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The increasing significance of barium (Ba) in environmental and geologic research in recent years has led to interest in the application of the Ba isotopic composition as a tracer for natural materials with complex matrices. Most Ba isotope measurement techniques require separation of Ba from the rest of sample prior to analysis. This paper presents a method using readily available materials and disposable columns that effectively separates Ba from a range of geologic and hydrologic materials, including carbonate minerals, silicate rocks, barite, river water, and fluids with high total dissolved solids and organic content such as oil and gas brines, rapidly and without need for an additional cleanup column. The technique involves off-the-shelf columns and cation exchange resin and a two-reagent elution that uses 2.5 N HCl followed by addition of 2.0 N HNO3. We present data to show that major matrix elements from almost any natural material are separated from Ba in a single column pass, and that the method also effectively reduces or eliminates isobaric interferences from lanthanum and cerium. [ABSTRACT FROM AUTHOR]

In this study, we report the first independent measurements of lutetium isotopic composition using multi-collector ICPMS in four commercial lutetium materials, including a new NRC candidate lutetium isotopic reference material, LUIS-1. The regression model was used to correct for the instrumental isotopic fractionation (mass bias) using NIST SRM 989 isotopic rhenium as the primary calibrator. The regression model is based on a short 15-min measurement sessions at varying ICP plasma power. Isotope ratio of R176/175 = 0.026553(11)k = 1, corresponding isotopic abundances of x176 = 0.025866(11)k = 1, x175 = 0.974134(11)k = 1, and an atomic weight of Ar(Lu) = 174.966693(13)k = 1 were obtained for lutetium in LUIS-1. Uncertainty estimation was performed using a mixture of modeling approaches in accordance with the JCGM 100:2008 "Guide to the Expression of Uncertainty in Measurement" and its Supplement 1. The relative contribution of the rhenium primary standard to the combined uncertainty of 176Lu/175Lu isotope ratio was 15%. [ABSTRACT FROM AUTHOR]

High-purity N was used to increase the mobile phase flow rate during ion purification of ion-exchange resin. This was performed to improve the efficiency of isotope separation and purification, and to meet the efficiency requirements of rapid multiple-collector-inductively coupled plasma mass spectrometry (MC-ICPMS) analysis. For Cu isotope separation, our results indicated that at a gas flow rate >60 mL/min, the separation chromatographic peaks broadened and the recovery rate decreased to <99.2%. On the other hand, no significant change in the Cu peaks was observed at a gas flow rate of 20 mL/min and the recovery rate was determined to be >99.9%. The Cu isotope ratio, measured by the standard-sample bracketing method, agreed with reference data within a ±2 SD error range. The separation time was reduced from the traditional 10 h (without N) to 4 h (with N), indicating that the efficiency was more than doubled. Moreover, Sr and Nd isotope separation in AGV-2 (US Geological Survey andesite standard sample) accelerated with a 20 mL/min gas flow, demonstrating that with the passage of N, the purified liquid comprised Rb/Sr and Sm/Nd ratios of <0.000 049 and <0.000 001 5, respectively. This indicated an effective separation of Rb from Sr and Sm from Nd. MC-ICPMS could therefore be applied to accurately determine Sr and Nd isotope ratios. The results afforded were consistent with the reference data within a ±2 SD error range and the total separation time was shortened from 2 d to <10 h. [ABSTRACT FROM AUTHOR]

Exposure to the neurotoxic element lead (Pb) continues to be a major human health concern, particularly for children in US urban settings, and the need for robust tools for assessment of exposure sources has never been greater. The latest generation of multicollector inductively coupled plasma mass spectrometry (MC-ICPMS) instrumentation offers the capability of using Pb isotopic signatures as a tool for environmental source tracking in public health. We present a case where MC-ICPMS was applied to isotopically resolve Pb sources in human clinical samples. An adult male and his child residing in Milwaukee, Wisconsin, presented to care in August 2015 with elevated blood lead levels (BLLs) (>200 μg/dL for the adult and 10 μg/dL for the child). The adult subject is a gunshot victim who had multiple bullet fragments embedded in soft tissue of his thigh for approximately 10 years. This study compared the high-precision isotopic fingerprints (<1 ‰ 2σ external precision) of Pb in the adult's and child's whole blood (WB) to the following possible Pb sources: a surgically extracted bullet fragment, household paint samples and tap water, and a Pb water-distribution pipe removed from servicing a house in the same neighborhood. Pb in the bullet and adult WB were nearly isotopically indistinguishable (matching within 0.05-0.56 ‰), indicating that bullet fragments embedded in soft tissue could be the cause of both acute and chronic elevated blood Pb levels. Among other sources investigated, no single source dominated the child's exposure profile as reflected in the elevated BLL. [ABSTRACT FROM AUTHOR]

Isotopic compositions of B and Sr in rocks and sediments can be used as tracers for plant provincial sources. This study aims to test whether tea leaf origin can be discriminated using B/B and Sr isotopic composition data, along with concentrations of major/trace elements, in tea specimens collected from major plantation gardens in Taiwan. The tea leaves were digested by microwave and analyzed by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS). The data showed significant variations in Sr/Sr ratios (from 0.70482 to 0.71462), which reflect changes in soil, groundwater or irrigation conditions. The most radiogenic tea leaves were found at the Taitung garden and the least radiogenic ones were from the Hualien garden. The δB was found to change appreciably ( δB = 0.38-23.73 ‰) which could be due to fertilizers. The maximum δB was also observed in tea samples from the Hualien garden. Principal component analysis combining Sr/Sr, δB and major/trace elements results successfully discriminated different sources of major tea gardens in Taiwan, except the Hualien gardens, and this may be due to rather complicated local geological settings. [ABSTRACT FROM AUTHOR]

Lead isotopic compositions of international silicate glasses, feldspar and copper-based samples are obtained using femtosecond laser ablation multiple collector inductively coupled plasma mass spectrometry (fLA-MC-ICPMS). Some international glass standards for the microanalysis are applied to evaluate the method reported here. The Pb isotopic composition of these NIST glasses (SRM 610, 612, 614), USGS (BHVO-2G, BCR-2G, BIR-1G and GSD-1G) and MPI-DING glasses (GOR132-G, KL2-G, T1-G, StHs60/80-G) agree well with recommended values in 2 s error. One of 15 copper-based metals is found to have homogenized Pb isotope data and can be used as an external calibration standard and quality control sample for chalcopyrite, ancient coins, etc., to trace the genesis of metal deposit and culture exchange among different dynasties (GBW02137, 208Pb/ 204Pb = 37.9661 ± 0.0005 (2 s), 207Pb/ 204Pb = 15.5770 ± 0.0002 (2 s), 206Pb/ 204Pb = 17.7462 ± 0.0002 (2 s)). We also prepared a feldspar glass to serve as the external calibration standard/QC for Pb isotope analysis using fLA-MC-ICPMS. [ABSTRACT FROM AUTHOR]

nalysis of naturally occurring isotopic variations is a promising tool for investigating Zn transport and cycling in geological and biological settings. Here, we present the recently installed double-spike (DS) technique at the MAGIC laboratories at Imperial College London. The procedure improves on previous published DS methods in terms of ease of measurement and precisions obtained. The analytical method involves addition of a Zn-Zn double-spike to the samples prior to digestion, separation of Zn from the sample matrix by ion exchange chromatography, and isotopic analysis by multiple-collector inductively coupled plasma mass spectrometry. The accuracy and reproducibility of the method were validated by analyses of several in-house and international elemental reference materials. Multiple analyses of pure Zn standard solutions consistently yielded a reproducibility of about ±0.05‰ (2 SD) for δZn, and comparable precisions were obtained for analyses of geological and biological materials. Highly fractionated Zn standards analyzed by DS and standard sample bracketing yield slightly varying results, which probably originate from repetitive fractionation events during manufacture of the standards. However, the δZn values (all reported relative to JMC Lyon Zn) for two less fractionated in-house Zn standard solutions, Imperial Zn (0.10 ± 0.08‰: 2 SD) and London Zn (0.08 ± 0.04‰), are within uncertainties to data reported with different mass spectrometric techniques and instruments. Two standard reference materials, blend ore BCR 027 and ryegrass BCR 281, were also measured, and the δZn were found to be 0.25 ± 0.06‰ (2 SD) and 0.40 ± 0.09‰, respectively. Taken together, these standard measurements ascertain that the double-spike methodology is suitable for accurate and precise Zn isotope analyses of a wide range of natural samples. The newly installed technique was consequently applied to soil samples and soil leachates to investigate the isotopic signature of plant available Zn. We find that the isotopic composition is heavier than the residual, indicating the presence of loosely bound Zn deposited by atmospheric pollution, which is readily available to plants. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

This paper reviews the problems encountered in eleven studies of Sr isotope analysis using laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) in the period 1995–2006. This technique has been shown to have great potential, but the accuracy and precision are limited by: (1) large instrumental mass discrimination, (2) laser-induced isotopic and elemental fractionations and (3) molecular interferences. The most important isobaric interferences are Kr and Rb, whereas Ca dimer/argides and doubly charged rare earth elements (REE) are limited to sample materials which contain substantial amounts of these elements. With modern laser (193 nm) and MC-ICPMS equipment, minerals with >500 ppm Sr content can be analysed with a precision of better than 100 ppm and a spatial resolution (spot size) of approximately 100 μm. The LA MC-ICPMS analysis of 87Sr/86Sr of both carbonate material and plagioclase is successful in all reported studies, although the higher 84Sr/86Sr ratios do suggest in some cases an influence of Ca dimer and/or argides. High Rb/Sr (>0.01) materials have been successfully analysed by carefully measuring the 85Rb/87Rb in standard material and by applying the standard-sample bracketing method for accurate Rb corrections. However, published LA-MC-ICPMS data on clinopyroxene, apatite and sphene records differences when compared with 87Sr/86Sr measured by thermal ionisation mass spectrometry (TIMS) and solution MC-ICPMS. This suggests that further studies are required to ensure that the most optimal correction methods are applied for all isobaric interferences. [ABSTRACT FROM AUTHOR]