Vapor generation in dielectric barrier discharge for sensitive detection of mercury by inductively coupled plasma optical emission spectrometry

Abstract

Mercury solution without or with formic acid was introduced into a low temperature argon plasma from dielectric barrier discharge (DBD). Mercury vapor generated in the DBD was separated from the liquid phase and finally swept into an inductively coupled plasma optical emission spectrometer (ICP-OES) for determination. The optimum conditions for the proposed technique and operation of the ICP-OES, as well as interferences from concomitants, were investigated in detail. It was found that the vapor generation efficiency of mercury could be significantly enhanced with the addition of formic acid. However, the efficiency was reduced sharply in the presence of chloride ions or oxidizing substances of high concentration. Under the optimized conditions, a limit of detection of 0.090 μg L⁻¹ and a precision of 2.1% RSD at a concentration of 10 μg L⁻¹ were achieved by the proposed method. The new DBD-induced mercury vapor generation provides several advantages including low power consumption (<25 W), green analytical chemistry, cost-effectiveness, smaller size, long operation lifetime, and ease of on-line operation. The methodology has been successfully applied to the determination of mercury in a certified reference water sample and mineral water samples.