Quantitative analysis of volatile halothane metabolites in biological tissues by gas chromatography

A simple and sensitive gas chromatographic method for the determination of 2-chloro-1, 1-difluoroethylene (CDE) and 2-chloro-1,1,1-trifluoroethane (CTE), two highly volatile metabolites of halothane, in blood, liver and isolated hepatic microscomes is described. The entire head-space in equilibrium with a known volume or weight of the sample is injected into the gas chromatograph equipped with a flame ionization detector. Quantification is accomplished with standards prepared by fortifying blank samples with known concentrations of CDE and CTE which are treated under the same conditions as the samples. Detection limits for CDE and CTE were 2 pmole/ml in blood and 10 pmole/g in liver and the mean relative standard deviations are no greater than ± 6% except for CTE in hepatic microsomes (± 9%). A preliminary study of blood CDE and CTE levels in humans anesthetized with halothane is reported.