IC Determination of Sulfite in Konjak Refined Powder and Shrimp

Samples of konjak refined powder and shrimp were distilled by steam distillation method to eliminate the interference of impurity, and acidified in closed vessel. The SO2 was evolved under nitrogen atmosphere and absorbed in formaldehyde solution. The content of sulfite in absorption solution was determined by IC. IonPac AS9-HC chromatographic column was used as ion exchange column, and a mixture of 8 mmol·L-1 Na2CO3 and 2.5 mmol·L-1 NaOH was used as eluent. Linear relationship between values of peak area and mass concentration of sulfite was obtained in the range within 6.0 mg·L-1, with detection limit (3S/N) of the method of 4.0 mg·kg-1. The proposed method has been used in the analysis of the samples of konjak refined powder and shrimp, giving values of recovery and RSD′s (n=8) in the ranges of 88.1%-98.3% and 1.4%-6.6% respectively.