Solution anode glow discharge (SAGD) at ten: A decade of development and applications

Solution anode glow discharge (SAGD) and its variants, such as flowing liquid anode atmospheric pressure glow discharge (FLA-APGD), liquid drop anode atmospheric pressure glow discharge (LDA-APGD), and liquid anode glow discharge (LAGD), constitute a rapidly developing group of excitation sources employed in optical emission spectrometry (OES). In these systems, the analyzed solution serves as the electrode, allowing for the direct introduction of the selected sample components into the plasma. The transport of analytes occurs mainly through the formation of volatile species. Such a configuration provides high discharge stability, good sensitivity, and low detection limits (DLs) for selected elements. This review summarizes the current state of knowledge on SAGD, focusing on the characteristics of the analyte transport mechanisms, spectroscopic and operational parameters, and the factors influencing discharge stability and emission intensity. Particular attention is paid to matrix effects, strategies for their mitigation through the use of matrix modifiers, and other approaches that enhance the robustness of the system against interferences.