Reliable gas chromatographic–mass spectrometric method combined with a headspace autosampler for isoflurane determination in blood

Isoflurane is a nonflammable, liquid, volatile inhalation anesthetic administered by vaporizing. Although it is now commonly used, fatal cases resulting from its abuse or misuse have been reported. A combined system of a gas chromatograph–mass spectrometer and a headspace autosampler is therefore proposed for the detection of blood isoflurane. This analytic method showed sharp and well separated peaks, and revealed a good linear relationship (r=0.9994) with a function of y=7.3768x−0.0222 at concentrations between 18.7 and 299.2 μg/ml. The limits of detection and quantitation of this method were 1.2 and 4.7 μg/ml, respectively. The within- and between-run precision for spiked samples, assessed by the coefficient of variations, ranged from 1.7 to 10.0% and from 4.1 to 12.8%, respectively. The within- and between-run accuracy, assessed by errors from theoretical values, were 2.2–7.8% and 2.4–9.6%, respectively. In addition, practical sample analysis showed a good applicability, with a within-run precision rate of 5.6 to 7.7% and a between-run precision rate of 5.2–10.6%. In summary, the present work presents a valid alternative for blood isoflurane analysis.