Electron-capture glc determination of a new antiarrhythmic agent, α,α-dimethyl-4-(α,α,β,β-tetrafluorophenethyl)benzylamine, in biological fluids

A highly specific and sensitive GLC method was developed for the analysis of α,α-dimethyl-4-(α,α,β,β-tetrafluoro-phenethyl)benzylamine, a new orally active antiarrhythmic drug, in biological fluids. The procedure involves the addition of an internal standard, 4-(α,α,β,β-tetrafluorophenethyl)benzylamine, to the plasma or urine samples followed by extraction of the drugs into benzene at pH 8. The extracted amines are converted to the trifluoroacetyl derivatives (characterized by GLC-mass spectrometry), chromatographed, and detected with a ⁶³Ni electron-capture detector. The sensitivity of the method is such that 10 ng of α,α-dimethyl-4-(α,α,β,β-tetrafluorophenethyl)benzylamine/ml of plasma can be analyzed. These levels are suitable for the analysis of samples obtained following a therapeutic dose.