Gas chromatographic determination of apomorphine in plasma

A method is described for the analysis of 1 to 10 microgram/ml concentrations of apomorphine in plasma. The procedure is based on ethyl acetate extraction, a back extraction cleanup-step, derivatization with heptafluorobutyric anhydride, and gas chromatography on a 3% OV-17 column using flame ionization detection. N-n-Propylnorapomorphine is employed as an internal standard and quantitative relative recoveries of drug are realized with relative standard deviations of 4.6%. The method permits analysis of apomorphine in the presence of its two monomethyl ether metabolites, apocodeine and isoapocodeine. The latter compounds are also chromatographically resolved as their heptofluorobutyrate derivatives.