A chromatographic method was developed for the determination of arabinose,galactose,glucose,sucrose,xylose,mannose and fructose in soy sauce sample using high-performance anion-exchange chromatography coupled with pulsed amperometric detection(HPAEC-PAD).The removal efficiency of the proteins in the soy sauce was evaluated by using 20% lead acetate,5% trichloroacetic acid,15% potassium ferrocyanide or 70% ethanol,respectively.The results indicated that the best sugar recovery was achieved when 70% ethanol was selected as the protein precipitation agent.Effects of column types,column temperature and NaOH concentrations on separation efficiencies of the saccharides were investigated.The optimal conditions were carried out on a Dionex CarboPac PA20 anion-exchange chromatographic column with 0.25 mol/L NaOH-water by gradient eluent at 20 ℃.The detection limits(25 μL injection,S/N=3) ranged from 2.0 μg/L to 8.0 μg/L,with a wide linear range of 0.1-80 mg/L.The relative standard deviations for the soy sauce sample were between 1.4% and 4.0%,and the recoveries of standard addition of the saccharides were in the range of 92%-104%.The method is suitable for the determination of common saccharides in soy sauce samples for with its simplicity,high sensitivity and good reproducibility. |