Quantitative estimation of diphenylhydantoin, primidone and phenobarbital in plasma by gas-liquid chromatography

A gas-liquid Chromatographic method for the simultaneous determination of phenobarbital, primidone and diphenylhydantoin in human plasma following therapeutic doses has been developed. After extraction, the anticonvulsants are methylated directly in the flash-heater of the gas chromatograph with trimethylanilinium hydroxide. Linear temperature programming is used to achieve separation and quantitation. The method has the advantages of specificity, sensitivity and simple derivative formation.