膨化食品铅测定前处理探讨

Study on pretreatment of lead detection for popped food

目的:建立测定膨化食品中铅的最佳前处理方法。方法:分别用湿法和干法消化样品,火焰原子吸收光谱法进行测定。结果:爆米花的铅含量为2.5μg/g,铅含量严重超标(0.5μg/g)[1]。HNO3-HC lO4消化体系、HNO3-H2O2消化体系、灰化法(加辅助剂)与灰化法(不加辅助剂)的加标回收率分别为96.7%、95.3%、90.4%和74.3%。结论:用两种湿法消化法和加辅助剂灰化法处理样品,测定爆米花中的铅具有灵敏度和精密度高、结果可靠等优点。尤其经过改进的HNO3-H2O2消化体系在消化过程的安全操作性和环保方面有较突出的优势,适合理化实验室和学校实验室对膨化食品的消化。

Objective：To build up the best pretreatment before determine the content of lead in popped food.Methods：Using the wet and dry method respectively to digest the sample,then using the flame atomic absorption spectrometry to measure the content of lead in popped food.Results：The contents of lead in popcorn is 2.5 μg/g,this date has superstandarded badly（0.5 μg/g）.The recovery rate of the HNO3-HClO4 digestive system,HNO3-H2O2 digestive system,ashing method（with and without auxiliary）,the recovery was 96.7%,95.3%,90.4% and 74.3% respectively.Conclusion：This two kinds of wet digestion method and the method adding the auxiliary in the digestion method,which is to measure the content of lead in the popcorn,have many advantages including the high sensitivity and the high precision and the dependable results.Particularly,there is more outstanding advantages at the safety operability and environmental protection in the improved HNO3-H2O2 digestive system,and it is suitable for chemical and physical laboratory and school laboratory for popped food digesting.