Development of direct-current, atmospheric-pressure, glow discharges generated in contact with flowing electrolyte solutions for elemental analysis by optical emission spectrometry

Abstract

Direct-current, atmospheric-pressure, glow discharge (dc-APGD) generated in contact with flowing sample solutions is a new, very promising excitation source for analytical optical emission spectrometry, due to its low maintenance requirements and its analytical performance. Since analyzed solutions act as liquid cathodes, this discharge system is useful for the direct determination of elements dissolved in solutions without having to produce their aerosols by pneumatic nebulization. The review presents different systems and designs of dc-APGD generated with the liquid cathode applied to spectrochemical analysis in the past 20 years. We discuss the effect of experimental conditions on analytical response and performance of the discharge. We include analytical figures of merit obtained with different discharge systems and their application to the analysis of environmental and biological samples containing various trace elements.