On-line solid-phase extraction gas chromatography ion trap tandem mass spectrometric detection for the nanogram per liter analysis of trace pollutants in aqueous samples

On-line solid-phase extraction-gas chromatography-ion-trap tandem mass spectrometry (SPE-GC-MS/MS) has been used for the trace-level determination of polar and apolar pesticides. The SPE-GC interface, an Autoloop 2000, was operated at an injection temperature of 90 degrees C which permitted the determination of thermolabile pesticides such as carbofuran and carbaryl. Rectilinear calibration curves were obtained for the analytes tested over a range of 0.1-500 ng L-1, using a sample volume of 10-100 mt for enrichment on an SPE cartridge packed with styrene-divinylbenzene copolymer. The detection limits for the pesticides were in the 0.01-4 ng L-1 range. For a number of pesticides acceptable tandem mass spectra were obtained at levels as low as 0.1 ng L-1 level in real-life water samples. As a demonstration of the applicability of this technique for inorganic anions, bromide and nitrite were converted into 4-bromoacetanilide and 2-phenylphenol, respectively. The reaction products were pooled and subjected to simultaneous analysis by the present method using full-scan mass spectrometric detection. The detection limits were 0.3 and 2 ng L-1, respectively.