基于Cs_2Br^+静态多接收正热电离质谱法高精度测定溴同位素  

High Precise Determination of Bromine Isotopic Ratios by Positive Thermal Ionization Mass Spectrometry Using Static Multicollection of Cs_2Br^+ Ions

作　　者：马云麒[1,2] 彭章旷 陈彦交[1,3] 杨剑[1,3] 肖应凯[1] 张艳灵[1] 

机构地区：[1]中国科学院青海盐湖研究所盐湖地质与环境实验室,西宁810008 [2]中国科学院青海盐湖研究所盐湖化学分析测试中心,西宁810008 [3]中国科学院大学,北京100049

出　　处：《分析化学》2016年第2期186-191,共6页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(Nos.41173019;41473117);中国科学院仪器设备功能开发技术创新项目(No.2016G106);中国科学院关键技术人才(2005)项目资助~~

摘　　要：采用Triton热电离质谱仪,在8 k V加速电压下,建立了基于Cs_2Br^+为检测离子的稳定溴同位素比值静态多接收测定方法,实现了溴同位素组成的高精度正热电离质谱法测定,并对溴同位素测试过程中B和Cl元素的影响、点样顺序的影响等进行了研究。结果表明,静态多接收法测定Br同位素和传统的峰跳扫法相比具有精度高(外精度在0.09‰~0.18‰之间)、涂样量小(10~20μg Br)和测试时间短(采集100个数据只需8min)的优点,不同含量的Cl对Br同位素比值的影响随着Cl含量的升高而增强,B的存在使溴同位素测定值偏低。涂样顺序对溴同位素测定结果没有表现出明显差异。同时,测定了4个溴化物化学试剂中的溴同位素组成,其同位素组成介于0.61‰~1.68‰,呈现出明显的溴同位素分馏现象。High precise determination of stable bromine isotopic ratios was carried out by thermal ionization mass spectrometer triton with 8 kV accelerating voltage using static muhicollection of Cs2Br~ ions. The effect of B and C1 content on the measurement of bromine isotope was studied. The static muhicollection method has many advantages, such as, high precision （ external accuracy lies between O. 09%o-0.18%o）, small amount of sample loading （10-20 trg Br） and short acquisitiotest time （just 8 min for 100 data acquisition）. The results showed that the effect of C1 on the measurement of Br isotope ratio increased with the increase of C1 content, and that the presence of B made the determined bromine isotope ratio lower than that without B. The effect of the sample loading sequence on the results of the determined Br the Br isotopic composition of four bromide was determined, its showing a significant bromine isotope fractionation. isotopic ratio was insignificant. Meanwhile, δ81 Br was between 0.61%o and 1.68%0,

关 键 词：溴同位素 正热电离质谱(P-TIMS) 静态多接收 Cs2Br+ 

分 类 号：P597[天文地球—地球化学] O657.63[天文地球—地质学]