首页|锂硼同位素MC-ICP-MS分析中的记忆效应研究

锂硼同位素MC-ICP-MS分析中的记忆效应研究

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锂(Li)和硼(B)同位素是地质作用过程中良好的示踪剂,被广泛应用于岩石起源、矿床成因和环境演化等领域.但锂、硼在MC-ICP-MS仪器分析中的"记忆效应"明显,不同实验室已报道的MC-ICP-MS分析中锂、硼背景占信号比变化范围大(0.01%～5%),所采用的背景控制方法和效果也各不相同,因此给锂、硼同位素的准确测定带来困难.为研究MC-ICP-MS锂、硼同位素记忆效应及其抑制方案,提高测试的稳定性,本文参考前人研究成果,设计不同背景清洗方案,并对各种国际标样(IRMM-016、JG-2、ERM-AE121、ERM-AE122、NASS-7)和实验室内部标准(Alfa Li、Alfa B)进行长期测试,检验实验方案的长期重现性.结果表明:仅使用 0.3%氯化钠溶液清洗背景可以显著降低锂背景信号,从 20mV下降至 4mV,并保证7Li背景值在 24h内低于 5mV,实验室内部标准溶液Alfa Li的δ7Li长期测试外精度为 0.13‰(2SD,n=73).氟化钠、氨水等清洗液并不能显著降低本研究所使用仪器的硼背景,因此选择使用灵活的空白扣除方法来保证数据稳定性.实验室内部标准溶液Alfa B的δ11B长期测试外精度为 0.19‰(2SD,n=60).本文锂、硼同位素国际标样的测试结果与前人数据在误差范围内一致,证明了实验结论的可靠性.
A Study on Memory Effects in Lithium and Boron Isotope Analysis Using MC-ICP-MS
Lithium(Li)and boron(B)isotopes are excellent tracers in geological processes.In order to study and eliminate the memory effects of lithium and boron element in isotopic measurements using MC-ICP-MS,different background rinsing protocols were designed with reference to previous research.The δ7Li and δ11B values of different types of reference materials were tested to evaluate the long-term reproducibility of the measurements using designated rinsing protocols for at least six months.The results show that using only 0.3%NaCl solution to clean the background for 60s can significantly reduce the lithium background signal and ensure the 7Li background signal is less than 5mV within 24h.The long-term external precision of δ7Li values for Alfa Li,an in-house standard,was 0.13‰(2SD,n=73).Rinsing solutions,such as NAF and NH3·H2O could not significantly reduce the boron background of the instrument.However,the flexible blank subtracting method was used for precise determination of δ11B values.The long-term external precision of δ11B values for Alfa B was 0.19‰(2SD,n=60).The average δ7Li and δ11B values of different types of reference materials were tested using these rinsing protocols,and the results were well consistent with reported data,supporting the applicability of the conclusions.The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202310260167.

memory effectlithiumboronMC-ICP-MS0.3%NaCl solutionblank deduction

唐清雨、陈露、田世洪、胡文洁、龚迎莉、字艳梅

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东华理工大学地球科学学院,江西南昌 330000

东华理工大学核资源与环境国家重点实验室,江西南昌 330000

清华大学能源与动力工程系,北京 100084

记忆效应 锂同位素 硼同位素 MC-ICP-MS 0.3%氯化钠溶液 空白扣除

东华理工大学科研项目(自然科学类)自然资源部离子型稀土资源与环境重点实验室开放基金中国铀业有限公司-东华理工大学核资源与环境国家重点实验室联合创新基金自然资源部深地科学与探测技术实验室开放基金

DHBK20200122022IRERE1022022NRE-LH-05Sino Probe Lab 202217

2024

10.15898/j.ykcs.202310260167

岩矿测试
中国地质学会岩矿测试技术专业委员会 国家地质实验测试中心

岩矿测试

CSTPCD北大核心
影响因子：1.344
ISSN：0254-5357
年,卷(期)：2024.43(2)
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