一种新的食品中亚硝酸盐含量测定方法研究

酸性条件下利用亚硝酸盐具有氧化性的特性氧化KI 生成I2，I2 和淀粉作用灵敏地生成I2- 淀粉蓝色络合物的特效反应，建立光度法测定食品中亚硝酸盐含量的新分析方法。研究表明，I2- 淀粉蓝色络合物最大吸收波长为540nm，在试液pH5、50ml 试液中加入1.0 × 10-2g/ml KI 10ml、0.3% 的淀粉4ml、反应时间6min 的最佳实验条件下，新建方法线性范围为8.0 × 10-4～7.0 × 10-6g/ml，检出限5.0 × 10-8g/ml，相对标准偏差0.7%。新方法具有选择性高、简单、准确和灵敏的优点。

A New Determination Method of Nitrite in Foods

Nitrite (NO2) can oxidize potassium iodide (KI) reagent into iodine (I2) under acidic condition, and I2 can react with starch into iodine-starch blue color complex. Consequently, based on these reactions a new absorption photometry was established for determining nitrate in the food. The experimental results showed that the optimum reaction conditions are as follows: pH 5, 1.0×10-2 g/ml KI solution 10 ml, 0.3% starch solution 3 ml and reaction time 6 min, and the maximum absorption wavelength of iodine-starch blue color complex is 540 nm. Under these above conditions, the linear range of this new method is 8.0×10-4 to 7.0×10-6 g/ml, the detection limit of nitrite is 5.0×10-8 g/ml and the relative standard deviation is 0.7%. Therefore, this new method is simple, rapid, sensitive and accuracy, and has enormous application value in food safety determination.