| Summary: | Electrolyte Cathode Discharge (ELCAD) spectrometry, a novel sensitive multielement direct analytical method for metal traces in aqueous solutions, was introduced in 1993 as a new sensing principle. Since then several works have tried to develop an operational mechanism for this exotic atmospheric glow plasma technique, however these attempts cannot be combined into a valid model description. In this review we summarize the conceptual and technical problems we found in this upcoming research field of direct sensors. The T<sub>G</sub> gas temperature and the n<sub>e</sub> electron density values published up to now for ELCAD are very confusing. These data were evaluated by three conditions. The first is the gas composition of the ELCAD plasma, since T<sub>G</sub> was determined from the emitted intensity of the N<sub>2</sub> and OH bands. Secondly, since the ELCAD is an atmospheric glow discharge, thus, the obtained T<sub>G</sub> has to be close to the T<sub>e</sub> electron temperature. This can be used for the mutual validation of the received temperature data. Thirdly, as a consequence of the second condition, the values of T<sub>G</sub> and n<sub>e</sub> have to agree with the Engel-Brown approximation of the Saha-equation related to weakly ionized glow discharge plasmas. Application of non-adequate experimental methods and theoretical treatment leads to unreliable descriptions which cannot be used to optimize the detector performance.
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