Thiopental monitoring by gas-chromatography.

A gaschromatographic method is presented for the determination of thiopental (and of its metabolite pentobarbital) in cases of severe head injuries treated by induction of therapeutic barbiturate coma. To 1 ml serum the internal standard and saturated ammonium sulphate solution are added. The mixture is extracted by chloroform and the concentrated organic phase is injected into the gaschromatograph (stationary phase: SP 2510 DA). Imprecision from day to day: Coefficient of variation 7.7%; recovery 97%. The specificity was checked by comparison with the retention time of more than 80 drugs. One determination is accomplished within 1 hour.