RESUMO
Very volatile organic compounds (VVOCs), such as methanol, acetaldehyde, ethanol, acetone, acetonitrile, and dichloromethane, were extracted from water samples using a needle-type extraction device based on purge and trap analysis. The extracted analytes could then be determined by gas chromatography-mass spectrometry. By introducing carbon molecular sieves as the extraction medium, aqueous VVOCs could be successfully extracted using the extraction needle. The limit of quantification for methanol, acetaldehyde, ethanol, acetone, acetonitrile, and dichloromethane were 75, 75, 7.5, 0.5, 10 and 0.5 µg/L, respectively. This newly developed method was also successfully applied to the determination of VVOCs in commercial samples, such as fruit juice.
Assuntos
Técnicas de Química Analítica/instrumentação , Técnicas de Química Analítica/métodos , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Compostos Orgânicos Voláteis/análise , Água/química , Bebidas/análise , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Poluentes Químicos da Água/análiseRESUMO
The musty-odor compounds (MOCs) 2-methylisoborneol (2-MIB) and geosmin in water samples were determined by a purge-and-trap method using a needle-type extraction device followed by gas chromatography-mass spectrometry. For the extraction of these compounds, a triple-layer-type extraction needle containing divinylbenzene and activated carbon particles as the particulate extraction media was introduced. Several experimental parameters, including the sample temperature during extraction, the addition of sodium chloride, and desorption conditions, were thoroughly optimized in this study. The detection limits for 2-MIB and geosmin were 1.0 and 0.5 ng L(-1), respectively. The method was successfully applied to the simultaneous determination of MOCs and other volatile organic compounds in tap-water samples.
