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 non-invasive 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 concen-trations 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