Abstract: The optimum detecting conditions of sulfite determination in food were studied. The spectrophotometric method for sulfite determination in food was developed. The results showed that at 25℃ and in a solution of pH7.0 phosphate buffer medium, sulfite can cause a color-fading of the malachite green dye which has an absorption maxima at 615 nm. The determination of sulfite is carried out by measuring the intensity of color-fading. The linear range for determination of sulfite is found to be 0～ 0.6mg/L with a correlation coefficient of 0.9997 and the regression equation is ΔA=0.65C+0.0603. The detection limit and recovery rate of the method are 0.1μg/ml and 95.8%～103.1%, respectively. The proposed method is simple, convenient and highly sensitive, and has been applied to the determination of sulfite in food with satisfactory results.

Key words: malachite green, spectrophotometry, sulfite, food