Abstract: Solid, liquid and semisolid dietary supplement were chosen as study subjects. High performance liquid chromatography (HPLC) method was developed to determine main active components, diallyl trisulfide (DATS) and diallyl disulfide (DADS), in dietary supplement. Effects of extract solvents, volume fraction of ethanol, temperature and chromatographic column on detection were studied. Samples were extracted with ethanol by ultrasonic, isolated by C18 column (250 mm×4.6 mm, 5 μm); V(acetonitrile)∶V(H2O)=68∶32 as mobile phase; The flow rate was 1.0 mL·min-1 and the UV wavelength was 240 nm. The results indicated that the standard curves of allicin showed good linearity in the range ration of 6.26-6262.24 mg·L-1 (r=0.9999), and the detection limits were 2.0 mg·kg-1 for DATS, 1.5 mg·kg-1 for DADS. The mean recoveries of two samples standard addition test for three matrices at high and low levels were 97.6%-105.8% for DADS and 95.3%-105.4% for DATS. The relative standard deviations of test repeatability were 1.5%-2.7%, and the relative standard deviations of test reproducibility were 3.8%-5.6%. Comparing the results by HPLC and gas chromatography, there was no significant difference. This method is rapid and accurate for the determination of allicin in dietary supplement．

Key words: allicin, HPLC, dietary supplement, DATS, DADS