原子荧光法中微波消解、干灰化前处理法测定食品中总砷的结果对比

The comparison of results in determining total arsenic by microwave digestion and dry ashing pretreatment with atomic fluorescence spectrometry in food

目的建立准确、可靠、稳定的方法测定食品中总砷的分析方法。方法利用干灰化法和微波消解法分别处理食品样品,对样品分析的最佳消解条件进行探讨,同时优化检测条件,用氢化物发生-原子荧光光谱法测定食品中总砷的含量。结果最佳检测条件:还原剂硼氢化钾的浓度为2.0%,灯电流为60 m A,载气流量为400 ml/min,载流为5%的盐酸,砷的浓度在0.00μg/L^50.00μg/L线性关系良好,相关系数为0.999 7,检出限为0.048μg/L。采用国家标准物质鸡肉粉(GBW 10018)和大米粉(GBW 10010)进行方法验证,所测结果均在标准参考值范围内,6次平行测定的相对标准偏差≤2.70%。结论微波消解法耗费时间短,但酸的用量大,适合砷存在形态相对简单的样品;干灰化法耗费时间较长,适用于挥发温度高、油脂含量高、砷存在形态比较复杂的样品。氢化物发生原子荧光光谱法准确、灵敏、简便高效,适用于食品中总砷含量的测定。

Objective To establish an accurate, reliable and stable method for determining total arsenie in food. Methods Food samples were treated using dry ashing method and mierowave digestion method, and the optimum digestion conditions of the sample analysis were diseussed, and at the same time the determination eonditions were optimized, and the the eontent of total arsenie in food was determined using hydride oeeurrenee atomie fluoreseenee speetrometrie method. Results The optimum test conditions ： The concentration of reducing agent potassium borohydride （ KBH4 ） was 2.0%. The lamp current was 60 mA. The flow rate of gas carrier was 400 ml/min. The current carrier of hydroehlofie aeid was 5%. The range of arsenie eoneentration was 0.00 μg/L - 50. 00 μg/L with good linear relation. The eorrelation coefficient was 0. 999 7. The detection limit was 0. 048 μg/L. Using the national standard material of chicken （GBW 10018） and rice （GBW 10010） for method validation, the measured results were in range of the standard referenee value. The relative standard deviation of six parallel detection results was less than 2.70%. Conclusion Time of microwave digestion method needed was short, but with large amount of acid. It was suitable for samples with simple structure relatively. A longer time was taken by dry ashing method. It was suitable for high volatile temperature, high content of oil, complex strueture of samples. Hydride generation atomic fluorescence spectrometry method was aeeurate and sensitive, simple and efficient. It was suitable for determination of total arsenic in food.