粉末压片-X射线荧光光谱法分析富硒土壤样品中的硒及主次量元素

目前土壤中Se主要采用原子荧光光谱法测定，存在用酸量大、前处理相对复杂等缺点，对于高含量Se的测定则需要高倍稀释，无疑会扩大分析误差。本文采用粉末压片波谱-能谱复合X射线荧光光谱法测定湖北富硒土壤样品中的Se等17个主次量元素，波谱分析10个元素的同时，能谱分析As、Cu、Rb、Sr、Zr、Ba、Ni等7个元素，大幅节省了测定时间。通过将不同国家标准物质按比例混合的方式配置混合标准样品，解决了现有Se标准物质在5～72μg/g含量范围不足的问题。对于高含量Se的测定，通过谱图分析，波谱数据优于能谱数据，对其精密度、准确度考核，相对标准偏差(RSD)小于10%,高含量Se样品的RSD小于0.70%,能够满足Se含量大于3.00μg/g土壤样品的定量分析要求，同时可提供16个主次量元素的定量或近似定量分析结果。

Determination of Selenium, Major and Minor Elements in Selenium-rich Soil Samples by X-ray Fluorescence Spectrometry with Powder Pellet Preparation

BACKGROUND:At present,the content of Se in soil is mainly determined by atomic fluorescence spectrometry,which has disadvantages such as large usage of acid and relatively complex pretreatment.Determination of high content of Se requires high dilution,which expands the analysis error.OBJECTIVES:To establish a method for the determination of Se and other elements in Se-rich soil samples by wavelength dispersive and energy dispersive X-ray fluorescence(WD-ED XRF).METHODS:WD-ED XRF was used to determine 17 major and minor elements such as Se in Hubei selenium-rich soil samples with powder pellet.While 10 elements were analyzed by WD-XRF,As,Cu,Rb,Sr,Zr,Ba,Ni were analyzed by ED-XRF,which significantly reduced the measurement time.RESULTS:By mixing different certified reference materials in proportion to configure mixed certified reference materials,the problem of insufficient content of the existing Se reference materials in the range of 5-72μg/g was solved.For the determination of high content Se,the relative standard deviation was less than 10%,and the RSD of high content Se sample was less than 0.70%,through the precision and accuracy assessment.CONCLUSIONS:The proposed method satisfies the quantitative analysis of soil samples with Se content greater than 3.00μg/g,and provides the quantitative or approximate quantitative analysis results of 16 major and minor elements.