[A gas-chromatographic method for the determination of carbamazepine, phenobarbital, phenytoin and primidone in the same extract of serum (author's transl)].

A gas-chromatographic method for the determination of the antiepileptic drugs carbamazepine, phenobarbital, phenytoin and primidone in the same extract of serum is presented. Saturated ammonium sulfate solution is added to 1 ml serum, followed by extraction with chloroform. The organic phase is separated and evaporated. The residue is dissolved in 100 microliter ethylacetate/acetic acid (100 ml + 1 ml) for gas-chromatography. The gas-chromatographic determination is carried out under isothermal conditions without derivatisation, using SP 2250 DA as stationary phase for the determination of phenobarbital and phenytoin, and Dexsil 300 for the determination of carbamazepine and primidone. The coefficient of variation for the precision from day to day ranges from 4.3 to 7.5%, the recovery from 93.5 to 111%. The specificity was proven by comparison with the relative retention times of about 100 drugs. The method is compared with the corresponding EMIT-tests.