三种不同消解方法对AAS法测定植物中Cu、Pb、Zn、Cd 的比较研究

摘要

To study the effects of different digestion methods for the determination of Cu, Pb, Zn and Cd in plant sam-ple, high pressure closed-vessel digestion, electric stove digestion and condensation reflux digestion were adopted to pre-process canola flower and the national standard reference material celery.In the optimal conditions of flame atomic absorption spectrometry, we determined Cu, Pb, Zn and Cd in plant sample, and selected the best digestion method according to the contrast of experimental determination value and given value by National Standards Identified Cen-ters, accuracy and precision, spiked recoveries and digestion effects of different digestion reagent.The results showed that condensation reflux digestion was the optimal of three different digestion methods in the removal of acid, and the optimal acid constitution was 8 mL of HNO3 , 2 mL HCIO4 and 2 mL of HF.Finally, we inferred the content of Pb and Cd in canola flower didn’t exceed the standard on the basis of GB 2762-2012 limits of contaminants in food.%为研究不同消解方法对植物样品中Cu、Pb、Zn、Cd 含量测定效果，分别采用高压罐密闭加热消解、电炉消解和冷凝管回流消解3种方法对油菜花和国家标准物质芹菜进行前处理。在火焰原子吸收分光光度法(AAS)优化条件下，对样品中的Cu、Pb、Zn、Cd含量进行测定，以实验测定值和国家标准认定中心给定值比较、三种消解方法的准确度和精密度、加标回收率以及不同消解试剂的消解效果为判定依据，选出最优消解方法。结果表明，冷凝管回流消解法的消解效果是最好的，最佳酸配比为8∶2∶2的浓硝酸、高氯酸和氢氟酸；同时，根据 GB 2762－2012食品中污染物限量标准得出油菜花Pb、Cd含量均未超标。