Headspace solid-phase microextraction and gas chromatographic-mass spectrometric screening for volatile hydrocarbons in blood

Optimization for headspace solid-phase microextraction (SPME) was studied w ith a view to performing gas chromatographic-mass spectrometric (GC-MS) scr eening of volatile hydrocarbons (VHCs) in blood. Twenty hydrocarbons compri sing aliphatic hydrocarbons ranging from rt-hexane to n-tridecane, and arom atic hydrocarbons ranging from benzene to trimethylbenzenes were used in th is study. This method can be used for examining a burned body to ascertain whether the victim had been alive or not when the burning incident took pla ce. n-Hexane, n-heptane and benzene, the main indicators of gasoline compon ents, were found as detectable peaks through the use of cryogenic oven trap ping upon SPME injection into a GC-MS instrument. The optimal screening pro cedure was performed as follows. The analytes in the headspace of 0.2 g of blood mixed with 0.8 ml of water plus 0.2 mug of toluene-d(3) at -5 degrees C were adsorbed to a 100-mum polydimethylsiloxane (PDMS) fiber for 30 min, and measured using the full-mass-scanning GC-MS method. The lower detection limits of all the compounds were 0.01 mug per 1 g of blood. Linearities (r (2)) within the range 0.01 to 4 mug per 1 g of blood were only obtained for the aromatic hydrocarbons at between 0.9638 (pseudocumene) and 0.9994 (tol uene), but not for aliphatic hydrocarbons at between 0.9392 (n-tridecane) a nd 0.9935 (n-hexane). The coefficients of variation at 0.2 mug/g were less than 8.6% (n-undecane). In conclusion, this method is feasible for the scre ening of volatile hydrocarbons from blood in forensic medicine. (C) 2000 El sevier Science B.V. All rights reserved.