Electrolyte-as-cathode glow discharge (ELCAD)/glow discharge electrolysis at the gas-solution interface

Electrolysis glow discharge (ELCAD), wherein an electrolyte serves as the cathode, is a potential new analytical source for on-line determination of trace heavy metals in waste and drinking waters, in addition to other liquid samples. The use of atomic emission spectrometry (AES) with ELCAD enhances the efficiency of the technique. Although possible applications of ELCAD-AES are widespread, the technique is currently unsuitable for the detection of toxic elements, such as mercury, at concentrations as low as the World Health Organization guideline level in drinking water (1 ng/mL). The aim of this contribution is to provide an overview of the brief history, development of instrumentation, fundamental mechanistic studies and applications of ELCAD. This review suggests that, whereas the scope of ELCAD-AES is diverse, it would benefit greatly from the involvement of more researchers to enhance the capabilities of the system, as otherwise this goal will not be achieved.