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Plasma Mass Spectrometry (plasma + mass_spectrometry)
Selected AbstractsA correlation found between gold concentration in blood and patch test reactions in patients with coronary stentsCONTACT DERMATITIS, Issue 3 2008Susanne Ekqvist Background:, Patients with dental gold restorations are known to have a higher level of gold concentration in blood (B-Au). Objectives:, To further investigate, in a study on patients with intracoronary stents and contact allergy to metals, the gold and nickel release from stainless steel stent with (Au stent) and without (Ni stent) gold plating. Method:, A total of 460 patients treated with stenting underwent patch testing with metals, and information on gold and nickel exposure and blood samples were collected. About 200 blood samples were randomly selected and the analysis of B-Au and nickel concentration in blood (B-Ni) was made using inductively coupled plasma mass spectrometry. Results:, There was a correlation between the intensity of Au patch test reaction and B-Au (P < 0.001). This correlation could not be seen between Ni patch test reaction and B-Ni. A Au stent gave a fivefold higher B-Au than a Ni stent. Conclusions:, Gold is released from the Au stent and patients with a Au stent have a fivefold higher B-Au than patients with an Ni stent. The patch test reactions for gold were correlated with B-Au. [source] A novel approach for analysis of oligonucleotide,cisplatin interactions by continuous elution gel electrophoresis coupled to isotope dilution inductively coupled plasma mass spectrometry and matrix-assisted laser desorption/ionization mass spectrometryELECTROPHORESIS, Issue 7 2008Wolfram Brüchert Abstract In this work we present a novel approach for in vitro studies of cisplatin interactions with 8-mer oligonucleotides. The approach is based on the recently developed coupling of continuous elution gel electrophoresis (GE) to an inductively coupled plasma-sector field mass spectrometer (ICP-SFMS) with the aim of monitoring the interaction process between this cytostatic drug and the nucleotides. In contrast to existing methods, the electrophoretic separation conditions used here allow both the determination of the reaction kinetics in more detail as well as the observation of dominant intermediates. Two different nucleotides sequences have been investigated for comparison purposes, one containing two adjacent guanines (5,-TCCGGTCC-3,) and one with a combination of thymine and guanine (5,-TCCTGTCC-3,), respectively. In order to gain further structural information, MALDI-TOF MS measurements have been performed after fraction collection. This allows for identification of the intermediates and the final products and confirms the stepwise coordination of cisplatin via monoadduct to bisadduct formation. Furthermore, the ICP-MS results were quantitatively evaluated in order to calculate the kinetics of the entire process. [source] Speciation of selenium compounds by open tubular capillary electrochromatography-inductively coupled plasma mass spectrometryELECTROPHORESIS, Issue 21 2006Shu-Yu Lin Abstract We introduce a T-type interface and a crossflow nebulizer to find ways to combine CEC with inductively coupled plasma MS (ICP-MS) detection for selenium speciation. For CEC separation, we employed a macrocyclic polyamine-bonded phase capillary as the separation column and a bare fused-silica capillary filled with the make-up liquid (0.05,M,HNO3). The effect of nebulizer gas flow rate, make-up liquid flow, type, concentration and pH of the mobile phase on the separation have been studied. Tris buffer of 50,mM at pH,8.50 gave the best performance for selenium speciation. The reproducibility of the retention time indicated that sample injection by electrokinetic and nebulizer gas flow was better than that by self-aspiration alone. The detection limits for selenate, selenite, selenocystine and selenomethionine were found to be 2.40, 3.53, 12.86 and 11.25,ng/mL, respectively. Due to the high sensitivity and element-specific detection, as well as the high selectivity of the bonded phase, quantitative analysis of selenium speciation in urine was also achieved. [source] Evaluation of ecotoxicity and fate of methylated butyltins in sediments and seawater from Tokyo Bay, JapanENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2007Ryo Kurihara Abstract We analyzed the fate of organotins in seawater and sediments from Tokyo Bay, Japan, by gas chromatography/inductively coupled plasma mass spectrometry. We also measured the toxicity of methylated butyltins by in vitro bioassays, the retinoid × receptor (RXR) activation method, and the marine luminescent bacterium Vibrio fischeri. Concentrations of tributyltin (TBT) and tributylmonomethyltin (TBMMT) in seawater were 0.0636 to 0.419 and 0.0050 to 0.108 ng Sn/L and in sediment were 7.51 to 17.8 and 3.67 to 6.87 ng Sn/wet weight g, respectively. Methylated butyltins did not activate RXR and were not toxic to bacteria. Tributylmonomethyltin in seawater would elute from sediment since TBMMT-to-TBT ratios showed a positive correlation (r2 = 0.858) between sediment and deep seawater. Both methylation and debutylation of TBT seem to be major routes of decomposition of TBT in sediment. Methylation of TBT would not only cause subsequent volatilization but also decrease the toxicity of TBT species in the marine environment. [source] Identification of Atlantic bluefin tuna (Thunnus thynnus) stocks from putative nurseries using otolith chemistryFISHERIES OCEANOGRAPHY, Issue 2 2003Jay R. Rooker Abstract Chemical signatures in the otoliths of teleost fishes represent natural tags that may reflect differences in the chemical and physical characteristics of an individuals' environment. Otolith chemistry of Atlantic bluefin tuna (Thunnus thynnus) was quantified to assess the feasibility of using these natural tags to discriminate juveniles (age 0 and age 1) from putative nurseries. A suite of six elements (Li, Mg, Ca, Mn, Sr and Ba) was measured in whole otoliths using solution-based inductively coupled plasma mass spectrometry. Otolith chemistry of age-1 T. thynnus collected from the two primary nurseries in the Mediterranean Sea and western Atlantic Ocean differed significantly, with a cross-validated classification accuracy of 85%. Spatial and temporal variation in otolith chemistry was evaluated for age-0 T. thynnus collected from three nurseries within the Mediterranean Sea: Alboran Sea (Spain), Ligurian Sea (northern Italy), and Tyrrhenian Sea (southern Italy). Distinct differences in otolith chemistry were detected among Mediterranean nurseries and classification accuracies ranged from 62 to 80%. Interannual trends in otolith chemistry were observed between year classes of age-0 T. thynnus in the Alboran Sea; however, no differences were detected between year classes in the Tyrrhenian Sea. Age-0 and age-1 T. thynnus collected from the same region (Ligurian Sea) were also compared and distinct differences in otolith chemistry were observed, indicating ontogenetic shifts in habitat or elemental discrimination. Findings suggest that otolith chemistry of juvenile T. thynnus from different nurseries are distinct and chemical signatures show some degree of temporal persistence, indicating the technique has considerable potential for use in future assessments of population connectivity and stock structure of T. thynnus. [source] Combining visual and geochemical analyses to source chert on Southern Baffin Island, Arctic CanadaGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 4 2009S. Brooke Milne A combined methodological approach using visual and geochemical methods is introduced and preliminary results of a study illustrating its effectiveness to determine chert source provenance are presented. This study focuses on lithic debitage and raw chert samples collected from the interior of southern Baffin Island, Arctic Canada. Chert is abundant throughout this region yet it occurs as small, scattered surface nodules that are highly variable in color. Prior to this study, little was known about the provenance of this local toolstone and whether it derived from local outcrops, glacial till sheets, or both. Given the pronounced variability exhibited by this chert, we use individual attribute analysis and petrography to impose some kind of analytical order upon an otherwise random aggregation of rocks. Thereafter, inductively coupled plasma mass spectrometry and secondary ion mass spectrometry are used to test the validity of these color categories to determine from how many geochemically distinct sources they derive. Using a standard that measures Al to a ratio of Ga/Zr, our results indicate that all of the raw chert samples derive from a single local source, while the debitage derives from four different sources, including the one that is local. We are confident that this combined methodological approach can be applied in other regions where chert variability is pronounced and source provenance is unknown. © 2009 Wiley Periodicals, Inc. [source] Pilot study experiments sourcing quartzite, Gunnison Basin, ColoradoGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 6 2008Bonnie L. Pitblado This paper reports the results of pilot-study efforts to develop methods to profile quartzite, a rock type to which geochemical and other sourcing techniques have only rarely been applied. The long-term goal of the research is to fingerprint sources of quartzite in the Gunnison Basin, southwest Colorado, used by Paleoindian people ca. 11,500,8,000 years ago to make stone tools. Success would facilitate reconstruction of Paleoindian mobility in the Southern Rocky Mountains and potentially anywhere prehistoric people used quartzite. The goals of this paper are more modest: to demonstrate that a small-scale exploration of sourcing techniques suggests reason for optimism that quartzites may be amenable to source discrimination. For the same twenty Gunnison Basin quartzite samples, this study evaluated petrography, ultraviolet fluorescence (UVF), wavelength dispersive X-ray fluorescence (WD-XRF), instrumental neutron activation analysis (INAA), and inductively coupled plasma mass spectrometry,both acid-digestion (AD-ICP-MS) and laser ablation (LA-ICP-MS),as means to differentiate among the specimens and the sources they represent. Although more testing is needed to verify and refine our results, the study suggests there is potential for petrography, INAA, and both versions of ICP-MS to discriminate among quartzites from different source localities in the Gunnison Basin. The greatest potential for discriminating among different sources of quartzite in the Gunnison Basin may lie in a methodology combining petrographic analysis and LA-ICPMS. Future testing is required to evaluate this two-fold approach. © 2008 Wiley Periodicals, Inc. [source] Compositional analysis of Yayoi-Heian period ceramics from Okinawa: Examining the potential for provenance studyGEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL, Issue 8 2006Scott M. Fitzpatrick In Okinawa, locally produced pottery dates back to the Initial Jomon period (,6500 14C yr B.P.). Later in time, especially during the Early Yayoi-Heian period (,300 B.C.,A.D. 300), ceramic assemblages appear to contain mainland (Japan) Yayoi pottery. A greater number of these sherds present in Okinawa over time coincide with an increasing amount of interaction with mainland Japan, as evidenced by other exchange items. In this preliminary study, the authors analyzed sherds from several Early Yayoi-Heian period deposits from sites in Okinawa using thin-section petrography and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The objective was to examine the applicability of these techniques for Okinawan ceramic provenance studies, assess intra- and intersite variation in mineralogical and chemical composition, and determine whether some sites exhibited a higher frequency of pottery from one locale versus another that might suggest the importation of pottery from mainland Japan. Results are equivocal, suggesting that the region's geological complexity may inhibit successful provenance study of ceramics using these and possibly other compositional techniques. © 2006 Wiley Periodicals, Inc. [source] Is Eradication of Helicobacter pylori With Colloidal Bismuth Subcitrate Quadruple Therapy Safe?HELICOBACTER, Issue 2 2001Rosemary H. Phillips ABSTRACT Background. When standard triple therapy fails to eradicate Helicobacter pylori, quadruple ,rescue' therapy is often used which, in Europe, generally comprises colloidal bismuth subcitrate (CBS) based triple therapy and a proton pump inhibitor. Since hypochlorhydria could greatly increase absorption of the toxic bismuth ion from CBS, we investigated the bismuth status of patients receiving anti- H. pylori quadruple therapy. Materials and Methods. In a prospective open label study 34 patients with nonulcer dyspepsia or peptic ulcer disease, who had failed to eradicate H. pylori with standard triple therapy, were subsequently treated with CBS, omeprazole, amoxycillin and metronidazole (BOAM). A further 35 patients received triple therapy for the eradication of H. pylori: CBS, amoxycillin and metronidazole (BAM) (n = 18); placebo bismuth, amoxycillin and metronidazole (AM) (n = 9); or omeprazole, amoxycillin and metronidazole (OAM) (n = 8). Whole blood bismuth levels were determined before and within 24 hours of completing treatment. Analysis of bismuth was by inductively coupled plasma mass spectrometry, and concentrations were compared between groups and with the Hillemand ,alarm level' for blood bismuth (50,100 µg/l). Results. BOAM gave higher blood bismuth levels than BAM (difference in means 13.1, CI 6.0,20.2, p < .001); three (8.8%) patients taking BOAM had concentrations within the Hillemand alarm level at 54.2, 64.7 and 91.8 µg/l. OAM and AM did not alter baseline blood bismuth levels. Conclusions. Caution should be observed in prescribing CBS with gastric acid suppression, and alternative bismuth preparations should be considered. [source] Stream Macroinvertebrate Community Affected by Point-Source Metal PollutionINTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 3 2007Hideyuki Doi Abstract The impacts of mining activities on aquatic biota have been documented in many stream ecosystems. In mining streams, point-source heavy metal pollution often appears in the stream. We hypothesize that this pollution is toxic to macroinvertebrates owing to high concentrations of metals and therefore affects macroinvertebrate community structure. We investigated macroinvertebrate community structure in mountain streams, including heavy metal-polluted sites and neutral-pH streams, to determine the relationship between community structure and environmental factors such as low pH and heavy metal concentrations. Based on multidimensional scaling ordination, the macroinvertebrate community at heavy metal pollution sites was remarkably different from that at the other sites. Inductively coupled plasma mass spectrometry revealed high concentrations of aluminum and iron in surface water at the polluted sites. Macroinvertebrate community structure at the metal pollution sites was significantly different from that at other sites in the same stream and in neutral-pH streams. Thus, point-source metal pollution may reduce the density and diversity of in situ macroinvertebrates. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Effect of diet on otolith composition in Pomatomus saltatrix, an estuarine piscivoreJOURNAL OF FISH BIOLOGY, Issue 6 2004J. A. Buckel To test the hypothesis that elemental composition of otoliths (sagittae) could be influenced by differences in natural prey type, young-of-the-year bluefish Pomatomus saltatrix were captured immediately after their migration from oceanic waters into mid-Atlantic Bight estuaries and fed either shrimp, Crangon septemspinosa and Palaemonetes spp. or fish Menidia menidia under similar temperature and salinity regimes in two separate 60 day experiments. Unlimited rations of fish and shrimp prey were provided in the first experiment which led to differences in bluefish growth rate between the two prey treatments; fish prey was limited in the second experiment to ensure that growth rates of bluefish in the two prey treatments were similar. Concentrations of seven elements in bluefish otoliths were determined using solution-based inductively coupled plasma mass spectrometry (ICPMS). There was no significant effect of diet on five of the seven elements examined (Na, Mg, K, Ca and Mn). The levels of Sr and Ba in the otoliths of shrimp-fed bluefish, however, were significantly higher than fish-fed bluefish in both experiments. Concentrations of Ba in shrimp-fed bluefish otoliths were double that found in fish-fed bluefish. The results suggest that diet can explain some of the variation in otolith chemistry previously attributed to physical and chemical properties of the water. [source] Trace Element Fingerprinting of Australian Ocher Using Laser Ablation Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) for the Provenance Establishment and Authentication of Indigenous Art,JOURNAL OF FORENSIC SCIENCES, Issue 4 2007Rachel L. Green B.Sc. Abstract:, The expansion of indigenous art and the interest it has generated both at a domestic and international level means large monetary transactions are taking place between art galleries or centers and purchasers. As such, an accurate and conclusive method for provenance determination of traditional indigenous artistic materials must be established that can, if necessary, be used to assist in authentication of artworks. Laser ablation inductively coupled plasma mass spectrometry was utilized for elemental differentiation and provenance establishment of ocher samples. This research was used to develop a robust scientific protocol which facilitates definitive and accurate determination of provenance of Australian ochers and the artworks created using them. Analysis of the results obtained through this study show that the trace metal distribution patterns alone appear to be sufficient evidence to establish provenance of specific ochers, although additional differentiation between ocher samples, using major element distribution patterns, was achieved through the utilization of X-ray analytical techniques. [source] Combined oxygen and silicon isotope analysis of biogenic silica,JOURNAL OF QUATERNARY SCIENCE, Issue 4 2008Melanie J. Leng Abstract There is increasing interest in the use of biogenic silica O and Si isotope ratios to understand climate and environmental processes. Virtually all of the fairly substantial body of literature deals with either oxygen or silicon. This is partly because measurement of oxygen isotope composition is done using either vacuum dehydration, isotope exchange or stepped fluorination techniques, while increasingly researchers are turning to multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) for Si isotope analysis, even though Si isotope analysis can be done using fluorination methods used for the oxygen isotope measurements. Here we describe a procedure for simultaneous determination of isotopic abundances of oxygen and silicon from the same aliquot of biogenic silica. Pure silica is dissociated into O and Si compounds using a fluorination technique, in which reaction with bromine pentafluoride (BrF5) produces oxygen (O2, subsequently converted to CO2), silicon tetrafluoride (SiF4) and other fluorine by-products (e.g. BrF3). These compounds are cryogenically separated using cold traps. Yields for oxygen and silicon recovery are 70,80% for biogenic silica depending on the nature of the hydrous layer and 97,99% for pure quartz. Reproducibility of the oxygen isotopic composition is ca. 0.3, and silicon between 0.06,0.12,. © Natural Environment Research Council (NERC) copyright 2008. Reproduced with the permission of NERC. Published by John Wiley & Sons, Ltd. [source] Raman spectroscopy of synthetic, geological and biological vaterite: a Raman spectroscopic studyJOURNAL OF RAMAN SPECTROSCOPY, Issue 2 2010U. Wehrmeister Abstract Raman spectroscopy was used to study vaterite samples of biological, geological and synthetic origin. The Raman band positions and the full width at half-maximum (FWHM) of the lattice modes and the internal modes of the carbonate ion of all specimens show no significant differences between vaterites of different origin. With increasing Mg concentrations, synthetic vaterite samples show increasing FWHM in the region of the lattice modes and the three ,1 bands, whereas no change in luminescence was detected. In contrast, in situ measurements of vaterite areas in freshwater cultured pearls (FWCPs) by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) together with the Raman spectra obtained at the same points show that the luminescence intensity in biological samples is affected by the magnesium content. The Raman spectroscopic features of vaterite and parisite-(Ce) are compared, and their similarities suggest that the structure of vaterite contains at least three crystallographically independent carbonate groups and similar carbonate group layers. A band at 263 cm,1 is observed for the first time in this study, whereas it could be demonstrated that bands previously reported at 130 and 190 cm,1 do not belong to vaterite. Copyright © 2009 John Wiley & Sons, Ltd. [source] Rapid speciation of iron by on-line coupling of short column capillary electrophoresis and inductively coupled plasma mass spectrometry with the collision cell techniqueJOURNAL OF SEPARATION SCIENCE, JSS, Issue 6 2007Bao-Hui Li Abstract A method for rapid speciation analysis of iron was developed by on-line coupling of short column capillary electrophoresis and inductively coupled plasma mass spectrometry. The collision cell technique was used to eliminate argon-based polyatomic interferences and a Micromist nebulizer was employed to increase the nebulization efficiency. Rapid speciation analysis of Fe(II) and Fe(III) was achieved within 1 min by short column capillary electrophoresis in a 14 cm×50 ,m id capillary at 28 kV voltage with a mixture of 15 mmol/L tris(hydroxymethyl)aminomethane + 1 mmol/L 1,10-phenanthroline + 1 mmol/L EDTA (pH 8.6) as running electrolyte. The precisions (RSD, n = 5) of migration time and peak area for Fe(II) and Fe(III) were in the range of 1.0,2.6 and 1.9,3.9%, respectively. The limits of detection (3,) of Fe(II) and Fe(III) were 10.0 and 8.3 ,g/L, respectively. [source] Environmental analysis by inductively coupled plasma mass spectrometryMASS SPECTROMETRY REVIEWS, Issue 4 2010Diane Beauchemin Abstract This article reviews the numerous ways in which inductively coupled plasma mass spectrometry has been used for the analysis of environmental samples since it was commercially introduced in 1983. Its multielemental isotopic capability, high sensitivity and wide linear dynamic range makes it ideally suited for environmental analysis. Provided that some care is taken during sample preparation and that appropriate calibration strategies are used to circumvent non-spectroscopic interferences, the technique is readily applicable to the analysis of a wide variety of environmental samples (natural waters, soils, rocks, sediments, vegetation, etc.), using quadrupole, time-of-flight or double-focusing sector-field mass spectrometers. In cases where spectroscopic interferences arising from the sample matrix cannot be resolved, then separation methods can be implemented either on- or off-line, which can simultaneously allow analyte preconcentration, thus further decreasing the already low detection limits that are achievable. In most cases, the blank, prepared by following the same steps as for the sample but without the sample, limits the ultimate detection limits that can be reached. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:560,592, 2010 [source] Laser ablation-inductively coupled plasma mass spectrometry in archaeometric researchMASS SPECTROMETRY REVIEWS, Issue 1 2010Martín Resano Abstract Laser ablation-inductively coupled plasma mass spectrometry (LA-ICPMS) is a solid sampling technique in continuous expansion in all types of research fields in which direct multi-elemental or isotopic analysis is required. In particular, this technique shows unique characteristics that made its use recommended in many archaeometric applications, where valuable solid artifacts are often the target samples, because it offers flexibility to achieve spatially resolved information with high detection power and a wide linear range, in a fast and straightforward way, and with minimal sample damage. The current review provides a systematic survey of publications that reported the use of LA-ICPMS in an archaeological context, highlights its main capabilities and limitations and discusses the most relevant parameters that influence the performance of this technique for this type of application. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:55,78, 2010 [source] Mass spectrometry in bioinorganic analytical chemistryMASS SPECTROMETRY REVIEWS, Issue 2 2006Ryszard Abstract A considerable momentum has recently been gained by in vitro and in vivo studies of interactions of trace elements in biomolecules due to advances in inductively coupled plasma mass spectrometry (ICP MS) used as a detector in chromatography and capillary and planar electrophoresis. The multi-isotopic (including non-metals such as S, P, or Se) detection capability, high sensitivity, tolerance to matrix, and large linearity range regardless of the chemical environment of an analyte make ICP MS a valuable complementary technique to electrospray MS and MALDI MS. This review covers different facets of the recent progress in metal speciation in biochemistry, including probing in vitro interactions between metals and biomolecules, detection, determination, and structural characterization of heteroatom-containing molecules in biological tissues, and protein monitoring and quantification via a heteroelement (S, Se, or P) signal. The application areas include environmental chemistry, plant and animal biochemistry, nutrition, and medicine. © 2005 Wiley Periodicals, Inc. Mass Spec Rev 25:255,289, 2006 [source] Origin of kamacite, schreibersite, and perryite in metal-sulfide nodules of the enstatite chondrite Sahara 97072 (EH3)METEORITICS & PLANETARY SCIENCE, Issue 2 2010Stephen W. LEHNER We have measured concentrations of Ni, Cu, Ga, Au, Ir, Ru, and Pd in these minerals with laser ablation, inductively coupled plasma mass spectrometry (ICP-MS). We also measured their Fe, Ni, P, Si, and Co concentrations with electron microprobe. In kamacite, ratios of Ru/Ir, Pd/Ir, and Pd/Ru cluster around their respective CI values and all elements analyzed plot near the intersection of the equilibrium condensation trajectory versus Ni and the respective CI ratios. In schreibersite, the Pd/Ru ratio is near the CI value and perryite contains significant Cu, Ga, and Pd. We propose that schreibersite and perryite formed separately near the condensation temperatures of P and Si in a reduced gas and were incorporated into Fe-Ni alloy. Upon further cooling, sulfidation of Fe in kamacite resulted in the formation of additional perryite at the sulfide interface. Still later, transient heating re-melted this perryite near the Fe-FeS eutectic temperature during partial melting of the metal-sulfide nodules. The metal-sulfide nodules are pre-accretionary objects that retain CI ratios of most siderophile elements, although they have experienced transient heating events. [source] Compositions of unzoned and zoned metal in the CBb chondrites Hammadah al Hamra 237 and Queen Alexandra Range 94627METEORITICS & PLANETARY SCIENCE, Issue 8 2005Andrew J. CAMPBELL We have measured concentrations of Ni, Cu, Ga, Ru, Pd, Ir, and Au within both zoned and unzoned metal grains in the CBb chondrites Hammadah al Hamra (HaH) 237 and Queen Alexandra Range (QUE) 94627 using laser ablation inductively coupled plasma mass spectrometry. The refractory elements Ni, Ru, and Ir are enriched in the grain cores, relative to the rims, in the zoned metal. All refractory elements are uniform across the unzoned metal grains, at concentrations that are highly variable between grains. The volatile elements Cu, Ga, and Au are usually depleted relative to chondritic abundances and are most often uniform within the grains but are sometimes slightly elevated at the outermost rim. The Pd abundances are nearly uniform, at close to chondritic abundances, in all of the metal grains. A condensation origin is inferred for both types of metal. The data support a model in which the zoned metal formed at high temperatures, in a relatively rapidly cooling nebular gas, and the unzoned metal formed at lower temperatures and at a lower cooling rate. The CBb metal appears to have formed by a process very similar to that of the CH chondrites, but the CBb meteorite components experienced even less thermal alteration following their formation and are among the most primitive materials known to have formed in the solar nebula. [source] Platinum group elements in impactites of the ICDP Chicxulub drill core Yaxcopoil-1: Are there traces of the projectile?METEORITICS & PLANETARY SCIENCE, Issue 6 2004Roald Tagle These are the main elements used for projectile identification. They were determined by nickel sulfide fire assay combined with inductively coupled plasma mass spectrometry. The concentration of PGE in the samples are low. The concentration patterns of the suevite samples resemble the pattern of the continental crust. We conclude that any meteoritic fraction in these samples is below 0.05%. A syn- and post-impact modification of the PGE pattern from meteoritic toward a continental crust pattern is very unlikely. The globally distributed fallout at the Cretaceous-Tertiary (K/T) boundary, however, has high PGE concentrations. Therefore, the lack of a significant meteoritic PGE signature in the crater is not an argument for a PGE-poor impactor. Taking the results of three-dimensional numerical simulations of the Chicxulub event into account, the following conclusions are drawn: 1) The main fraction of the impactor was ejected into and beyond the stratosphere, distributed globally, and deposited in the K/T boundary clay; and 2) the low amount of projectile contamination in the Yax-1 lithologies may reflect an oblique impact. However, the role of volatiles in the mixing process between projectile and target is not well-understood and may also have played a fundamental role. [source] Speciation and distribution of arsenic and localization of nutrients in rice grainsNEW PHYTOLOGIST, Issue 1 2009E. Lombi Summary ,,Arsenic (As) contamination of rice grains and the generally low concentration of micronutrients in rice have been recognized as a major concern for human health. Here, we investigated the speciation and localization of As and the distribution of (micro)nutrients in rice grains because these are key factors controlling bioavailability of nutrients and contaminants. ,,Bulk total and speciation analyses using high-pressure liquid chromatography (HPLC),inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge spectroscopy (XANES) was complemented by spatially resolved microspectroscopic techniques (µ-XANES, µ-X-ray fluorescence (µ-XRF) and particle induced X-ray emission (PIXE)) to investigate both speciation and distribution of As and localization of nutrients in situ. ,,The distribution of As and micronutrients varied between the various parts of the grains (husk, bran and endosperm) and was characterized by element-specific distribution patterns. The speciation of As in bran and endosperm was dominated by As(III),thiol complexes. ,,The results indicate that the translocation from the maternal to filial tissues may be a bottleneck for As accumulation in the grain. Strong similarities between the distribution of iron (Fe), manganese (Mn) and phosphorus (P) and between zinc (Zn) and sulphur (S) may be indicative of complexation mechanisms in rice grains. [source] The Pigmentation of Human Iris Influences the Uptake and Storing of ZincPIGMENT CELL & MELANOMA RESEARCH, Issue 5 2004Despina Kokkinou Age-related macular degeneration (AMD) is more prevalent among the elderly Caucasians than in Africans. A significant association between light iris colour, fundus pigmentation and incidence of AMD is reported, suggesting a possible correlation with melanin pigment. Zinc is known to bind to melanin in pigmented tissues and to enhance antioxidant capacity by function as a cofactor or gene expression factor of antioxidant enzymes in the eye. In this in vitro study, we investigated the uptake and storage of zinc in human irides. Irides of blue and brown human eyes were used. The number of melanocytes was measured. Tissues without any treatment served as controls. The irides were incubated with 100 ,M zinc chloride in culture medium for 24 h. Specimens of the tissues were stored for the uptake examination. The remained pieces were further incubated for 3 and 7 d to investigate the storage of zinc. The concentration of zinc was measured by inductively coupled plasma mass spectrometry (ICP-MS). Melanocytes count was significantly higher in the brown tissues (P < 0.0001). Zinc concentration of blue coloured irides after 24 h zinc treatment was close to the controls. We did not observe any significant storing. In contrast, the concentration of zinc in brown irides was significantly increased after 24 h (P , 0.01) and remained at a high level for 7 d. The uptake of zinc is likely dependent on the amount of pigmentation in human iris. Therefore, we assume that in patients suffering from AMD the degree of pigmentation of the irides and eventually fundi should be under consideration when the patients are treated with zinc supplementation. [source] An investigation of the effect of silane water-crosslinking on the properties of poly(L-lactide)POLYMER INTERNATIONAL, Issue 5 2010Changyu Han Abstract A silane-grafting water-crosslinking approach was developed to crosslink poly(L -lactide) (PLLA) by grafting vinylalkoxysilane onto PLLA using dicumyl peroxide, followed by silane hydrolysis to form siloxane linkages between PLLA chains. The degree of silane grafting onto PLLA was qualitatively characterized using Fourier transform infrared spectroscopy and quantitatively determined using inductively coupled plasma mass spectrometry. Crosslinked PLLA films were obtained by curing of silane-grafted PLLA in hot water. Gel fractions were evaluated in order to calculate the crosslinking reaction kinetics and crosslinking density. Various techniques were used to investigate the effect of silane water-crosslinking on the thermomechanical properties, hydrolysis resistance and biodegradation of PLLA. In addition to an improvement in thermal stability and mechanical properties, hydrolysis resistance was significantly enhanced as a result of silane water-crosslinking of PLLA. Moreover, the biodegradation of silane water-crosslinked PLLA was retarded compared with neat PLLA. Copyright © 2010 Society of Chemical Industry [source] Compound-specific bromine isotope analysis of brominated diphenyl ethers using gas chromatography multiple collector/inductively coupled plasma mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 14 2010Henry Holmstrand The bromine isotope composition is potentially diagnostic in both degradation monitoring and source apportionment of organobromines in the environment. A method for compound-specific bromine isotope analysis (,81Br) based on gas chromatography multiple collector inductively coupled plasma mass spectrometry (GC/ICPMS) was developed for common brominated diaromatic compounds. Brominated diphenyl ethers (BDEs) in Bromkal 70-5DE, a technical flame-retardant mixture containing mainly BDEs #47, #99 and #100, were used as test substances, with standard bracketing for the samples achieved through co-injected monobromobenzene (MBB) with a known ,81Br of ,0.39, vs. Standard Mean Ocean Bromine (SMOBr). Three different heated transfer lines were constructed and tested to achieve efficient conduction of the BDEs from the gas chromatograph to the ICPMS instrument. The MBB was analyzed with a precision of 0.4, (1,s, n,=,18). The precision for BDEs was 1.4,1.8, (1,s, n,=,10,12 depending on the congener). The lower precision for the BDEs than for MBB may reflect the heat required to prevent condensation of the analytes in ICP torch assembly. The use of an internal standard of similar chemical structure to the analytes alleviates this problem, as illustrated by a difference of 0.3,±,0.7, (1,s, n,=,6) between the ,81Br values of co-injected methoxy BDE-47 and BDE-47 extracted from whale blubber. Improvements in precision and accuracy may be achieved by the use of a more efficient heating of the torch assembly in conjunction with a set of internal standards that match the target compounds. Copyright © 2010 John Wiley & Sons, Ltd. [source] Electrospray ionisation with selected reaction monitoring for the determination of Mn-citrate, Fe-citrate, Cu-citrate and Zn-citrateRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 15 2009Volker Nischwitz Citrate complexes of Mn and Fe, and potentially those of Cu and Zn, are considered as important low molecular mass species in human serum and cerebrospinal fluid (CSF). For example, Mn is supposed to enter the brain under excess exposure as Mn-citrate leading to neurotoxic effects. Mn-citrate has been characterised in human CSF using chromatography and electrophoresis online with inductively coupled plasma mass spectrometry, but not yet with molecular mass spectrometry. Therefore, this study explores the potential of electrospray ionisation (ESI) with selected reaction monitoring (SRM) for the detection of metal-citrate complexes, in particular Mn-citrate. The collision-induced dissociation of precursor ions with various metal:citrate stoichiometries was studied for Mn-citrate, Fe-citrate, Cu-citrate and Zn-citrate. High selectivity was achieved for Mn(II)-citrate even in respect to Fe(III)-citrate which forms isobaric precursor ions. The limit of detection for Mn-citrate was estimated to be around 250,µg,L,1 (referring to the total Mn content in the standard) using flow injection. The sensitivity was sufficient for the determination of Mn-citrate in standard solutions and in an extract of an Mn-citrate-containing supplement. An improved ESI source design is expected to reduce the limits of detection significantly. The developed ESI-SRM method has the potential to provide complementary data for the quality control of current separation methods for metal citrates using element-selective detection, with application to biomedical samples and further matrices. Copyright © 2009 John Wiley & Sons, Ltd. [source] Imaging of uranium on rat brain sections using laser ablation inductively coupled plasma mass spectrometry: a new tool for the study of critical substructures affined to heavy metals in tissuesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2008J. Sabine Becker The specific toxicity of trace metals and compounds largely depends on their bioavailability in different organs or compartments of the organism considered. Imaging mass spectrometry (IMS) using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) with a spatial resolution in the 100,µm range was developed and employed to study heavy metal distribution in brain tissues for toxicological screening. Rat brain post-mortem tissues were stained in an aqueous solution of either uranium or neodymium (metal concentration 100,µg,g,1) for 3,h. The incubation of heavy metal in thin slices of brain tissue is followed by an imaging mass spectrometric LA-ICP-MS technique. Stained rat brain tissue (thickness 30,µm) were scanned with a focused laser beam (wavelength 266,nm, diameter of laser crater 100,µm and laser power density 3,×,109,W,cm,2). The ion intensities of 235U+, 238U+, 145Nd+ and 146Nd+ were measured by LA-ICP-MS within the ablated area. For quantification purposes, matrix-matched laboratory standards were prepared by dosing each analyte to the pieces of homogenized brain tissue. Imaging LA-ICP-MS allows structures of interest to be identified and the relevant dose range to be estimated. Copyright © 2008 John Wiley & Sons, Ltd. [source] Sensitive determination of bromine and iodine in aqueous and biological samples by electrothermal vaporization inductively coupled plasma mass spectrometry using tetramethylammonium hydroxide as a chemical modifierRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 12 2008Hiroko Kataoka A procedure for the simultaneous determination of bromine and iodine by inductively coupled plasma (ICP) mass spectrometry was investigated. In order to prevent the decrease in the ionization efficiencies of bromine and iodine atoms caused by the introduction of water mist, electrothermal vaporization was used for sample introduction into the ICP mass spectrometer. To prevent loss of analytes during the drying process, a small amount of tetramethylammonium hydroxide solution was placed as a chemical modifier into the tungsten boat furnace. After evaporation of the solvent, the analytes instantly vaporized and were then introduced into the ICP ion source to detect the 79Br+, 81Br+, and 127I+ ions. By using this system, detection limits of 0.77,pg and 0.086,pg were achieved for bromine and iodine, respectively. These values correspond to 8.1,pg,mL,1 and 0.91,pg,mL,1 of the aqueous bromide and iodide ion concentrations, respectively, for a sampling volume of 95,µL. The relative standard deviations for eight replicate measurements were 2.2% and 2.8% for 20,pg of bromine and 2,pg of iodine, respectively. Approximately 25 batches were vaporizable per hour. The method was successfully applied to the analysis of various certified reference materials and practical situations as biological and aqueous samples. There is further potential for the simultaneous determination of fluorine and chlorine. Copyright © 2008 John Wiley & Sons, Ltd. [source] Cloud point extraction combined with electrothermal vaporization inductively coupled plasma mass spectrometry for the speciation of inorganic selenium in environmental water samplesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2006Beibei Chen A new method based on cloud point extraction (CPE) separation and electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICPMS) detection has been proposed for the speciation of inorganic selenium in environmental waters. When the temperature of the system is higher than the cloud point temperature (CPT) of the selected surfactant Triton X-114, the complex of Se(IV) with ammonium pyrrolidine dithiocarbamate (APDC) seems to be extracted into the surfactant-rich phase, whereas the Se(VI) remains in aqueous solutions. Thus, an insitu separation of Se(IV) and Se(VI) could be realized. The concentrated analyte was introduced into the ETV-ICP mass spectrometer for determination of Se((IV) after dilution with 200,µL methanol. Se(VI) was reduced to Se(IV) prior to determining total selenium, and its assay was based on subtracting Se(IV) from total selenium. The main factors affecting the CPE and the vaporization behavior of the analyte were investigated in detail. Under the optimized experimental conditions, the limit of detection (LOD) for Se(IV) was 8.0,ng/L with an enhancement factor of 39 when 10,mL of sample solution was preconcentrated to 0.2,mL. The relative standard deviation (RSD) was found to be 3.9% (CSe(IV),=,1.0,µg/L, n,=,7). The proposed method was applied to the speciation of inorganic selenium in different environmental water samples with the recovery for the spiked samples in the range of 82,102%. Copyright © 2006 John Wiley & Sons, Ltd. [source] Development of a liquid chromatography/electrospray selected reaction monitoring method for the determination of organoarsenic species in marine and freshwater samplesRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 19 2006Richard Schaeffer Cation- and anion-exchange high-performance liquid chromatography/electrospray selected reaction monitoring (HPLC/ES-SRM) methods were developed for the determination of 15 organoarsenic compounds in marine and freshwater samples. The results demonstrate that the developed HPLC/ES-SRM methods are powerful approaches for the identification of organoarsenic species in crude sample extracts. The detection limits, linearity as well as reproducibility for most of the species are comparable or even better than those measured by the HPLC/inductively coupled plasma mass spectrometry (ICPMS) technique. The qualitative analysis of the extracts shows that the developed methods allow for the identification of arsenicals which were not detectable by ICPMS. It was also demonstrated that the signal suppression caused by matrix effects means a significant limitation in the quantification of arsenicals by ES-SRM detection. This drawback is manifested especially in the case of the slightly retained species. The three sample-cleanup chromatographic methods including off-line size-exclusion, on-line reversed-phase and on-line oppositely charged ion-exchange approaches proved to be ineffective for separation of the signal-suppressive matrix from the analytes. The standard addition calibration seems to be a suitable solution for such problems. Copyright © 2006 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||