高压密闭消解-电感耦合等离子体质谱法测定地球化学样品中的50种元素

选择电感耦合等离子体质谱法测定地球化学样品中50种元素的含量。取0.1000g样品,置于高压密闭消解罐的聚四氟乙烯(PTFE)内胆中,加入氢氟酸3mL及硝酸1mL,放入密闭钢套中,拧紧。在150℃下消解2h,待冷却降压后取出内胆,加入高氯酸0.25mL,于150℃加热蒸发至白烟冒尽。加入硝酸1mL和水1mL,将内胆置于钢套中,于150℃再次密闭消解12h。自然冷却,将内胆中溶液转移至PTFE比色管中,加水定容至10.0mL,摇匀。分取此母液1.00mL,置于10mLPTFE比色管中,用约φ2.2%硝酸溶液稀释至10.0mL,保持溶液中硝酸浓度在3%左右。此溶液用于测定(S1组)Li、Be、V等28种元素和(S2组)Sc、Y、La等16种元素。另取母液1.00mL,置于10mLPTFE比色管中,加入φ10%氢氟酸溶液2滴,500g·L^-1的酒石酸溶液1.0mL,用约φ2.5%硝酸溶液稀释至10.0mL,摇匀。此溶液供测定(S3组)Ti、Zr、Nb等6种元素。对质谱干扰较严重的被测元素分别建立了11个校准方程用于校准相关测定数据。用所提出方法分析了6种地球化学国家一级标准物质(GBW07359,GBW07360,GBW07361,GBW07408,GBW07427,GBW07446),对其中与本方法有关的50种元素进行测定,所得结果与认定值相符,达到了地质矿产实验室测试质量规范的要求。

High Pressure Sealed Digestion-Determination of 50 Elements in Geochemical Samples by Inductively Coupled Plasma Mass Spectrometry

ICP-MS was applied to the determination of 50 elements in geochemical sample. The sample (0.100 0 g) was digested with 3 mL of HF and 1 mL of HNO3 in the PTFE-liner of the pressurized hermeticallysealed digestion system at 150℃ for 2 h. After cooling and de-pressurizing, the liner was taken out and 0.25 mL of HC1O4 was added to the digested s*olution and the mixed solution was evaporated by heating at 150 ℃ until ending of the acid-fuming. 1 mL each of HNO3 and H2O was added, and the liner was replaced into the steel case of the digestor and the mixture in the liner was digested once more at 150℃ for 12 h. After natural cooling, the solution in the liner was transferred to a 10 mL PTFE colorimetric tube, and its volume was made up to 10.0 mL with water. A aliquot of 1. 0 mL was taken from this mother sample solution and transferred to another 10 mL PTFE colorimetric tube and its volume was diluted to 10.0 mL with φ 2.2% HNO3 solution to keep the concentration of HNO3 at ca.φ 3%. This solution was used for MS determination of 28 elements (including Li, Be, V and etc. as shown in SI) and of 16 elements (including Sc, Y, La and etc. as shown in S2). Another aliquot of 1.0 mL was taken from the mother solution and placed into another 10 mL PTFE colorimetric tube, 2 drops of φ 10% HF solution and 1 mL of 500 g·L^-1 tartaric acid solution were added, and its volume was diluted to 10.0 mL with ca.(φ 2.5% HNO3 solution. This solution was used for determination of the remaindering 6 elements (including Ti, Zr, Nb and etc. as shown in S3). Eleven equations were established for calibration of errors of determined values of the respective 11 elements due to MS interferences. The proposed method was applied to the analysis of 6 CRMs of GBW 07359, GBW 07360, GBW 07361, GBW 07408, GBW 07427 and GBW 07446 in which the related 50 elements was determined giving results in consistency with the certified values, and meeting with the requirements for testing quality given in the management standard for geological laboratories.