Determination of propafenone and its main metabolite 5-hydroxypropafenone in human serum with direct injection into a column-switching chromatographic system.

Column-switching chromatographic systems using conventional reversed-phase Separon SGX C18 and restricted access media LiChrospher ADS RP-18 precolumns were applied for the determination of propafenone and its main metabolite 5-hydroxypropafenone in human serum samples. The LiChrospher ADS RP-18 precolumn has been found to be more suitable for the sample clean-up. Serum samples were directly injected into the chromatographic system. Proteins and other endogenous compounds were removed by washing with 10% 2-propanol in water and the analytes separated on the Gromsil ODS AB analytical column. The chromatograms were detected at 246 nm. The method validation confirms the suitability of the column-switching system for the quantitation of propafenone and its metabolite. The presented assay shows good linearity with high correlation coefficients (0.992-0.999), high recoveries (96.6+/-6.1-103.5+/-5.8) and excellent values of the repeatabilities (1.23-4.5%). The limits of quantitation are 25-40 ng/ml for the injection volume of 50 microl. The complete analysis including the precolumn reconditioning and the sample clean-up requires 26 min, the sample throughput is approximately four samples in an hour.