forming additional interference Current, this kind of...

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Problems solved by technology

[0003] The main defect of the existing ordinary dissolved oxygen electrochemical sensor is that although the cathode also uses inert metal materials such as gold, the purity of the material is not enough, and other metal impurities contained will electrochemically react with the anode in the electrolyte, forming additional interference Current, this kind of interference current is even greater than the effective current during trace detection; the working area of ​​the cathode is too small, generally between 0.3mm and 1.0mm in diameter, so the electrical signal generated by the redox reaction is extremely weak during trace detection; The insulator between the cathode and the anode is glass, and the degree of insulation in the electrolyte decreases, resulting in leakage. This leakage has a negligible effect on the measurement of dissolved oxygen at the mg / L level, but it will obliterate the effective signal in the trace measurement.

The existing ordinary dissolved oxygen electrochemical sensors are only suitable for the detection of surface water due to the limitations of materials and structures, and its content is at the mg / L level. When it is barely used for ultra-low content detection, the error is large and unstable

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