Consecutive Gas Chromatographic Determination of Phenytoin, Phenobarbital, Primidone, Phenylethylmalondiamide, Carbamazepine, Trimethadione, Dimethadione, Ethosuximide, and Valproate from the Same Serum Specimen

A quantitative gas-liquid chromatographic procedure is described for the consecutive determination of phenytoin, phenobarbital, primidone, phenylethylmalondiamide, carbamazepine, trimethadione, dimethadione, ethosuximide and valproate from a single serum specimen of 1.2 ml. After extraction from serum by two different procedures, the anticonvulsants are chromatographed without further purification on a 3% OV 17 column either with or without derivative formation by means of "on-column" methylation. Multiple internal standards are employed in order to enhance the reproducibility of drug-concentration measurement.