Isolation and quantification of dialkylmercury species by headspace solid phase microextraction and gas Chromatography with Atomic Emission detection

Abstract

A methodology to quantify dialkylmercury compounds using Headspace Solid Phase Microextraction (HS-SPME) and Gas Chromatography with Atomic Emission Detection (GC-AED) was developed. The parameters for Hg detection were optimized by factorial design and response surfaces. Univariate experiments were employed to determine the HS-SPME conditions; 75 μm Carboxen / PDMS and 65 μm PDMS / DVB were the best fibers. However, the former was excluded from further experiments due to extensive thermal degradation of analytes during desorption. The optimized procedure allowed detection of the analytes from aqueous samples with LOD of 1.7 ng L-1 and 0.2 ng L-1 for dimethyl- and diethylmercury, respectively. The analytical curves are linear in the range from 36 to 180 ng L-1 (Me2Hg) and 38 to 190 ng L-1 (Et2Hg), with LOQ of 38 ng L-1 (Me2Hg) and 29 ng L-1 (Et2Hg) and correlation coefficients of 0.998 for Me2Hg and 0.999 for Et2Hg.