Direct derivatization and gas chromatographic determination of barbiturates in autopsy liver tissues

A new gas chromatographic procedure is presented for the determination of barbiturates in autopsy tissues (liver and blood). The barbiturates are separated from the interference of co-extracted, free fatty acids in an acid-catalyzed methylation of the fatty acids and quantified as the N,N-dimethyl derivatives following reaction with dimethyl sulphate. Derivatization and recovery are shown to be simple, efficient procedures leading to substantially higher analytical results.