摘要
采用酸溶-电感耦合等离子体发射光谱法(ICP-OES)测定地质样品中的全硼量,关键环节在于如何防止样品消解过程中硼元素的损失,降低测量过程中的基体干扰、光谱干扰和记忆效应。基于以上问题,本文采用氢氟酸-硝酸-高氯酸-磷酸在低压密闭溶样罐中消解样品,溶出的硼元素与少量磷酸充分络合,防止硼的挥发损失;以基体及主成分浓度与样品相类似的地质类固体标准物质绘制标准曲线做线性校准,有效匹配和降低样品的基体干扰;采用仪器自带的操作软件,观察分析谱线附近是否存在其他元素的干扰,来确定背景扣除最佳的位置及宽度,降低ICP-OES测量中的光谱干扰;以10%的王水作为进样系统的冲洗液,有效消减测量过程中的记忆效应。当稀释因子为200时,方法的检出限(3SD)为1.2μg/g,定量限(10SD)为4.0μg/g;用岩石、土壤及水系沉积物国家一级标准物质对精密度及准确度进行分析验证,11次测定相对标准偏差为1.8%~7.9%,相对误差为-3.6%~6.3%;以外检分析结果为参考,对硼含量在定量限以上的样品测定,相对误差为-9.3%~12.5%。
BACKGROUND: Total boron in geological samples is determined by inductively coupled plasma-optical emission spectroscopy(ICP-OES) with acid digestion. The key steps are preventing the loss of boron during the sample digestion stage and reducing matrix interference, spectral interference and memory effect during measurement.OBJECTIVES: To establish a method for the determination of boron in geological samples by ICP-OES with low-pressure closed digestion.METHODS: Using HF-HNO3-HClO4-H3PO4 to digest samples in a low-pressure closed sample tank, the dissolved boron element is fully complexed with a small amount of phosphoric acid to prevent the volatilization loss of boron. The standard curve was calibrated using the geological solid standard material with similar concentration of matrix and major components to effectively match and reduce the matrix interference of the sample. The operating software provided by the instrument was used to observe and analyze the interference of other elements near the spectral line and to determine the best position and width of background subtraction to reduce the spectral interference in the ICP-OES measurement. 10% Aqua regia was used as the rinsing liquid of the sample introduction system, which effectively reduced the memory effect during measurement.RESULTS: When the dilution factor was 200, the detection limit(3 SD) was 1.2μg/g, and the quantitative limit(10 SD) was 4.0μg/g. The precision and accuracy were analyzed and verified by using the national first-class standard substances in rock, soil and river sediment, the relative standard deviations(n=11) were from 1.8% to 7.9%, and the relative errors were from-3.6% to 6.3%. Compared with the results of external tests, the relative error of boron content above the quantitative limit ranged from-9.3% to 12.5%.CONCLUSIONS: The method is suitable for the accurate measurement of boron above 4.0μg/g in geological samples.
作者
杜宝华
盛迪波
罗志翔
王全
DU Bao-hua;SHENG Di-bo;LUO Zhi-xiang;WANG Quan(Hunan Nuclear Central Laboratory,Changsha 410100,China)
出处
《岩矿测试》
CAS
CSCD
北大核心
2020年第5期690-698,共9页
Rock and Mineral Analysis
关键词
电感耦合等离子体发射光谱法
低压密闭消解
标准物质校准
地质样品
硼
记忆效应
inductively coupled plasma-optical emission spectrometry
low-pressure closed digestion
calibration of reference materials
geological samples
boron
memory effect
