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Complexation of cadmium and copper by fluvial humic matter and effects on their toxicity
Date: 2006-12-18

Authors: Corami, F;Capodaglio, G;Turetta, C;Bragadin, M;Calace, N;Petronio, BM;
Products: µflow PFA-100 nebulizer

Abstract: The effects of humic acids and fulvic acids isolated from the River Arno (Italy) on the bioavailability and toxicity of cadmium and copper were assessed in relation to changes in their speciation. Measurements of the complexing capacity of solutions containing these organic ligands were carried out by a titration procedure followed by DPASV and toxicity tests were carried out using lysosomes isolated from rat liver. The complexing capacity of the physiological medium containing about 13 mg/L of humic acids, expressed as ligand concentrations, was 0.30 and 0.072 µmol/L for cadmium and copper respectively; the corresponding conditional stability constants were 4.2 x 1011 and 1.3 x 108 (mol/L)-1. The complexing capacities of the solution containing the same amount of fulvic acids were 0.33 and 0.164 µmol/L for cadmium and copper respectively, the conditional stability constants were 3.2 x 1011 and 2.4 x 107 (mol/L)-1. The humic acids reduced the toxicity of cadmium by about 5 times: the EC50 changed from 4.4 to 20.4 µmol/L. The dose effect curve of copper presented a bi-sigmoid trend and two EC50 values can be determined: The EC50(1) in the presence of humic acids changed from 2.0 to 3.1 µmol/L, while the EC50(2) increased from 22.3 to 45.3 µmol/L. The fulvic acids reduced the cadmium toxicity by about the same amount as humic acids, from 4.4 to 18.6 µmol/L, but they had no effect on copper toxicity. Analysing the chemical speciation of cadmium and copper in the presence of humic components and under toxicity test conditions we can say that the appreciable decrease of EC50 is not related to changes in their speciation; we can hypothesize that this is due to different processes, as well as to blocking of the lysosomal membrane. On the basis of the shape of the dose-effect curves obtained for cadmium and copper respectively, we can say that the toxic effects of the two metals are different and we can hypothesize that copper could exercise its toxic activity by inhibiting the ATP-driven proton pump and the function of the Cl- selective channel.

Journal: Ann Chim
Volume: 97  -  Pages: 25-37
DOI: 10.1002/adic.200690083

Plasma temperature measurement of a low-pressure inductively coupled plasma using spectroscopic methods
Date: 2003-07-09

Authors: Sung, Y;Lim, HB;
Products: µflow PFA-100 nebulizer

Abstract: Direct nebulization of an aqueous sample was successfully carried out in our laboratory in a lab-built low pressure-inductively coupled plasma (LP-ICP) using a double membrane desolvator (DMD). For the particular LP-ICP used, rotational temperatures of selected diatomic molecules and excitation temperatures of Fe II and Fe I were measured. The OH radical showed two rotational temperatures, low and high. The former were obtained in the range 800 to 1100 K, while the latter were obtained between 1850 and 2800 K. The molecular nitrogen ion consistently obtained the same temperatures as those of the high rotational temperatures of the OH radical. This result suggests that the high density of rotational states of these molecules, N+2 and OH radical, allows collisional energy exchange between molecular rotational and argon translational degrees of freedom in the plasma. An increase of plasma gas flow from 0.3 to 1.1 L min1 produced a decrease of excitation temperatures of Fe II from 10400 to 9200 K. The excitation temperature of Fe I was measured to be about 6000 K. Noticeably, the excitation temperature of Fe ion was high, and even higher than that reported in an atmospheric ICP. This experiment provides proof that the mechanism of ionization and excitation was influenced mainly by the character of electrons in the low-pressure plasma.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 18  -  Pages: 897-901
DOI: 10.1039/B303191H

Low-pressure ICP-AES with electrothermal vaporizer and a pneumatic nebulizer for aqueous sample introduction
Date: 2005-05-01

Authors: Jung, T;Kim, Y;Lim, HB;
Products: µflow PFA-100 nebulizer

Abstract: A typical electrothermal vaporization (ETV) using a tantalum was built for low-pressure ICP-AES. The analytical performance of the ETV was tested and compared with that of a PFA pneumatic nebulizer with a double membrane desolvator (DMD). The limits of detection of the ETV were obtained in the range of 3.4 ng to 758 ng for Zn, Cu, Co, Fe, and Mg, while those of the PFA nebulizer were in the range of 53 ppb to 286 ppb. A relative standard deviation (RSD) of 4.3 - 8.5% for ETV was obtained, while 2.15 - 6.84% RSD was found for DMD.

Journal: Analytical Sciences
Volume: 21  -  Pages: 569-71
DOI: 10.2116/analsci.21.569

Aqueous sample introduction into a low-pressure inductively coupled plasma using a double membrane desolvator
Date: 2001-06-04

Authors: Sung, Yi;Lim, HB;
Products: µflow PFA-100 nebulizer

Abstract: A low-pressure inductively coupled plasma atomic emission system with a double membrane desolvator (DMD) was built in the laboratory. For high solvent removal efficiency by the DMD, the plasma was easily turned on and sustained for more than 8 h while an aqueous sample solution was nebulized. The dimensions of the torch are similar to that of a mini-torch, but there is no intermediate tube. Inner diameters of the torch and the sample injector tube are 10 mm and 1.5 mm, respectively. The plasma gas flowed tangentially and formed a plasma. A narrow central channel was formed inside the plasma when the aerosol gas flowed, and atomic emission was observed at the end-on side of the plasma. The system was optimized by changing various operating factors while the Mg signal was monitored. As the flow rate of the plasma gas changed from 0.2 to 1.0 L min-1, the signal-to-background ratio (S/B) increased. When the total gas flow of the DMD changed from 1.4 to 3.5 L min-1 and the flow rate ratio of the inner to the outer gas was fixed at 5:2, the S/B of Mg II doubled while the OH emission intensity decreased by approximately 67%. The chamber pressure was maintained in the range of a few Torr, which also influenced system optimization. Unlike atmospheric pressure ICP-AES, this low-pressure ICP system showed a much stronger intensity of the Mg II, 280.270 nm line compared to that of Mg I, 285.213 nm.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 16  -  Pages: 767-770
DOI: 10.1039/B101224J

Solution-based determination of trace elements in biogenic carbonates: comparison of two sample introduction systems for use in flow injection ICPMS analysis
Date: 2009-05-11

Authors: Robinson, CD;Devalla, S;Rompaisa, M;Davies, IM;
Products: 1 mm id quartz injector,PFA-ST microconcentric nebulizer/PC 3 Peltier-cooled cyclonic spray chamber

Abstract: The elemental composition of fish ear stones (otoliths) is used to inform upon environmental conditions, fish migrations, population structure, and nursery areas. We compared two nebuliser/spray chamber configurations for determining concentrations of Mg, Ca, Mn, Cu, Zn Rb, Sr, Ba, La and Pb in acidic otolith digests using flow injection ICPMS with: (1) cross-flow nebulizer/Scott spray chamber and (2) microconcentric nebuliser/Peltier-cooled cyclonic spray chamber. For most elements, both configurations had acceptable accuracy (within certified or indicative ranges) and precision (<10%) using FEBS-1 certified reference material (CRM), although more elements met these criteria using the second arrangement. Improved detection limits, accuracy, and precision were obtained using the micro-flow nebulizer and cooled spray chamber and this configuration also used 50% less sample, it is therefore the preferred arrangement for solution-based otolith analysis, particularly when sample size is limited.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 24  -  Pages: 939-943
DOI: 10.1039/B904170B

Determination of phosphorus in phosphorylated deoxyribonucleotides using capillary electrophoresis and high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry with an octopole reaction cell
Date: 2003-05-09

Authors: Pröfrock, D;Leonhard, P;Prange, A;
Products: 100 µL PFA micro-flow nebulizer

Abstract: The determination of phosphorus in a biologically relevant sample matrix such as DNA is described. The analytical methodology used is based on a robust on-line coupling of capillary electrophoresis (CE) or high performance liquid chromatography (HPLC) with inductively coupled plasma mass spectrometry, equipped with an octopole reaction system (ORS-ICP-MS). Polyatomic ions formed in the plasma and the interface region of the ICP-MS that interfere with the determination of P at mass 31 were minimised by the addition of helium to the collision cell. Instrumental detection limits of 125 ng L-1 for 31P, and in the range of 18 to 49 ng L-1 for the other trace elements, were achieved under the conditions described. In order to demonstrate the high separation and detection efficiency of the system, the method developed has been applied to the element specific detection of phosphorus in monophosphorylated deoxynucleotides and to enzymatically digested calf thymus DNA after CE and HPLC separation, respectively. Both hyphenated techniques provide baseline separation of the four deoxynucleotide monophosphates (dNMP), which are present in the DNA chain. With CE-ICP-MS, detection limits for phosphorus down to 53 µg L-1 (2´ -deoxyguanosin-5´ -monophosphate, dAMP) (corresponding to 0.6 pg P absolute) have been achieved. RSDs of the migration times were about 5%. Using HPLC-ICP-MS, detection limits down to 3 µg L-1 (2´ -deoxythymidine-5´ -monophosphate, dTMP) (corresponding to 0.03 ng P absolute) were obtained. The migration/elution order of the deoxynucleotides investigated was obtained by comparison with the migration/retention times of commercially available dNMP's. Furthermore it was checked if HPLC-ESI-MS can be operated under the same chromatographic conditions for the confirmation of the elution order and for the characterisation of unknown peaks. Finally, flow injection analysis (FIA) was used for the quantification of the phosphorus content in the dNMP samples. Using FIA, detection limits for phosphorus of 2.5 µg L-1 corresponding to 25 pg phosphorus absolute were achieved.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 18  -  Pages: 708-713
DOI: 10.1039/B302445H

Vanadium induces dopaminergic neurotoxicity via protein kinase Cdelta dependent oxidative signaling mechanisms: Relevance to etiopathogenesis of Parkinson's disease
Date: 2009-10-15

Authors: Ngwa, HA;Kanthasamy, A;Anantharam, V;Song, C;Witte, T;Houk, R;Kanthasamy, AG;
Products: 100 l/min self-aspirating PFA nebulizer

Abstract: Environmental exposure to neurotoxic metals through various sources including exposure to welding fumes has been linked to an increased incidence of Parkinson's disease (PD). Welding fumes contain many different metals including vanadium typically present as particulates containing vanadium pentoxide (V2O5). However, possible neurotoxic effects of this metal oxide on dopaminergic neuronal cells are not well studied. In the present study, we characterized vanadium-induced oxidative stress-dependent cellular events in cell culture models of PD. V2O5 was neurotoxic to dopaminergic neuronal cells including primary nigral dopaminergic neurons and the EC50 was determined to be 37 µM in N27 dopaminergic neuronal cell model. The neurotoxic effect was accompanied by a time-dependent uptake of vanadium and upregulation of metal transporter proteins Tf and DMT1 in N27 cells. Additionally, vanadium resulted in a threefold increase in reactive oxygen species generation, followed by release of mitochondrial cytochrome c into cytoplasm and subsequent activation of caspase-9 (> fourfold) and caspase-3 (> ninefold). Interestingly, vanadium exposure induced proteolytic cleavage of native protein kinase Cdelta (PKCδ, 72-74 kDa) to yield a 41 kDa catalytically active fragment resulting in a persistent increase in PKCδ kinase activity. Co-treatment with pan-caspase inhibitor Z-VAD-FMK significantly blocked vanadium-induced PKCδ proteolytic activation, indicating that caspases mediate PKCδ cleavage. Also, co-treatment with Z-VAD-FMK almost completely inhibited V2O5-induced DNA fragmentation. Furthermore, PKCδ knockdown using siRNA protected N27 cells from V2O5-induced apoptotic cell death. Collectively, these results demonstrate that vanadium can exert neurotoxic effects in dopaminergic neuronal cells via caspase-3-dependent PKCδ cleavage, suggesting that metal exposure may promote nigral dopaminergic degeneration.

Journal: Toxicology and Applied Pharmacology
Volume: 240  -  Pages: 273-285
DOI: 10.1016/j.taap.2009.07.025

Precise determination of the lithium isotope ratio in geological samples using MC-ICP-MS with cool plasma
Date: 2013-01-24

Authors: Choi, MS;Ryu, JS;Park, HY;Lee, K;Kil, Y;Shin, HS;
Products: 100 PFA microFlow PFA nebulizer

Abstract: Lithium has two naturally occurring isotopes, 6Li and 7Li, with approximate relative abundances of 7.5% and 92.5%, respectively. Due to large Li isotope variations in nature, lithium isotopes have the potential to reveal important information relevant to nuclear technology, biomedicine, astrophysics, and geochemistry. With the advent of multi-collector inductively coupled mass spectrometry (MC-ICP-MS), studies of Li isotopes have largely focused on the analysis of geological materials, with varying degrees of accuracy. However, this technique has often been affected by either baseline interferences or isobaric interferences on mass 6 and 7 during ionization in Ar plasma, which is mainly due to the Li compound with hydrogen gas, and double-charged nitrogen and carbon ions at higher levels of RF power. In this study, we reduced baseline interferences in Ar plasma using a cool plasma (~800 W) technique with a X-type cone. Lithium was separated using a cation exchange column (BioRad AG50W-X8, 200-400 mesh) with a mixture of 6 N HNO3 and 80% methanol at <0.2 mL min-1 elution speed. The short-term reproducibility of δ7Li values of the NASS-5 seawater standard was 30.55 ± 0.45‰ (2σ, n = 15). Measured δ7Li values of rock and seawater standards ranged from 2.48 to 30.55‰, in good agreements with reported values.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 28  -  Pages: 505-509
DOI: 10.1039/C2JA30293D

Reconstructing Diets and Origins of Vikings at Hrísbrú, Mosfell Valley, Iceland: The Carbon, Nitrogen, and Strontium Isotope Evidence
Date: 2014-01-01

Authors: Grimes, V;Fuller, BT;Guiry, EJ;
Products: 100 µL microflow PFAST nebulizer

Abstract: The Viking North Atlantic differs significantly from the popular image of violent raids and destruction characterizing the Viking Age in Northern Europe. In Iceland, Scandinavian seafarers discovered and settled a large uninhabited island. In order to survive and succeed, they adapted lifestyles and social strategies to a new environment. The result was a new society: the Icelandic Free State. This volume examines the Viking Age in Iceland through the discoveries and excavations of the Mosfell Archaeological Project (MAP) in Iceland's Mosfell Valley. Directed by Professor Jesse Byock with Field Director Davide Zori, MAP brings together scholars and researchers from Iceland, Britain, Canada, Denmark, Norway, Sweden, Germany, and the United States. The Project incorporates the disciplines of archaeology, history, saga studies, osteology, zoology, paleobotany, genetics, isotope studies, place-names studies, environmental science, and historical architecture. The decade-long research of MAP has led to the discovery of an exceptionally well-preserved Viking chieftain's farmstead, including a longhouse, a pagan cremation site, a conversion-era stave church, and a Christian graveyard. The research results presented here tell the story of how the Mosfell Valley developed from a ninth-century settlement of Norse seafarers into a powerful Icelandic chieftaincy of the Viking Age.

Journal: Viking Archaeology in Iceland: Mosfell Archaeological Project
Volume: 20  -  Pages: 105-116
DOI: 10.1484/M.CURSOR-EB.1.102215

Neodymium isotope ratio measurements by LC-MC-ICPMS for nuclear applications: investigation of isotopic fractionation and mass bias correction
Date: 2014-12-08

Authors: Guéguen, F;Isnard, H;Nonell, A;Vio, L;Vercouter, T;Chartier, F;
Products: 100 µL/min microconcentric PFA nebulizer

Abstract: Accurate measurements of neodymium isotope ratios in irradiated nuclear fuel samples are fundamental for the validation of neutronic calculation codes, in particular for burn-up qualification. To prevent possible spectral and non-spectral interferences, neodymium is generally purified from the complex sample matrices prior to measurements by mass spectrometric techniques. This work describes the on-line coupling of ion exchange chromatography with multi-collector inductively coupled plasma mass spectrometry for Nd isotope ratio measurements. In the first part of the paper, the causes of the isotope ratio drifts traditionally observed during transient signal acquisitions are investigated. Both mass-dependent isotopic fractionation on the chromatographic column and distinct time lags between amplifier responses of the Faraday cup configuration were shown to be the main phenomena involved in the observed isotope ratio drifts. In the second part, we present a new approach for mass bias correction called "Intra Injection Sample-Standard Bracketing (IISSB)" based on direct "on-line" injection of the standard via the chromatographic system before and after the analyte. This new method, particularly adapted to analysis of nuclear materials, was validated by on-line measurements on a simulated sample representative of fission products present in an irradiated uranium material. Reproducibilities obtained by IISSB were found to be comparable with those found in off-line measurements and classical sample-standard bracketing technique for mass bias correction on all Nd isotope ratios.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 30  -  Pages: 443-452
DOI: 10.1039/C4JA00361F

Determination of 90Sr in contaminated environmental samples by tuneable bandpass dynamic reaction cell ICP-MS
Date: 2006-11-17

Authors: Taylor, VF;Evans, RD;Cornett, RJ;
Products: 100 µL/min PFA nebulizer

Abstract: A rapid method for the extraction and determination of 90Sr in natural water, plant and sediment samples was developed using extraction chromatography and dynamic reaction cell ICP-MS, with O2 as a reaction gas. While isobaric interference from the stable isotope 90Zr was efficiently removed by this method, interferences produced from in-cell reactions with Fe+ and Ni+ required suppression by tuneable bandpass, and in sediments, additional chromatographic separation. Method detection limits were 0.1 pg g-1
(0.5 Bq g-1), 0.04 pg g-1(0.2 Bq g-1), and 3 pg L-1 (5 Bq L-1) for sediments, plant and water samples, respectively, and 90Sr concentrations determined by ICP-MS were in good agreement with activities determined by Cerenkov counting and with certified reference values. While mass spectrometric determination does not rival detection limits achievable by radiometric counting, radiometric determination of 90Sr, a pure beta-emitter, is hindered by long analysis times (several weeks); the comparatively fast analysis achieved via ICP-MS enables same-day preparation and analysis of samples, making this an important technique for the environmental monitoring of areas contaminated by radioactivity.

Journal: Anal Bioanal Chem
Volume: 387  -  Pages: 343-50
DOI: 10.1007/s00216-006-0938-8

Isotope ratio determination of objects in the field by portable laser ablation sampling and subsequent multicollector ICPMS
Date: 2013-03-19

Authors: Glaus, R;Dorta, L;Zhang, Z;Ma, Q;Berke, H;Günther, D;
Products: 100 µL/min PFA nebulizer

Abstract: 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.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 28  -  Pages: 801-809
DOI: 10.1039/C3JA30379A

Determination of Thallium in the USGS Glass Reference Materials BIR-1G, BHVO-2G and BCR-2G and Application to Quantitative Tl Concentrations by LA-ICP-MS
Date: 2013-02-19

Authors: Nielsen, SG;Lee, CTA;
Products: 100 µL/min PFA nebulizer

Abstract: Here, we present determinations of thallium (Tl) concentrations in the USGS reference materials BIR-1G, BHVO-2G and BCR-2G measured by solution ICP-MS. The Tl content in these three glasses spans a range of about 2-230 ng g-1, which is similar to the values published for the respective powder materials. The determined range of Tl concentrations in these three glass reference materials makes them ideal for investigating Tl concentrations in basaltic and andesitic volcanic glasses. We also performed a series of laser ablation ICP-MS measurements on the three samples, which show that this technique is able to determine Tl concentrations in glass samples with concentrations as low as
2 ng g-1.

Journal: Geostandards and Geoanalytical Research
Volume: 37  -  Pages: 337-343
DOI: 10.1111/j.1751-908x.2012.00203.x

Three centuries of Eastern European and Altai lead emissions recorded in a Belukha ice core
Date: 2012-03-15

Authors: Eichler, A;Tobler, L;Eyrikh, S;Gramlich, G;Malygina, N;Papina, T;Schwikowski, M;
Products: 100 µL self-aspirating PFA-nebulizer

Abstract: Human activities have significantly altered atmospheric Pb concentrations and thus, its geochemical cycle, for thousands of years. Whereas historical Pb emissions from Western Europe, North America, and Asia are well documented, there is no equivalent data for Eastern Europe. Here, we present ice-core Pb concentrations for the period 1680-1995 from Belukha glacier in the Siberian Altai, assumed to be representative of emissions in Eastern Europe and the Altai. Pb concentrations and 207Pb/206Pb ratios were strongly enhanced during the period 1935-1995 due to the use of Pb additives in Russian gasoline mined in the Rudny Altai. Comparable to Western Europe and North America, Eastern European Pb emissions peaked in the 1970s. However, the subsequent downward trend in Eastern Europe was mainly caused by the economic crisis in the U.S.S.R. and not by a phase-out of leaded gasoline. Pb concentrations in the period 1680-1935, preceding the era of intensified industrialization in Russia, reflect the history of local emissions from Rudny Altai mining and related metallurgical processing primarily for the production of Russian coins. During this time, Altai ore Pb contributed about 40% of the regional atmospheric Pb.

Journal: Environ. Sci. Technol.
Volume: 46  -  Pages: 4323-30
DOI: 10.1021/es2039954

Infectious prion protein alters manganese transport and neurotoxicity in a cell culture model of prion disease
Date: 2011-10-01

Authors: Martin, DP;Anantharam, V;Jin, H;Witte, T;Houk, R;Kanthasamy, A;Kanthasamy, AG;
Products: 100 µL/min self-aspirating perfluoroalkoxy (PFA) nebulizer

Abstract: Protein misfolding and aggregation are considered key features of many neurodegenerative diseases, but biochemical mechanisms underlying protein misfolding and the propagation of protein aggregates are not well understood. Prion disease is a classical neurodegenerative disorder resulting from the misfolding of endogenously expressed normal cellular prion protein (PrP(C)). Although the exact function of PrP(C) has not been fully elucidated, studies have suggested that it can function as a metal binding protein. Interestingly, increased brain manganese (Mn) levels have been reported in various prion diseases indicating divalent metals also may play a role in the disease process. Recently, we reported that PrP(C) protects against Mn-induced cytotoxicity in a neural cell culture model. To further understand the role of Mn in prion diseases, we examined Mn neurotoxicity in an infectious cell culture model of prion disease. Our results show CAD5 scrapie-infected cells were more resistant to Mn neurotoxicity as compared to uninfected cells (EC(50)=428.8 µM for CAD5 infected cells vs. 211.6 µM for uninfected cells). Additionally, treatment with 300 µM Mn in persistently infected CAD5 cells showed a reduction in mitochondrial impairment, caspase-3 activation, and DNA fragmentation when compared to uninfected cells. Scrapie-infected cells also showed significantly reduced Mn uptake as measured by inductively coupled plasma-mass spectrometry (ICP-MS), and altered expression of metal transporting proteins DMT1 and transferrin. Together, our data indicate that conversion of PrP to the pathogenic isoform enhances its ability to regulate Mn homeostasis, and suggest that understanding the interaction of metals with disease-specific proteins may provide further insight to protein aggregation in neurodegenerative diseases.

Journal: Neurotoxicology
Volume: 32  -  Pages: 554-62
DOI: 10.1016/j.neuro.2011.07.008

α-Synuclein protects against manganese neurotoxic insult during the early stages of exposure in a dopaminergic cell model of Parkinson's disease
Date: 2015-02-01

Authors: Harischandra, DS;Jin, H;Anantharam, V;Kanthasamy, A;Kanthasamy, AG;
Products: 100 µL/min self-aspirating PFA nebulizer

Abstract: The pathological role of α-synuclein (α-Syn) aggregation in neurodegeneration is well recognized, but the physiological function of normal α-Syn remains unknown. As α-Syn protein contains multiple divalent metal binding sites, herein we conducted a comprehensive characterization of the role of α-Syn in manganese-induced dopaminergic neurotoxicity. We established transgenic N27 dopaminergic neuronal cells by stably expressing human wild-type α-Syn at normal physiological levels. α-Syn-expressing dopaminergic cells significantly attenuated Mn-induced neurotoxicity for 24-h exposures relative to vector control cells. To further explore cellular mechanisms, we studied the mitochondria-dependent apoptotic pathway. Analysis of a key mitochondrial apoptotic initiator, cytochrome c, revealed that α-Syn significantly reduces the Mn-induced cytochrome c release into cytosol. The downstream caspase cascade, involving caspase-9 and caspase-3 activation, during Mn exposure was also largely attenuated in Mn-treated α-Syn cells in a time-dependent manner. α-Syn cells also showed a dramatic reduction in the Mn-induced proteolytic activation of the pro-apoptotic kinase PKCδ. The generation of Mn-induced reactive oxygen species (ROS) did not differ between α-Syn and vector control cells, indicating that α-Syn exerts its protective effect independent of altering ROS generation. Inductively coupled plasma-mass spectrometry (ICP-MS) revealed no significant differences in intracellular Mn levels between treated vector and α-Syn cells. Notably, the expression of wild-type α-Syn in primary mesencephalic cells also rescued cells from Mn-induced neurotoxicity. However, prolonged exposure to Mn promoted protein aggregation in α-Syn-expressing cells. Collectively, these results demonstrate that wild-type α-Syn exhibits neuroprotective effects against Mn-induced neurotoxicity during the early stages of exposure in a dopaminergic neuronal model of PD.

Journal: Toxicol. Sci.
Volume: 143  -  Pages: 454-68
DOI: 10.1093/toxsci/kfu247

Manganese upregulates cellular prion protein and contributes to altered stabilization and proteolysis: relevance to role of metals in pathogenesis of prion disease
Date: 2010-06-01

Authors: Choi, CJ;Anantharam, V;Martin, DP;Nicholson, EM;Richt, JA;Kanthasamy, A;Kanthasamy, AG;
Products: 100 µL/min self-aspirating PFA nebulizer

Abstract: Prion diseases are fatal neurodegenerative diseases resulting from misfolding of normal cellular prion (PrP(C)) into an abnormal form of scrapie prion (PrP(Sc)). The cellular mechanisms underlying the misfolding of PrP(C) are not well understood. Since cellular prion proteins harbor divalent metal-binding sites in the N-terminal region, we examined the effect of manganese on PrP(C) processing in in vitro models of prion disease. Exposure to manganese significantly increased PrP(C) levels both in cytosolic and in membrane-rich fractions in a time-dependent manner. Manganese-induced PrP(C) upregulation was independent of messenger RNA transcription or stability. Additionally, manganese treatment did not alter the PrP(C) degradation by either proteasomal or lysosomal pathways. Interestingly, pulse-chase analysis showed that the PrP(C) turnover rate was significantly altered with manganese treatment, indicating increased stability of PrP(C) with the metal exposure. Limited proteolysis studies with proteinase-K further supported that manganese increases the stability of PrP(C). Incubation of mouse brain slice cultures with manganese also resulted in increased prion protein levels and higher intracellular manganese accumulation. Furthermore, exposure of manganese to an infectious prion cell model, mouse Rocky Mountain Laboratory-infected CAD5 cells, significantly increased prion protein levels. Collectively, our results demonstrate for the first time that divalent metal manganese can alter the stability of prion proteins and suggest that manganese-induced stabilization of prion protein may play a role in prion protein misfolding and prion disease pathogenesis.

Journal: Toxicol. Sci.
Volume: 115  -  Pages: 535-46
DOI: 10.1093/toxsci/kfq049

Phosphatidylserine-functionalized Fe3O4@SiO2 nanoparticles combined with enzyme-encapsulated liposomes for the visual detection of Cu2+
Date: 2015-12-14

Authors: He, Y;Li, M;Jiang, W;Yang, W;Lin, L;Xu, L;Fu, F;
Products: 1000 µg/mL stock standard solution of Cu 2+

Abstract: We herein reported on novel phosphatidylserine-functionalized Fe3O4@SiO2 NPs (nanoparticles) and enzyme-encapsulated liposomes for the visual detection of Cu2+ by employing phosphatidylserine for Cu2+ recognition and the enzymatic catalysis/oxidation of 3,3´ ,5,5´ -tetramethylbenzidine sulfate (TMB) as a signal generator. Phosphatidylserine (1,2-dioleoyl-sn-glycero-3-phospho-L-serine, DOPS) was covalently assembled on the Fe3O4@SiO2 NP surface to obtain DOPS-functionalized Fe3O4@SiO2 NPs, and was used to encapsulate horseradish peroxidase (HRP) to form HRP-encapsulated DOPS liposomes. It was demonstrated that DOPS-functionalized Fe3O4@SiO2 NPs can specifically bind HRP-encapsulated DOPS liposomes in the presence of Cu2+ at basic pH. The HRP-encapsulated DOPS liposome bound on the DOPS-functionalized Fe3O4@SiO2 NPs was then separated from solution with a magnet. Upon the addition of TMB-H2O2 solution, the HRP-encapsulated DOPS liposome bound on the DOPS-functionalized Fe3O4@SiO2 NPs was broken to release HRP, and the released HRP catalyzes the H2O2-mediated oxidation of TMB, which gives rise to a change from colourless to blue in solution colour and a new absorption peak at 652 nm. This provided a sensing platform for the sensitive, specific and field-portable colorimetric detection of Cu2+. By using the sensing platform, a selective and sensitive visual sensor for the detection of Cu2+ was developed. The proposed method has outstanding advantages including adequate sensitivity (the sensitivity can be improved by using a greater volume of the water sample), shorter analysis time, relatively low cost, operation at room temperature and stronger resistibility to the matrix. It can be used to detect as little as 0.1-0.5 µM of Cu2+ in river water using naked-eye observation and 0.05 µM of Cu2+ in river water using UV-visible spectrophotometry when 2 mL of the water sample was used for detection, within 15 min and with a recovery of 95-101% and a RSD < 5% (n = 5). A visual detection limit of 0.1-0.5 µM is much lower than the maximum allowable level of Cu2+ (˜20 µM) in drinking water defined by the USA EPA. The above features make our sensor a promising approach for the rapid and on-site detection of trace free copper ions in aqueous environments by only naked-eye observation.

Journal: Journal of Materials Chemistry B
Volume: 4  -  Pages: 752-759
DOI: 10.1039/C5TB01926E

Ice-core based assessment of historical anthropogenic heavy metal (Cd, Cu, Sb, Zn) emissions in the Soviet Union
Date: 2014-03-04

Authors: Eichler, A;Tobler, L;Eyrikh, S;Malygina, N;Papina, T;Schwikowski, M;
Products: 100-µL self-aspirating PFA-nebulizer

Abstract: The development of strategies and policies aiming at the reduction of environmental exposure to air pollution requires the assessment of historical emissions. Although anthropogenic emissions from the extended territory of the Soviet Union (SU) considerably influenced concentrations of heavy metals in the Northern Hemisphere, Pb is the only metal with long-term historical emission estimates for this region available, whereas for selected other metals only single values exist. Here we present the first study assessing long-term Cd, Cu, Sb, and Zn emissions in the SU during the period 1935-1991 based on ice-core concentration records from Belukha glacier in the Siberian Altai and emission data from 12 regions in the SU for the year 1980. We show that Zn primarily emitted from the Zn production in Ust-Kamenogorsk (East Kazakhstan) dominated the SU heavy metal emission. Cd, Sb, Zn (Cu) emissions increased between 1935 and the 1970s (1980s) due to expanded non-ferrous metal production. Emissions of the four metals in the beginning of the 1990s were as low as in the 1950s, which we attribute to the economic downturn in industry, changes in technology for an increasing metal recovery from ores, the replacement of coal and oil by gas, and air pollution control.

Journal: Environ. Sci. Technol.
Volume: 48  -  Pages: 2635-42
DOI: 10.1021/es404861n

Normal cellular prion protein protects against manganese-induced oxidative stress and apoptotic cell death
Date: 2007-08-01

Authors: Choi, CJ;Anantharam, V;Saetveit, NJ;Houk, RS;Kanthasamy, A;Kanthasamy, AG;
Products: 100-µL/min self-aspirating PFA nebulizer

Abstract: The normal prion protein is abundantly expressed in the central nervous system, but its biological function remains unclear. The prion protein has octapeptide repeat regions that bind to several divalent metals, suggesting that the prion proteins may alter the toxic effect of environmental neurotoxic metals. In the present study, we systematically examined whether prion protein modifies the neurotoxicity of manganese (Mn) by comparing the effect of Mn on mouse neural cells expressing prion protein (PrPC-cells) and prion-knockout (PrPKO-cells). Exposure to Mn (10µM-10mM) for 24 h produced a dose-dependent cytotoxic response in both PrPC-cells and PrPKO-cells. Interestingly, PrPC-cells (EC50 117.6µM) were more resistant to Mn-induced cytotoxicity, as compared to PrPKO-cells (EC50 59.9µM), suggesting a protective role for PrPC against Mn neurotoxicity. Analysis of intracellular Mn levels showed less Mn accumulation in PrPC-cells as compared to PrPKO-cells, but no significant changes in the expression of the metal transporter proteins transferrin and DMT-1. Furthermore, Mn-induced mitochondrial depolarization and reactive oxygen species (ROS) generation were significantly attenuated in PrPC-cells as compared to PrPKO-cells. Measurement of antioxidant status revealed similar basal levels of glutathione (GSH) in PrPC-cells and PrPKO-cells; however, Mn treatment caused greater depletion of GSH in PrPKO-cells. Mn-induced mitochondrial depolarization and ROS production were followed by time- and dose-dependent activation of the apoptotic cell death cascade involving caspase-9 and -3. Notably, DNA fragmentation induced by both Mn treatment and the oxidative stress inducer hydrogen peroxide (100µM) was significantly suppressed in PrPC-cells as compared to PrPKO-cells. Together, these results demonstrate that prion protein interferes with divalent metal Mn uptake and protects against Mn-induced oxidative stress and apoptotic cell death.

Journal: Toxicol. Sci.
Volume: 98  -  Pages: 495-509
DOI: 10.1093/toxsci/kfm099

Trace metal determination in natural waters by automated solid phase extraction system and ICP-MS: the influence of low level Mg and Ca
Date: 2014-10-01

Authors: Wang, BS;Lee, CP;Ho, TY;
Products: 2 mL sample loop

Abstract: A fully automated high pressure pretreatment system with Nobias Chelate-PA1 resin (PA1) was developed for trace metal determination by ICP-MS in natural waters. By varying the concentrations of Mg and Ca to mimic the concentrations in the eluate obtained by PA1 or iminodiacetate type resins, the overall analytical performance of the system was assessed for the determination of Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Cd, Ag, Pb and REE. Comparing with the low mM level Mg and Ca (both ranging from 1 to 4mM) eluted by iminodiacetate type resins, the eluate obtained by PA1 contains sub-µM level Mg and Ca, which remarkably decrease matrix effect in ICP-MS analysis and significantly improve the analytical performance. With recovery better than 90% for most the trace metals examined, the accuracy was further verified through the analysis of five natural water reference materials with salinity spanning from 0 to 35‰. We have successfully applied the pretreatment system to determine trace metals in the seawater samples collected in the Western Philippine Sea through Taiwan GEOTRACES cruise.

Journal: Talanta
Volume: 128  -  Pages: 337-44
DOI: 10.1016/j.talanta.2014.04.077

Online determination of copper in aluminum alloy by microchip solvent extraction using isotope dilution ICP-MS method
Date: 2009-09-15

Authors: Kagawa, T;Ohno, M;Seki, T;Chikama, K;
Products: 20 µL/min microflow nebulizer

Abstract: Isotope dilution mass spectroscopy (IDMS)/ICP-MS combined with microchip solvent extraction was successfully applied for the online determination of copper in an aluminum alloy. The microchip solvent extraction was developed for the separation of Cu from major element, and optimal pH range was wider than that of the batchwise extraction method. The dimensions of the microchip were 30 mm x 70 mm and that of micro-channel on the microchip was 180 µm wide and 40 µm deep. The copper complex with 8-hydroxyquinoline was extracted into o-xylene at pH 5.5 and back extracted with 0.1 mol l-1 nitric acid at flow rate of 20 µl min-1. The total extraction efficiency (water/organic solvent/nitric acid) was around 40%. IDMS/ICP-MS was coupled with solvent extraction for precise determination of Cu. The extraction and back-extraction on the microchip took about 1s and the total measurement time for the IDMS/ICP-MS was about 40s/sample. The blank value of this method was 0.1 ng g-1. The proposed method was used for the determination of Cu in Al standard materials (JSAC 0121-C, The Japan Society for Analytical Chemistry and 7074 Al alloy, Nippon Light Metal Co. Ltd.). The obtained analytical results are in good agreement with the certified values.

Journal: Talanta
Volume: 79  -  Pages: 1001-5
DOI: 10.1016/j.talanta.2009.02.017

Radiocarbon calibration curve spanning 0 to 50,000 years BP based on paired 230Th/234U/238U and 14C dates on pristine corals
Date: 2005-06-22

Authors: Fairbanks, RG;Mortlock, RA;Chiu, TC;Cao, L;Kaplan, A;Guilderson, TP;Fairbanks, TW;Bloom, AL;Grootes, PM;Nadeau, MJ;
Products: 50 ml/min PFA micro nebulizer

Abstract: Radiocarbon dating is the most widely used dating technique in the world. Recent advances in Accelerator Mass Spectrometry (AMS) and sample preparation techniques have reduced the sample-size requirements by a factor of 1000 and decreased the measurement time from weeks to minutes. Today, it is estimated that more than 90 percent of all measurements made on accelerator mass spectrometers are for radiocarbon age dates. The production of 14C in the atmosphere varies through time due to changes in the Earth's geomagnetic field intensity and in its concentration, which is regulated by the carbon cycle. As a result of these two variables, a radiocarbon age is not equivalent to a calendar age. Four decades of joint research by the dendrochronology and radiocarbon communities have produced a radiocarbon calibration data set of remarkable precision and accuracy extending from the present to approximately 12,000 calendar years before present. This paper presents high precision paired 230Th/234U/238U and 14C age determinations on pristine coral samples that enable us to extend the radiocarbon calibration curve from 12,000 to 50,000 years before present. We developed a statistical model to properly estimate sample age conversion from radiocarbon years to calendar years, taking full account of combined errors in input ages and calibration uncertainties. Our radiocarbon calibration program is publicly accessible at: along with full documentation of the samples, data, and our statistical calibration model.

Journal: Quaternary Science Reviews
Volume: 24  -  Pages: 1781-1796
DOI: 10.1016/j.quascirev.2005.04.007

Determination of the lithium isotopic composition of planktic foraminifera and its application as a paleo-seawater proxy
Date: 2005-06-15

Authors: Hall, JM;Chan, LH;McDonough, WF;Turekian, KK;
Products: 50 µL/min PFA nebulizer

Abstract: To investigate the potential use of Li isotopes in foraminifera as a paleo-lithium seawater proxy, the Li isotopic compositions of planktic foraminifera (Orbulina universa, Globigerinoides sacculifer, Globorotalia menardii, and Globorotalia truncatulinoides) were determined by thermal ionization mass spectrometry (TIMS), using phosphate as an ion source, and multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). Rigorous cleaning procedures were employed to purify foraminiferal tests of detrital, metal oxide, and organic phases in single species analyses. Data generated using both methods reveal that δ7Li in planktic foraminifera resemble seawater such that the isotopic fractionation from the precipitation of foraminiferal calcite appears to be minimal. Down-core measurements indicate that the δ7Li of O. universa has remained constant over the last 44 ka in the North Atlantic, suggesting little change of Li isotopic composition of ocean water during the last glaciation, consistent with the long mean residence time of Li. Results suggest that planktic foraminifera may provide a reliable record of the lithium isotopic composition of ocean water in the past. The first measurements of seawater δ7Li from the Indian Ocean average 33.0 ± 1.2‰ (2σ) throughout the water column. This value is within error of values previously reported for the Atlantic and Pacific Oceans as is expected based on the long mean residence time of Li in the ocean. There is no evidence for a significant decrease in Li/Cl ratios, as reported by some workers, with Indian Ocean waters averaging 9.10 ± 0.11 µg/g.

Journal: Marine Geology
Volume: 217  -  Pages: 255-265
DOI: 10.1016/j.margeo.2004.11.015

Strategies for isotope ratio measurements with a double focusing sector field ICP-MS
Date: 1999-04-11

Authors: Hamester, M;Wiederin, D;Wills, J;Kerl, W;
Products: Low-flow Micromist microconcentric nebulizer

Abstract: A single collector double focusing sector field ICP-MS is evaluated for the determination of isotope ratios. Spectral interferences (e.g. 40Ar23Na on 63Cu) can lead to calculation of inaccurate ratios. The use of high resolution enables such interferences to be separated from the isotopes of interest. External reproducibilities of < 0.02% are shown for uninterfered isotopes (measured at low resolution R = 300) and < 0.1% for interfered isotopes which required the use of medium (R = 4000) and high resolution (R = 10000).

Journal: Fresenius' Journal of Analytical Chemistry
Volume: 364  -  Pages: 495-498
DOI: 10.1007/s002160051374

Determination of selenium in sediments by inductively coupled plasma-mass spectrometry: high resolution versus hydride generation
Date: 2001-02-14

Authors: Moor, C;Koble, J;
Products: PFA-nebulizer

Abstract: Two approaches were compared for the determination of Se in two marine sediments (MESS-2 and the round robin sample IMEP-14). A special hydride technique was used to minimize chemical interferences. The technique is based on a double loop flow injection-hydride system with a short reaction time of 100 ms, followed by immediate separation of the volatile products. In order to ensure a quantitative reduction of selenium, a pre-reduction had to be done to convert all Se to Se(IV). The hydride system was coupled to a quadrupole ICP-MS. Another promising method is the direct determination of Se using a sector field ICP-MS. High resolution and good stability of the mass calibration are important for such determinations. With both approaches, it was possible to find the certified value of the reference material within the measurement uncertainty.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 16  -  Pages: 285-288
DOI: 10.1039/B009912K

Novel separation method for highly sensitive speciation of cancerostatic platinum compounds by HPLC-ICP-MS
Date: 2005-01-01

Authors: Hann, S;Stefánka, Z;Lenz, K;Stingeder, G;
Products: PFA-nebulizer

Abstract: A high-performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) method is presented for analysis of cisplatin, monoaquacisplatin, diaquacisplatin, carboplatin, and oxaliplatin in biological and environmental samples. Chromatographic separation was achieved on pentafluorophenylpropyl-functionalized silica gel. For cisplatin, carboplatin, and oxaliplatin limits of detection of 0.09, 0.10, and 0.15 µg L-1, respectively, were calculated at m/z 194, using aqueous standard solutions. (3 µL injection volume). The method was utilized for model experiments studying the stability of carboplatin and oxaliplatin at different chloride concentrations simulating wastewater and surface water conditions. It was found that a high fraction of carboplatin is stable in ultrapure water and in solutions containing 1.5 mol L-1 Cl-, whereas oxaliplatin degradation was increased by increasing the chloride concentration. In order to support the assessment of oxaliplatin eco-toxicology, the method was tested for speciation of patient urine. The urine sample contained more than 17 different reaction products, which demonstrates the extensive biotransformation of the compound. In a second step of the study the method was successfully evaluated for monitoring cancerostatic platinum compounds in hospital waste water.

Journal: Anal Bioanal Chem
Volume: 381  -  Pages: 405-12
DOI: 10.1007/s00216-004-2839-z

Interlaboratory comparison of magnesium isotopic compositions of 12 felsic to ultramafic igneous rock standards analyzed by MC-ICPMS
Date: 2015-09-25

Authors: Teng, FZ;Yin, QZ;Ullmann, CV;Chakrabarti, R;vonStrandmann, PA;Yang, W;Li, WY;Ke, S;Sedaghatpour, F;Wimpenny, J;Meixner, A;Romer, RL;Wiechert, U;Jacobsen, SB;
Products: ACM

Abstract: To evaluate the interlaboratory mass bias for high-precision stable Mg isotopic analysis of natural materials, a suite of silicate standards ranging in composition from felsic to ultramafic were analyzed in five laboratories by using three types of multicollector inductively coupled plasma mass spectrometer (MC-ICPMS). Magnesium isotopic compositions from all labs are in agreement for most rocks within quoted uncertainties but are significantly (up to 0.3‰ in 26Mg/24Mg, >4 times of uncertainties) different for some mafic samples. The interlaboratory mass bias does not correlate with matrix element/Mg ratios, and the mechanism for producing it is uncertain but very likely arises from column chemistry. Our results suggest that standards with different matrices are needed to calibrate the efficiency of column chemistry and caution should be taken when dealing with samples with complicated matrices. Well-calibrated standards with matrix elements matching samples should be used to reduce the interlaboratory mass bias.

Journal: Geochemistry, Geophysics, Geosystems
Volume: 16  -  Pages: 3197-3209
DOI: 10.1002/2015GC005939

Lanthanide distribution in human placental tissue by membrane desolvation-ICP-MS
Date: 2010-06-29

Authors: Kruger, PC;Schell, LM;Stark, AD;Parsons, PJ;
Products: ACM desolvation unit

Abstract: Lanthanide elements are finding increasing use in industrial, technological, and medical applications, due to their unique magnetic, optic, and catalytic properties. Consequently, the risk of human exposure to these nonessential elements is rising, and the ability to measure the lanthanides in human tissues and body fluids is gaining in importance. In this study, the concentrations of naturally occurring lanthanide elements, as well as Sc, were measured in human placental tissues, consisting of ˜160 samples each of placenta body, membrane, and umbilical cord, for evaluation of possible maternal and fetal exposure to these metals. Measurements were conducted using ICP-MS instrumentation coupled to a membrane desolvation introduction system, in order to enhance sensitivity for these elements, as well as to decrease oxide formation. Method detection limits (MDLs) ranged from 0.3 ng g-1 to 4 ng g-1. Method validation entailed the use of a mussel tissue reference material (RM) certified for most of the analytes of interest, spike recovery experiments and, for some analytes, a caprine liver secondary RM. Heavier lanthanides (Eu-Lu) were not detectable in most placental tissues. Lighter lanthanides (La-Sm) were detected in the ng g-1 range. The placenta body accumulated the greatest concentrations of lanthanides. Lanthanide concentrations in placenta appeared to follow a pattern similar to that found in the Earth's crust, indicating natural human exposure to these analytes.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 25  -  Pages: 1298-1307
DOI: 10.1039/C004884D

Real-time monitoring and determination of Pb in a single airborne nanoparticle
Date: 2010-06-04

Authors: Suzuki, Y;Sato, H;Hikida, S;Nishiguchi, K;Furuta, N;
Products: Aero membrane dryer unit

Abstract: We used a differential mobility analyzer, an aerosol particle mass analyzer, and a gas exchange device to continuously introduce airborne nanoparticles (ANPs) to an inductively coupled plasma mass spectrometer. Pb concentrations in single ANPs with a diameter of 90 nm and a mass of 0.458 fg (density is 1.20 g cm-3) were determined. The developed method enabled us to determine Pb in ANPs having a Pb content of more than 10%.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 25  -  Pages: 947-949
DOI: 10.1039/C004790B

The Mayak Worker Dosimetry System (MWDS 2013): Soluble Plutonium Retention in the Lungs of An Occupationally Exposed USTUR Case
Date: 2016-06-10

Authors: Tolmachev, SY;Nielsen, CE;Avtandilashvili, M;Puncher, M;Martinez, F;Thomas, EM;Miller, FL;Morgan, WF;Birchall, A;
Products: apex® HF sample introduction system

Abstract: For the first time, plutonium retention in human upper airways was investigated based on the dosimetric structure of the human respiratory tract proposed by the International Commission on Radiological Protection (ICRP). This paper describes analytical work methodology, case selection criteria, and summarizes findings on soluble (ICRP 68 Type M material) plutonium distribution in the lungs of a former nuclear worker occupationally exposed to plutonium nitrate [239Pu(NO3)4]. Thirty-eight years post-intake, plutonium was found to be uniformly distributed between bronchial (BB), bronchiolar (bb) and alveolar-interstitial (AI) dosimetric compartments as well as between the left and right lungs. 239+240Pu and 238Pu total body activity was estimated to be 2333 ± 23 and 42.1 ± 0.7Bq, respectively. The results of this work provide key information on the extent of plutonium binding in the upper airways of the human respiratory tract.

Journal: Radiat Prot Dosimetry
Volume:   -  Pages:
DOI: 10.1093/rpd/ncw136

Determination of rare earth elements in tomato plants by inductively coupled plasma mass spectrometry techniques
Date: 2009-10-30

Authors: Spalla, S;Baffi, C;Barbante, C;Turetta, C;Turretta, C;Cozzi, G;Beone, GM;Bettinelli, M;
Products: apex ACM membrane

Abstract: In recent years identification of the geographical origin of food has grown more important as consumers have become interested in knowing the provenance of the food that they purchase and eat. Certification schemes and labels have thus been developed to protect consumers and genuine producers from the improper use of popular brand names or renowned geographical origins. As the tomato is one of the major components of what is considered to be the healthy Mediterranean diet, it is important to be able to determine the geographical origin of tomatoes and tomato-based products such as tomato sauce. The aim of this work is to develop an analytical method to determine rare earth elements (RRE) for the control of the geographic origin of tomatoes. The content of REE in tomato plant samples collected from an agricultural area in Piacenza, Italy, was determined, using four different digestion procedures with and without HF. Microwave dissolution with HNO3 + H2O2 proved to be the most suitable digestion procedure. Inductively coupled plasma quadrupole mass spectrometry (ICPQMS) and inductively coupled plasma sector field plasma mass spectrometry (ICPSFMS) instruments, both coupled with a desolvation system, were used to determine the REE in tomato plants in two different laboratories. A matched calibration curve method was used for the quantification of the analytes. The detection limits (MDLs) of the method ranged from 0.03 ng g-1 for Ho, Tm, and Lu to 2 ng g-1 for La and Ce. The precision, in terms of relative standard deviation on six replicates, was good, with values ranging, on average, from 6.0% for LREE (light rare earth elements) to 16.5% for HREE (heavy rare earth elements). These detection limits allowed the determination of the very low concentrations of REE present in tomato berries. For the concentrations of REE in tomato plants, the following trend was observed: roots > leaves > stems > berries.

Journal: Rapid Commun. Mass Spectrom.
Volume: 23  -  Pages: 3285-92
DOI: 10.1002/rcm.4244

Elemental speciation by parallel elemental and molecular mass spectrometry and peak profile matching
Date: 2006-12-15

Authors: Sacks, GL;Derry, LA;Brenna, JT;
Products: apex cyclonic spray chamber

Abstract: Trace elemental speciation in complex, real-world matrixes is a daunting task because of the low concentration of metals/metalloids and the correspondingly high molecular chemical noise. We constructed a liquid chromatography parallel elemental and molecular mass spectrometry (PEMMS) system and evaluated the use of peak elution profiles to identify trace molecular species containing specific heteroatoms, using the case of Se in yeast. We demonstrate that it is possible to use the HPLC-inductively coupled plasma (ICP)MS peak profile (retention time, width) to identify candidate ions with matching peak profiles in the molecular MS data. Proof of principle was demonstrated by C18 separation of three Se-amino acid standards (0.005-15 ppm as Se). The molecular MS (atmospheric pressure chemical ionization time-of-flight, APCI-TOF-MS) data set was converted into selected ion chromatograms of 0.05 Th width. ICPMS and APCI-TOF-MS ion chromatograms were fit by the Haarhoff-VanderLinde function using the following parameters: area, retention time, width, and skew. The ICPMS fit parameters were more reproducible than the APCI-TOF-MS fit parameters from run to run, and the APCI-TOF-MS signal was expected to limit correlation in most circumstances. Retention time and width were found to correlate well between the two MS systems for APCI-TOF-MS peaks with signal-to-fit-error (S/FE) of >25. Correction factors for differences in flow path length and peak broadening were required. The normalized correction factors were species and concentration independent and were stable from run to run. The skew parameter was found to be highly susceptible to noise and was not generally useful in matching ICPMS and APCI-TOF-MS peaks. An artificially noisy sample was generated by spiking 30 ppb Se-methionine (SeMet) and 5 ppb Se-methylselenocysteine (SeMSC) with unselenized yeast extract and run by PEMMS. The PEMMS software was able to detect four molecular MS peaks associated with SeMet and two for SeMSC, while filtering out >40 coeluting spectral peaks associated with chemical noise in each sample. In summary, we have demonstrated that correlated information in peak shape between parallel detectors can facilitate detection of trace elemental species in complex matrixes.

Journal: Anal. Chem.
Volume: 78  -  Pages: 8445-55
DOI: 10.1021/ac0612170

Calcium isotope analysis by mass spectrometry
Date: 2009-06-23

Authors: Boulyga, SF;
Products: apex desolvation nebulizer

Abstract: The variations in the isotopic composition of calcium caused by fractionation in heterogeneous systems and by nuclear reactions can provide insight into numerous biological, geological, and cosmic processes, and therefore isotopic analysis finds a wide spectrum of applications in cosmo- and geochemistry, paleoclimatic, nutritional, and biomedical studies. The measurement of calcium isotopic abundances in natural samples has challenged the analysts for more than three decades. Practically all Ca isotopes suffer from significant isobaric interferences, whereas low-abundant isotopes can be particularly affected by neighboring major isotopes. The extent of natural variations of stable isotopes appears to be relatively limited, and highly precise techniques are required to resolve isotopic effects. Isotope fractionation during sample preparation and measurements and instrumental mass bias can significantly exceed small isotope abundance variations in samples, which have to be investigated. Not surprisingly, a TIMS procedure developed by Russell et al. (Russell et al., 1978. Geochim Cosmochim Acta 42: 1075-1090) for Ca isotope measurements was considered as revolutionary for isotopic measurements in general, and that approach is used nowadays (with small modifications) for practically all isotopic systems and with different mass spectrometric techniques. Nevertheless, despite several decades of calcium research and corresponding development of mass spectrometers, the available precision and accuracy is still not always sufficient to achieve the challenging goals. The present article discusses figures of merits of presently used analytical methods and instrumentation, and attempts to critically assess their limitations. In Sections 2 and 3, mass spectrometric methods applied to precise stable isotope analysis and to the determination of 41Ca are described. Section 4 contains a short summary of selected applications, and includes tracer experiments and the potential use of biological isotope fractionation in medical studies, paleoclimatic and paleoceanographic, and other terrestrial as well as extraterrestrial investigations.

Journal: Mass Spectrom Rev
Volume: 29  -  Pages: 685-716
DOI: 10.1002/mas.20244

Mass spectrometry and natural variations of iron isotopes
Date: 2006-05-04

Authors: Dauphas, N;Rouxel, O;
Products: apex desolvation nebulizer

Abstract: Although the processes that govern iron isotope variations in nature are just beginning to be understood, multiple studies attest of the virtue of this system to solve important problems in geosciences and biology. In this article, we review recent advances in the geochemistry, cosmochemistry, and biochemistry of iron isotopes. In Section 2, we briefly address the question of the nucleosynthesis of Fe isotopes. In Section 3, we describe the different methods for purifying Fe and analyzing its isotopic composition. The methods of SIMS, RIMS, and TIMS are presented but more weight is given to measurements by MC-ICPMS. In Section 4, the isotope anomalies measured in extraterrestrial material are briefly discussed. In Section 5, we show how high temperature processes like evaporation, condensation, diffusion, reduction, and phase partitioning can affect Fe isotopic composition. In Section 6, the various low temperature processes causing Fe isotopic fractionation are presented. These involve aqueous and biologic systems.

Journal: Mass Spectrom Rev
Volume: 25  -  Pages: 515-50
DOI: 10.1002/mas.20078

Novel insights into Fukushima nuclear accident from isotopic evidence of plutonium spread along coastal rivers
Date: 2014-08-19

Authors: Evrard, O;Pointurier, F;Onda, Y;Chartin, C;Hubert, A;Lepage, H;Pottin, AC;Lefèvre, I;Bonté, P;Laceby, JP;Ayrault, S;
Products: apex desolvation nebulizer

Abstract: The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident led to important releases of radionuclides into the environment, and trace levels of plutonium (Pu) were detected in northeastern Japan. However, measurements of Pu isotopic atom and activity ratios are required to differentiate between the contributions of global nuclear test fallout and FDNPP emissions. In this study, we used a double-focusing sector field ICP-MS to measure Pu atom and activity ratios in recently deposited sediment along rivers draining the most contaminated part of the inland radioactive plume. Results showed that plutonium isotopes (i.e., 239Pu, 240Pu, 241Pu, and 242Pu) were detected in all samples, although in extremely low concentrations. The 241Pu/239Pu atom ratios measured in sediment deposits (0.0017-0.0884) were significantly higher than the corresponding values attributed to the global fallout (0.00113 ± 0.00008 on average for the Northern Hemisphere between 31°-71° N: Kelley, J. M.; Bond, L. A.; Beasley, T. M. Global distribution of Pu isotopes and 237Np. Sci. Total. Env. 1999, 237/238, 483-500). The results indicated the presence of Pu from FDNPP, in slight excess compared to the Pu background from global fallout that represented up to ca. 60% of Pu in the analyzed samples. These results demonstrate that this radionuclide has been transported relatively long distances (˜45 km) from FDNPP and been deposited in rivers representing a potential source of Pu to the ocean. In future, the high 241Pu/239Pu atom ratio of the Fukushima accident sourced-Pu should be measured to quantify the supply of continental-originating material from Fukushima Prefecture to the Pacific Ocean.

Journal: Environ. Sci. Technol.
Volume: 48  -  Pages: 9334-40
DOI: 10.1021/es501890n

Stable isotopes as a tool to apportion atmospheric iron
Date: 2009-06-15

Authors: Majestic, BJ;Anbar, AD;Herckes, P;
Products: apex desolvation nebulizer

Abstract: Identification of atmospheric iron is a key parameter to understanding the source of iron in urban and remote areas. Atmospheric deposition of desert dust, which also can include an anthropogenic component, is a primary nutrient source for most of the open ocean. To better assess particulate matter (PM) sources specific to iron, we measured the iron isotopic composition of aerosols in two size fractions: PM with aerodynamic diameters less than 2.5 µm and less than 10 µm (PM2.5 and PM10, respectively). Using colocated samplers, atmospheric aerosol samples were collected in the U.S. desert Southwest at a mixed suburban/agricultural site near Phoenix, AZ. The measurements are presented as δ56Fe relative to the IRMM-014 (Institute for Reference Materials and Measurements) standard. Using multiple collector inductively coupled plasma mass spectrometry, we found differences in iron isotopic composition within the PM10 aerosol. Half of the PM10 samples had an iron isotopic signature similar to crustal material (+0.03 ‰), which implicates wind-blown soil-dust as the primary source. The other PM10 samples showed a lighter iron isotopic composition, centered at -0.18 ‰. Further analysis showed thatthe lighter iron was associated with winds originating from the southwest. This strongly suggests that there is a different PM10 source in this direction, with a distinct iron isotopic composition. The iron in the PM2.5 samples was usually substantially lighter than the corresponding PM10 samples, which is consistent with coarse and fine particles having different sources, again with distinctively different isotopic compositions. The magnitude of the iron isotopic difference between the PM10 and the PM2.5 size fractions (δ56FePM10 - δ56FePM2.5) correlated with the PM2.5 concentrations of elements known to be emitted from industrial sources (Pb, Cd, As, V, and Cr). This observation implies that the isotopically light iron is created or emitted alongside industrial processes. Our data demonstrate that iron isotope composition can be a valuable tool in the source-apportionment of iron in atmospheric particles.

Journal: Environ. Sci. Technol.
Volume: 43  -  Pages: 4327-33
DOI: 10.1021/es900023w

Lithium and its isotopes as tracers of subduction zone fluids and metasomatic processes: Evidence from the Catalina Schist, California, USA
Date: 2012-01-15

Authors: Penniston-Dorland, SC;Bebout, GE;von Strandmann, PA;Elliott, T;Sorensen, SS;
Products: apex desolvation nebulizer

Abstract: The Catalina Schist, well-studied for its tectonometamorphic history and geochemical evolution, provides a field area in which to evaluate the extent of Li mobility in subduction-zone fluids and the degree to which Li isotopes can trace metamorphic fluid-rock interactions. A suite of 63 samples of the Catalina Schist that represent a range of metamorphic grades and diverse lithologies was analyzed for Li concentration and isotope composition. Metasedimentary rocks show no evidence for significant loss of Li, with increasing metamorphic grade, despite the wide range of prograde P-T histories represented by the five tectonometamorphic units (with the highest-grade rocks having experienced peak temperatures near 750 °C). Metamafic rocks similarly show no change in Li concentration, as a function of grade, that can be directly related to varying degrees of devolatilization. The Li concentrations and δ7Li of metasedimentary rocks appear to best correlate with a chemical alteration index that likely reflects differential extents of weathering in the sediment sources. The δ7Li of most metamafic rocks (including gabbroic metaconglomerate cobbles), veins and mélange matrix reflects overprinting of the Li isotope compositions derived (through transfer of Li in fluids) from sedimentary lithologies in the same tectonometamorphic units. Thus it appears that Li was mobilized in fluids released from metasedimentary rocks but that the loss was insufficient to affect the bulk δ7Li and Li content of the metasedimentary rocks. Veins and mélange matrix have the highest Li concentrations of all samples analyzed, ranging up to 70 ppm. Some veins and amphibolite-grade mafic rocks have low δ7Li suggestive of Li diffusion through an intergranular fluid. Taken together, these observations suggest mobilization of Li during high pressure/temperature (P/T) fluid-rock interactions that also resulted in enrichments in B, N, and some large ion lithophile elements (K, Rb, Cs, Ba) in the veins, mélange matrix, and cobbles. This study demonstrates that, although Li is mobile in high P/T metamorphic fluids, it does not partition into fluids to the extent demonstrated for N, B, and Cs, the latter elements showing large depletions in the higher-grade Catalina Schist metasedimentary rocks. Thus, even in relatively warm subduction zones, deeply subducted metasedimentary rocks are expected to largely retain their Li inventory to depths of at least 40 km, the maximum depth at which units of the Catalina Schist experienced peak metamorphism.

Journal: Geochimica et Cosmochimica Acta
Volume: 77  -  Pages: 530-545
DOI: 10.1016/j.gca.2011.10.038

Ligand extraction of rare earth elements from aquifer sediments: implications for rare earth element complexation with organic matter in natural waters
Date: 2010-12-01

Authors: Tang, J;Johannesson, KH;
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Abstract: The ability of organic matter as well as carbonate ions to extract rare earth elements (REEs) from sandy sediments of a Coastal Plain aquifer was investigated for unpurified organic matter from different sources (i.e., Mississippi River natural organic matter, Aldrich humic acid, Nordic aquatic fulvic acid, Suwannee River fulvic acid, and Suwannee River natural organic matter) and for extraction solutions containing weak (i.e., CH3COO-) or strong (i.e., View the MathML source) ligands. The experimental results indicate that, in the absence of strong REE complexing ligands in solution, the amount of REEs released from the sand is small and the fractionation pattern of the released REEs appears to be controlled by the surface stability constants for REE sorption with Fe(III) oxides/oxyhydroxides. In the presence of strong solution complexing ligands, however, the amount and the fractionation pattern of the released REEs reflect the strength and variation of the stability constants of the dominant aqueous REE species across the REE series. The varying amount of REEs extracted by the different organic matter employed in the experiments indicates that organic matter from different sources has different complexing capacity for REEs. However, the fractionation pattern of REEs extracted by the various organic matter used in our experiments is remarkable consistent, being independent of the source and the concentration of organic matter used, as well as solution pH. Because natural aquifer sand and unpurified organic matter were used in our experiments, our experimental conditions are more broadly similar to natural systems than many previous laboratory experiments of REE-humic complexation that employed purified humic substances. Our results suggest that the REE loading effect on REE-humic complexation is negligible in natural waters as more abundant metal cations (e.g., Fe, Al) out-compete REEs for strong binding sites on organic matter. More specifically, our results indicate that REE complexation with organic matter in natural waters is dominated by REE binding to weak sites on dissolved organic matter, which subsequently leads to a middle REE (MREE: Sm-Ho)-enriched fractionation pattern. The experiments also indicate that carbonate ions may effectively compete with fulvic acid in binding with dissolved REEs, but cannot out compete humic acids for REEs. Therefore, in natural waters where low molecular weight (LMW) dissolved organic carbon (DOC) is the predominant form of DOC (e.g., lower Mississippi River water), REEs occur as "truly" dissolved species by complexing with carbonate ions as well as FA, resulting in heavy REE (HREE: Er-Lu)-enriched shale-normalized fractionation patterns. Whereas, in natural terrestrial waters where REE speciation is dominated by organic complexes with high molecular weight DOC (e.g., "colloidal" HA), only MREE-enriched fractionation patterns will be observed because the more abundant, weak sites preferentially complex MREEs relative to HREEs and light REEs (LREEs: La-Nd).

Journal: Geochimica et Cosmochimica Acta
Volume: 74  -  Pages: 6690-6705
DOI: 10.1016/j.gca.2010.08.028

Distribution and source of (129I, 239,240Pu, 137Cs in the environment of Lithuania
Date: 2016-01-01

Authors: Ežerinskis, Ž;Hou, XL;Druteikienė, R;Puzas, A;Šapolaitė, J;Gvozdaitė, R;Gudelis, A;Buivydas, S;Remeikis, V;
Products: apex desolvation nebulizer

Abstract: Fifty five soil samples collected in the Lithuania teritory in 2011 and 2012 were analyzed for 129I, 137Cs and Pu isotopes in order to investigate the level and distribution of artificial radioactivity in Lithuania. The activity and atomic ratio of 238Pu/(239,240)Pu, 129I/127I and 131I/137Cs were used to identify the origin of these radionuclides. The 238Pu/239+24 0Pu and 240Pu/239Pu ratios in the soil samples analyzed varied in the range of 0.02-0.18 and 0.18-0.24, respectively, suggesting the global fallout as the major source of Pu in Lithuania. The values of 10-9 to 10-6 for 129I/127I atomic ratio revealed that the source of 129I in Lithuania is global fallout in most cases though several sampling sites shows a possible impact of reprocessing releases. Estimated 129I/131I ratio in soil samples from the southern part of Lithuania shows negligible input of the Chernobyl fallout. No correlation of the 137Cs and Pu isotopes with 129I was observed, indicating their different sources terms. Results demonstrate uneven distribution of these radionuclides in the Lithuanian territory and several sources of contamination i.e. Chernobyl accident, reprocessing releases and global fallout.

Journal: J Environ Radioact
Volume: 151 Pt 1  -  Pages: 166-73
DOI: 10.1016/j.jenvrad.2015.09.020

Sources of contamination and remedial strategies in the multi-elemental trace analysis laboratory
Date: 2010-01-01

Authors: Rodushkin, I;Engström, E;Baxter, DC;
Products: apex desolvation nebulizer

Abstract: In theory, state of the art inductively coupled plasma mass spectrometry (ICP-MS) instrumentation has the prerequisite sensitivity to carry out multi-elemental trace analyses at sub-ng L-1 to sub-pg L-1 levels in solution. In practice, constraints mainly imposed by various sources of contamination in the laboratory and the instrument itself, and the need to dilute sample solutions prior to analysis ultimately limit detection capabilities. Here we review these sources of contamination and, wherever possible, propose remedial strategies that we have found efficacious for ameliorating their impact on the results of multi-elemental trace analyses by ICP-MS. We conclude by providing a list of key points to consider when developing methods and preparing the laboratory to routinely meet the demands of multi-elemental analyses at trace analytical levels by ICP-MS.

Journal: Anal Bioanal Chem
Volume: 396  -  Pages: 365-77
DOI: 10.1007/s00216-009-3087-z

Mercury isotope fractionation in waters and sediments of the Murray Brook mine watershed (New Brunswick, Canada): Tracing mercury contamination and transformation
Date: 2012-04-25

Authors: Foucher, D;Hintelmann, H;Al, TA;MacQuarrie, KT;
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Abstract: Mercury isotope fractionation was investigated in different environmental compartments of a mining-impacted ecosystem, the watershed of the Murray Brook deposit in northern New Brunswick, Canada. Mercury contaminated ground water, surface water as well as sediment and samples of suspended particulate matter were collected alongside Gossan Creek downstream of mine tailings and analyzed for mercury isotopic composition. While leachates from the tailings and ground water samples showed a uniform and similar mercury isotopic signature confirming the predominant role of the mining residues in the contamination of the surrounding environment, samples collected from the surface flow system provided evidence of significant mass-dependent fractionation of mercury with distance from the source. As dissolved mercury contents steadily decreased from 31.1 to 1.4 µg Hg L-1 with distance from the headwaters of the stream, δ202Hg in the creek water progressively increased resulting in a fractionation of ˜ 0.9‰ over 1.6 km. As a result, mercury isotopic ratios in the creek appeared to closely follow a Rayleigh model assuming a constant fractionation factor α (reactant/product) of 1.00038. Stream bed sediments also demonstrated an enrichment of heavy isotopes along the creek with an isotopic shift of ˜ 1‰ over the distance of Gossan Creek (3100 m). Although mercury losses from the water column result partly from partitioning to the sediments, measured mercury isotopic ratios differences between dissolved and solid phases were likely small and this study did not observe significant fractionation due to partitioning processes. Results rather suggested that fractionation observed in the surface water system of Gossan Creek is most likely the result of a combined effect of reduction and volatilisation processes, the lighter isotopes being preferentially reduced and evaporated from the water column. Additional sediment samples collected along reaches of Eighteen Mile Brook and the Upsalquitch River that receive water from Gossan Creek, and from tributaries unaffected by the mine contamination were analyzed for mercury isotopic composition. Data obtained from those sediments clearly demonstrated that mercury derived from mining activities is isotopically different from mercury naturally present in the area. Measured isotopic differences can ultimately be employed to trace sources of mercury, notwithstanding potential fractionation caused by natural transformation processes.

Journal: Chemical Geology
Volume: 336  -  Pages: 87-95
DOI: 10.1016/j.chemgeo.2012.04.014

Environmental applications of single collector high resolution ICP-MS
Date: 2007-08-01

Authors: Krachler, M;
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Abstract: The number of environmental applications of single collector high resolution ICP-MS (HR-ICP-MS) has increased rapidly in recent years. There are many factors that contribute to make HR-ICP-MS a very powerful tool in environmental analysis. They include the extremely low detection limits achievable, tremendously high sensitivity, the ability to separate ICP-MS signals of the analyte from spectral interferences, enabling the reliable determination of many trace elements, and the reasonable precision of isotope ratio measurements. These assets are improved even further using high efficiency sample introduction systems. Therefore, external factors such as the stability of laboratory blanks are frequently the limiting factor in HR-ICP-MS analysis rather than the detection power. This review aims to highlight the most recent applications of HR-ICP-MS in this sector, focusing on matrices and applications where the superior capabilities of the instrumental technique are most useful and often ultimately required.

Journal: J Environ Monit
Volume: 9  -  Pages: 790-804
DOI: 10.1039/b703823m

Chromium isotope ratio measurements in environmental matrices by MC-ICP-MS
Date: 2016-05-09

Authors: Pontér, S;Pallavicini, N;Engström, E;Rodushkin, DC;
Products: apex desolvation nebulizer

Abstract: An analytical procedure consisting of high pressure/temperature acid digestion using an UltraCLAVE system and a one pass, single column matrix separation using DOWEX AG 1X8 anion exchange resin was applied to the determination of Cr concentrations and δ53Cr in chromites, soils, and biological matrices (epiphytic lichens and mosses) using a combination of ICP-SFMS and MC-ICP-MS. The overall reproducibility of the method was assessed by replicate preparation and Cr isotope ratio measurements performed by different operators in multiple analytical sessions over a few months and was found to be 0.11‰ (2σ). The accuracy was evaluated using commercially available reference materials for which measured data were compared with certified values (for Cr concentrations) and previously published results (for isotope data). The results demonstrate a uniform Cr isotope composition in soil depth profiles sampled in different urban environments. A strong negative correlation between δ53Cr and Cr concentrations in lichens and mosses indicates that airborne Cr from local anthropogenic source(s) is depleted in heavy isotopes.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 31  -  Pages: 1464-1471
DOI: 10.1039/C6JA00145A

Assessment of the natural variability of B, Cd, Cu, Fe, Pb, Sr, Tl and Zn concentrations and isotopic compositions in leaves, needles and mushrooms using single sample digestion and two-column matrix separation
Date: 2015-09-09

Authors: Rodushkin, I;Pallavicini, N;Engström, E;Sörlin, D;öhlander, B;Ingri, J;Baxter, DC;
Products: apex desolvation nebulizer

Abstract: An analytical procedure allowing multi-elemental analyses and isotope ratio measurements of eight of these (B, Cd, Cu, Fe, Pb, Sr, Tl and Zn) in matrices relevant for bio-monitoring using a single high-pressure acid digestion was developed. Method blanks, separation efficiency of matrix elements, repeatability and reproducibility were evaluated using sets of preparation blanks, certified reference materials and duplicate samples prepared and analyzed over a period of several months. The method was used to assess the natural variability of concentrations and isotopic compositions in bio-indicators (tree leaves, needles and mushrooms, over 240 samples) collected mainly from a confined area in North-East Sweden. Ranges found from leaves and needles were compared with data obtained for limited numbers of samples collected in Spain, Italy, France, United Kingdom and Iceland.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 31  -  Pages: 220-233
DOI: 10.1039/C5JA00274E

The Uranium Mineralization of the Macusani District, Southeast Peru: Mineralogy, Geochemistry, Geochronology and Ore-Genetic Model
Date: 2016-04-29

Authors: Li, V.V.;
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Abstract: Uranium mineralization of the Quenamari Meseta, Macusani District, SE Peru, is hosted by peraluminous, sillimanite-andalusite-muscovite-biotite rhyolites of the 12.3 - 6.8 Ma Macusani Formation of the Miocene-Pliocene Quenamari Group. The main ore mineral, meta-autunite, (Ca[(UO2)(PO4)]2(H2O)6-8), occurs in fractures in association with weeksite and hydrous Mn- and Fe-mineraloids. The absence of U4+ minerals, as well as any hydrothermal alteration associated with the U ore, strongly suggests that meta-autunite is the primary U mineral. LA-ICP-MS U-Th-Pa geochronology of the meta-autunite revealed that the main ore-forming events occurred at 69 ka, 130 ka and 314-317 ka, and probably at ca. 103-113 ka, 210 ka and 400 ka, all long after the last magmatic activity in the area. The obtained ages unambiguously relate U ore formation to low-temperature Quaternary processes. The δ18O and δ2H values of the mineralizing fluids, inferred from those of the meta-autunite, range from -21.7‰ to -12.2‰ and from -181 to -123‰, respectively, consistent with ore formation from low-temperature meteoric fluids. The timing of ore formation, as well as the mineralogical and geochemical characteristics of meta-autunite and host rocks, such as REE patterns and alteration assemblages, suggests that U was leached from the glassy matrix of the rhyolites, transported by meteoric waters and precipitated as meta-autunite. The majority of known deposits are located on the upper walls of active fluvial canyons, which suggests that the geomorphological environment that is now focusing groundwater flow was also favourable for meta-autunite precipitation. Meta-autunite probably precipitated through the mixing of low-temperature fluids and interaction of the uranyl ion with Fe- and Mn-mineraloids.Thus, although the Macusani U deposits are volcanic-hosted, they differ radically from documented magmatic-hydrothermal systems.

Journal: Thesis
Volume: 1  -  Pages: 1-212

Analysis of mass dependent and mass independent selenium isotope variability in black shales
Date: 2014-06-06

Authors: Strandmann, PA;Coath, CD;Catling, DC;Poulton, SW;Elliott, T;
Products: apex desolvation nebulizer

Abstract: The measurement of selenium isotope ratios is of increasing interest for understanding redox conditions in present and past surface environments. Se has six stable isotopes, and is therefore well suited for isotope analysis by double spiking. However due to relatively large interferences on every isotope, and complex chemical purification methods that frequently do not generate 100% yields, rigorously determining the accuracy of measurements is critical. Here we present analyses of USGS shale standards (SCo-1 and SGR-1b), as representatives of material which might be of interest to Se isotope studies. We have made analyses using two separate double spikes (74Se-78Se and 78Se-82Se), and compare them to previously published results. In addition, we present models of the effects of uncorrected interferences on double spike inversions. This leads us to propose δ82/76Se (parts per thousand deviation of 82Se/76Se from NIST SRM-3149) values of -0.22 ± 0.15 for SCo-1, and +0.25 ± 0.17 for SGR-1b. Further, we present a new method of measuring Se isotopes by desolvation nebulisation. Se sensitivity is enhanced by a factor of 100-200 times by doping solutions with pure Mg, leading to almost a factor of two less material required compared to the more standard hydride generation. Interferences are different compared to our standard hydride generation protocol, but analyses of double spiked NIST-3149 shows that this method can generate accurate isotope ratios. Finally, mass independent fractionation (MIF) of sulphur isotopes has generated considerable interest for constraining the early oxygenation of the atmosphere. Given the chemical similarities between S and Se, Archean shales with S MIF might be expected to exhibit Se MIF. However, within our analytical uncertainty of ±0.4-0.5‰ (parts per 10,000), there is no resolvable Se MIF in these samples, indicating different atmospheric cycling of Se and S.

Journal: Journal of Analytical Atomic Spectrometry
Volume: 29  -  Pages: 1648-1659
DOI: 10.1039/C4JA00124A

Glaciology-Ultratrace Analysis of Samples from Remote Areas
Date: 2014-01-09

Authors: Barbante, C;Cozzi, G;
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Abstract: Remote regions such as Antarctica and Greenland have been studied for many years because of the treasure of important chemical information preserved in their pristine ice caps. Considering their geographical position, the influence of anthropogenic pollution of many chemical compounds can be detected by sophisticated analytical approaches to detect their ultralow concentrations (down to femtograms per gram). To be reliable, these chemical data must be obtained after observing severe pre-analytical cleanliness protocols to preserve the original elemental concentration from contamination due to sampling and general handling operations. Furthermore, very sensitive analytical techniques such as inductively coupled plasma mass spectrometry (ICP-MS) have to be used to detect ultralow levels of contaminants in snow and ice samples. Here, we present a description of all the steps necessary to carry out analytical measurements at ultratrace levels in snow and ice samples collected in remote regions such as the Polar ice caps.

Journal: Encyclopedia of Analytical Chemistry
Volume:   -  Pages: 1-12
DOI: 10.1002/9780470027318.a9243

Reduction of radioactive backgrounds in electroformed copper for ultra-sensitive radiation detectors
Date: 2014-07-07

Authors: Hoppe, E;Aalseth, C;Farmer, O;Hossbach, T;Liezers, M;Mileyb, H;Overman, N;Reeves, J;
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Abstract: Ultra-pure construction materials are required for the next generation of neutrino physics, dark matter and environmental science applications. These materials are also important for use in high-purity germanium spectrometers used in screening materials for radiopurity. The next-generation science applications require materials with radiopurity levels at or below 1 µBq/kg 232Th and 238U. Yet radiometric analysis lacks sensitivity below ˜10 µBq/kg for the U and Th decay chains. This limits both the selection of clean materials and the validation of purification processes. Copper is an important high-purity material for low-background experiments due to the ease with which it can be purified by electrochemical methods. Electroplating for purification into near-final shapes, known as electroforming, is one such method. Continued refinement of the copper electroforming process is underway, for the first time guided by an ICP-MS based assay method that can measure 232Th and 238U near the desired purity levels. An assay of electroformed copper at a µBq/kg level has been achieved and is described. The implications of electroformed copper at or better than this purity on next-generation low-background experiments are discussed.

Journal: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Volume: 764  -  Pages: 116-121
DOI: 10.1016/j.nima.2014.06.082

U-Pb Detrital Zircon Analysis-Results of an InterµLaboratory Comparison
Date: 2013-08-08

Authors: Košler, J;Sláma, J;Belousova, E;Corfu, F;Gehrels, GE;Gerdes, A;Horstwood, MS;Sircombe, KN;Sylvester, PJ;Tiepolo, M;Whitehouse, MJ;Woodhead, JD;
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Abstract: Inter-laboratory comparison of laser ablation ICP-MS and SIMS U-Pb dating of synthetic detrital zircon samples provides an insight into the state-of-the art of sedimentary provenance studies. Here, we report results obtained from ten laboratories that routinely perform this type of work. The achieved level of bias was mostly within ±2% relative to the ID-TIMS U-Pb ages of zircons in the detrital sample, and the variation is likely to be attributed to variable Pb/U elemental fractionation due to zircon matrix differences between the samples and the reference materials used for standardisation. It has been determined that ~ 5% age difference between adjacent age peaks is currently at the limit of what can be routinely resolved by the in situ dating of detrital zircon samples. Precision of individual zircon age determination mostly reflects the data reduction and procedures of measurement uncertainty propagation, and it is largely independent of the instrumentation, analytical technique and reference samples used for standardisation. All laboratories showed a bias towards selection of larger zircon grains for analysis. The experiment confirms the previously published estimates of the minimum number of grains that have to be analysed in order to detect minor zircon age populations in detrital samples.

Journal: Geostandards and Geoananlytical Research
Volume: 37  -  Pages: 243-259
DOI: 10.1111/j.1751-908X.2013.00245.x

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