Flowing and Nonflowing Liquid Electrode Discharge Microplasma for Metal Ion Detection by Optical Emission Spectrometry

Liquid electrode discharge microplasma offers a simple, portable, and small platform for fast spectrochemical determination of metal ions in solution samples with lower consumption of consumables (e.g., working gases, electric current, and cooling water). Various liquid electrode discharge devices for metal ions determination with optical emission spectrometry have been developed in the past 20years. We aim here to provide an overview of this field and to show the similarities and differences, and strengths and weaknesses of different flowing liquid electrode discharge systems and nonflowing liquid electrode discharge systems. We also discuss sample flow rates in flowing systems, required sample volume in nonflowing systems, and the two systems' applications to real complex samples in this review.