Enflurane as an internal standard in monitoring halogenated volatile anaesthetics by headspace gas chromatography–mass spectrometry

Recently, we proposed the use of a run-only headspace-GC–MS method for the biological monitoring of ppb concentrations of unmodified volatile anaesthetics (isoflurane, sevoflurane and halothane, plus nitrous oxide) in post-shift urine of operating theatre personnel. The adoption of enflurane (a volatile anaesthetic no longer used in clinical practice) as a proper and viable internal standard improves intra-day and inter-day accuracy in halide quantitation, providing a GC–MS reference method useful in the practice of biomonitoring of exposure of operating theatre personnel to modern volatile anaesthetics (isoflurane, sevoflurane, halothane).