Determination of capsaicin and dihydrocapsaicin by micellar electrokinetic capillary chromatography and its application to various species of Capsicum, Solanaceae.

An easy, rapid and sensitive method of analysis for capsaicin and dihydrocapsaicin and its application for determination of these two amides in fruit extracts of different varieties of Capsicum frutescens by micellar electrokinetic capillary chromatography has been developed. Optimum separation was achieved with a fused-silica capillary column (600 mm x 0.075 mm I.D) and a running buffer at pH 9.0 prepared from 15 mM sodium tetraborate and 15 mM sodium dihydrogenphosphate, and 67.5 mM sodium dodecyl sulphate. Addition of 15% (v/v) methanol in the running buffer was found to be essential for the separation. The applied voltage was +22.5 kV. The compounds were detected by UV at 214 nm. Both capsaicin and dihydrocapsaicin were detected within 11 min, with an excellent resolution.