几种腌制蔬菜中亚硝酸盐含量的测定

目的建立测定腌制蔬菜中亚硝酸盐含量的方法。方法在弱酸性溶液中亚硝酸盐与对氨基苯磺酸反应生成的重氮化合物,重氮化合物再与盐酸萘乙二胺偶联生成紫红色的偶氮染料,用分光光度法测定。结果经过校正,亚硝酸盐含量x（μg）与吸光度A之间在λmax=540 nm处,具有良好的线性关系,在亚硝酸盐的量为0～20μg/50 mL水溶液中,服从Beer定律,其线性方程为A=（1.447x-0.138）×10-2,相关系数R=0.9990,其中x是亚硝酸盐的量（μg）。利用此方法所测定的当地出售的几种常见腌制蔬菜中亚硝酸盐的含量均未超过相关标准。结论用分光光度法测定腌制蔬菜中亚硝酸盐的含量,方法简单、方便、快捷、实用,可对食品中亚硝酸盐含量的测定中推广应用。

The determination of the nitrite content of several pickled vegetables

Aim To establish a method for determining the content of the nitrite in several pickled vegetables, which are saled in the market. Methods Nitrite react with 4-aminobenzenesulfonic acid in weak acidic media to produce 4-sulfobenzenediazonium, which reacted with N＇-（naphthalen-l-yl）ethane-1, 2-diamine hydrochloride to produce a red diazene compound, the red compound was detected by; spectrophotometer. Results The calibration graph for aqueous procedure was obtained by plotting absorbance values at 540 nm against nitrite concentration. Beer＇s law was obeyed over the range 0～20 lag of nitrite in an overall aqueous volume of 50 mL. The calibration graph is a straight line, obeying equationA = （1. 447x-0. 138） × 10^-2 , whereA is the absorbance andx （μg） is the amount of nitrite, with correlation coefficient R =0. 999 0. The nitrite content in several pickled vegetables sold in the market were determined by the method. The determining results shown that the content level of nitrite in the pickled vegetables was within the range of Chinese National Food Standard. Conclusion The method is accurate, rapid, simple, can be applied in determining the nitrite content of the pickled vegetables.