Unmodified sevoflurane and its metabolite, hexafluoroisopropanol (HFIP), have both been proposed as biomarkers of exposure in post-shift urine for operating room personnel exposed to inhalation anaesthetic sevoflurane. We used headspace sorptive extraction (HSSE) and thermal desorption-capillary GC-MS to assess sensitively both compounds in the urine matrix (after a HFIP deconjugation step). In GC-MS splitless mode, calibration plots (approximately 15-650 microg/L) were linear (r2 > 0.9910) and the limits of detection (1 microg/L for both biomarkers) showed increased sensitivity for HFIP with respect to the previously described headspace GC-MS method. The method was suitable for biological monitoring of both biomarkers of exposure to sevoflurane.