电感耦合等离子体质谱法测定地质样品中痕量碲

采用HF-HNO₃体系密闭溶解样品,用HCl-NaBr-甲基异丁基酮(MIBK)体系对Te进行萃取和反萃取,加入乙醇对测定信号强度进行增敏,以¹²⁵Te作为测定同位素,建立了电感耦合等离子体质谱法(ICP-MS)测定地质样品中痕量Te的方法。对溶样条件进行了优化,确定溶样条件如下:采用7.0mLHF与HNO₃体积比为1∶3的混合酸,于160℃控温电热板上溶样3h。增敏试验表明,控制测定液中乙醇的体积分数为4%效果最佳。以待测元素质量浓度为横坐标,以待测元素与内标元素的信号强度之比为纵坐标绘制校准曲线,线性相关系数大于0.9999。方法检出限为0.0054μg/g。采用实验方法对地质标准物质中痕量Te进行测定,测定结果与认定值基本保持一致,相对标准偏差(RSD,n=12)均在6.7%以内。分别用实验方法与氢化物发生原子荧光光谱法(HG-AFS)对土壤样品1#~4#及铅锌矿样品6#~10#中Te进行测定,结果基本一致。

Determination of trace tellurium in geological sample by inductively coupled plasma mass spectrometry

After the sample was dissolved with HF-HNO₃ in closed system, Te was extracted and reextracted with HCl-NaBr-methyl isobutyl ketone (MIBK), and ethanol was added to enhance the intensity of determination signal. Thus, a determination method of trace Te in geological sample by inductively coupled plasma mass spectrometry (ICP-MS) was established with ¹²⁵Te as determination isotope. The sample dissolution conditions were optimized as follows: the sample was dissolved with 7.0mL of HF-HNO₃ mixed acid with volume ratio of 1∶3 when it was heated on electric hot plate at 160℃ for 3h. The sensitivity enhancing test indicated that the effect was optimal when the volume fraction of ethanol in determination solution was 4%. The calibration curve was plotted with the mass concentration of test element as x-axis and the signal intensity ratio of test element to internal standard element as y-axis. The linear correlation coefficient was higher than 0.9999. The detection limit was 0.0054μg/g. The content of trace Te in certified reference materials of geological sample were determined according to the experimental method, and the results were basically consistent with the certified values. The relative standard deviations (RSD, n=12) were all lower than 6.7%. The content of Te in soil samples (1#-4#) and lead-zinc ore samples (6#-10#) was determined by the experimental method, and the results were consistent with those obtained by hydride generation atomic fluorescence spectrometry (HG-AFS).