Sector Field Mass Spectrometer Research Articles

Scanning-assisted focal plane-detection system for a sector-field mass spectrometer - Part-I: Simulation and data processing

In this paper, a novel detection system, the Scanning-Assisted Focal Plane-Detection System (SAFPDS), is proposed as a focal plane detector for sector-field mass spectrometers. The principle of SAFPDS is to decouple the spatial resolution and local count rate of the microchannel plate (MCP) focal plane-detection system in order to enhance the local count rate and dynamic range limited by the MCP. This decoupling is achieved by deflecting ions along the vertical direction of the focal plane detector using an ion deflector during acquisition. Simulations of the SAFPDS are reported for optimal geometrical design, operation, and performance. Additionally, a dedicated novel data processing protocol for deriving a representative mass spectrum from the 3D-recorded data obtained with SAFPDS is developed in combination with the SAFPDS hardware. Our study shows that this protocol effectively enhances the spectrometer's Figure of Merit (FOM), defined as the integral of the mass resolution (m/Δm) over the relevant mass range, by a factor of 2.4. Furthermore, the evaluation of the spectrometer equipped with SAFPDS highlights its capability to enhance the local count rate and dynamic range of sector field mass spectrometers with an MCP-based detector by at least one order of magnitude. Importantly, this enhancement is achieved with a deterioration in mass resolving power that remains below 30%, which we consider acceptable given the significant improvements in local count rate and dynamic range.

Stable isotope analysis of atmospheric CO2 using a Gasbench II-Cold Trap-IRMS setting.

The measurement of the stable carbon and oxygen isotope ratio of (atmospheric) carbon dioxide (CO2 ) is a useful technique for the investigation and identification of the sources and sinks of the most abundant greenhouse gases by far. For this reason, we are presenting a measuring system here that enables a wide range of users to carry out stable isotope analysis of atmospheric CO2 using off-the-bench hardware and software. The fully automated system uses cryogenic and gas chromatographic separation to analyse CO2 from 12-mL whole air samples and consists of an autosampler, a Gasbench II (GB), a downstream cryo trap and a continuous flow gas interface feeding into a sector field mass spectrometer (GC Pal/GB/Cold Trap/ConFlo IV/DeltaV Plus). The evaluation of the system performance was based on the analysis of samples prepared from eight CO2 sources (four CO2 reference gases and four artificial air tanks). The overall measurement uncertainty (averaged single standard deviation (1σ) of measurement replicates from each CO2 source) in the determination of the carbon and oxygen isotope ratio was 0.04‰ and 0.09‰ (n = 24). Furthermore, we were able to show that the measurement data also allowed for the quantification of the CO2 mole fraction, with a precision of 1.2μmol mol-1 in the analysis range of 400-500 μmol mol-1 . Our protocol provides a detailed description of the measurement set-up and the analysis procedure, how raw data should be evaluated and gives recommendations for sample preparation and sampling to enable a fully automated whole air sample analysis. The quantification limit of CO2 mole fractions and measurement precision for carbon and oxygen isotope ratios of CO2 should meet the requirements of a wide range of users.

Heterogeneity of otolith chemical composition from two-dimensional mapping: Relationship with biomineralization mechanisms and implications for microchemistry analyses.

Although otoliths are widely used as archives to infer life-history traits and habitat use in fishes, their biomineralization process remains poorly understood. This lack of knowledge is problematic as it can lead to misinterpretation of the different types of signals (e.g., optical or chemical) that provide basic data for research in fish ecology, fisheries management, and species conservation. Otolith calcification relies on a complex system involving a pericrystalline fluid, the endolymph, whose organic and inorganic compositions are spatially heterogeneous for some constituents. This property stems from the particular structure of the calcifying saccular epithelium. In this study, we explored the spatial heterogeneity of elemental incorporation in otoliths for two species of high economic interest, European hake Merluccius merluccius (L. 1758) and European sea bass Dicentrarchus labrax (L. 1758). Two-dimensional mappings of chemical elements were obtained using UV high-repetition-rate femtosecond laser ablation (fs-LA) system coupled to a high-resolution inductively coupled plasma sector field mass spectrometer analyses on transverse sections of sagittae. Results highlighted a clear asymmetry between proximal (sulcus) and distal (antisulcus) concentrations for elements such as magnesium (Mg), phosphorus (P), manganese (Mn), and potassium (K) with concentration gradient directions that varied depending on the element. Strontium (Sr) and barium (Ba) did not show a proximo-distal gradient. These results are discussed in light of current knowledge on the endolymph composition and the mechanisms that lead to its compartmentalization, highlighting the need for further research on otolith biomineralization. Operational implications for studies based on otolith chemical composition are also discussed with emphasis on advice for sampling strategies to avoid analytical biases and the need for in-depth analyses of analytical settings before comparing otolith signatures between species or geographical areas.

Hugo Bondy (1900–1985): an Austrian scientist of mass spectrometry in the twentieth century

Hugo Bondy (1900–1985), a fairly unknown Austrian scientist working in academia in the twentieth century made important contributions to the development of double-focusing sector field mass spectrometers. This article describes his life and scientific contributions in a fascinating biography meriting his achievements in the development and construction of new mass spectrometers. The article divides into three sections according to Bondy’s biography. In the first section, his education, career in academia, and research in mass spectrometry are displayed. The second section reconstructs his expulsion from the university, his persecution and resistance in the Nazi era, and his failed attempt to be reinstated at his position as a scientist. In the third and last section, Bondy’s career in the Austrian Federal Ministry of Education is depicted by focusing on his youth work, a controversy of his political affiliations, and his accomplishments and character in the civil service. Bondy’s life is taken as an example to uncover the process of exclusion in science with all its consequences. But also, the ethical aspects of science for education and the application of a scientific attitude to society are revealed by his actions.Graphical abstract

Development of an In SituU‐Th Disequilibrium Dating Method Utilising Multiple‐Spot Femtosecond Laser Ablation‐CRC‐ICP‐MS

In situ 238U‐230Th dating was conducted using an ICP‐mass spectrometer coupled with a laser ablation sampling system (LA‐ICP‐MS). To minimise the contribution of mass spectrometric interferences on 230Th, a kinetic energy discrimination technique using a collision/reaction cell (CRC) system was employed. The major problem associated with the CRC‐ICP‐MS system is the lower transmission efficiencies of ions than sector field mass spectrometers. To improve the signal‐to‐background ratio for analytes, a combination of a multiple‐spot laser ablation (msLA) system together with a sensitivity‐enhanced dry plasma cone was employed. Analytical accuracy was evaluated through analyses of three zircon reference materials (GJ‐1, OD‐3 and Plešovice) and the resulting 230Th/238U ratios for GJ‐1 and Plešovice zircons agreed with the secular equilibrium value. The developed technique was applied to Quaternary volcanic zircon and monazite samples from Japan. The resulting ages are 113.5 +5.4‐5.2 ka for the Toya tephra, 105.1 +6.4‐6.1 ka for the Sambe Kisuki tephra, 55.2 +7.7‐7.2 ka for the Hikageyama lava and 16.2 +4.2‐4.1 ka for the Susaki pumice (95% confidence levels). The resulting ages are consistent with previous chronological constraints including zircon fission track ages. The data obtained here demonstrate clearly that the combination of the CRC‐ICP‐MS system and the msLA protocol can become a powerful analytical tool for in situ U‐Th disequilibrium dating.

Microanalysis using secondary ion emission By Raimond Castaing and Georges Slodzian

Secondary ion mass spectrometry (SIMS) is an analytical technique used to probe the composition of solids through the sputtering of the sample with a focussed primary ion beam and analyzing the emitted secondary ions generated under impact. These secondary ions ranging from elementals to low molecular weight organics offer precious information on the molecular composition and spatial organization within samples. Today, the combination of modern SIMS methodologies and instrumentation offers the most sensitive surface analysis approach, with elemental detection limits ranging from parts per million to parts per billion. In this month’s special feature article, we retrace the steps taken by Raimond Castaing and Georges Slodzian who in the early 1960’s developed a SIMS instrument based on a magnetic double focusing sector field mass spectrometer and using argon for the primary ion beam. This seminal work was first published in 1962, in French, in the Journal de Microscopie, which limited access to the scientific community at large. This article is now available in English and is beautifully prefaced by Georges Slodzian who revisits his steps as a young graduate student in the Castaing laboratory and discusses the scientific legacy of this article in the development of modern SIMS instrumentation.

Investigation of mass-scale drift effects in the milli-mass range: Influence on high mass resolution mode multicollector-inductively coupled plasma mass spectrometer isotope ratio measurements.

The consequences, possible origins, and prevention of mass-scale drifts in the high mass resolution mode (HR, M/ΔM ≈ 8000) under constant conditions were investigated and simulated in case of a multicollector-inductively coupled plasma mass spectrometer (MC-ICP-MS) using silicon enriched in 28 Si as the main element in this survey. A drifting mass scale strongly impairs the precise and accurate determination of isotope ratios, depending especially on the peak/plateau width. For example, 29 Si+ in Si highly enriched in 28 Si has an extremely small mass plateau width of ΔM ≤ 4 × 10-3 u, compare ΔM(56 Fe+ ) ≈ 18 × 10-3 u, which is to our knowledge one of the smallest plateaus routinely investigated in isotope ratio measurements, thus requiring extreme stability. During warm-up of the double-focusing sector field mass spectrometer, a mass drift up to ΔM/Δt ≥ 0.006 u/hr has been observed. Long-term studies on mass scale stability and simulations concerning fluctuations of the magnetic field B, acceleration voltage Uacc and ESA voltage UESA are reported. A change of one of these quantities of 0.01% induces changes of the mass scale of 6 × 10-3 u, 3 × 10-3 u, and 1 × 10-3 u in the case of B, Uacc , and UESA , respectively. After identifying electrical charging/discharging effects in the mass spectrometer affecting the mass scale stability, the instrument was completely dismantled and carefully reinstalled. Additional stability tests using silicon, strontium, and lead finally yielded a mass drift of ΔM/Δt ≤ 0.001 u/8 h in the case of silicon. This enhanced stability guarantees measurements of isotope ratios on smallest plateaus with lowest uncertainty. The importance of a stable mass scale is pointed out and the relevant quantities of a typical magnetic sector field mass spectrometer are discussed.

Determination of low-level arsenic, lead, cadmium and mercury concentration in breast milk of Hungarian women

ABSTRACTBreast milk was taken at different stages of lactation from 27 healthy lactating women living in Budapest and its metropolitan area with ages comprising between 25 and 41 years who exclusively breastfed their full-term newborns. Samples were subjected to microwave-assisted (MW) acid digestion in PTFE vessels containing quartz microvials. After fine-tuning of the MW-assisted acid digestion method by determination of total organic carbon content of the digested samples, the volume ratio for sample: 67% by weight HNO3 : 30% by weight H2O2 solutions = 1 : 2 : 1 proved to be suitable for determination of As, Cd and Pb by inductively coupled plasma sector field mass spectrometer. Mercury concentration was <0.4 µg/L in all samples. The order of Cd, As and Pb mean concentration in the samples were 0.188 ± 0.071 μg/L < 0.41 ± 0.20 μg/L < 1.74 ± 0.77 μg/L, respectively. Mean and median concentration of As and Pb data generally grouped into two-week intervals of lactation decreased by about 25–35% after two months. Moreover, statistically significant increase was observed for Pb concentration with the age of the mothers according to paired sample t-test almost 20 years after the prohibition of the marketing of leaded gasoline in the European Union and about 40 years after the ban on Pb pipes for drinking water delivery in Hungary (Pearson’s correlation coefficient 0.8285; at p < 0.05). However, according to our dietary intake estimations, no other threat for newborns fed by exclusive breastfeeding was detected.

Aging of Lithium Ion Battery Electrolytes – Novel Analysis Techniques for Elucidation of Potentially Hazardous Decomposition Products

In present time, energy and consequently energy storage are topics of utmost importance. With regard to the latter, the lithium ion battery (LIB) is the most promising candidate to fulfill the demanding requirements of energy storage in terms of energy density, cycling stability and safety. But, electrolytes of state-of-the-art LIBs exhibit diverse decomposition mechanisms and thus decomposition products. Hence, identification of compounds and as a result mechanistic conclusions were in focus in recent years.[1] Additionally, quantitative data of the potential hazardousness of those compounds is crucial. This importance is even more emphasized since some decomposition products show structural similarities to phosphorus-based pesticides or even worse, chemical warfare agents. For structural elucidation of compounds, high-resolution organic mass spectrometric techniques were used as they deliver excellent sensitivity and low limits of detection. Concerning quantification, inductively coupled plasma-mass spectrometry (ICP-MS) was used due to the high structural variety of compounds and lack of commercially available analytical standards. For this purpose, a sector-field mass spectrometer (SF-MS) delivered reliable quantitative data in high resolution and in a broad linear range while still offering excellent detection limits. Thus, quantities could be assigned to the respective compounds that were identified parallel. Prior to detection, the species of interest were separated depending on their chemical characteristics. Since a large variety of compounds with different chemical properties was found, comprehensive analysis using different chromatographic techniques was adjusted accordingly for specific separation of compounds. The results were interpreted with regard to total decomposition products in electric vehicles and toxicological aspects, eventually, delivering a risk estimate of potentially hazardous compounds of LIB electrolytes. In this study, investigation of LIB electrolytes from lab-scale and field-tested EVs are interrelated regarding variety and especially quantity of phosphorous compounds of the decomposition route of the conducting salt LiPF6.[2] Simulated abusive treatment through use of elevated temperature outside of the stability window of electrolyte components and voltages exceeding the nominal cycling range are analyzed and interrelated with extracted electrolytes of field-tested cells. [1] S. Nowak and M. Winter, Journal of The Electrochemical Society, 2015, 162 (14), A2500-A2508. [2] V. Kraft, W.Weber et al., RSC Advances, 2016; 6 (1), 8-17.

Granular activated charcoal from peanut (Arachis hypogea) shell as a new candidate for stabilization of arsenic in soil

A sandy soil of pH = 5.0 artificially contaminated with 15 mg/kg As in form of arsenate ions [iAs(V)] corresponding to the permissible value in force in Hungary was incubated for 4 weeks after amendment with different peanut shell-derived activated charcoal (AC) materials at an application rate of 2 wt%. Composite formation with silicate materials and adsorption mechanism for As were corroborated by attenuated total-reflection Fourier-transform infrared spectroscopy. Moreover, 0.01 M oxalic acid (OA) was also applied to investigate further enhancement through protonation of iAs(V) and/or AC. Assessment of As stabilization was achieved by a fit-to-purpose BCR sequential soil extraction procedure (extraction of the water-soluble and carbonatic fraction with 0.11 M acetic acid solution and the easily reducible one by 0.5 M hydroxylamine hydrochloride). Arsenic phytoavailability was estimated by leaching with 0.02 M EDTA solution (pH = 4.65). Samples were analyzed by inductively coupled plasma sector field mass spectrometer applying high resolution mode. Total-reflection X-ray fluorescence spectrometer was used to check data accuracy. The largest As stabilization rate (approximately 30%) compared to the reference soil treatment was obtained when granular Florisil®-AC was applied. Stabilization efficiency did not improve by using OA. A 5 wt% AC application rate for the Florisil® composite resulted in a similar As distribution to the 2 wt% one also at a 30 mg/kg iAs(V) dosage. The amounts of immobilized As increased almost proportionally with the higher AC application rate by doubling the iAs(V) dose. Similarly, studies conducted on solutions proved that As adsorption onto ACs was slightly exponential.

Imaging Artifacts in Continuous Scanning 2D LA-ICPMS Imaging Due to Nonsynchronization Issues.

Pulsed laser ablation (LA) devices in laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) imaging have become very advanced, delivering laser pulses with high temporal accuracy and stable energy density. However, unintentional imaging artifacts may be generated in 2D element maps when the LA repetition rate and the data acquisition parameters of ICPMS instruments with a sequential mass spectrometer (i.e., quadrupole filter or sector-field mass spectrometer) are desynchronized. This may potentially lead to interference patterns, visible as ripples in elemental images, and thus, compromised image quality. This paper describes the background of aliasing in continuous scanning mode through simulation experiments and ways to modulate the effect. The existence of this image degradation source is demonstrated experimentally via real-life imaging of a homogeneous glass standard.

Determination of Rare Earth Elements in multi-year high-resolution Arctic aerosol record by double focusing Inductively Coupled Plasma Mass Spectrometry with desolvation nebulizer inlet system

An inductively coupled plasma sector field mass spectrometer (ICP-SFMS) was used to develop an analytical method for the fast determination of Na, Al, Sc, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Y, Mo, Cd, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Pb in Arctic size-segregated aerosol samples (PM10), after microwave acidic digestion. The ICP-SFMS was coupled with a microflow nebulizer and a desolvation system for the sample introduction, which reduced the isobaric interferences due to oxides and the required volume of sample solutions, compared to the usual nebulization chamber methods. With its very low limit of detection, and taking into account the level of blanks, this method allowed the quantification of many metals in very low concentration. Particular attention was given to Rare Earth Elements (REEs - La to Lu). The efficiency in the extraction of REEs was proved to be acceptable, with recoveries over 83% obtained with a Certified Reference Material (AMiS 0356). The analytical method was then applied to particulate matter samples, collected at ground level in Ny Ålesund (Svalbard Islands, Norway), during spring and summer, from 2010 to 2015, with daily resolution and using a low-volume device. Thus, for the first time, a large atmospheric concentrations dataset of metals in Arctic particulate matter at high temporal resolution is presented. On the basis of differences in LREE/HREE ratio and Ce and Eu anomalies in spring and summer samples, basic information to distinguish local and long-range transported dust were achieved.

Studies on Isotope Ratio Measurement of Cl by Inductively Coupled Plasma Triple-quad Mass Spectrometry.

Fundamental studies on isotope ratio measurement of Cl were carried out using inductively coupled plasma triple-quad mass spectrometry (ICP-MS/MS) and the analytical performance obtained was compared to that obtained by ICP sector field mass spectrometer (ICP-SFMS). Though the polyatomic ion interferences of 16O18O1H and 36Ar1H with respect to 35Cl and 37Cl, respectively, made a negative effect on the accuracy and the precision for isotope ratio measurements of Cl, the ICP-SFMS could eliminate these interferences by medium mass resolution mode (m/Δm = 4000) and achieved the isotope ratio measurements with 0.2 - 0.5% of relative standard deviation (RSD) at the concentrations of Cl from 1 to 10 mg kg-1. In the case of ICP-MS/MS, both the single-MS mode without collision reaction gas and the MS/MS mode with collision reaction gases such as oxygen (O2) and hydrogen (H2) were examined and compared their analytical sensitivities as well as the precisions of isotope ratio measurement of Cl. The precisions of Cl isotope ratio measurements were 3 - 14% of RSD at the concentrations of Cl from 5 to 100 mg kg-1, when single-MS mode was carried out, even though the similar isotope ratios of 35Cl/37Cl could be obtained. In the case of O2 gas for MS/MS mode with mass-shift method, precisions of 0.3 - 2% of RSD were obtained at the concentration range of 1 - 100 mg kg-1. In the case of H2 gas, similar sensitivities as those obtained by ICP-SFMS and the precisions of 0.2 - 0.5% of RSD at the concentration range of 1 - 10 mg kg-1 were obtained. From these results, it was evaluated that the ICP-MS/MS in MS/MS mode with collision reaction gas could be used for Cl isotope ratio measurements for such studies as stable isotope tracers, isotope abundance measurements in nuclear chemistry and accurate determinations by isotope dilution mass spectrometry.

Ion Mobility Studies on the Negative Ion-Molecule Chemistry of Isoflurane and Enflurane

In the present work we present an investigation of the negative ion-molecule chemistry of the anaesthetics isoflurane, ISOF, and enflurane, ENF, in an ion mobility spectrometry/mass spectrometry (IMS/MS), in both air and nitrogen. Hexachloroethane (HCE) was introduced in both air and nitrogen to produce Cl– as a reactant ion. This study was undertaken owing to uncertainties in the chemical processes, which lead to the cluster ions reported in other work (Eiceman et al. Anal. Chem. 61, 1093–1099, 1). In particular for ISOF the product ion observed was ISOF.Cl–, and it was suggested that the Cl– was formed by dissociative electron attachment (DEA) although there was mention of a chlorine containing contaminant. We show in this study that ISOF and ENF do not produce Cl– in an IMS system either by capture of free electrons or reaction with O2–. This demonstrates that the Cl– containing ions, reported in the earlier study, must have been the result of a chlorine containing contaminant as suggested. The failure of ISOF and ENF to undergo DEA was initially surprising given the high calculated electron affinities, but further calculations showed that this was a result of the large positive vertical attachment energies (VAEs). This experimental work has been supported by electronic structure calculations at the B3LYP level, and is consistent with those obtained in a crossed electron-molecular beam two sector field mass spectrometer. An unusual observation is that the monomer complexes of ISOF and ENF with O2– are relatively unstable compared with the dimer complexes.Graphical ᅟ

87Sr/86Sr isotope ratio measurements by laser ablation multicollector inductively coupled plasma mass spectrometry: Reconsidering matrix interferences in bioapatites and biogenic carbonates

This study is dedicated to the systematic investigation of the effect of interferences on Sr isotopic analyses in biological apatite and carbonate matrices using laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC ICP-MS). Trends towards higher 87Sr/86Sr ratios for LA-MC ICP-MS compared to solution-nebulization based MC ICP-MS when analysing bioapatite matrices (e.g. human teeth) and lower ratios in case of calcium carbonates (e.g. fish ear stones) were observed. This effect can be related to the presence of significant matrix-related interferences such as molecular ions (e.g. (40Ca-31P-16O)+, (40Ar-31P-16O)+, (42Ca-44Ca)+, (46Ca40Ar)+) as well as in many cases concomitant atomic ions (e.g. 87Rb+, 174Hf2+). Direct 87Sr/86Sr ratio measurements in Ca-rich samples are conducted without the possibility of prior sample separation, which can be accomplished routinely for solution-based analysis. The presence of Ca-Ar and Ca-Ca molecular ion interferences in the mass range of Sr isotopes is shown using the mass resolving capabilities of a single collector inductively coupled plasma sector field mass spectrometer operated in medium mass resolution when analysing bioapatites and calcium carbonate samples.The major focus was set on analysing human tooth samples, fish hard parts and geological carbonates. Potential sources of interferences were identified and corrected for. The combined corrections of interferences and adequate instrumental isotopic fractionation correction procedures lead to accurate data even though increased uncertainties have to be taken into account. The results are discussed along with approaches presented in literature for data correction in laser ablation analysis.

The impact of iron status and smoking on blood divalent metal concentrations in Norwegian women in the HUNT2 Study

Low iron (Fe) stores may result in increased absorption of divalent metals, in particular cadmium (Cd). We have previously shown that in non-smoking women participating in the Norwegian HUNT2 cohort study this also included other divalent metals, e.g. manganese (Mn) and cobalt (Co). The diet is the main source of metals in non-smoking individuals, whereas in smoking individuals tobacco smoke contributes significant amounts of Cd and lead (Pb). The aim of the present study was to investigate the impact of smoking on the relationship between low iron status and divalent metals.Blood concentrations of the divalent metals Cd, Mn, Co, Pb, copper (Cu) and zinc (Zn), determined using an Element 2 sector field mass spectrometer (ICP-MS), were investigated in smoking women of fertile age (range 21–55 years) (n=267) from the HUNT2 cohort. Among these, 82 were iron-deplete (serum ferritin<12μg/L) and 28 had iron deficiency anaemia (serum ferritin<12μg/L & Hb<120g/L). 150 (56%) women smoked 10 or more cigarettes daily, 101 (38%) had smoked for more than 20 years, and 107 (40%) had smoked for 11–20 years. Results from the smoking population were compared with results from our previous study in non-smoking women (n=448) of which 132 were previous smokers, all from the same cohort.Increasing concentrations of Cd in blood were observed for previous smokers, low-to-moderate smokers and high intensity smokers in all subgroups compared to never smokers, and according to age groups, education level, BMI and serum ferritin. Smokers had higher Pb concentrations than non-smokers in all subgroups, but less pronounced than for Cd. Smoking was not associated with Mn and Co concentrations in blood.In multiple regression models, low ferritin was associated with increased blood concentrations of Cd, Pb, Mn and Co. Ferritin was strongly associated with Cd at low smoking intensity, but was not a significant factor in heavy smokers, where intensity and duration of smoking emerged as main determinants. Ferritin associations with Co and Pb varied with tertiles of blood Cd. Ferritin emerged as the main determinant of blood Co and Mn, while for blood Pb, age and smoking intensity had higher impact. Cu and Zn remained within reference values and no significant associations with ferritin were found. Strong positive associations between blood concentrations of Pb, Mn, Cd and Co were observed, also when controlled for their common association with ferritin. Apart from these associations, the models showed no significant interactions between the divalent metals studied. Mild anaemia (110<Hb<120g/L) did not seem to have any effect independent of low ferritin.The results indicate that low serum ferritin facilitates absorption of certain divalent metal ions in female smokers as well as the previously shown effect in non-smokers. Even if smoking provides Pb and Cd, the mutual associations between Cd and other divalent metals in blood persisted in medium and heavy smokers. This indicates that the interrelationship between Cd and divalent metals not only reflect effects on the absorption, but possibly also on kinetic processes such as transportation in blood and other compartments, including excretion.

Greenland ice cores constrain glacial atmospheric fluxes of phosphorus

Phosphorus is a limiting nutrient for primary productivity, but little is known about past atmospheric fluxes to the open ocean. In this study, phosphate and phosphorus concentrations have been determined in the North Greenland Eemian Ice Drilling Project ice core for selected periods during the last glacial. Phosphate was determined continuously by using a molybdenum blue spectroscopic absorption method and discretely using an ion chromatograph. Total P was determined discretely using an inductively coupled plasma sector field mass spectrometer. For the last glacial period, we found concentrations of between 3 and 62 nM PO43− and 7 and 929 nM P. We find glacial atmospheric fluxes of phosphorus to Greenland were 4 to 11 times higher than in the past century, with the highest input during the cold glacial stadials (GS). Changes in P and PO43− fluxes between mild glacial interstadials (GI) and GS correlate positively with dust variability. The soluble fraction of P is larger in the mild GIs as compared to the dust-rich GSs. For the very high phosphate and phosphorus loads during the Last Glacial Maximum, the relationship between phosphate and dust is weaker than in GIs and milder GSs, suggesting either secondary phosphate sources or multiple dust sources. Based on crustal abundances, we find that dust inputs are sufficient to account for all P deposited during all periods investigated except the Last Glacial Maximum. During the glacial, sea salts contributed 10−3 nM P, while land biogenic emissions were a minor source of P.

Ra-226 and Rn-222 in saline water compartments of the Aral Sea region

The Aral Sea has been shrinking since 1963 due to extensive irrigation and the corresponding decline in the river water inflow. Understanding of the current hydrological situation demands an improved understanding of the surface water/groundwater dynamics in the region. 222Rn and 226Ra measurements can be used to trace groundwater discharge into surface waters. Data of these radiometric parameters were not previously available for the study region. We determined 222Rn activities after liquid phase extraction using Liquid Scintillation Counting (LSC) with peak-length discrimination and analyzed 226Ra concentrations in different water compartments of the Amu Darya Delta (surface waters, unconfined groundwater, artesian water, and water profiles from the closed Large Aral Sea (western basin).The water samples comprise a salinity range between 1 and 263g/l. The seasonal dynamics of solid/water interaction under an arid climate regime force the hydrochemical evolution of the unconfined groundwater in the Amu Darya Delta to high-salinity Na(Mg)Cl(SO4) water types. The dissolved radium concentrations in the waters were mostly very low due to mineral over-saturation, extensive co-precipitation of radium and adsorption of radium on coexisting solid substrates.The analysis of very low 226Ra concentrations (<10ppq) at remote study sites is a challenge. We used the water samples to test and improve different analytical methods. In particular, we modified a procedure developed for the α-spectrometric determination of 226Ra after solid phase extraction of radium using 3M Empore™ High Performance Extraction Disks (Purkl, 2002) for the analysis of the radionuclide using an ICP sector field mass spectrometer. The 226Ra concentration of 17 unconfined groundwater samples ranged between 0.2 and 5 ppq, and that of 28 artesian waters between <0.2 and 13ppq. The ICP-MS results conformed satisfactorily to analytical results based on γ-measurements of the 222Rn ingrowth after purging and trapping on super-cooled charcoal. The 226Ra concentrations were positively correlated with the salinity and the dissolved NaCl concentrations. The occurrence of unusually high 226Ra activities is explained by radium release from adsorption sites with increasing salinity. The inferred spatial variability of 222Rn in the Aral Sea and of 222Rn and 226Ra in the groundwater of the Amu Darya Delta is discussed in the context of our own previous hydrochemical studies in the study sites. Relatively low 222Rn activities in the unconfined GW (1–9.5Bq/l) indicate the alluvial sediments hosting the GW to be a low-238U(226Ra) substrate. Positive correlations between U and 226Ra, and U and 222Rn are likely related to locally deposited Fe(Mn)OOH precipitates. The 222Rn activity of the GW, however, distinctly exceeds the 222Rn concentration in the Aral Sea (10mBq/l), in principle, making 222Rn a sensitive tracer for the inflow of GW. The high water volume of the Large Aral Sea and wind induced mixing of its water body, however, hamper the detection of local groundwater inflow.

Dissociative electron attachment to the volatile anaesthetics enflurane and isoflurane and the chlorinated ethanes pentachloroethane and hexachloroethane

Negative ion formation through dissociative electron attachment to the gas-phase volatile anaesthetics enflurane and isoflurane (C3H2ClF5O) and to two chlorinated ethanes, pentachloroethane (C2HCl5) and hexachloroethane (C2Cl6), have been studied in a crossed electron-molecular beam two sector field mass spectrometer experiment. Anion efficiency curves for the negatively charged fragments have been measured over an electron energy range of approximately 0–17eV, with an energy resolution of ∼1eV. For the chlorinated ethanes, resonance features were generally found at ∼0eV and at 7.5eV. For the volatile anaesthetics, no zero energy resonances were observed. Instead, product anions were detected mainly in the 2–3eV and 9eV energy regions, with the exception of Cl−, whose dominant resonance occurs at approximately 0.6eV and 0.9eV for isoflurane and enflurane, respectively. To aid in the interpretation of the experimental results, quantum chemical calculations providing thermochemical thresholds of anion formation are also presented.

A new peak recognition algorithm for detection of ultra-small nano-particles by single particle ICP-MS using rapid time resolved data acquisition on a sector-field mass spectrometer

The size detection limit of single particle ICP-MS is improved by rapid data acquisition combined with a new peak recognition algorithm.