[Determination of sulfide in gourmet powder by anion exchange chromatography with pulsed amperometric detection]

A chromatographic method was developed for the determination of sulfide in gourmet powder. The samples were dissolved in 2 g/L sodium hydroxide solution directly, and filtrated with a 0.22 microm nylon membrane. The sulfide and other anions such as high concentration of glutamate were separated well in 6 min by an IonPac AS7 Anion Exchange column (250 mm x4 mm). A mixed solution of 100 mmol/L sodium hydroxide, 500 mmol/L sodium acetate and 0.5% ethylenediamine was used isocratically as the mobile phase. The detection limit of the sulfide was 0.3 microg/L at 25 microL injection (S/N = 3). Moreover, the method had a wide linear range (0.001-1 mg/L) and satisfactory recovery (94.2%-99.0%). The method was applied in the determinations of the sulfide in 99% monosodium glutamate, special delicious monosodium glutamate and salted monosodium glutamate samples. The method is simple, fast and good in separation performance, and has high selectivity and sensitivity.