Measurement of tocainide in serum by capillary gas chromatography.

A rapid and simple analytical method is described for the determination of tocainide in serum using flame ionization capillary gas chromatography. Following a single extraction with chloroform, tocainide is quantitated on an OV-17 bonded fused silica column, utilizing orphenadrine as internal standard. No interference was detected from endogenous substrates, tocainide metabolites, or other commonly used antiarrhythmic drugs. The lowest detectable tocainide concentration by this method is approximately 0.2 mg/L of serum, which is sufficiently sensitive for therapeutic monitoring. Utilizing temperature programming, this method for tocainide is applicable for several antiarrhythmic drugs.