高压粉末制样波长色散X射线荧光光谱法测定生物样品中23种元素

Determination of 23 Elements in Biological Samples by Wavelength Dispersion X-ray Fluorescence Spectrometry with High Pressure Powder Pelleting Preparation

应用X射线荧光光谱法（XRF）分析生物样品时,采用传统低压粉末制样方法（压强220-440 MPa）难以将样品压制成符合测定需要的样片,样片表面粗糙,粉末容易脱落,污染XRF仪器样品室,影响仪器的长期稳定性。本文采用高压粉末制样方法在1760 MPa下压制则完全克服了低压制样的弊端,制备的样片表面光滑、致密,大幅改善了制样重现性,5次制样重现性为0.1%-2.6%,且降低了仪器的维护成本。在此基础上,建立了波长色散X射线荧光光谱法直接测定生物样品中23种主次量元素（Al、Ca、Cl、K、Mg、Na、P、S、Si、Ba、Br、Co、Cr、Cu、Fe、Mn、Ni、Pb、Rb、Sr、Ti、V、Zn）的分析方法,采用经验系数法、散射线内标法和峰背景作内标校正基体效应,大部分元素的方法精密度提高至0.4%-11.3%,检出限为0.08-140.96μg/g。经国家一级生物标准物质验证,表明方法准确可靠,能满足日常分析要求。

In the determination of biological samples by X-ray Fluorescence Spectrometry（ XRF）,sample powder pellets pressed by traditional sample preparation technique at 220- 440 MPa are not compact and smooth,so the sample room of XRF instrument becomes contaminated by dropped sample powder,which can then influence longterm stability. Biological sample powder can be pressed into smooth and compact pellets using high pressure of1760 MPa,therefore the sample preparation reproducibility is improved to 0. 1%- 2. 6%（ RSD,n = 5）.A method for direct determination of 23 major and minor elements（ Al,Ca,Cl,K,Mg,Na,P,S,Si,Ba,Br,Co,Cr,Cu,Fe,Mn,Ni,Pb,Rb,Sr,Ti,V and Zn） in biological samples by Wavelength Dispersion X-ray Fluorescence Spectrometry was established on this sample preparation basis. The matrix effects can be corrected by using Rh-Kα（ from the X-ray tube target） Compton-scattered radiation and by using the background as the internal standard. The precision of the method is 0. 4%- 11. 3%（ RSD） for most elements and the detection limits is 0. 08- 140. 96 μg / g. The feasibility of the proposed method was tested by analyzing several national biological standard materials; the results obtained were consistent with the certified values.