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本文介绍了一种测定植物样品中某些金属元素的X射线荧光光谱分析方法。对于试样中含量较高的元素系采用粉末压片法测定。其标准样品的制备是采用纤维素粉稀释标准参考物质GSD~*配制,以峰背比法校正基体效应。用此法测定了日本胡椒叶标样NIES Nol,中国桃叶标样(82301)及粮食样玉米粉中Fe、Mn、Cu、Zn、Sr、Rb、K、Ca等元素,所得结果示于表1。各元素的检出限为Fe—1ppm,Mn—1ppm、Cu—3ppm、Zn—2ppm,Sr—2ppm、Rb—2ppm、K—3ppm、Ca—4ppm。GSD系中华人民共和国地质矿产部制备的八个水系沉积物标准样品中GSD6和GSD8。对植物中含量比较低的元素则先用混合酸(HNO_3+HClO_4=4+1)将试样消解,然后用络合剂DDTC将欲测定的元素浓缩富集到一张滤膜上。本文研究了富集这些元素的最佳条件(pH沉淀剂种类及干扰离子的影响),对Cu、Ni、Co三元素所得回收率分别为98.2—99.9%,86.8—89.9%,89.5—91.5%,用此法测定了大米及小麦秸杆中Cu、Ni、Co的含量,所得结果与其它方法相符。
This article describes a method for the determination of some of the metal elements in plant samples by X-ray fluorescence spectrometry. The higher content of the elements in the sample is determined by the powder tablet method. The preparation of the standard sample is prepared by diluting the standard reference material GSD ~ * with cellulose powder to correct the matrix effect by the peak-to-back ratio method. The contents of Fe, Mn, Cu, Zn, Sr, Rb, K, Ca and other elements in Japanese pepper leaf standard NIES Nol, Chinese peach leaf standard (82301) and grain-like corn meal were determined by this method. 1. The detection limits of the respective elements were Fe-1ppm, Mn-1ppm, Cu-3ppm, Zn-2ppm, Sr-2ppm, Rb-2ppm, K-3ppm, Ca-4ppm. GSD Department of Geology and Mineral Resources of the People’s Republic of China prepared eight standard sediment samples GSD6 and GSD8. For plants with lower contents, the sample is first digested with mixed acid (HNO 3 + HClO 4 = 4 + 1), and then concentrated with the complexing agent DDTC to concentrate the desired element on a membrane. In this paper, the optimum conditions for the enrichment of these elements (pH precipitants and the influence of interfering ions) were studied. The recoveries of Cu, Ni and Co were 98.2-99.9%, 86.8-89.9% and 89.5-91.5% The contents of Cu, Ni and Co in rice and wheat straw were determined by this method. The obtained results were consistent with other methods.