Abstract: A compact electrochemical cell utilized for the detection of numerous toxic gases. The cell includes working and counter electrodes, surrounded by a liquid electrolyte, all of which is enclosed behind a gas permeable, hydrophobic membrane. The working electrode may be a single electrode or may be composed of multiple glassy carbon electrodes arranged in a planar electrode array. The counter electrode is either spatially separated from the array or comprises one or more electrodes in the array. The electrolyte composition varies with the type of gas to be detected and can be aqueous, partially aqueous, or substantially non-aqueous. The electrolyte includes an alkali metal halide. A fixed potential applied between the working and counter electrodes is sufficient to initiate electrochemical reactions in the presence of the gas to be detected without interfering reactions of the electrolyte or air.