Investigation of propofol concentrations in human breath by solid-phase microextraction gas chromatography-mass spectrometry.

Propofol has been detected in human breath after being used as an intravenous anaesthetic, and this could provide a noninvasive method for monitoring propofol anaesthesia. The physicochemical properties of propofol allow it to diffuse across the alveolocapillary membrane and to be prepared as a calibration gas. In this study, headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS), coupled with an external standard, was applied to assess propofol levels in the breath and plasma from three subjects under intravenous anaesthesia. Lower quantitation limits were 3.6 ng/l and 0.2 mg/l for propofol analysis in breath and arterial plasma, respectively. Intraday precision and recovery percentages for propofol detection in breath were 4.3 - 6.7% and 98 - 108%, respectively, and in plasma they were 3.8 - 6.1% and 90.1 - 125.1%, respectively. Propofol concentrations were 4.3 - 33.5 ng/l in breath and 3.2 - 6.8 mg/l in arterial plasma. A correlation was shown between propofol concentration in breath and plasma. Thus, HS-SPME-GC-MS, coupled with an external standard, could be a reliable and sensitive analytical technique for detecting propofol in breath during anaesthesia.