Isolation and quantification of dialkylmercury species by headspace solid phase microextraction and gas chromatography with atomic emission detection.

Foi desenvolvida uma metodologia para quantificar compostos dialquilmerc?ricos usando Microextra??o em Fase S?lida em Headspace (HS-SPME) e Cromatografia Gasosa com Detec??o por Emiss?o At?mica (GC-AED). Os par?metros para detec??o de Hg foram otimizados usando planejamento fatorial e superf?cies de resposta. Experimentos univariados foram empregados para determinar as condi??es de HS-SPME; as melhores fibras foram 75 ?m de Carboxen / PDMS e 65 ?m de PDMS / DVB. Por?m, as primeiras foram descartadas pela extensa degrada??o t?rmica dos analitos na dessor??o. O procedimento otimizado permite detectar os analitos em amostras aquosas com limite de detec??o de 1,7 e 0,2 ng L-1 para dimetil- and dietilmerc?rio, respectivamente. As curvas anal?ticas s?o lineares nas faixas de 36 a 180 ng L-1 (Me2Hg) e 38 a 190 ng L-1 (Et2Hg), com limite de quantifica??o de 38 ng L-1 (Me2Hg) e 29 ng L-1 (Et2Hg) e coeficientes de correla??o de 0,998 para Me2Hg e 0,999 para Et2Hg.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 ?m Carboxen / PDMS and 65 ?m 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