Atomic Emission Spectroscopy of Microarc Discharge in Sea Water for On-Site Detection of Metals

Abstract

Recently, marine resources have been attracting much attention owing to their growing role in sustainable development. Growing interest in the exploration of marine resources and numerous studies on ecology and biochemistry has made the high-precision analysis of sea water necessary. In this paper, the possibility of using the atomic emission spectroscopy of microarc discharges generated in sea water for on-site contaminants detection and elemental composition analysis has been studied. We analyzed the discharge process and optical emission spectra from microarc discharges in three types of liquid, namely, artificial sea water composed of ten main components, reference solutions containing a single component each, and naturally sampled deep sea water. Microarc discharges were generated under low breakdown voltages using a compact experimental setup with a needle-to-plate electrode system immersed in each liquid in a quartz cuvette. In the spectra, the emission peaks of the main components of sea water and contaminants from the electrodes were detected, and reference solutions were used for the identification of unassigned peaks. To study the effect of electrode materials on the optical emission spectra and plasma parameters, three types of needle electrodes were used. The effect of the experimental conditions on the measured optical emission spectra was studied, and the applicability of proposed method for on-site detection of metals and elemental composition analysis was confirmed.