There are two main methods to determine boron isotopic composition.One is the solution method,in which boron is purified after the samples are dissolved in solution and the boron isotope ratios are determined by therm...There are two main methods to determine boron isotopic composition.One is the solution method,in which boron is purified after the samples are dissolved in solution and the boron isotope ratios are determined by thermal ionization mass spectrometry(P-TIMS and N-TIMS) or multicollector inductively coupled plasma mass spectrometry(MC-ICP-MS).The other is an in-situ analysis method,in which the in-situ boron isotopic ratios in minerals are analyzed directly using secondary ion mass spectrometry(SIMS) or laser ablation multicollector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS).In the in-situ analysis method for boron isotopes,the multifarious chemical purification and separation processes of the solution method are avoided,with increased work efficiency.In addition,the microzones and microbeddings of minerals can be analyzed in-situ to reveal the fine processes and conditions of mineral formation.In this study,using the standard-sample-bracketing(SSB) method,mass bias of the instrument and the fractionation of isotopes were calibrated,and the in-situ determination method of LA-MC-ICP-MS for boron isotopes was established.Through detailed analyses on a series of boron isotope standards and samples,a matrix effect was assessed but not detected,and the analysis results were in accordance with the formerly reported values or P-TIMS determined values,within the error range.The analytical results for IAEA B4 and IMR RB1 with relatively high boron contents were δ 11B =-(8.36±0.58)‰(2σ,n=50) and δ 11B =-(12.96±0.97)‰(2σ,n=57),respectively;the analytical result for IAEA B6 with rela-tively low boron content was δ 11B =-(3.29±1.12)‰(2σ,n=35).In-situ measurements for B isotopes were performed on geo-logical samples such as tourmaline,ulexite,ludwigite,inyoite and ascharite,with the results consistent with those determined by P-TIMS,within the error range.展开更多
为了高效地从地质/环境样品中分离纯化Li元素并进行Li同位素测定,经反复实验和改良发现:采用8 m L容积(树脂体积)离子交换柱,选取AG 50W-X12阳离子交换树脂,以0.5 mol/L HNO3为淋洗液,过柱一次,并收集20~48 m L区间的淋洗液,即可一步实...为了高效地从地质/环境样品中分离纯化Li元素并进行Li同位素测定,经反复实验和改良发现:采用8 m L容积(树脂体积)离子交换柱,选取AG 50W-X12阳离子交换树脂,以0.5 mol/L HNO3为淋洗液,过柱一次,并收集20~48 m L区间的淋洗液,即可一步实现Li的完全纯化分离。对于高盐样品,建议过柱两次确保Na/Li<1,以达到上机测试的要求。由多种单元素标准混合的工作溶液(IEECAS-Li)经此流程分离后,采用Neptune Plus MC-ICP-MS测量得到的δ7Li值为8.31‰±0.12‰,与未混合的标准值(8.33‰±0.20‰)在误差范围内一致。采用此流程,获得的岩石标准物质AGV-2、BHVO-2和海水标准物质NASS-6的δ7Li值(2 s.d.,n=5)也与推荐值一致,分别为6.83‰±0.75‰、4.32‰±0.33‰和31.10‰±0.60‰。由此,我们建立了一套高效分离纯化Li及其同位素的MC-ICP-MS测试程序。将该程序用到Li含量在15 ng/g^90μg/g之间的实际样品中,δ7Li的长期内精度均好于0.30‰,且重现性高,表明该方法的分析精度和准确度都达到了国际标准水平。尤为重要的是,本方法可用于精确测量含痕量Li的环境样品的Li同位素组成。展开更多
增益(Gain)校正有助于消除MC-ICP-MS不同高阻放大器之间的阻值差异,进而提高同位素分析的精度和准确度,但有关Gain的偏移和校正频率对同位素测试的影响和作用原理还缺乏系统认识。本研究结合本实验室Neptune Plus MC-ICP-MS的Gain校正数...增益(Gain)校正有助于消除MC-ICP-MS不同高阻放大器之间的阻值差异,进而提高同位素分析的精度和准确度,但有关Gain的偏移和校正频率对同位素测试的影响和作用原理还缺乏系统认识。本研究结合本实验室Neptune Plus MC-ICP-MS的Gain校正数据,以实际测试的汞同位素数据为例,评估了放大器Gain校正系数偏移对同位素测试的影响。结果显示,当测试标样和样品的校正系数偏移幅度一致时,汞同位素测试结果基本无变化;当偏移幅度存在明显差异且单一放大器校正系数的相对偏移幅度超过–0.070‰~0.058‰时,汞同位素的测试结果大于分析误差。Gain校正系数单日的相对变化幅度(–0.028‰~0.028‰)可保证汞同位素测试结果小于分析误差,但长期的偏移却会导致汞同位素变化远超分析误差。此外,仪器的硬件、温度和真空度等也是Gain校正系数变化的重要影响因素,因此建议定期维护仪器,并每日进行Gain校正,以保证测试结果的稳定和准确。展开更多
基金supported by the National Special Research Program for Non-Profit Trades (Sponsored by MLR, 200911043-20 and 200811114)
文摘There are two main methods to determine boron isotopic composition.One is the solution method,in which boron is purified after the samples are dissolved in solution and the boron isotope ratios are determined by thermal ionization mass spectrometry(P-TIMS and N-TIMS) or multicollector inductively coupled plasma mass spectrometry(MC-ICP-MS).The other is an in-situ analysis method,in which the in-situ boron isotopic ratios in minerals are analyzed directly using secondary ion mass spectrometry(SIMS) or laser ablation multicollector inductively coupled plasma mass spectrometry(LA-MC-ICP-MS).In the in-situ analysis method for boron isotopes,the multifarious chemical purification and separation processes of the solution method are avoided,with increased work efficiency.In addition,the microzones and microbeddings of minerals can be analyzed in-situ to reveal the fine processes and conditions of mineral formation.In this study,using the standard-sample-bracketing(SSB) method,mass bias of the instrument and the fractionation of isotopes were calibrated,and the in-situ determination method of LA-MC-ICP-MS for boron isotopes was established.Through detailed analyses on a series of boron isotope standards and samples,a matrix effect was assessed but not detected,and the analysis results were in accordance with the formerly reported values or P-TIMS determined values,within the error range.The analytical results for IAEA B4 and IMR RB1 with relatively high boron contents were δ 11B =-(8.36±0.58)‰(2σ,n=50) and δ 11B =-(12.96±0.97)‰(2σ,n=57),respectively;the analytical result for IAEA B6 with rela-tively low boron content was δ 11B =-(3.29±1.12)‰(2σ,n=35).In-situ measurements for B isotopes were performed on geo-logical samples such as tourmaline,ulexite,ludwigite,inyoite and ascharite,with the results consistent with those determined by P-TIMS,within the error range.
文摘为了高效地从地质/环境样品中分离纯化Li元素并进行Li同位素测定,经反复实验和改良发现:采用8 m L容积(树脂体积)离子交换柱,选取AG 50W-X12阳离子交换树脂,以0.5 mol/L HNO3为淋洗液,过柱一次,并收集20~48 m L区间的淋洗液,即可一步实现Li的完全纯化分离。对于高盐样品,建议过柱两次确保Na/Li<1,以达到上机测试的要求。由多种单元素标准混合的工作溶液(IEECAS-Li)经此流程分离后,采用Neptune Plus MC-ICP-MS测量得到的δ7Li值为8.31‰±0.12‰,与未混合的标准值(8.33‰±0.20‰)在误差范围内一致。采用此流程,获得的岩石标准物质AGV-2、BHVO-2和海水标准物质NASS-6的δ7Li值(2 s.d.,n=5)也与推荐值一致,分别为6.83‰±0.75‰、4.32‰±0.33‰和31.10‰±0.60‰。由此,我们建立了一套高效分离纯化Li及其同位素的MC-ICP-MS测试程序。将该程序用到Li含量在15 ng/g^90μg/g之间的实际样品中,δ7Li的长期内精度均好于0.30‰,且重现性高,表明该方法的分析精度和准确度都达到了国际标准水平。尤为重要的是,本方法可用于精确测量含痕量Li的环境样品的Li同位素组成。
文摘增益(Gain)校正有助于消除MC-ICP-MS不同高阻放大器之间的阻值差异,进而提高同位素分析的精度和准确度,但有关Gain的偏移和校正频率对同位素测试的影响和作用原理还缺乏系统认识。本研究结合本实验室Neptune Plus MC-ICP-MS的Gain校正数据,以实际测试的汞同位素数据为例,评估了放大器Gain校正系数偏移对同位素测试的影响。结果显示,当测试标样和样品的校正系数偏移幅度一致时,汞同位素测试结果基本无变化;当偏移幅度存在明显差异且单一放大器校正系数的相对偏移幅度超过–0.070‰~0.058‰时,汞同位素的测试结果大于分析误差。Gain校正系数单日的相对变化幅度(–0.028‰~0.028‰)可保证汞同位素测试结果小于分析误差,但长期的偏移却会导致汞同位素变化远超分析误差。此外,仪器的硬件、温度和真空度等也是Gain校正系数变化的重要影响因素,因此建议定期维护仪器,并每日进行Gain校正,以保证测试结果的稳定和准确。
