Sevoflurane analysis in serum by headspace gas chromatography with application to various biological matrices

Sevoflurane is a nonflammable general anesthetic administered by inhalation of vaporized liquid that rapidly partitions out of aqueous biological matrices into a gaseous phase because of its volatility and hydrophobicity. We describe a headspace analysis of sevoflurane that can be performed without the use of an expensive automated headspace analyzer. Sevoflurane standards (0-109 mg/L) and quality control specimens (12.2 and 72.9 mg/L) were prepared and quantitated on an intraday and interday basis. Headspace gas was manually injected (150 degrees C) with a 2.5-mL gas-tight syringe into a Perkin-Elmer model 8500 gas chromatograph equipped with a 6-ft x 2-mm i.d. glass column (100 degrees C) containing 0.2% Carbowax 1500 on Carbopak C packing with a flame-ionization detector (200 degrees C), which allowed for elution of the internal standard, 1-propanol (1.56 min), and sevoflurane (2.92 min). Linear regression of the peak-area ratios of sevoflurane to 1-propanol (6.38 g/L), versus the sevoflurane concentrations yielded an average intraday correlation coefficient of 0.989 (S.D. = 0.003, n = 5) and mean quality control specimen values of 14.19 mg/L (C.V. = 5.1%, n = 5) and 66.72 mg/L (C.V. = 3.3%, n = 5). The average interday standard curve correlation coefficient was 0.987 (S.D. = 0.01, n = 5), and the mean quality control specimen values were 12.22 mg/L (C.V. = 13.7%, n = 5) and 74.27 mg/L (C.V. = 8.7%, n = 5). The chromatographic method described produced accurate and reproducible results with a simple on-column headspace gas injection. This method allows for quantitation of sevoflurane in various biological matrices by chromatographic separation of the headspace gas in a sealed specimen container.