ION-SELECTIVE ELECTRODE FOR PROCAINAMIDE DETERMINATION IN BLOOD-SERUM

A procainamide-selective electrode was constructed and applied for the determination of procainamide concentration in blood serum. The detec tion limit was 1.5 mu g ml(-1), but determination down to 0.5 mu g ml( -1) was possible with an appropriate calibration. The results correlat ed well with those obtained by a fluorescence polarization immunoassay which is widely used for the determination of serum procainamide conc entration. The present method is simple, rapid, economical and is unaf fected by common cations present in blood and only slightly by N-acety lprocainamide, a metabolite of the drug. It is therefore useful for th erapeutic drug monitoring in a clinical setting.