Rapid micro-method for the measurement of phenobarbitone, primidone and phenytoin in blood plasma or serum by gas-liquid chromatography.

A rapid gas-liquid chromatographic method has been developed for the analysis of phenobarbitone, primidone and phenytoin in small (50 microliter) volumes of either blood plasma or serum. Neither solvent transfer nor evaporation are required in the extraction, which takes less than 3 min to complete, and a quantitative analysis may be performed, in duplicate, within 20 min. Sources of interference in the assay are minimal, and prior treatment of the column with gamma-glycidoxypropyltrimethoxysilane facilitates the measurement of as little as 10 ng of underivatized drug "on-column" using a flame-ionisation detector. The method has proved valuable when used for detection and measurement of these three compounds at concentrations of 2 mg/1 or greater.