Ultrasensitive determination of mercury by atmospheric pressure glow discharge optical emission spectroscopy coupled with solution cathode glow discharge microplasma

Abstract

Here, we described an analytical system based on microplasma for online separation, preconcentration, excitation and determination of Hg. Owing to the combination of solution cathode glow discharge (SCGD) microplasma which in situ converted the dissolved Hg²⁺ to volatile species efficiently and atmospheric pressure glow discharge (APGD) microplasma which excited volatile Hg species efficiently, the proposed system successfully achieved the ultrasensitive determination of Hg. After the optimization of operating parameters, the detection limit (DL) of Hg was found to be 0.25 μg L⁻¹, and the relative standard deviation (RSD) at the analyte concentration of 100 μg L⁻¹ was 0.17%. The accuracy and practicality of the developed method were demonstrated by the analysis of the GBW10029 (fish) certified reference material (CRM) and human hair samples. The results obtained were within the reference range of the certified values (850 ± 30 μg kg⁻¹), and were in good agreement with the values obtained using inductively coupled plasma-mass spectrometry (ICP-MS).