粉末压片制样-X射线荧光光谱法分析地球化学调查样品测量条件的优化

Optimization of Measurement Conditions for Geochemical Survey Sample Analysis by X-ray Fluorescence Spectrometry with Pressed Powder Pellet Sample Preparation

在X射线荧光光谱(XRF)分析中,粉末压片制样是被广泛应用的一种制样方法,但由于存在样品粒度、矿物和基体效应对其测量条件进行优化。本文应用XRF法测量地球化学调查样品中24种主次量元素,综合优化了制样压力、仪器工作电压和工作电流、待测元素分析谱线、探测器的调节和探测效率等实验条件。在最优测量条件下,用土壤和水系沉积物国家标准物质GBW07402、GBW07404、GBW07424、GBW07426、GBW07429验证方法的准确度,结果表明个别元素如GBW07402中的Na2O、GBW07404中的Pb相对误差大于10%,其余元素的相对误差小于10%,但均达到了地球化学调查样品的质量监控要求。经优化的仪器测量条件为我国地球化学调查样品提供了可靠的基础数据。

BACKGROUND:Powder compaction is a widely used sample preparation method for X-ray Fluorescence Spectrometry.However,due to the existence of mineral and matrix effects,the measurement conditions should be optimized. OBJECTIVES:To measure 24 major and minor elements in geochemical survey samples. METHODS:The ZSX PrimusⅡtype Wavelength Dispersive X-ray Fluorescence Spectrometer was used to determine the optimum experimental conditions,such as sample preparation pressure,working voltage and current of the instrument,spectral lines of the elements to be measured and the efficiency of the detector.The optimum experimental conditions were verified by analyzing the National Standard Materials(GBW07402,GBW07404,GBW07424,GBW07426,and GBW07429). RESULTS:According to the optimum experimental conditions,the National Standard Materials of soil and stream sediments are analyzed.Individual elements such as Na 2 O in GBW07402 and Pb in GBW07404 have relative errors greater than 10%,and other elements have relative errors less than 10%.The relative errors meet the quality control requirements of geochemical survey samples. CONCLUSIONS:The requirement of data quality monitoring has been achieved for the analysis of geochemical survey samples and the optimized instrument measurement conditions provide reliable basic data for such samples in China.