Determination Of Lead Isotope Ratios Research Articles

Precise determination of lead isotope ratios by MC-ICP-MS without matrix separation exemplified by unique samples of diverse origin and history

Pb isotope ratios in samples of diverse origin can be accurately measured without matrix separation.

Determination of lead isotope ratios by inductively coupled plasma mass spectrometry and comparison of lead isotope ratios among different samples

Determination of lead isotope ratios by inductively coupled plasma mass spectrometry and comparison of lead isotope ratios among different samples

Optimisation of a current generation ICP-QMS and benchmarking against MC-ICP-MS spectrometry for the determination of lead isotope ratios in environmental samples

Novel ANOVA methodology was used to benchmark ICP-QMS against MC-ICP-MS for Pb isotope ratios, demonstrating “fitness-for-purpose” in source apportionment.

Determination of lead isotope ratios in Mn–Fe-rich nodules by laser ablation multi-collector inductively coupled plasma mass spectrometry

In this study, Pb isotope ratios in ferromanganese nodules were determined with good repeatability and minimum laboratory bias using laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS).

Determination of lead isotope ratios in uranium mine products in South Africa by means of inductively coupled plasma mass spectrometry

Nuclear terrorism has led to newer investigative methods for building national nuclear forensic libraries. The objective of this work was to resolve these signatures by applying the ICP-MS for isotope ratio (IR) analysis on uranium containing samples. Lead (Pb) isotope ratios for the studied gold mine has 207Pb/204Pb values between 13–20 and 206Pb/204Pb values ranging from 16–25, which confirm that the Carletonville gold fields are of uraninite detrital pyrite deposits. Trace elemental concentrations indicated a pyrite type of uranium deposit. Uranium in the deposit exhibits geochemical signatures of the radiogenic formations of the ore enhanced in 206Pb.

Non-matrix-matched determination of lead isotope ratios in ancient bronze artifacts by femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry

In this study, lead isotopic ratios in bronze artifacts were non-matrix-matched determined directly by femtosecond laser ablation multi-collector inductively coupled plasma mass spectrometry (fsLA-MC-ICP-MS). We evaluated the necessity of matrix matching for lead isotope ratio analyses of bronzes by adopting thallium solution to correct mass discrimination during mass spectrometer measurements. Lead isotope ratios of four bronze reference materials were measured by fsLA-MC-ICP-MS to determine the quality of data when calibrating samples with standards having different physical characteristics and chemical compositions. The average 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb, 207Pb/206Pb and 208Pb/206Pb ratios determined by fsLA-MC-ICP-MS were within 0.06% of that by solution nebulizer MC-ICP-MS (SN-MC-ICP-MS). The results indicate that accurate lead isotopic compositions could be obtained by fsLA-MC-ICP-MS technique after non-matrix-matched standards calibration. Additionally, the lead isotopic compositions are presented for five Chinese bronze reference materials using fsLA-MC-ICP-MS. Homogeneity of lead isotope distribution was expressed as the RSD range from 0.010% to 0.017% for 208Pb/204Pb, 207Pb/204Pb, 206Pb/204Pb ratios. Therefore, the five bronze materials could potentially serve as external calibration standards and quality control samples for in situ lead isotope measurements of ancient bronze artifacts. The fsLA-MC-ICP-MS technique could be applied to differentiate the high radiogenic lead in bronze artifacts from common lead.

Recent literature on lichens—235

Recent literature on lichens—235

Lead isotope ratios for bullets, a descriptive approach for investigative purposes and a new method for sampling of bullet lead

To establish a link between a bullet fired from a suspected firearm, investigation of striation marks are one of the corner stones in the forensic laboratory. Nevertheless, on some occasions, the bullet may be deformed to such extent that traditional investigation of striation marks will be impossible.Fragments of lead can be investigated by lead isotope ratio determination in order to distinguish between bullets with different origin. This approach initially seems reasonable, since the abundance of lead isotopes varies significantly in nature.To make a method valid for forensic purposes, it is important to have a fundamental understanding of the variation within a box of lead bullets and the expected variation between boxes. Studies of variability within and between boxes of ammunition are imperative to perform any type of forensic interpretation, both in an investigative and evaluative context.This work presents an extensive study of variability within and between boxes of ammunition by use of multicollector inductive coupled mass spectrometry. As a first approximation to classify bullets to any given source, a simple and robust graphical method is presented. In addition, an easy-to-use sampling procedure of lead is presented.

Determination of lead isotope ratios in environmental matrices by quadrupole ICP-MS working at low sample consumption rates

Measurement of lead isotope ratios in environmental matrices using inductively coupled plasma-dynamic reaction cell-mass spectrometry at low sample consumption rates was investigated. Two micro-sample introduction systems were evaluated, namely the PFA micronebuliser associated with a low-volume spray chamber, working at 150 μL min−1 and the total-consumption sample introduction system TISIS, operating at 20 μL min−1. In both cases, the dynamic reaction cell pressurised with ammonia was applied to improve the precision by collisional damping. Under optimal operating conditions, 208Pb/207Pb and 206Pb/207Pb ratios were accurately determined with an internal precision of 0.12–0.13% and 0.17–0.18% (%RSD, n = 10, c = 10 μg L−1; t = 10 s). The sample consumption for the assessed sample introduction systems was less than 1.5 mL and 200 μL, allowing the precise analysis of limited-size samples and pre-concentrates. The developed method was characterised in terms of the analytical working range, in-cell interference, and uncertainty estimation. The applicability of the analytical method was demonstrated by the analysis of the lichen reference material CRM 482, as well as those of several environmental samples collected from polar regions, including atmospheric particulate, snow, marine suspended particulate matter and sediment. In particular, by combining a simple pre-concentration procedure with the application of TISIS, it was possible to perform the lead isotope analysis of Antarctic snow samples at the pg g−1 concentration level.

Application of laser ablation inductively coupled plasma multicollector mass spectometry in determination of lead isotope ratios in common glass for forensic purposes

Samples of glass used as trace evidence in criminal cases are commonly small, with particle sizes below a millimeter. To perform chemical analysis suitable for forensic purposes, methods capable of analyzing such small samples are required.In this paper, analyses of lead isotope ratios by means of laser ablation inductively coupled multicollector mass spectrometry (LA-MC-ICP-MS) are presented. Sampling by use of laser ablation allows fragments down to 0.1mg to be analyzed with sufficient precision to discriminate between glasses of different origin. In fact, the use of lead isotopes determined by LA-MC-ICP-MS approaches the discrimination attainable by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) analysis of dissolved samples of 5mg or more.Further, we have obtained a probability distribution by two dimensional kernel density estimates for the collected data set as an alternative presentation method to the well-established bivariate plot. The underlying information available from kernel density estimates is of importance for forensic scientists involved in probabilistic interpretation of physical evidence.

Isotope ratio determination of objects in the field by portable laser ablation sampling and subsequent multicollector ICPMS

Laser ablation coupled to multicollector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) allows accurate and precise isotope ratio determination of solid samples in a quasi-nondestructive manner, making the technique interesting for isotopic provenance studies of valuable historical artifacts. In order to enable LA-MC-ICPMS analysis of objects that cannot be transported to the laboratory for analysis, a portable laser ablation sampling device was applied. Ablated material was collected on filters, which were subsequently analyzed in the laboratory by means of MC-ICPMS. Filters were analyzed by: (I) acid digestion followed by solution nebulization MC-ICPMS and (II) fast scanning filter ablation coupled to MC-ICPMS. For both procedures, the analytical performance was investigated for lead isotope ratio measurements in ceramics, lead ore (galena) and the metallic lead standard NIST SRM 981. Filter digestion followed by solution analysis allowed determination of lead isotope ratios with external precisions of better than 0.10‰. Mass-dependent deviations towards lighter isotope ratios of 0.10‰ per u were observed for metallic lead, which indicates to a low extent isotopic fractionation during the sampling procedure. Filter ablation coupled to MC-ICPMS resulted in reduced precision compared to the solution measurements. However, it enabled straightforward simultaneous isotopic and elemental analysis by splitting the carrier gas flow to a MC-ICPMS and quadrupole ICPMS. In summary, portable LA sampling followed by MC-ICPMS analysis was shown to enable lead isotope ratio determinations of objects in the field with an analytical performance similar to a laboratory-based analysis. The approach was applied to lead isotope provenancing of ancient Chinese ceramics.

Determination of Lead Isotope Ratios in Bullet Samples for Forensic Purpose by Single Collector High-resolution ICP-MS

単一検出器型の高分解能誘導結合プラズマ質量分析計（ICP-MS）を用いる高精度な鉛同位体比分析法を開発した．ICP-MSの測定条件や質量差別効果の補正法について最適な分析条件を検討した．補正法として，挟み込み法，内部補正法，両者の併用の3種類について検討した結果，挟み込み法で最も良い結果が得られた．銃弾試料28点の鉛同位体比（208Pb/206Pb，207Pb/206Pb）の日内測定精度の相対標準偏差の平均が共に0.034％ と，単一検出器型のICP-MSでも多重検出器型ICP-MSと比較しても劣らない精度で鉛同位体比分析が可能であった．この分析条件を用いて鉛同位体比による銃弾の識別を試みたところ，銃弾の識別率はライフル用銃弾13点で69％，ハンドガン用銃弾15点で87％ と，鉛同位体比が銃弾の識別において非常に有力な手法であることを示した．なお，本稿には示していないが，同装置による微量元素分析の結果を同位体比と併用するとすべての銃弾の識別が可能であった．

Lead contamination and its potential sources in vegetables and soils of Fujian, China

Lead (Pb) contents and partition in soils collected from eleven vegetable-growing lands in Fujian Province, China, were investigated using a modification of the BCR (Community Bureau of Reference) sequential extraction procedure coupled with the Pb isotope ratio technique. Pb contents in Chinese white cabbage (B. Chinensis L.) grown on the lands for this study were also measured. Results showed that Pb concentrations in fifty samples of topsoil ranged from 456 to 21.5 mg kg(-1), with each mean concentration of six sampling lands exceeding the national standard (50 mg kg(-1)); while Pb concentrations in edible portions of thirty-two vegetable samples ranged from 0.009 to 2.20 mg kg(-1), with four sampling sites exceeding the national sanitary standard (0.2 mg kg(-1)). A significant correlation (r = 0.971, P < 0.01) of Pb contents in the acid-extractable fractions by BCR approach and the vegetables was observed, which indicates that the acid-extractable Pb is useful for evaluating the metal bioavailability for plants and potential risk for human health in soils. The determination of lead isotope ratios in different chemical forms of soils by BCR sequential extraction procedures provides useful information on the Pb isotopic composition associated with different soil fractions (especially in the acid-extractable fractions), and the result is helpful for the further study on controlling and reducing Pb contamination in vegetable-growing soils.

Quantification of transient signals in multiple collector inductively coupled plasma mass spectrometry: accurate lead isotope ratio determination by laser ablation of individual fluid inclusions

This work establishes the analytical protocol for accurate Pb isotopic analysis of fast transient signals by multiple-collector ICP-MS instruments. Individual synthetic fluid inclusions of known Pb and Tl isotopic compositions (dissolved SRM 981 with or without SRM 997 from NIST, enclosed in quartz by a hydrothermal crack annealing technique) were liberated by 193 nm UV laser ablation (LA). Data were recorded on Faraday detectors, for which correction schemes for bias in amplifier response (“tau correction”) are presented and evaluated. tau-Corrected Pb isotope data reveal LA-induced isotope fractionation amounting to ∼0.5% amu−1 for Pb isotopes over the course of an entire fluid inclusion ablation. Instrumental mass bias correction was effected within-run using Tl provided by the fluid inclusion itself or admixed to the ablation aerosol via desolvated nebulization. Isotope ratios derived from the transient signals were either based on individual readings or on bulk signal integration, of which the latter produces significantly more accurate data. The external precision achieved by ablating SRM 610 glass with a 60 µm beam is ±0.011% (2 SD, relative) for 208Pb/206Pb and 207Pb/206Pb ratios and ±0.032% for Pb isotope ratios normalized to mass 204 (n = 18). Inclusion-to-inclusion reproducibilities (n = 11; ∼0.1 ng Pb per inclusion) are ±0.05% (2 SD; 208Pb/206Pb and 207Pb/206Pb) and ±0.13% (20xPb/204Pb), respectively; inclusions containing as little as 0.005 ng Pb returned ±0.1% and ±0.8%. These results are accurate as demonstrated by analysis of synthetic fluid inclusions containing SRM 981 Pb. The analytical protocol presented here for measuring isotope ratios on minute analyte quantities by multiple-collector ICP-MS in fast transient signal mode has great potential for applications to geochemical, archaeological, environmental and possibly biochemical problems.

ICP-MS determination of lead isotope ratios in legal and counterfeit cigarette tobacco samples

A method for the determination of Pb isotope ratios (IR) in cigarette tobacco by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) has been developed and applied to tobacco samples from genuine and counterfeit cigarettes obtained in the USA. The IR 207Pb/206Pb, 208Pb/206Pb, 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb were measured using a Q-ICP-MS instrument. Two certified reference materials, grown in the USA and Bulgaria, were also analysed for comparison with the tobacco samples, as were tobacco samples from cigarettes obtained in Pakistan and China. The precision of the results was sufficient to distinguish between the counterfeit and genuine USA cigarettes. All of the genuine cigarettes and both reference materials, grown in different regions, were statistically distinct based on the measured ratios. The counterfeit cigarettes were indistinguishable from the reference material grown in Bulgaria. The technique shows promise as a method for identifying counterfeit cigarettes, possibly determining the source region.

Determination of lead isotope ratios in clinopyroxene by inductively coupled plasma mass spectrometry applying solution nebulization or laser ablation sample introduction techniques

Lead isotope ratios were determined in clinopyroxene originating from Hungary and in a Japanese basalt standard (JB-2) by a single-collector inductively coupled plasma sector field mass spectrometer applying solution nebulization and laser ablation (LA) as sample introduction techniques. The solutions were prepared by dissolution of samples in a mixture of HF/HNO3 and isolation of analyte by Pb-selective crown ether resin. The separation of Pb from the matrix and other compounds lowered the contribution of the major interference (204Hg) to the counts of 204Pb to less than 1%. More than 94.5% and 98.4% of the Pb content of the clinopyroxene and JB-2 samples, respectively, could be collected on the resin. The relative standard deviations of the measured Pb isotope ratios obtained by solution technique changed between 0.3% and 0.5%. In the case of LA with repetition rate of 10 Hz and spot size of 100 µm these values were between 1.3% and 1.6%.

Laser ablation-inductively coupled plasma-dynamic reaction cell-mass spectrometry for the determination of lead isotope ratios in ancient glazed ceramics for discriminating purposes

The potential of laser ablation-single collector-inductively coupled plasma-mass spectrometry for discrimination among Spanish antique lead-glazed ceramics according to age and workshop has been investigated. In order to obtain the required precision, pressurizing the dynamic reaction cell (DRC) with Ne proved to be a significant help. In this way, it was feasible to obtain RSD values in the range 0.15–0.25% (internal precision) for the ratios calculated using the most abundant Pb isotopes (206Pb, 207Pb and 208Pb), under optimized conditions. These values are 2–3 times lower than those that could be achieved in standard (vented) mode and proved to be sufficient for distinguishing between the different groups of samples under study. The method finally proposed was demonstrated to show interesting features, such as the potential to obtain spatially resolved isotopic information in approximately 30 min measurement time per sample, with negligible (ng level) sample damage. On the other hand, it has to be mentioned that the use of the DRC results in an undesired enhancement in the mass discrimination that has to be corrected for. Only by using a perfectly matrix-matched standard (in the current work, one sample of each group that was analyzed by an alternative procedure in order to obtain a suitable reference value), accurate correction for this effect became possible. Obviously, this is somewhat inconvenient, but the possibility of analyzing the vast majority of the samples in a fast, quasi non-destructive, spatially resolved and cost-effective way (particularly when comparing with the use of dedicated techniques for isotopic analysis) may be appealing for archaeological laboratories.

Measurement of Pb isotope ratios by continuous leach–inductively coupled plasma–mass spectrometry: quantification of precision and accuracy

Precision and accuracy have been quantified for the determination of lead isotope ratios using continuous leach–inductively coupled plasma–mass spectrometry (CL-ICP-MS) by optimizing acquisition parameters and minimizing the number of elements in the method. By analysing for only 204 Pb, 206 Pb, 207 Pb, 208 Pb, 200 Hg, and 202 Hg, counting times can be increased allowing improvements in isotope ratio precision over normal CL-ICP-MS determinations, which measure these elements as part of a much larger suite. At total Pb concentrations of 1 ppb in solution, results show that precisions of 6.7% to 8.3% and 7.8% to 21% can be achieved for 207 Pb/ 206 Pb and 207 Pb/ 204 Pb, respectively, over the 0% to 30% HNO 3 concentrations used in CL-ICP-MS. Accuracy, as measured against the certified values for NIST 981, ranges from 0.5% to 1.4% and 1.4% to 21% for 207 Pb/ 206 Pb and 207 Pb/ 204 Pb, respectively. The improvement in precision and accuracy afforded by this technique allows greater differentiation of isotopically distinct reservoirs of Pb within natural samples collected for exploration and environmental geochemistry.

Precise and accurate determination of lead isotope ratios in mining wastes by ICP-QMS as a tool to identify their source

A methodology for a precise and accurate determination of lead isotope ratios in mining wastes by inductively coupled plasma quadrupole-based mass spectrometry (ICP-QMS) has been developed. The study of instrumental bias factors led to the conclusion that internal correction to compensate mass discrimination is required as well as an interference equation correction when Hg is present. The proposed method has been applied to determine lead isotope ratios in several mining wastes, soils and sediments collected at three mining areas in Spain (Aran Valley, Cartagena and Osor). Statistical analysis highlights that 206Pb/ 207Pb and 208Pb/ 207Pb lead isotope ratios can be used as a fingerprint of mining waste origin which is related to the geological age of the lead ore. On the other hand, no statistically significant isotopic differences between original ore samples (galena) and processing wastes within a mining district were found, corroborating a unique lead source. Moreover, the lead isotopic composition of soil and sediment samples collected at the studied mining areas is close to that determined in the mining tailings from the same areas, suggesting that the unusual high content of lead in these samples is derived from mining activities rather than from other lead sources.

Determination of lead isotope ratios in crude oils with Q-ICP/MS

A method was developed to directly measure lead isotope ratios in crude oils by ICP-MS. Sample introduction strategy was based on the mixing of a USN produced dry aerosol together with an organic aerosol. Two introduction systems, a USN and a Scott-type spray chamber, were fitted to a specifically designed dual inlet torch. This specific configuration allowed simultaneous introduction of organic solutions and aqueous solutions in the plasma, and permitted mass bias correction of lead isotope ratios using the certified Pb isotope standard NIST SRM 981. Crude oils diluted to total Pb concentrations ranging from 0.6 to 10 ng g−1 were analysed for their Pb isotope ratios. A careful optimisation of instrumental settings was performed for the measurement of lead isotope ratios. In order to determine the best operating conditions, isotope ratio precision, different dwell times, number of sweeps/replicate, and settle times were investigated while keeping the same total acquisition time/run of 43.2 seconds distributed between 202Hg, 204Pb, 206Pb, 207Pb, and 208Pb isotopes. The use of 1.5 ms as a settle time and 1000 sweeps for 43.2 s of total acquisition time/run and 7.5 s of stabilisation time/run appeared to be a good compromise between high precision and fair time management. Routine measurements of 10 replicate (i.e. run) organic samples containing 10 ng g−1 of lead provided precision better than 0.2% for 208Pb/207Pb, 208Pb/206Pb, 206Pb/207Pb ratios, and better than 0.5% for 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios. The isotopic measurements of crude oils of specific geochemical interest exhibited good accuracy and reproducibility, making highly convenient the use of this technique, at least for petroleum geochemistry. This study brings new isotopic information for the reconstruction of petroleum system history.