过氧化钠碱熔-电感耦合等离子体质谱法测定地质样品中锆铌铪钽锂铍钒磷铀锰

地质样品中Zr、Nb、Hf、Ta、Li、Be、V、P、U、Mn的准确测定有利于地球化学、岩石成因等地质环境的研究。采用过氧化钠碱熔、盐酸酸化的方法处理样品,选择⁶Li校正Li、Be,¹⁰³Rh校正V、P、Zr、Nb、Mn,¹⁸⁵Re校正Ta、Hf、U,建立了电感耦合等离子体质谱法(ICP-MS)测定地质样品中这些元素的方法。熔样试验表明,对于0.100 0 g地质样品,以1.0 g 过氧化钠为熔剂于750 ℃马弗炉中熔融8 min,样品可熔解完全。基体干扰试验表明:将溶液稀释10倍,待测液中Na⁺的质量浓度小于1.0 mg/mL,其产生的干扰可忽略;样品中主量元素K、Ca、Fe、Mg、Al对测定的干扰可忽略。对待测溶液的放置时间进行了优化,选择放置时间为1 d以内。在优化的实验条件下,所测10种元素校准曲线的线性相关系数均在0.999以上,检出限为0.10～2.64 μg/g,定量限为0.33~8.80 μg/g。按照实验方法对土壤、水系沉积物和岩石的标准物质及实际样品中的Zr、Nb、Hf、Ta、Li、Be、V、P、U、Mn进行测定。结果表明,标准物质的测定结果与认定值基本一致,相对标准偏差(RSD)不大于4.8%,相对误差(RE)不大于5.1%;实际样品的相对标准偏差均不大于4.9%。

Determination of zirconium,niobium,hafnium,tantalum,lithium,beryllium,vanadium,phosphorus,uranium and manganese in geological samples by inductively coupled plasma mass spectrometry with sodium peroxide alkali fusion

The accurate determination of Zr, Nb, Hf, Ta, Li, Be, V, P, U and Mn in geological sample is beneficial to the study of geological environments such as geochemistry and petrogenesis. The sample was treated by alkali fusion with sodium peroxide and acidification with hydrochloric acid. ⁶Li was selected to correct Li and Be. ¹⁰³Rh was selected to correct V, P, Zr, Nb and Mn. ¹⁸⁵Re was selected to correct Ta, Hf and U. The method for determination of these elements in geological sample by inductively coupled plasma mass spectrometry (ICP-MS) was established. The sample fusion experiments showed that 0.100 0 g of geological sample could be fully fused by 1.0 g of sodium peroxide in muffle furnace at 750 ℃ for 8 min. The matrix interference tests showed that the mass concentration of Na⁺ in testing solution was less than 1.0 mg/mL after dilution for 10 times, and the interference caused could be ignored. The interference of major elements in sample including K, Ca, Fe, Mg and Al could be also ignored. The standing time of testing solution was optimized, which should be within 1 d. Under the optimized experimental conditions, the linear correlation coefficients of calibration curves for ten testing elements were all higher than 0.999. The limits of detection were between 0.10 μg/g and 2.64 μg/g. The limits of quantification were between 0.33 μg/g and 8.80 μg/g. The contents of Zr, Nb, Hf, Ta, Li, Be, V, P, U and Mn in certified reference materials of soil, stream sediments and rocks as well as actual samples were determined according to the experimental methods. The results showed that the determination results of certified reference materials were basically consistent with the certified values. The relative standard deviations (RSD) were not more than 4.8%, and the relative errors (RE) were not more than 5.1%. The RSDs of actual samples were all not more than 4.9%.