阻抑动力学光度法测定粮食中痕量砷Ⅴ

Inhibitory Kinetics Spectrophotometric Determination of Trace ArsenicⅤ

研究发现 ,在硫酸介质中 ,痕量砷 能灵敏地阻抑铬 催化高碘酸钾氧化间磺酸基偶氮氯膦褪色的指示反应。研究了阻抑褪色反应的最佳条件及动力学参数 ,建立了一种测定痕量砷 的新方法。其测定范围为 0 .0～ 16 μg砷 L ;检测限为 4 .0× 10 - 7g L砷 。该法用于大米、黄豆、豌豆和玉米中痕量砷 的测定 ,结果满意。

In H 2SO 4 medium, Chromium? can catalyze the discoloration reaction of m sulfonyl chlorophosphonazo oxidized by KIO 4. Trace arsenic? can sensitively inhibit the catalytic reaction. The optimum condition and rinetic parameters were investigated. A new method for the determination of trace arsenic? was proposed. The linear range is 0.0～16 μg/L, and the detection limit is 4.0×10 -7 g/L, It has been applied to the determination of trace arsenic? in rice, soybean, pea and corn samples with satisfactory results.