基于X射线荧光光谱法测定常见生物样品中常量和微量元素

摘要

基于大米、小麦、玉米等23种国家生物成分系列标准物质,探讨了X射线荧光光谱法在常见生物样品中常量和微量元素测定中的应用.在对各待测元素的激发电流电压、分析线、背景位置、干扰谱线、分析晶体、准直器、探测器和脉冲高度分布等条件进行分析的基础上,采用粉末压片法制样,基于回归曲线法和康普顿散射线内标法求取各待测元素的标准曲线常数、元素间吸收效应的影响系数和谱重叠系数.结果表明:国家生物成分系列标准物质具有足够宽的含量范围和适当的含量梯度,基本能覆盖常见生物样品中各元素的含量范围.方法检出限能够保证测定结果的有效性,测量精密度为2.62％～14.79％,且标准物质各元素的测定值与标准值基本相符.方法具有简便、灵敏和准确的特点,能够满足分析的需求.%Based on 23 national standard materials of biological component such as rice, wheat and corn, this paper discusses the application of X-ray Fluorescence Spectrometry ( XRF) for the analysis of major and minor elements in biological samples. After a selection of analysis conditions such as stimulation current and voltage, analysis line, background, interrupting element spectrum line, analysis crystal, collimator, and pulse height distribution ( PHD), the pressed powder pellet technique was used to prepare standard samples. Correction of work curve, element inter-element absorption effect and spectral line overlap effect were obtained by the regulation method and the internal standard method of Rh Ka (from the X-ray tube target) Compton-scattered radiation. The results indicate that the national standard material of biological component serial was appropriate both in content range and gradient for the common biological sample analysis. The detection limit verifies the validity of the measured results, with the precision of 2. 62% - 14. 79% , and the measured result being consistent with the certified value. X-ray fluorescence spectrometric method is simple, sensitive, and accurate in biological sample analysis. The accuracies of the experiment meet the requirements for common biological sample analysis.