Determination of diallyl thiosulfinate (allicin) in garlic (Allium sativum L.) by highperformance liquid chromatography with a post-column photochemical reactor

An analytical method for the determination of allicin (diallyl thiosulfinate) in garlic (Allium sativum L.) samples using reversed-phase HPLC with both UV and electrochemical detection (ED) and on-line post-column photochemical reaction is reported. Standard allicin was synthesised and its behaviour at the chosen analytical conditions was tested. The postcolumn irradiation at 254 nm on the one hand decreased the response of allicin to UV detector, and on the other hand, allowed the determination of this compound, which is otherwise electrochemically inactive, using the electrochemical detector. Detection limits of 0.1 and of 0.01 mg/l using UV and ED detectors, respectively, and linearity of response in the range 1¯8 mg/l were obtained. Samples of garlic extracts, obtained following two different extraction procedures, were analysed and the results obtained using both UV and electrochemical detectors were compared.