A comparison of lead-isotope measurements on exploration-type samples using inductively coupled plasma and thermal ionization mass spectrometry

Thermal ionization mass spectrometry (TI-MS) has long been the method of choice for Pb-isotope determinations. More recently, however, inductively coupled plasma mass spectrometry (ICP-MS) has been used to determine Pb-isotope ratios for mineral exploration. The ICP-MS technique, although not as precise as TI-MS, may promote a wider application of Ph-isotope ratio methods because it allows individual isotopes to be determined more rapidly, generally without need for chemical separation (e.g., Smith et al., 1984; Hinners et al., 1987). To demonstrate the utility of the ICP-MS method, we have conducted a series of Pb-isotope measurements on several suites of samples using both TI-MS and ICP-MS.     

浅谈多接收器电感耦合等离子体质谱仪的日常维护

多接收器电感耦合等离子体质谱仪(以下简称MC-ICP-MS)广泛应用于同位素的准确测定,为地质、环境、考古等科学研究提供了破解"指纹密码"的重要工具,为地质科学研究提供了获取实验数据的重要手段.由于仪器部件老化、日常维护保养不到位和重要技术人员流动等原因,如果仪器长时间"带病"工作,故障率会增高,甚至濒临瘫痪,就很难保证同位素测试数据的可靠性.因此,掌握MC-ICP-MS各个部件的工作原理和特性及维护要领,加强日常的仪器维护,维持仪器正常运转,对于保障测试结果的准确度与精密度势在必行.本文结合长期实践经验,以Neptune仪器为例,重点介绍了MC-ICP-MS主要部件工作原理及维护要领,并对一些常见故障做详细分析,提出解决方案,以供相关技术人员参考与借鉴.     

电感耦合等离子体质谱法测定地质样品中的碲

本文采用电感耦合等离子体质谱法,对地质样品中的碲的测定进行了研究,建立了一种快速、准确、简便的测定土壤样品中碲的方法。该方法克服了常规方法的局限性。此方法对6个国家标准物质进行了方法验证,12次测定精密度、准确度均符合标准要求。     

Standard-sample bracketing calibration method combined with Mg as an internal standard for silicon isotopic compositions using multi-collector inductively coupled plasma mass spectrometry

Silicon isotope analysis traditionally uses a standard-sample bracketing (SSB) method that relies upon greater instrument stability than can be consistently expected. The following proposed method reduces the level of instrumental stability required for the analysis process and provides a valid solution for high-precision and accurate studies of Si isotopic compositions. Rock samples were dissolved by using alkali fusion and acidification. Silicon isotopes were purified with an ion exchange resin. Interfering peaks for isotopes were separated by using a Nu Plasma 1700 multi-collector inductively coupled plasma mass spectrometry (MS) system in high-resolution mode (M/ΔM > 8000 RP). Two magnesium isotopes (²⁵Mg and ²⁶Mg) and three silicon isotopes (²⁸Si, ²⁹Si, and ³⁰Si) were analyzed in the same data collection cycle. Mg isotopes were used as an internal standard to calibrate the mass discrimination effects in MS analysis of Si isotopes in combination with the SSB method in order to reduce the effects of MS interference and instrumental mass discrimination on the accuracy of measurements. The conventional SSB method without the Mg internal standard and the proposed SSB method with Mg calibration delivered consistent results within two standard deviations. When Mg was used as an internal standard for calibration, the analysis precision was better than 0.05 ‰ amu.     

电感耦合等离子体发射光谱法测定水中硅和锶

本文提出的等离子体发射光谱法测定水中的硅和锶,具有检出限低、线性范围宽,样品无需处理,可直接进样测量等优点。检出限：硅(以二氧化硅计)为0．5mg／L;锶为0．001mg／L。方法简便、准确,结果令人满意。     

电感耦合等离子体质谱法测定饮用水中微量元素

采用电感耦合等离子体质谱法快速测定饮用水中的微量元素,样品处理简便,检出限低,重现性好,分析速度快。方法检出限为0．007～0．911μg／L,精密度达到0．73％～4．87％。     

高分辨电感耦合等离子体质谱法测定植物样品中的12种元素

植物样品经逆王水体系微波消解稀释至一定体积后,直接用高分辨等离子体质谱法（HR-ICP-MS）同时测定溶液中的Cr、Mn、Co、Ni、Cu、Zn、As、Se、Mo、Cd、Hg、Pb共12种无机元素的含量。在HR-ICP-MS仪上优化选择各元素的同位素、分辨率和内标元素,有效消除测定过程中的质谱与非质谱干扰。其中,各元素的检出限在0.55～48.6 ng/g之间 (稀释因子=250) ,相对标准偏差RSD（n=12) 均＜10%。该方法经国家一级生物标准物质验证,测定结果接近标准值,方法准确可靠,适用于快速准确测定植物样品中的12种元素。     

电感耦合等离子体发射光谱法测定区域化探样品中高含量的砷

采用1∶1王水处理样品,用电感耦合等离子体发射光谱法(ICP-AES)测定地球化学样品中的砷元素。测定样品采用国家一级标准物质进行试验,并与标准值进行比较,测定值与标准值相符,满足《地质矿产实验室质量管理规范》的质量要求。经试验,该方法精密度(RSD,n=12)为1.48%~5.63%,检出限(ug/g)6.42,加标回收率为95.15%~104.6%,其方法简便快速,操作周期短,适合大批量地区化学样品中高含量砷的快速测定。     

利用多接收器电感耦合等离子体质谱仪(MC-ICPMS)测定镁铁-超镁铁质岩石中的铼-锇同位素组成

报道了用多接收器电感耦合等离子体质谱仪(MC-ICPMS)测定Re-Os同位素组成的质谱方法和化学分离方法,并应用该方法测定了天然镁铁-超镁铁质岩石样品中的Os同位素组成及Re、Os含量.Re同位素组成的MC-ICPMS测定利用膜除溶雾化器(Aridus)和静态法拉第杯接收的方式完成,采用Ir标准溶液在线校正仪器的质量分馏.Os同位素组成的MC-ICPMS测定采用常规雾化器和离子计数器静态接收的方式完成,并用10%的HCl-EtOH和10%的HCl溶液交替清洗进样系统来消除Os的"记忆效应".岩石样品的Re和Os化学分离采用Carius管溶样法,结合CCl4萃取以及微蒸馏的方法分离纯化Os,利用阴离子交换树脂的方法分离纯化Re.运用上述方法,对6个镁铁-超镁铁质岩石样品中的Re、Os含量和187Os/188Os同位素比值进行了测定,获得了理想的分析结果.     

Th/U/U and Pa/U ages from a single fossil coral fragment by multi-collector magnetic-sector inductively coupled plasma mass spectrometry

The ²³⁰Th/²³⁴U/²³⁸U age dating of corals via alpha counting or mass spectrometry has significantly contributed to our understanding of sea level, radiocarbon calibration, rates of ocean and climate change, and timing of El Nino, among many applications. Age dating of corals by mass spectrometry is remarkably precise, but many samples exposed to freshwater yield inaccurate ages. The first indication of open-system ²³⁰Th/²³⁴U/²³⁸U ages is elevated ²³⁴U/²³⁸U_initial values, very common in samples older than 100,000 yr. For samples younger than 100,000 yr that have ²³⁴U/²³⁸U_initial values close to seawater, there is a need for age validation. Redundant ²³⁰Th/²³⁴U/²³⁸U and ²³¹Pa/²³⁵U ages in a single fossil coral fragment are possible by Multi-Collector Magnetic Sector Inductively Coupled Plasma Mass Spectrometry (MC-MS-ICPMS) and standard anion exchange column chemistry, modified to permit the separation of uranium, thorium, and protactinium isotopes from a single solution. A high-efficiency nebulizer employed for sample introduction permits the determination of both ²³⁰Th/²³⁴U/²³⁸U and ²³¹Pa/²³⁵U ages in fragments as small as 500 mg. We have obtained excellent agreement between ²³⁰Th/²³⁴U/²³⁸U and ²³¹Pa/²³⁵U ages in Barbados corals (30 ka) and suggest that the methods described in this paper can be used to test the ²³⁰Th/²³⁴U/²³⁸U age accuracy.Separate fractions of U, Th, and Pa are measured by employing a multi-dynamic procedure, whereby ²³⁸U is measured on a Faraday cup simultaneously with all minor isotopes measured with a Daly ion counting detector. The multi-dynamic procedure also permits correcting for both the Daly to Faraday gain and for mass discrimination during sample analyses. The analytical precision of ²³⁰Th/²³⁴U/²³⁸U and ²³¹Pa/²³⁵U dates is generally better than ±0.3% and ±1.5%, respectively (2 Relative Standard deviation [RSD]). Additional errors resulting from uncertainties in the decay constant for ²³¹Pa and from undetermined sources currently limit the ²³¹Pa/²³⁵U age uncertainty to about ±2.5%. U isotope data and ²³⁰Th/²³⁴U/²³⁸U ages agree with National Institute of Standards and Technology (NIST) reference materials and with measurements made by Thermal Ionization Mass Spectrometry (TIMS) in our laboratory.     

电感耦合等离子体质谱法测定黑色页岩中的铂钯

对于黑色页岩中的铂钯元素,试样经过灼烧除去硫以及有机质后,用王水分解,经树脂富集,再将树脂灰化后溶解,采用电感耦合等离子体质谱仪测量,取代比色法,得到了更好的检出限,以及准确度。     

激光剥蚀电感耦合等离子体质谱微区分析 进展评述

激光剥蚀电感耦合(LA-ICP-MS)等离子体以其高空间分辨率、高灵敏度、多元素同时测定并可提供同位素比值信息的检测能力在原位微区分析中已得到广泛应用。现从仪器的发展、基础研究等方面评述了近年来LA-ICP-MS微区分析的进展,重点介绍了与等离子体质谱(ICP-MS)联用的激光器(纳秒和飞秒激光器)的发展、校正方法、分馏效应及其在地球科学微量元素、同位素、包裹体分析中的应用。并简要地阐述了LA-ICP-MS分析技术存在的局限和发展趋势。     

Determination of indium in natural waters by flow injection inductively coupled plasma mass spectrometry

Two methods have been developed to measure indium (In) in natural waters by flow injection inductively coupled plasma mass spectrometry (ICPMS). One is the isotope dilution technique using an¹¹³In enriched spike and the other utilizes natural yttrium present in the sample as an internal standard. In the former, optimization of the¹¹³In spike to minimize error is often difficult for samples in which In concentrations are variable, whereas in the latter method, a separate determination of Y in the sample is necessary and hence more sample is required. Using about 1 liter of a water sample, 200 fold preconcentration of In was performed by solvent extraction and back extraction technique and then introduced into the ICPMS to measure the¹¹³In/¹¹⁵In or¹¹⁵In/⁸⁹Y ratios. The detection limits were 0.01–0.02 pmol kg⁻¹ for both methods. Application of the methods to seawater samples yielded the concentrations of 0.06–0.15 pmol kg⁻¹ for the Pacific and 0.6–1.5 pmol kg⁻¹ for the Atlantic. The large inter-oceanic variation of In best resembles that of Al amongst the 3B group of elements in the periodic table. River and estuarine samples gave a more variable range of concentrations of 0.01–15 pmol kg⁻¹. Most of the In supplied by rivers is removed by scavenging in the estuarine mixing zone, suggesting that the fluvial input of In to the ocean is small.     

Rapid and highly reproducible analysis of rare earth elements by multiple collector inductively coupled plasma mass spectrometry

A method has been developed for the rapid chemical separation and highly reproducible analysis of the rare earth elements (REE) by isotope dilution analysis by means of a multiple collector inductively coupled plasma mass spectrometer (MC-ICP-MS). This technique is superior in terms of the analytical reproducibility or rapidity of analysis compared with quadrupole ICP-MS or with thermal ionization mass spectrometric isotope dilution techniques. Samples are digested by standard hydrofluoric-nitric acid-based techniques and spiked with two mixed spikes. The bulk REE are separated from the sample on a cation exchange column, collecting the middle-heavy and light REE as two groups, which provides a middle-heavy REE cut with sufficient separation of the light from the heavier REE to render oxide interferences trivial, and a Ba-free light REE cut. The heavy (Er-Lu), middle (Eu-Gd), and light REE (La-Eu) concentrations are determined by three short (1 to 2 min) analyses with a CETAC Aridus desolvating nebulizer introduction system. Replicate digestions of international rock standards demonstrate that concentrations can be reproduced to <1%, which reflects weighing errors during digestion and aliquotting as inter-REE ratios reproduce to ≤0.2% (2 SD). Eu and Ce anomalies reproduce to <0.15%. In addition to determining the concentrations of polyisotopic REE by isotope dilution analysis, the concentration of monoisotopic Pr can be measured during the light REE isotope dilution run, by reference to Pr/Ce and Pr/Nd ratios measured in a REE standard solution. Pr concentrations determined in this way reproduce to <1%, and Pr/REE ratios reproduce to <0.4%. Ce anomalies calculated with La and Pr also reproduce to <0.15% (2 SD). The precise Ce (and Eu) anomaly measurements should allow greater use of these features in studying the recycling of materials with these anomalies into the mantle, or redox-induced effects on the REE during recycling and dehydration of oceanic lithosphere, partial melting, metamorphism, alteration, or sedimentation processes. Moreover, this technique consumes very small amounts (subnanograms) of the REE and will allow precise REE determinations to be made on much smaller samples than hitherto possible.     

Determination of rare earth elements,thorium and uranium in seaweed samples on the coast in Niigata Prefecture by inductively coupled plasma mass spectrometry

The determination of rare earth elements (REEs), Th and U in seaweeds of various species and in ambient surface seawater were performed by inductively coupled plasma mass spectrometry. The seaweeds and the seawater samples were collected at 10 different coastal areas of Niigata Prefecture in Japan twice a year (spring and autumn) in 2004 and 2005. Results showed that concentration of REEs in seaweed species from Niigata Prefecture were about 10³ times higher than those in seawater, and the enrichment factors of REEs were larger in heavy REE than light REE. A significant concentration difference of REEs, Th and U was found among species even in the same phylum. Undaria pinnatifida had the highest concentration of U. Considering that U. pinnatifida has low concentrations of REEs among typical brown algae, different REEs and U uptake mechanisms are suggested. The concentration of REEs, Th and U did not vary remarkably between sampling points and/or seasons.     

岩石样品Hf化学分离及MC-ICP-MS同位素分析：离子交换色谱法的应用

介绍的离子交换色谱分离岩石样品Lu-Hf的方法,是对现有方法的改进。整个流程以使用HCl为主,配合少量HF,即可达到有效地分离Hf和Lu的目的,Lu和Hf的回收率在90％以上。经MC—ICP。MS分析,每个国际岩石标样的两个平行样获得了在误差范围内一致^176 Hf／^177 Hf比值,其中BHVO-1、BHVO-2和BCR-2的^176 Hf／^177 Hf比值与国内外文献报道的结果在误差范围内一致。     

电感耦合等离子体发射光谱法测定生物样品中铁、钙、镁、磷、钾、钠

本文介绍了电感耦合等离子体发射光谱法测定生物样品中Fe、Ca、Mg、K、Na、P等元素的分析方法,参加了国家植物标准物质定值,结果令人满意。     

微波消解-电感耦合等离子体质谱法测定土壤中稀土元素条件优化

稀土元素因其用途广泛,已经得到了越来越多的关注,被应用于各个行业.研究表明,稀土元素对作物的光合作用、产量、抗逆、品质、发育和养分吸收等具有重要作用.作物中的稀土元素主要来自对土壤中稀土元素的吸收,因此,有效分解并快速测定土壤中的稀土元素,可以合理指导稀土元素的施用,对作物的生长和土壤的营养状况具有重要作用.本文比较了...