地质样品中痕量氯溴和硫的X射线荧光光谱法测定  

Determination of Trace Br, Cl and S in Rock, Soil and Sediment Samples by X-Ray Fluorescence Spectrometry

作　　者：詹秀春[1] 陈永君[1] 郑妙子[1] 王健[1] 李迎春[1] 李冰[1] 张勤[2] 

机构地区：[1]国家地质实验测试中心,北京100037 [2]中国地质科学院物化探研究所,河北廊坊065000

出　　处：《岩矿测试》2002年第1期12-18,共7页Rock and Mineral Analysis

基　　金：国土资源部地质大调查项目 (DKD 990 40 17)

摘　　要：报道了粉末压样 -X射线荧光光谱法测定地质样品中痕量Cl、Br、S的分析方法。采用水系沉积物、岩石和土壤等国家一级标准物质进行校准。实验表明 ,对于不同岩性样品中Br的分析 ,特别是当Br的含量低于 2 μg/g时 ,采用谱峰强度 (未扣除背景 )与背景强度的比进行校准所得到的结果 ,明显优于铑靶线的Compton散射线内标法 ,分析精度 (RSD ,n =6 )为 2 .4%～1 5 .3 % ,大多数优于 1 0 % ;平均值的相对误差低于 2 4 %。对于Cl的分析 ,只需对Ca的影响加以校正即可得到非常好的结果 ;不同样品中Cl的分析精度 (RSD ,n =6 )为 2 .1 %～ 1 3 .6 % ,大多数优于 5 % ;平均值的相对误差不大于 2 5 % ,多数优于 1 0 %。S的校准曲线的离散性较大 ,矿物学效应是影响S分析准确度的主要因素 ,其分析精度 (RSD ,n =6 )为 0 .87%～ 5 .6 % ,除个别样品外 ,平均值的相对误差优于 3 6 %。Cl和S均存在分析结果随测量时间 (次数 )的增加而增高的现象 ,必须在制样后立即测量。方法的检出限 (μg/g)Br、Cl、S分别为 0 .43、5 .8和 2 .2。An X ray fluorescence spectrometric method has been developed for the determination of trace Br, Cl and S in rock, soil and sediment samples. Pressed powder pellets were used for measurements. Calibration was carried out using Chinese National Standard Materials with similar matrix elemental compositions to the samples. For Br, two matrix correction techniques, namely the scattering background internal standard method (in which raw peak intensity instead of net peak intensity is used) and the commonly used target Compton scattering internal standard method, were tested. And the former was found out more effective when the analyte concentration levels are near the detection limits. The precision is generally better than 10% RSD and the relative deviation of the average (6 measurements) is better than 24%. The fact that the measured concentration of S and Cl became higher and higher when the same sample pellet was repeatedly measured, brought about some analytical problems. Thus only newly prepared sample pellets can be used for S and Cl analysis. For Cl analysis, direct correlation generally exists between its concentration and XRF intensity. Matrix correction is needed only when the sample contains extremely high concentration of Ca. The precision is generally better than 5% RSD and the relative deviation of the average (6 measurements) is better than 25%. S is the most problematic element to analyze. The precision is really good with 0.87%～5.6% RSD( n =6).But the poor relative deviation (36%, some even worse) excludes its use in precise analysis. Extensive experiments were conducted in finding out the factors affecting the S accuracy. And it was concluded that the mineral effect plays the most important role. The detection limits of this method are 0.43, 2.2 and 5.8 μg/g for Br, S and Cl respectively.

关 键 词：地质样品 X射线荧光光谱 氯 溴 硫 水系沉积物 岩石 土壤 

分 类 号：P575.4[天文地球—矿物学]