Analysis of whole congener mixtures of polybromodiphenyl ethers by gas chromatography-mass spectrometry in both environmental and biological samples at femtogram levels.

A sensitive and selective method for the determination of the whole congener distribution of polybromodiphenyl ethers in environmental and biological samples in one single instrumental run is described. The method is based on gas chromatography coupled to low-resolution mass spectrometry in negative ion chemical ionization mode. It allows determination of these compounds at concentration levels lower than 10(-14)g. A programmed temperature vaporization injector has been used to ensure maximum compound transfer to the chromatographic column while maintaining low thermal degradation levels of the more brominated congeners. Selectivity was increased by modification of the MS source parameters for optimization of the abundance of the high mass fragment ions. Under optimized condition, good repeatability (1.7-9.1%) and reproducibility (4.1-20%), and low detection limits, ranging between 1.5 and 15 pg ml(-1), were obtained. These features afforded reliable quantification of these compounds in snow and human samples at the concentrations in which these compounds are found.