Quantitative determination of isoflurane enantiomers in blood samples during and after surgery via headspace chromatography-mass spectrometry

The quantitative analysis of the chiral volatile anesthetic isoflurane (1) for biomedical applications by means of enantioselective gas chromatography (mass sensitive detector, selected ion monitoring) was studied. Two method s for the quantification of the enantiomers in blood samples drawn during a nd after narcosis were compared. Either the isomeric enflurane (2) was sele cted as an internal standard or a single enantiomer of 1 was used for the s tandard addition method, an approach referred to as 'enantiomer labeling'. Concentrations up to 0-3 mu mol/l of the single enantiomers could be differ entiated two days after anesthesia. The presented data imply that the body clearance for (+)-(S)-1 and (-)-(R)-1 proceeds to a measurable degree of en antioselectivity. (C) 1999 Elsevier Science B.V. All rights reserved.