高精度铅同位素比值MC-ICP-MS测试方法及土壤标准物质铅同位素组成  

High Precision Analysis of Pb Isotope Ratios Using MC-ICP-MS and the Pb Isotope Compositions of Soil Standard Materials

作　　者：黄国锋 王中伟 谢志宜 刘军 陈多宏 HUANG Guo-feng;WANG Zhong-wei;XIE Zhi-yi;LIU Jun;CHEN Duo-hong(Guangdong Ecological and Environmental Monitoring Center,Guangzhou 510308,China)

机构地区：[1]广东省生态环境监测中心,广东广州510308

出　　处：《分析测试学报》2025年第1期116-125,共10页Journal of Instrumental Analysis

摘　　要：利用多接收电感耦合等离子体质谱仪(MC-ICP-MS)精准测定了国家土壤标准物质的铅同位素比值,研究了MC-ICP-MS测定铅同位素时的分馏效应,发现仪器存在非质量分馏效应,应用Baxter法和标准与实际样品的交叉组合法(SSB)校正仪器的质量和非质量分馏,校正后NIST SRM 981标准溶液的铅同位素比值具有较高的准确度和精确度。采用MC-ICP-MS测定了3个国家土壤标准物(GBW07564、GBW07406a、GBW07980)的铅同位素比值。对土壤进行微波消解和纯化,回收率大于98%,全流程空白小于0.22 ng。GBW07564铅同位素的^(206)Pb/^(204)Pb为19.9603±0.0303、^(207)Pb/^(204)Pb为15.7675±0.0061、^(208)Pb/^(204)Pb为39.0868±0.0264(n=9,2SD);GBW07406a铅同位素的^(206)Pb/^(204)Pb为18.8024±0.0018、^(207)Pb/^(204)Pb为15.7442±0.0025、^(208)Pb/^(204)Pb为39.1943±0.0086(n=9,2SD);GBW07980铅同位素的^(206)Pb/^(204)Pb为18.6142±0.0057、^(207)Pb/^(204)Pb为15.7378±0.0044、^(208)Pb/^(204)Pb为38.9629±0.0153(n=9,2SD)。这些土壤标准物质的^(206)Pb/^(207)Pb分别为1.2659±0.0014、1.1942±0.0001、1.1828±0.0001(n=9,2SD),^(208)Pb/^(206)Pb分别为1.9582±0.0018、2.0845±0.0003、2.0932±0.0002(n=9,2SD),大致在自然界土壤铅同位素^(206)Pb/^(207)Pb(大于1.17)、^(208)Pb/^(206)Pb(小于2.11)变化范围内,且容易获得,化学和铅同位素组成均一,适合作为监控土壤铅同位素化学及质谱分析数据可靠性的同位素土壤标准物质。Lead isotope ratios for national soil reference materials was accurately determinated by us⁃ing multiple collectors inductively coupled plasma mass spectrometry(MC-ICP-MS).The fraction⁃ation properties of MC-ICP-MS in the determination of lead isotope was studied,which exhibits mass-independent fractionation.The Baxter and the standard-sample bracketing(SSB)method were used to corrected the mass-dependent fractionation and mass-independent fractionation in the instru⁃ment.The lead isotope ratio of the NIST SRM 981 standard solution which was corrected has high ac⁃curacy and precision.The lead isotope ratio of three national soil reference materials(GBW07564,GBW07406a,GBW07980)were determined using MC-ICP-MS,and the soil was digested by mi⁃crowave and purified.The recovery was more than 98%,and the blank of the whole process was less than 0.22 ng.The lead isotope ratio of GBW07564 is 19.9603±0.0303 for ^(206)Pb/^(204)Pb,15.7675±0.0061 for ^(207)Pb/^(204)Pb,and 39.0868±0.0264 for ^(208)Pb/^(204)Pb(n=9,2SD);the lead isotope ratio of GBW07406a is 18.8024±0.0018 for ^(206)Pb/^(204)Pb,15.7442±0.0025 for ^(207)Pb/^(204)Pb,and 39.1943±0.0086 for ^(208)Pb/^(204)Pb(n=9,2SD);the lead isotope ratio of GBW07980 is 18.6142±0.0057 for ^(206)Pb/^(204)Pb,15.7378±0.0044 for ^(207)Pb/^(204)Pb,and 38.9629±0.0153 for ^(208)Pb/^(204)Pb(n=9,2SD).The ^(206)Pb/^(207)Pb of these soil reference materials are 1.2659±0.0014,1.1942±0.0001,1.1828±0.0001(n=9,2SD),and the ^(208)Pb/^(206)Pb are 1.9582±0.0018,2.0845±0.0003,2.0932±0.0002(n=9,2 SD),respectively.These values are roughly within the range of natural soil lead isotopes ^(206)Pb/^(207)Pb(more than 1.17)and ^(208)Pb/^(206)Pb(less than 2.11).These samples are easily obtain⁃able,and their chemical and lead isotope compositions are uniform,making them suitable as isotope soil reference materials for monitoring the reliability of soil lead isotope chemistry and mass spectrom⁃etry analysis data.

关 键 词：土壤标准物质 铅同位素 多接收电感耦合等离子体质谱(MC-ICP-MS) Baxter法 标准与实际样品的交叉组合法(SSB) 非质量分馏 

分 类 号：O657.6[理学—分析化学] S151.9[理学—化学]