Allied Corporation

Sandra B Clay

Donald N Campbell

John C Schmidt

An electrochemical gas sensor is described for detecting a gas constituent, for example hydrazine in a gas ambient incorporating an electrochemical cell including a reference electrode, counter electrode and sensing electrode spaced apart and with an electrolyte in contact with each electrode and comprising n-methyl-2-pyrrolidone and a salt soluble therein, for example tetraalkyl ammonium salt. The invention overcomes the problem of specificity, service life and operating temperature range associated with aqueous electrochemical gas sensors.

Electrochemical gas sensor

An electrochemical gas detection cell, particularly suitable for detecting H.sub.2 S, includes an electrochemical gas sensor which has a reference electrode, a sensing electrode and a counter electrode. The counter electrode is composed of carbon. The sensing electrode is composed of either gold or platinum and the reference electrode is composed of platinum. Circuitry is provided to supply voltage to the electrodes, the sensing electrode bias can be held below 300 mv., with respect to the reference electrode. The agent H.sub.2 S can be readily detected when the bias is about 250 mv. The cell is associated with signal processing circuitry which produce audible and visual outputs. A nonaqueous electrolyte is provided. The electrolyte may be composed of either propylene carbonate or n-methyl-2-pyrrolidone and one of conductive compatible salts, such as tetrabutyl ammonium tetrafluoroborate.

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Baltimore, MD, United States of America

Sandra B Clay