分光光度法测定不同食品基质中亚硝酸盐含量

目的建立测定不同食品基质中亚硝酸盐含量的分光光度法。方法取适量样品,按不同基质进行提取和净化,用分光光度法测定亚硝酸盐含量(以亚硝酸钠计)。结果方法检出限:液态乳和发酵乳中为0.02 mg/kg,其他样品中为0.2 mg/kg。淀粉类样品在添加浓度1.0~5.0 mg/kg范围内,回收率为77.6%~113%,RSD为1.9%~13.4%;肉制品类样品在添加浓度2.0~10.0 mg/kg范围内,回收率为77.5%~111.5%,RSD为2.1%~7.8%;腌菜类样品在添加浓度2.0~10.0 mg/kg范围内,回收率为58.5%~78.1%,RSD为4.0%~12.5%;液态乳、发酵乳类样品在添加浓度0.2~1.0 mg/kg范围内,回收率为81.5%~98.8%,RSD为1.4%~8.1%。结论该方法对不同食品基质样品的前处理方法进行了优化,干扰少,准确度、灵敏度高,能满足各类食品中亚硝酸盐的测定。

Determination of nitrite in different food substrate by spectrophotometry

To develop a method for determination of nitrite in different food matrices by spectrophotometry.Methods Food samples were extracted and cleaned up according to the different matrices, and the nitrite was determined of by spectrophotometry. Results The detection limit was 0.02 mg/kg (NaNO₂) for liquid milk and yogurt, and was 0.2 mg/kg for the others. The average recovery for starch products at spiking level of 1.0-5.0 mg/kg was in the range of 77.6%-113%, with the RSD of 1.9%-13.4%. The average recovery for meat products at spiking level of 2.0-10.0 mg/kg was in the range of 77.5%-111.5%, with the RSD of 2.1%-7.8%. The average recovery for pickled vegetables at spiking level of 2.0-10.0 mg/kg was in the range of 58.5%-78.1%, with the RSD of 4.0%-12.5%. The average recovery for liquid milk and acidified milk at spiking level of 0.2-1.0 mg/kg was in the range of 81.5%-98.8%, with the RSD of 1.4%-8.1%.Conclusion The pretreatment method was optimized, and the improved method was suitable for the determination of nitrite in different food with less interference, high accuracy and sensitivity.