SENSITIVE DETERMINATION OF XYLENES IN WHOLE-BLOOD BY CAPILLARY GAS-CHROMATOGRAPHY WITH CRYOGENIC TRAPPING

A new and sensitive method for measurement of o-, m- and p-xylenes in human whole blood by capillary gas chromatography (GC) with cryogenic trapping is presented. After heating 0.5 mi of whole blood and 0.5 ml of distilled water containing the xylenes and aniline (internal standa rd, I.S.) in a 4.0-ml vial at 100 degrees C for 30 min, 2 mi of the he adspace vapor was drawn into a glass syringe. All vapor was introduced through the GC port into an AT-Wax middle-bore capillary column in th e splitless mode at an oven temperature of 5 degrees C to trap the ent ire analytes, and the oven temperature was then programmed up to 180 d egrees C. The present conditions gave sharp peaks for xylenes and anil ine (I.S.), and low background noises for whole blood samples; the pea ks of p- and m-xylenes showed about 96% separation with the AT-Wax col umn. As much as 41.0-46.38 of xylenes, which had been spiked to whole blood could be recovered. The calibration curves showed linearity in t he range of 0.1-0.5 mu g/0.5 mi of whole blood. The detection limit wa s estimated to be about 10 ng/0.5 ml. The coefficients of intra-day an d inter-day variations for xylenes were not greater than 9.38%. The da ta for actual detection of xylenes in post-mortem blood of self-igniti on suicide cases by the present method were also presented. (C) 1998 P ublished by Elsevier Science B.V. All rights reserved.