Improved extraction of thinner components from human body fluids by headspace solid-phase microextraction with a...

An improved method for extraction of thinner components in human whole blood and urine samples by headspace solid-phase microextraction (SPME) with a Carboxen/polydimethylsiloxane-coated fiber is presented. The body fluid samples, containing ethyl acetate, benzene, 1-butanol, toluene, butyl acetate, isoamyl acetate and ethylbenzene as internal standard (IS), were heated at 70 degrees C in a silicone-rubber septum-capped vial in the presence of distilled water plus NaCl; a Carboxen/polydimethylsiloxane-coated SPME fiber was then exposed to the headspace of the vial to allow adsorption of the compounds before capillary gas chromatography (GC) with flame-ionization detection. For whole blood, extraction efficiencies of 1-butanol, ethyl acetate and isoamyl acetate were 8.72-31.1%, and those of IS, butyl acetate, toluene and benzene were 42.9-74.1%. For urine, those of all compounds were 10.7-75.4%. The regression equations for six thinner components extracted from whole blood and urine were linear in the range of 3-500 ng/0.5 ml for ethyl acetate and 1-butanol, and 0.5-500 ng/0.5 ml for benzene, toluene, butyl acetate and isoamyl acetate. The detection limits for each of the components were 0.25-1.5 ng/0.5 ml for both samples. The coefficients of within-day and day-to-day variation for all components were satisfactory and not greater than 11 and 13%, respectively. The data obtained from actual determination of ethyl acetate, benzene and toluene in rat whole blood and urine after inhalation of the compounds were also presented.