Gas chromatographic-mass spectrometric analysis of dichlorobenzene isomers in human blood with headspace solid-phase...

Headspace solid-phase microextraction (HS-SPME) was utilized for the determination of three dichlorobenzene isomers (DCBs) in human blood. In the headspace at 30 degrees C, DCBs were absorbed for 15 min by a 100-micron polydimethylsiloxane (PDMS) fiber. They were then analyzed by capillary column gas chromatography-mass spectrometry (GC-MS). By setting the initial column oven temperature at 20 degrees C, the three isomers were resolved at the baseline level. p-Xylene-d10 was used as the internal standard (I.S.). For quantitation, the molecular ion at m/z 146 for each isomer and the molecular ion at m/z 116 for I.S. were selected. For day-to-day precision, relative standard deviations in the range 3.2-10.7% were found at blood concentrations of 1.0 and 10 micrograms/ml. Each compound was detectable at a level of at least 0.02 microgram per 1 g of whole blood (by full mass scanning). HS-SPME-GC-MS, when performed at relatively low temperatures, was found to be feasible in toxicological laboratories. Using this method, the plasma levels of one patient who had drunk a pesticide-like material were measured.