Simultaneous determination of diphenylhydantoin, mephobarbital, carbamazepine, phenobarbital and primidone in serum using direct chemical ionization mass spectrometry.

A quantitative method for the simultaneous determination of five anticonvulsants in serum has been developed using chemical ionization mass spectrometry without prior chromatographic separation. The technique was shown to be rapid, simple and sensitive, allowing the routine analysis of 50 microliter of serum with good within-day and day-to-day precision.