Co-reporter:Andrea Raab, Michael Stiboller, Zuzana Gajdosechova, Jenny Nelson, Jörg Feldmann
Journal of Food Composition and Analysis 2016 Volume 53() pp:49-60
Publication Date(Web):October 2016
DOI:10.1016/j.jfca.2016.09.008
•Essential and non-essential elements were determined in dietary supplements.•Most elements: daily intake is below the recommended daily intake/legal limits.•Use of some algae based supplements can lead to excess daily intake of iron or iodine.•Levels of inorganic As above the Chinese legal limit were found in some supplements.•None of the tested dietary supplements poses are direct risk to healthy adults.The element content of sixty seven food supplements falling into five different categories was determined with an Agilent 8800 Triple Quadrupole ICP-MS and the maximum daily intake calculated. The determined elements were: Rb, Cs, Mg, Ca, Sr, Ba, V, Cr, Mn, Fe Co, Cu, Zn, Mo, Se, I, Br, B, Al, As, Cd, Sb and Pb. The majority of supplements contained significantly less essential elements than the recommended daily intake. Exceptions were two algae based products leading to a very high iron intake. The use of 3 other algae based products would result in increased iodine intake. Of the non-essential elements determined the intake of inorganic arsenic from all supplements was below the limit set by ANSI 173, but several algae based and one garlic based supplement contained levels of inorganic arsenic above the limit set in China for food supplements. Generally garlic, fish oil and krill oil based products pose little risk of inadvertent increased intake of essential and non-essential elements. Algae based products can lead to intakes above the recommended limits for specific elements and generally contain higher amounts of all elements. None of the tested food supplements poses a direct risk to healthy adults.
Co-reporter:Janine Bosle, Sven Goetz, Andrea Raab, Eva M. Krupp, Kirk G. Scheckel, Enzo Lombi, Andrew A. Meharg, Paul A. Fowler, and Jörg Feldmann
Analytical Chemistry 2016 Volume 88(Issue 24) pp:
Publication Date(Web):November 21, 2016
DOI:10.1021/acs.analchem.6b03730
Maternal diet and lifestyle choices may affect placental transfer of cobalamin (Cbl) to the fetus. Fetal liver concentration of Cbl reflects nutritional status with regards to vitamin B12, but at these low concentration current Cbl measurement methods lack robustness. An analytical method based on enzymatic extraction with subsequent reversed-phase-high-pressure liquid chromatography (RP-HPLC) separation and parallel ICPMS and electrospray ionization (ESI)-Orbitrap-MS to determine specifically Cbl species in liver samples of only 10–50 mg was developed using 14 pig livers. Subsequently 55 human fetal livers were analyzed. HPLC–ICPMS analysis for cobalt (Co) and Cbl gave detection limits of 0.18 ng/g and 0.88 ng/g d.m. in liver samples, respectively, with a recovery of >95%. Total Co (Cot) concentration did not reflect the amount of Cbl or vitamin B12 in the liver. Cbl bound Co contributes only 45 ± 15% to Cot. XRF mapping and μXANES analysis confirmed the occurrence of non-Cbl cobalt in pig liver hot spots indicating particular Co. No correlations of total cobalt nor Cbl with fetal weight or weeks of gestation were found for the human fetal livers. Although no gender difference could be identified for total Co concentration, female livers were significantly higher in Cbl concentration (24.1 ± 7.8 ng/g) than those from male fetuses (19.8 ± 7.1 ng/g) (p = 0.04). This HPLC–ICPMS method was able to quantify total Cot and Cbl in fetus liver, and it was sensitive and precise enough to identify this gender difference.
Co-reporter:Edi Bralatei, Severine Lacan, Eva M Krupp, and Jörg Feldmann
Analytical Chemistry 2015 Volume 87(Issue 22) pp:11271
Publication Date(Web):October 13, 2015
DOI:10.1021/acs.analchem.5b02386
Rice is a staple food eaten by more than 50% of the world’s population and is a daily dietary constituent in most South East Asian countries where 70% of the rice export comes from and where there is a high level of arsenic contamination in groundwater used for irrigation. Research shows that rice can take up and store inorganic arsenic during cultivation, and rice is considered to be one of the major routes of exposure to inorganic arsenic, a class I carcinogen for humans. Here, we report the use of a screening method based on the Gutzeit methodology to detect inorganic arsenic (iAs) in rice within 1 h. After optimization, 30 rice commodities from the United Kingdom market were tested with the field method and were compared to the reference method (high-performance liquid chromatography-inductively coupled plasma-mass spectrometry, HPLC-ICP-MS). In all but three rice samples, iAs compound can be determined. The results show no bias for iAs using the field method. Results obtained show quantification limits of about 50 μg kg–1, a good reproducibility for a field method of ±12%, and only a few false positives and negatives (<10%) could only be recorded at the 2015 European Commission (EC) guideline for baby rice of 100 μg kg–1, while none were recorded at the maximum level suggested by the World Health Organization (WHO) and implemented by the EC for polished and white rice of 200 μg kg–1. The method is reliable, fast, and inexpensive; hence, it is suggested to be used as a screening method in the field for preselection of rice which violates legislative guidelines.
Co-reporter:Fatai Adigun Aborode, Andrea Raab, Simon Foster, Enzo Lombi, William Maher, Eva M. Krupp and Joerg Feldmann
Metallomics 2015 vol. 7(Issue 7) pp:1056-1066
Publication Date(Web):26 Feb 2015
DOI:10.1039/C5MT00025D
Three month old Thunbergia alata were exposed for 13 days to 10 μM selenite to determine the biotransformation of selenite in their roots. Selenium in formic acid extracts (80 ± 3%) was present as selenopeptides with Se–S bonds and selenium–PC complexes (selenocysteinyl-2-3-dihydroxypropionyl-glutathione, seleno-phytochelatin2, seleno-di-glutathione). An analytical method using HPLC-ICPMS to detect and quantify elemental selenium in roots of T. alata plants using sodium sulfite to quantitatively transform elemental selenium to selenosulfate was also developed. Elemental selenium was determined as 18 ± 4% of the total selenium in the roots which was equivalent to the selenium not extracted using formic acid extraction. The results are in an agreement with the XAS measurements of the exposed roots which showed no occurrence of selenite or selenate but a mixture of selenocysteine and elemental selenium.
Co-reporter:Stanislav Musil, Ásta H. Pétursdóttir, Andrea Raab, Helga Gunnlaugsdóttir, Eva Krupp, and Jörg Feldmann
Analytical Chemistry 2014 Volume 86(Issue 2) pp:993
Publication Date(Web):December 19, 2013
DOI:10.1021/ac403438c
Because of the toxicity of inorganic arsenic (iAs), only iAs needs to be monitored in food and feedstuff. This demands the development of easy and quick analytical methods to screen large number of samples. This work focuses on hydride generation (HG) coupled with an ICPMS as an arsenic detector where the HG is added as a selective step to determine iAs in the gaseous phase while organically bound As remains in the solution. iAs forms volatile arsine species with high efficiency when treated with NaBH4 at acidic conditions, whereas most other organoarsenic compounds do not form any or only less volatile arsines. Additionally, using high concentrations of HCl further reduces the production of the less volatile arsines and iAs is almost exclusively formed, therefore enabling to measure iAs without a prior step of species separation using chromatography. Here, we coupled a commercially available HG system to an ICPMS and optimized for determination of iAs in rice and samples of marine origin using different acid concentrations, wet and dry plasma conditions, and different reaction gas modes. Comparing this method to conventional HPLC–ICPMS, no statistical difference in iAs concentration was found and comparable limits of detections were achieved using less than half the instrument time.
Co-reporter:Kenneth O. Amayo, Andrea Raab, Eva M. Krupp, Talke Marschall, Michael Horsfall Jr., Jörg Feldmann
Journal of Trace Elements in Medicine and Biology 2014 Volume 28(Issue 2) pp:131-137
Publication Date(Web):April 2014
DOI:10.1016/j.jtemb.2013.11.004
Identification of arsenolipids in biological samples is today a challenge and in particular the need for speciation data for toxicological assessment. Fish is one of the major contributors of arsenic in diet. However, the majority of work in this area has only focused on the water soluble compounds. The aim of this study is to provide some data on total arsenic and in particular to gain insights into the types of arsenolipids in the muscle tissues of four commercial and commonly consumed fish species. Determination of total arsenic was carried out by ICP-MS following microwave-assisted acid digestion of the samples and the concentrations found for total arsenic in the muscles ranged from 4.8 to 6.0 μg/g d.w. Sequential extraction was carried out using hexane and MeOH/DCM followed by reversed phase HPLC-ICP-MS/ESI-MS analysis of the MeOH/DCM fraction. Eight arsenolipids including three arsenic fatty acids (AsFAs) and five arsenic hydrocarbons (AsHCs) were identified. The result showed that fish with higher arsenolipid (AsLp) content (brill and sardine) are dominated by AsHC, while those with the smaller proportion of AsLp (mackerel and red mullet) have predominately arsenic in the form of AsFA.
Co-reporter:Ásta H. Pétursdóttir, Nils Friedrich, Stanislav Musil, Andrea Raab, Helga Gunnlaugsdóttir, Eva M. Krupp and Jörg Feldmann
Analytical Methods 2014 vol. 6(Issue 14) pp:5392-5396
Publication Date(Web):24 Mar 2014
DOI:10.1039/C4AY00423J
The inorganic arsenic (iAs) concentration was measured in 44 rice product samples, covering a wide range, using both hydride generation (HG) ICP-MS and HPLC-ICP-MS. Linear regression showed good linearity (R2 of 0.99) with a slope close to 1 (0.969 ± 0.015) and similar sensitivity showing that HPLC can robustly be replaced by a simple HG system, shortening the measurement time and resulting in easier data treatment as no manual integration of peaks is necessary. With upcoming regulations on the iAs concentration in rice in the EU, it is important that regulators do not prescribe only one standard method since it excludes new instrumental developments.
Co-reporter:Kenneth O Amayo, Andrea Raab, Eva M Krupp, Jörg Feldmann
Talanta 2014 Volume 118() pp:217-223
Publication Date(Web):15 January 2014
DOI:10.1016/j.talanta.2013.09.056
•We identified sixteen arsenolipids in cod-liver oil.•Among the arsenolipids identified nine of them have not been reported before.•The degradation products of arsenolipids were also identified.•These results are essential in toxicological assessment and in epidemiologic studies of arsenic.Oils from marine samples are known to contain high concentrations of arsenolipids. However, their identification in lipid matrix poses a significant challenge especially when present in low concentrations. Here, we report the identification of sixteen arsenolipids in cod-liver oil. The fish oil was fractionated on a silica gel column and the fraction enriched with arsenic analysed using RP-HPLC online with ICP-MS and ES-Orbitrap-MS. Among the arsenolipids identified nine compounds have not been reported before. Structural assignment was achieved by arsenic signal from ICP-MS, retention time behaviour and accurate mass determination of fragment and molecular peaks. In addition, the unknown degradation products of arsenolipids eluting in the void volume were investigated using fraction collection, cation exchange chromatography and accurate mass determination, and were found to contain predominantly dimethylarsinic acid (DMA) with trace amounts of methylarsonic acid (MA), dimethylarsenopropanoic acid (DMAP) and dimethylarsenobutanoic acid (DMAB). This finding is essential in epidemiologic studies where urinary DMA and other arsenic metabolites have been used as biomarker in accessing human exposure to arsenic.
Co-reporter:Andrea Raab, Chris Newcombe, Dominik Pitton, Rainer Ebel, and Jörg Feldmann
Analytical Chemistry 2013 Volume 85(Issue 5) pp:2817
Publication Date(Web):February 8, 2013
DOI:10.1021/ac303340t
Approaches for the unambiguous identification of lipophilic arsenic species in Saccharina latissima (sugar kelp) have been studied. Parallel use of high resolution ICPMS and electrospray ionization (ESI)-MS after separation revealed that Saccharina latissima contained three distinct classes of lipophilic As-species, a family of arsenic containing phospholipids (AsPL), all including As in the form of As–sugar–PO4, As-containing hydrocarbons (AsHC), and As-containing polyunsaturated fatty acids (AsFA). For detailed identification, the use of phospholipases, in particular phospholipase A2, was essential to define the fatty acid composition (determination of regioisomers) of the lipids without purification of the sample, while fragmentation of the molecules by MS2 measurements alone did not supply this information. Some of the identified AsPL contained unsaturated fatty acids (C16:1, C18:1 to C18:3), but saturated fatty acids dominated the AsPL. The fatty acid bound to the position 2″ was predominantly C16:0. Complete lipid hydrolysis showed that this alga did not contain arsenic containing fatty acids (AsFA) bound to complex lipids. Our investigations indicate that in addition to RP-HPLC-ICPMS/ESI-MS a range of different derivatization methods should be used for the comprehensive identification of unknown lipid-soluble arsenic compounds.
Co-reporter:Kenneth O. Amayo, Andrea Raab, Eva M. Krupp, Helga Gunnlaugsdottir, and Jörg Feldmann
Analytical Chemistry 2013 Volume 85(Issue 19) pp:9321
Publication Date(Web):August 28, 2013
DOI:10.1021/ac4020935
The identification of molecular structures of an arsenolipid is pivotal for its toxicological assessment and in understanding the arsenic cycling in the environment. However, the analysis of these compounds in a lipid matrix is an ongoing challenge. So far, only a few arsenolipids have been reported, including arsenic fatty acids (AsFAs) and arsenic hydrocarbons (AsHCs). By means of RP-HPLC-ICPMS/ESMS, we investigated Capelin oil (Mallotus villosus) for possible new species of arsenolipids. Twelve arsenolipids were identified in the fish oil including three AsFAs and seven AsHCs. Among the AsHCs, four that were identified had protonotated molecular masses of 305, 331, 347, and 359 and have not been reported before. In addition, the compounds with molecular formulas C20H44AsO+ and C24H44AsO+ were found in low concentrations and showed chromatographic properties and MS data consistent with cationic trimethylarsenio fatty alcohols. Derivatization by acetylation and thiolation coupled with accurate mass spectrometry was successfully used to establish the occurrence of this new class of arsenolipids as cationic trimethylarsenio fatty alcohols (TMAsFOH).
Co-reporter:Zhiwei Qin, Andrea Raab, Eva Krupp, Hai Deng and Jörg Feldmann
Journal of Analytical Atomic Spectrometry 2013 vol. 28(Issue 6) pp:877-882
Publication Date(Web):28 Mar 2013
DOI:10.1039/C3JA50086A
The lack of specific fluorine detection at trace levels hampers the screening of microorganisms which can form novel fluorometabolites. So far only target analysis by ESI-MS using accurate mass and certain fragmentation or preconcentration and clean-up procedures has been used to perform 19F and 13C/1H NMR for the identification of novel fluorocompounds. Here we demonstrate that the analysis of complex media from microorganism cultures can be screened using a set of HPLC separations which are coupled parallel to CS-MAS as a fluorine specific detector and the ESI-MS as the molecular detection. This makes it possible to identify fluorine containing species without prior knowledge of the compounds and the use of clean up procedures. Here specifically we identify traces of a fluorometabolite (5′-fluoro-5′-deoxy-adenosine, 5′-FDA) in complex media of Streptomyces cattleya without preconcentration and target analysis.
Co-reporter:Dagmar S. Urgast and Jörg Feldmann
Journal of Analytical Atomic Spectrometry 2013 vol. 28(Issue 9) pp:1367-1371
Publication Date(Web):21 May 2013
DOI:10.1039/C3JA50058F
This article describes the advantages and possibilities of using LA-ICP-MS for isotope ratio measurements, briefly comparing quadrupole, sector-field and multi-collector systems. It also discusses problems and limitations of the respective set-ups. A special focus lies on biological samples from stable isotope tracer experiments and on spatially resolved isotope ratio measurements including imaging of isotope ratios. The article explores if there are valid reasons why until now almost no one used LA-ICP-MS to image isotope ratios. It wants to encourage the ICP-MS community to realise the potential of using LA-ICP-MS for isotope ratio measurements in biological samples and to hopefully spur further developments and applications.
Co-reporter:Adrien Mestrot, Britta Planer-Friedrich and Jörg Feldmann
Environmental Science: Nano 2013 vol. 15(Issue 9) pp:1639-1651
Publication Date(Web):07 Jun 2013
DOI:10.1039/C3EM00105A
It has been known for over a hundred years that microorganisms can produce volatile arsenic (As) species, termed “arsines”. However, this topic has received relatively little attention compared to As behaviour in soils and biotransformation through the trophic level in the marine and terrestrial environment. We believe this is due to long-standing misconceptions regarding volatile As stability and transport as well as an absence, until recently, of appropriate sampling methods. First and foremost, an attempt is made to unify arsines' designations, notations and formulas, taking into account all the different terms used in the literature. Then, the stability of As volatile species is discussed and new analytical developments are explored. Further, the special cases of diffuse low-level emissions (e.g. soil and sediment biovolatilisation), and point sources with high-level emissions (geothermal environments, landfills, and natural gas) are comprehensively reviewed. In each case, future possible areas of research and unknown mechanisms are identified and their importance towards the global As biogeochemical cycle is explored. This review gathers new information regarding mechanisms, stability, transport and sampling of the very elusive arsines and shows that more research should be conducted on this important process.
Co-reporter:Zhiwei Qin, David McNee, Heike Gleisner, Andrea Raab, Kwaku Kyeremeh, Marcel Jaspars, Eva Krupp, Hai Deng, and Jörg Feldmann
Analytical Chemistry 2012 Volume 84(Issue 14) pp:6213
Publication Date(Web):June 11, 2012
DOI:10.1021/ac301201y
Driven by increasing demand for the monitoring of industrial perfluorinated compounds (PFCs), the identification of novel fluorine containing compounds (FOCs) and the tracking of organofluorine drugs and their degradation products, there is a clear need for sensitive, fluorine-specific detection of unknown FOCs. Here we report the first ever direct fluorine-specific (speciation) method; capable of individually detecting untargeted FOCs in environmental and biological samples through the application of continuum source molecular absorption spectrometry (CS-MAS) using a commercial CS-AAS. Two model FOCs (2,4,6, trifluorobenzoic acid (TFBA) and 5-fluoroindol-5-carboxylic acid (FICA)) were used, achieving fluorine-specific detection across a range of 0.1 to 300 ng/mL fluorine, corresponding to a limit of detection of 4 pg F and 5.26 nM for both compounds. Both TFBA and FICA showed a similar response to CS-MAS detection, potentially enabling the quantification of fluorine content in novel FOCs without having molecular standards available. This paper also reports the use of reverse-phase high performance liquid chromatography (RP-HPLC) coupled off-line with CS-MAS for the identification of single organofluorines in a mixture of FOCs via fraction collection. The linear range of both FOCs was determined to be from 1 to 500 ng/mL. The limits of detection of those species were just above 1 ng/mL (100 pg) and can therefore compete with targeted analytical methods such as ESI-MS. Finally, as a proof of principle the analysis of a fluoride-containing groundwater sample from Ghana demonstrated that this method can be used in the detection of novel FOCs, with identification achieved through parallel ESI-MS. Coupled HPLC–CS-MAS/ESI-MS is the first analytical methodology capable of selectively detecting and identifying novel FOCs, making possible the quantification of all fluorine containing compounds in one sample. This is the necessary analytical requirement to perform fluoronomics.
Co-reporter:Dagmar S. Urgast, Sarah Hill, In-Sook Kwun, John H. Beattie, Heidi Goenaga-Infante and Jörg Feldmann
Metallomics 2012 vol. 4(Issue 10) pp:1057-1063
Publication Date(Web):02 Aug 2012
DOI:10.1039/C2MT20119D
Zinc stable isotope tracers (67Zn and 70Zn) were injected into rats at two different time points to investigate the feasibility of using tracers to study zinc kinetics at the microscale within distinct tissue features. Laser ablation coupled to multi-collector ICP-MS was used to analyse average isotope ratios in liver thin sections and to generate bio-images showing zinc isotope ratio distribution in brain thin sections. Average isotope ratios of all samples from treated animals were found to be statistically different (P < 0.05) from samples from untreated control animals. Furthermore, differing isotope ratios in physiological features of the brain, namely hippocampus, amygdala, cortex and hypothalamus, were identified. This indicates that these regions differ in their zinc metabolism kinetics. While cortex and hypothalamus contain more tracer two days after injection than 14 days after injection, the opposite is true for hippocampus and amygdala. This study showed that stable isotope tracer experiments can be combined with laser ablation MC-ICP-MS to measure trace element kinetics in tissues at a microscale level.
Co-reporter:Ásta H. Pétursdóttir;Helga Gunnlaugsdóttir
Analytical and Bioanalytical Chemistry 2012 Volume 404( Issue 8) pp:2185-2191
Publication Date(Web):2012 November
DOI:10.1007/s00216-012-6347-2
The addition of an online post-column hydride generation (HG) step to the commonly used high-performance liquid chromatography inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) setup for arsenic speciation proved to significantly improve the detection limits for the determination of inorganic arsenic (iAs) as arsenate in seafood samples, where the limit of detection and limit of quantification were found to be 0.0004 and 0.0014 mg kg−1, respectively with HG. HG as an additional step further added to the selectivity of the determination of the iAs species and increased the detection and quantification of low levels of iAs (<0.002 mg kg−1) in samples with complicated matrices.
Co-reporter:Dagmar S. Urgast;Dag G. Ellingsen
Analytical and Bioanalytical Chemistry 2012 Volume 404( Issue 1) pp:89-99
Publication Date(Web):2012 July
DOI:10.1007/s00216-012-6101-9
In recent years, bismuth has been promoted as a “green element” and is used as a substitute for the toxic lead in ammunition and other applications. However, the bioavailability and toxicity of bismuth is still not very well described. Following a hunting accident with bismuth-containing shots, a bioavailability study of bismuth from metal pellets inoculated into rat limb muscles was carried out. Bismuth could be found in urine and blood of the animals. Bio-imaging using laser ablation ICP-MS of thin sections of the tissue around the metal implant was carried out to find out more about the distribution of the metal diffusing into the tissue. Two laser ablation systems with different ablation cell designs were compared regarding their analytical performance. Low concentrations of bismuth showing a non-symmetrical pattern were detected in the tissue surrounding the metal implant. This was partly an artefact from cutting the thin sections but also bio-mobilisation of the metals of the implant could be seen. An accumulation of zinc around the implant was interpreted as a marker of inflammation. Challenges regarding sample preparation for laser ablation and bio-imaging of samples of diverse composition became apparent during the analysis.
Co-reporter:Kenneth O. Amayo, Asta Petursdottir, Chris Newcombe, Helga Gunnlaugsdottir, Andrea Raab, Eva M. Krupp, and Jörg Feldmann
Analytical Chemistry 2011 Volume 83(Issue 9) pp:3589
Publication Date(Web):March 30, 2011
DOI:10.1021/ac2005873
Although it has been known for decades that arsenic forms fat-soluble arsenic compounds, only recent attempts to identify the compounds have been successful by using a combination of fractionation and elemental and molecular mass spectrometry. Here we show that arsenolipids can directly be identified and quantified in biological extracts using reversed-phase high-performance liquid chromatography (RP-HPLC) simultaneously online-coupled to high-resolution inductively coupled plasma mass spectrometry (ICPMS) and high-resolution electrospray mass spectrometry (ES-MS) without having a lipophilic arsenic standard available. Using a methanol gradient for the separation made it necessary to use a gradient-dependent arsenic response factor for the quantification of the fat-soluble arsenic species in the extract. The response factor was obtained by using the ICPMS signal of known concentration of arsenic. The arsenic response was used to determine species-specific response factors for the different arsenic species. The retention time for the arsenic species was utilized to mine the ES-MS data for accurate mass and their tandem mass spectrometry (MS/MS) fragmentation pattern to give information of molecular formula and structure information. The majority of arsenolipids, found in the hexane phase of fish meal from capelin (Mallotus villosus) was in the form of three dimethylarsinoyl hydrocarbons (C23H38AsO, C17H38AsO, C19H42AsO) with minor amounts of dimethylarsinoyl fatty acids (C17H36AsO3, C23H38AsO3, C24H38AsO3). One of the dimethylarsinoyl fatty acids (C24H38AsO3), with an even number of carbon in the fatty acid chain, was identified for the first time in this work. This molecular formula is unusual and in contrast to all previously identified arsenic-containing fatty acids with odd numbers of carbon.
Co-reporter:Eva M. Krupp, John K. Merle, Karsten Haas, Gary Foote, Nicolas Maubec, and Jörg Feldmann
Environmental Science & Technology 2011 Volume 45(Issue 3) pp:943-950
Publication Date(Web):December 21, 2010
DOI:10.1021/es102512u
Organotin compounds are used as pesticides and fungicides as well as additives in plastics. This study identifies the de novo generation of novel volatile organotins in municipal waste deposits and their release via landfill gas. Besides tetramethyltin (Me4Sn), a strong neurotoxin, and 5 previously reported organotins, 13 novel ethylated, propylated, and butylated tetraalkyltin compounds were identified. A concentration of 2−4 μg of Sn m−3 landfill gas was estimated for two landfill sites in Scotland. The atmospheric stability of Me4Sn and methylated tin hydrides was determined empirically in a static atmosphere in the dark and under UV light to simulate night- and daytime conditions. Theoretical calculations were carried out to help predict the experimentally obtained stabilities and to estimate the relative stabilities of other alkylated species. Assuming first-order kinetics, the atmospheric half-life for Me3SnH was found to be 33 ± 16 and 1311 ± 111 h during day- and nighttime conditions, respectively. Polyalkylation and larger alkyl substitutes tend to reduce the atmospheric stability. These results show that substantial concentrations of neurotoxic organotin compounds can be released from landfill sites and are sufficiently stable in the atmosphere to travel over large distances in night- and daytime conditions to populated areas.
Co-reporter:Jörg Feldmann;Eva M. Krupp
Analytical and Bioanalytical Chemistry 2011 Volume 399( Issue 5) pp:1735-1741
Publication Date(Web):2011 February
DOI:10.1007/s00216-010-4303-6
In this opinion paper the toxicokinetic behaviour of arsenosugars is reviewed and compared with that of inorganic arsenic and arsenobetaine. It is concluded that the arsenosugars are similar to inorganic arsenic in terms of metabolite formation and tissue accumulation. As a pragmatic means of generating uniform data sets which adequately represent the toxicity of arsenic in food we recommend reporting partly speciated arsenic concentrations in food commodities in three fractions: i) toxic inorganic arsenic as arsenate (after oxidation); ii) arsenobetaine as established non-toxic arsenic; and iii) potentially toxic arsenic, which includes arsenosugars and other organoarsenicals.
Co-reporter:Sairoong Ouypornkochagorn and Jörg Feldmann
Environmental Science & Technology 2010 Volume 44(Issue 10) pp:3972
Publication Date(Web):April 23, 2010
DOI:10.1021/es903667y
The most common routes of arsenic exposure are ingestion and inhalation, whereas dermal uptake has been considered as a minor uptake route based on uptake experiments with arsenate. Here the kinetics of arsenite, dimethylarsinic acid (DMA(V)) and arsenosugar penetration through full thick human skin (from one volunteer) was determined using a Franz Cell design and compared to that of arsenate. The accumulation in the epidermis and dermis was performed by using laser ablation ICP-MS as a bioimaging method, and the biotransformation reactions through the uptake experiment were monitored by hyphenated elemental mass spectrometry. The penetration and accumulation of arsenic is strongly dependent on its speciation. While arsenosugars penetrated through the unbroken skin at a similar rate as arsenate, arsenite and DMA(V) were taken up percutaneously at a rate which was more than a factor of 29 and 59 higher than that of arsenate. The dermal uptake route of arsenic has been underestimated in risk assessments where exposure to arsenite or DMA(V) would occur. The accumulation potential of arsenosugars and DMA(V) was however minimal, whereas arsenate and arsenite accumulated in the epidermis and in the dermis. No significant species transformations were observed.
Co-reporter:Ronit Jakob, Anja Roth, Karsten Haas, Eva M. Krupp, Andrea Raab, Patricia Smichowski, Darío Gómez and Jörg Feldmann
Environmental Science: Nano 2010 vol. 12(Issue 2) pp:409-416
Publication Date(Web):17 Nov 2009
DOI:10.1039/B915867G
Biovolatilisation of arsenic as their arsines in the form of AsH3, and mono-, di and trimethylarsine has often been determined under laboratory conditions. Although environmental point sources such as landfill sites or hot springs have been characterised, only limited knowledge is available on how widespread the formation of volatile methylated arsenic compounds are in the environment. Here we studied the atmospheric stability of the different arsines and quantified their oxidation products in atmospheric particulate matter (PM10) in two locations in Argentina. The atmospheric half-life of the arsines range from 19 weeks for AsH3 to 2 d for trimethylarsine (TMAs) at 20 °C in the dark, while during simulated daytime conditions the stability is reduced for all arsines and in particular for the methylated arsines by three orders of magnitude which suggests that TMAs can only be dispersed at night. At both locations the arsenic concentration was in all samples below 1 ng As m−3, which is considered as rural background for arsenic. The oxidation products, i.e. methylarsonate (MA), dimethylarsinate (DMA) and trimethylarsine oxide (TMAO) were identified by using HPLC-ICP-MS/ES-MS in more than 90% of the 49 PM10 samples taken from 8 sampling points at the two geographically different locations. TMAO was the predominate organoarsenicals in both locations (66 and 69%, respectively) while DMA was determined to be between 13 and 19% of all organoarsenicals at the two locations. The concentration of the organoarsenicals ranged from 4 to 60 pg As as TMAO m−3, while the maximum concentration for DMA and MA were 16 and 6 pg As m−3, respectively. No difference in terms of the concentration or distribution of the organoarsenicals in the PM10 samples was identified as significant. Since the two locations were different in climate and industrial impact and sampled in different seasons, these data suggest that methylated arsenicals do occur as background chemicals in the environment. Due to the low atmospheric stability of the methylated arsines, it is suggested that biovolatilization of arsenic as methylated arsines is a widespread phenomenon. More studies however are necessary to identify the major sources and determine the flux of the volatilization process in order to determine whether or not the process has environmental significance.
Co-reporter:Dagmar S. Urgast, Gillian C. Adams, Andrea Raab and Jörg Feldmann
Environmental Science: Nano 2010 vol. 12(Issue 5) pp:1126-1132
Publication Date(Web):22 Feb 2010
DOI:10.1039/B924351H
European whelks (Buccinum undatum) have shown to accumulate high levels of arsenic. Since the accumulation process is not well understood it is necessary to gain information about the geographical variability of the arsenic concentration in them. Here we show that the mean arsenic concentrations of the whelks are site specific and vary by a factor of 3.5 in ten different geographical locations. At fishing grounds where whelks exhibited low arsenic concentrations the arsenic concentration increased linearly with size, whereas the whelks with high arsenic levels from a different location showed no correlation. Although the overall arsenic concentration in the whelks differed between 45 and 655 mg kg−1 d.w., the inorganic arsenic concentration did not exceed 0.4 mg kg−1 d.w. The main arsenic compound is arsenobetaine, which is widely considered as non-toxic. The exposure to toxic inorganic arsenic when eating whelks cannot be estimated from their size or their total arsenic concentration.
Co-reporter:Chris Newcombe, Andrea Raab, Paul N. Williams, Claire Deacon, Parvez I. Haris, Andrew A. Meharg and Jörg Feldmann
Environmental Science: Nano 2010 vol. 12(Issue 4) pp:832-837
Publication Date(Web):16 Feb 2010
DOI:10.1039/B921588C
Arsenobetaine has always been referred to as a non-toxic but readily bioavailable compound and the available data would suggest that it is neither metabolised by nor accumulated in humans. Here this study investigates the urine of five volunteers on an arsenobetaine exclusive diet for twelve days and shows that arsenobetaine was consistently excreted by three of the five volunteers. From the expected elimination pattern of arsenobetaine in rodents, no significant amount of arsenobetaine should have been detectable after 5 days of the trial period. The arsenobetaine concentration found in the urine was constant after 5 days and varied between 0.2 and 12.2 µg As per L for three of the volunteers. Contrary to the established belief that arsenobetaine is neither accumulated nor generated by humans, the presented results would suggest that either accumulated arsenobetaine in the tissues is slowly released over time or that arsenobetaine is a human metabolite of dimethylarsinic acid or inorganic arsenic from the trial food, or both. Either possibility is intriguing and raises fundamental questions about human arsenic metabolism and the toxicological and environmental inertness of arsenobetaine.
Co-reporter:Adrien Mestrot, M. Kalle Uroic, Thomas Plantevin, Md. Rafiqul Islam, Eva M. Krupp, Jörg Feldmann and Andrew A. Meharg
Environmental Science & Technology 2009 Volume 43(Issue 21) pp:8270-8275
Publication Date(Web):September 17, 2009
DOI:10.1021/es9018755
Arsenic volatilization in the environment is thought to be an important pathway for transfer from terrestrial pools to the atmosphere. However, this phenomenon is not well characterized due to inherent sampling issues in trapping, quantifying and qualifying these arsine gases; incudling arsine (AsH3), monomethyl arsine (MeAsH2), dimethyl arsine (Me2AsH) and trimethyl arsine (TMAs). To quantify and qualify arsines in air we developed a novel technique based on silver nitrate impregnated silica gel filled tubes. The method was characterized by mesuring the recovery of trapped arsines after elution of this chemo-trap with hot boiling diluted nitric acid. Results from three separate experiments, measured by ICP-MS, showed that the method is reproducible and quantitative. Arsine species recovery ranged from 80.1 to 95.6%, with limit of detection as low as 3.8 ng per chemo-trap tube. Moreover, HPLC-ICP-MS analysis of hot boiling water eluted traps showed that the corresponding oxy ions of the arsines were formed with the As—C bonds of the molecule intact, hence, allowing qualification of trapped arsine species. A microcosm study examining volatile arsenic evolution from field contaminated Bangladeshi paddy soils (24.2 mg/kg arsenic) was used to show the application of silver nitrate chemo-trapping appraoch. Traps were placed on the inlet and the oulet of microcosms containing the soils that were either (cattle derived) manured or not, or flooded or not, in a factorial design. The headspace was purged with air at a flow rate of 12 mL/min. Results showed that as much as 320 ng of arsenic (0.014% of total soil content) could be emitted in a 3 week period for manured and flooded soils and that TMAs was the dominant species evolved, with lesser quantities of Me2AsH. No volatile arsenic evolution was observed for nonmanured treatments, and arsine release from the nonflooded, manured treatment was much less than the flooded treatment.
Co-reporter:M. Kalle Uroic, Eva M. Krupp, Charlie Johnson and Jörg Feldmann
Environmental Science: Nano 2009 vol. 11(Issue 12) pp:2222-2230
Publication Date(Web):25 Sep 2009
DOI:10.1039/B913322D
Volatile arsenic compounds in natural gas, existing in the form of trimethylarsine (TMAs), have been determined using gas cryo-trapping gas chromatography coupled to inductively coupled plasma-mass spectrometry (CT-GC-ICP-MS). The results from a number of different gas wells revealed a huge concentration spread ranging from below the detection limit of 0.2 up to 1800 µg/m3 TMAs (as As) in the gas. Due to the toxicity and corrosive nature of these arsines, they need near real time monitoring via a method that can easily be implemented on site, i.e. during gas exploitation. Here, we introduce a novel method which utilises silver nitrate impregnated silica gel tubes for quantitative chemotrapping of trimethylarsine (TMAs) from a natural gas matrix. Subsequent elution with hot nitric acid followed by online photo-oxidation hydride generation atomic fluorescence spectrometry (HG-AFS) is used for the determination of TMAs gas standards in nitrogen and natural gas samples, respectively. The chemotrapping method was validated using CT-GC-ICP-MS as a reference method. The recovery of arsenic from nitrogen or natural gas matrix ranged from 85 to 113% for a range of 20 to 2000 ng As. Trapping efficiency was >98%, from the methods LOD of 20 ng to 4.8 µg (absolute amount As) with sample sizes of 0.02 and 2 L gas. Method performance was established by comparing the results obtained for eight natural gas samples containing between 1 and 140 µg As/m3 with those achieved by the reference method (CT-GC-ICP-MS).
Co-reporter:Jörg Feldmann
Analytical and Bioanalytical Chemistry 2008 Volume 390( Issue 7) pp:1683-1684
Publication Date(Web):2008 April
DOI:10.1007/s00216-008-1901-7
Co-reporter:StephenH. Wright Dr.;Andrea Raab Dr.;JiojiN. Tabudravu Dr.;Jörg Feldmann ;PaulF. Long Dr.;ChristopherN. Battershill Dr.;WalterC. Dunlap Dr.;BruceF. Milne Dr.;Marcel Jaspars
Angewandte Chemie International Edition 2008 Volume 47( Issue 42) pp:8090-8092
Publication Date(Web):
DOI:10.1002/anie.200802060
Co-reporter:Katharina Bluemlein;Andrea Raab
Analytical and Bioanalytical Chemistry 2008 Volume 390( Issue 7) pp:1739-1751
Publication Date(Web):2008 April
DOI:10.1007/s00216-007-1724-y
The weakest step in the analytical procedure for speciation analysis is extraction from a biological material into an aqueous solution which undergoes HPLC separation and then simultaneous online detection by elemental and molecular mass spectrometry (ICP–MS/ES-MS). This paper describes a study to determine the speciation of arsenic and, in particular, the arsenite phytochelatin complexes in the root from an ornamental garden plant Thunbergia alata exposed to 1 mg As L−1 as arsenate. The approach of formic acid extraction followed by HPLC–ES-MS/ICP–MS identified different AsIII–PC complexes in the extract of this plant and made their quantification via sulfur (m/z 32) and arsenic (m/z 75) possible. Although sulfur sensitivity could be significantly increased when xenon was used as collision gas in ICP–qMS, or when HR-ICP–MS was used in medium resolution, the As:S ratio gave misleading results in the identification of AsIII–PC complexes due to the relatively low resolution of the chromatography system in relation to the variety of As–peptides in plants. Hence only the parallel use of ES-MS/ICP–MS was able to prove the occurrence of such arsenite phytochelatin complexes. Between 55 and 64% of the arsenic was bound to the sulfur of peptides mainly as AsIII(PC2)2, AsIII(PC3) and AsIII(PC4). XANES (X-ray absorption near-edge spectroscopy) measurement, using the freshly exposed plant root directly, confirmed that most of the arsenic is trivalent and binds to S of peptides (53% As–S) while 38% occurred as arsenite and only 9% unchanged as arsenate. EXAFS data confirmed that As–S and As–O bonds occur in the plants. This study confirms, for the first time, that As–peptides can be extracted by formic acid and chromatographically separated on a reversed-phase column without significant decomposition or de-novo synthesis during the extraction step.
Co-reporter:StephenH. Wright Dr.;Andrea Raab Dr.;JiojiN. Tabudravu Dr.;Jörg Feldmann ;PaulF. Long Dr.;ChristopherN. Battershill Dr.;WalterC. Dunlap Dr.;BruceF. Milne Dr.;Marcel Jaspars
Angewandte Chemie 2008 Volume 120( Issue 42) pp:8210-8212
Publication Date(Web):
DOI:10.1002/ange.200802060
Co-reporter:E.M. Krupp, C. Johnson, C. Rechsteiner, M. Moir, D. Leong, J. Feldmann
Spectrochimica Acta Part B: Atomic Spectroscopy 2007 Volume 62(Issue 9) pp:970-977
Publication Date(Web):September 2007
DOI:10.1016/j.sab.2007.07.009
Speciation of trialkylated arsenic compunds in natural gas, pressurized and stable condensate samples from the same gas well was performed using (Cryotrapping) Gas Chromatography-Inductively Coupled Plasma Mass Spectrometry. The major species in all phases investigated was found to be trimethylarsine with a highest concentration of 17.8 ng/L (As) in the gas phase and 33.2 μg/L (As) in the stable condensate phase. The highest amount of trimethylarsine (121 μg/L (As)) was found in the pressurized condensate, along with trace amounts of non-identified higher alkylated arsines. Volatile arsenic species in natural gas and its related products cause concern with regards to environment, safety, occupational health and gas processing. Therefore, interest lies in a fast and simple field method for the determination of volatile arsenicals. Here, we use simple liquid and solid sorption techniques, namely absorption in silver nitrate solution and adsorption on silver nitrate impregnated silica gel tubes followed by total arsenic determination as a promising tool for field monitoring of volatile arsenicals in natural gas and gas condensates. Preliminary results obtained for the sorption-based methods show that around 70% of the arsenic is determined with these methods in comparison to volatile arsenic determination using GC-ICP-MS. Furthermore, an inter-laboratory- and inter-method comparison was performed using silver nitrate impregnated silica tubes on 14 different gas samples with concentrations varying from below 1 to 1000 μg As/m3 natural gas. The results obtained from the two laboratories differ in a range of 10 to 60%, but agree within the order of magnitude, which is satisfactory for our purposes.
Co-reporter:Andrea Raab Dr.;Stephen H. Wright Dr.;Marcel Jaspars Dr.;Andrew A. Meharg Dr.;Jörg Feldmann Dr.
Angewandte Chemie 2007 Volume 119(Issue 15) pp:
Publication Date(Web):13 MAR 2007
DOI:10.1002/ange.200604805
Arsenmetabolismus: Der Nachweis des Dimethylarsinothioylglutathion-Komplexes in Arsen ausgesetztem Kohl belegt, dass fünfwertiges Arsen an Biomoleküle binden kann, wenn es durch Sulfid aktiviert ist (siehe Bild; AsV violett, S gelb, O rot, N blau). Das Ergebnis unterstreicht, dass Sulfidreaktionen eine Rolle bei der Reaktivität von Arsenintermediaten und dem Arsenmetabolismus in Organismen spielen könnten.
Co-reporter:Andrea Raab Dr.;Stephen H. Wright Dr.;Marcel Jaspars Dr.;Andrew A. Meharg Dr.;Jörg Feldmann Dr.
Angewandte Chemie International Edition 2007 Volume 46(Issue 15) pp:
Publication Date(Web):13 MAR 2007
DOI:10.1002/anie.200604805
As biomolecules go: By identifying the dimethylarsinothioyl glutathione complex in arsenic-exposed cabbage, it was shown that pentavalent arsenic can bind to biomolecules when it is activated by sulfide (see picture; AsV purple, S yellow, O red, N blue). The result highlights that sulfide reactions may play a role in the reactivity of arsenic intermediates and the metabolic pathway of arsenic in organisms.
Co-reporter:Rajendra Regmi;Bruce F. Milne;Jörg Feldmann
Analytical and Bioanalytical Chemistry 2007 Volume 388( Issue 4) pp:775-782
Publication Date(Web):2007 June
DOI:10.1007/s00216-006-1076-z
The major arsenosugar compounds have been reported to be hydride-generation-active, however to a lesser extent in comparison with the inorganic arsenicals. We report here for the first time the identity and quantity of the volatile arsenicals generated by As-sugar-SO3, As-sugar-SO4, dimethylarsinoyl acetic acid and dimethylarsinoyl ethanol. Only one major volatile compound was identified for all four compounds studied: dimethylarsine. This means that the As–C bond to the longer carbon chain was cleaved during the hydride-generation process. Theoretical calculations at the RHF/6-31G(d,p) ab initio level confirm that this As–C bond is much weaker than the As–CH3 bonds. Furthermore, it was revealed that the sulphur analogue of dimethylarsinic acid (DMAS ) is hydride-generation-active at pH 7 in contrast to dimethylarsinic acid, despite the fact that arsenic is also pentavalent. This has been substantiated by the calculation of the change in susceptibility of the arsenic towards nucleophilic attack when oxygen is replaced by sulphur. Hence, DMAS can easily be mistaken for a trivalent arsenic species.
Co-reporter:Sanjay K. Mitra, Kijeung Jiang, Karsten Haas and Jörg Feldmann
Environmental Science: Nano 2005 vol. 7(Issue 11) pp:1066-1068
Publication Date(Web):27 Sep 2005
DOI:10.1039/B511767D
For the first time we are able to report the identification and quantification of several unexpected alkylated tin compounds such as dimethyldiethyltin, trimethylethyltin and propyltrimethyltin in European municipal waste deposits, by using GC-ICP-MS. Future studies will reveal whether their origin is from the degradation of butyl-, or octyltin compounds or simply products of de novo synthesis within the landfill environment.
Co-reporter:Helle R. Hansen, Marcel Jaspars and Jörg Feldmann
Analyst 2004 vol. 129(Issue 11) pp:1058-1064
Publication Date(Web):16 Aug 2004
DOI:10.1039/B409661B
It has been shown, that in vitro incubation of Laminaria digitata extract (containing mainly As-sugar 1 (glycerol-arsenoribose) and As-sugar 3 (sulfonate-arsenoribose)) with liver cytosol, produced the same two arsenicals, as when L. digitata extract was treated with H2S. By parallel use of HPLC-ICP-MS and HPLC-ES-MS the compounds displayed mainly m/z 345 and m/z 409. A pure As-sugar 1 standard was obtained, and a standard of arsinothioyl-sugar 1 (m/z 345) was produced, by purging a solution of As-sugar 1 with gaseous H2S. The identity of arsinothioyl-sugar 1 was characterised by ES-MS, 1D and 2D NMR. Arsinothioyl-sugar 1 showed the same chromatographic behaviour and MS characteristics as one of the two arsenic-containing compounds (m/z 345) produced by incubation of L. digitata extracts with liver cytosol, and as the product of the incubation of As-sugar 1 with liver cytosol (HPLC-ICP-MS, HPLC-ES-MS). Assuming that As-sugar 3 reacts in a similar way to As-sugar 1 with H2S, it is most likely that the second unknown (m/z 409) is arsinothioyl-sugar 3. The degradation of As-sugar 1 in acidic solution (100 mM HCl) was followed by 1H-NMR, and the relative slow degradation (t1/2
= 17 h) suggests that arsenosugars are taken up from the stomach in their original chemical form, hence the study of arsenosugar incubation in tissue is highly relevant. The arsinothioyls are a new group of organoarsenicals, which have only recently been identified in nature. Here, arsinothioyl sugars are detected for the first time. The in vitro formation of arsinothioyl-sugars in liver cytosol suggests that arsinothioyls may be of large biochemical and toxicological importance.
Co-reporter:Andrea Raab, Andrew A. Meharg, Marcel Jaspars, David R. Genney and Jörg Feldmann
Journal of Analytical Atomic Spectrometry 2004 vol. 19(Issue 1) pp:183-190
Publication Date(Web):21 Oct 2003
DOI:10.1039/B307945G
Complexes of arsenic compounds and glutathione are believed to play an essential part in the metabolism and transport of inorganic arsenic and its methylated species. Up to now, the evidence of their presence is mostly indirect. We studied the stability and chromatographic behaviour of glutathione complexes with trivalent arsenic: i.e. AsIII(GS)3, MAIII(GS)2 and DMAIII(GS) under different conditions. Standard ion chromatography using PRP X-100 and carbonate or formic acid buffer disintegrated the complexes, while all three complexes are stable and separable by reversed phase chromatography (0.1% formic acid/acetonitrile gradient). AsIII(GS)3 and MAIII(GS)2 were more stable than DMAIII(GS), which even under optimal conditions tended to degrade on the column at 25 °C. Chromatography at 6 °C can retain the integrity of the samples. These results shed more light on the interpretation of a vast number of previously published arsenic speciation studies, which have used chromatographic separation techniques with the assumption that the integrity of the arsenic species is guaranteed.
Co-reporter:Silvia Wehmeier;Andrea Raab;Jörg Feldmann
Applied Organometallic Chemistry 2004 Volume 18(Issue 12) pp:
Publication Date(Web):23 NOV 2004
DOI:10.1002/aoc.692
Glutathione (γ-GluCysGly, GSH) and methylcobalamin (CH3-B12) may play a role in the biomethylation process of antimony. To understand better the transformation of antimony in biological systems, we studied abiotic and biomethylation processes and the influence of GSH in the methylation.
CH3-B12, acting as a possible methylating agent for antimony, was studied with GSH and in the absence of GSH. The most abundant product of this reaction was monomethylantimony, with a small concentration of the dimethylantimony species, as identified by hydride generation cryotrapping gas chromatography inductively coupled plasma mass spectrometry (HG-CT-GC-ICP-MS). In the same experiments we found that tris(γ-GluCysGly)trithioantimonite [Sb(GS)3] and di(γ-GluCysGly)methyldithioantimonite [(CH3)Sb(GS)2] complexes were present using flow-injection electrospray ionization MS. Both complexes were also identified in a fermented sewage sample, suggesting that these complexes may play a role as intermediates in the biomethylation of antimony.
However, CH3-B12 is not the sole methylation agent, since it does not produce any trimethylantimony species as identified in anaerobic sewage sludge cultures inoculated with enriched 123Sb(V). Species-specific 123/121Sb isotope ratio measurements of the different methylantimony species suggest a stepwise methylation of antimony according to the Challenger mechanism. Copyright © 2004 John Wiley & Sons, Ltd.
Co-reporter:Helle Rusz Hansen;Russell Pickford;Jane Thomas-Oates ;Marcel Jaspars ;Jörg Feldmann Dr.
Angewandte Chemie 2004 Volume 116(Issue 3) pp:
Publication Date(Web):29 DEC 2003
DOI:10.1002/ange.200352740
Arsen im Schafspelz: Im Urin einer seltenen Rasse von Schafen, die sich von Seegras ernähren (siehe Bild), wurde eine Thioorganoarsenat-Verbindung (2-Dimethylarsinothioylessigsäure) nachgewiesen. Die Ergebnisse weisen darauf hin, dass der Arsenstoffwechsel von Säugetieren komplexer ist als bisher vermutet. Damit stellen sich neue Fragen nach der Toxizität solcher Organoarsinothio(y)l-Verbindungen.
Co-reporter:Helle Rusz Hansen;Russell Pickford;Jane Thomas-Oates ;Marcel Jaspars ;Jörg Feldmann Dr.
Angewandte Chemie International Edition 2004 Volume 43(Issue 3) pp:
Publication Date(Web):29 DEC 2003
DOI:10.1002/anie.200352740
Arsenic in sheep's clothing: the first characterization of a thio-organoarsenate compound (2-dimethylarsinothioyl acetic acid) isolated from a biological source (a rare breed of seaweed-eating sheep; see picture) is reported. The result indicates that mammalian arsenic metabolism is much more complex than has been claimed before, which opens up new questions about the toxicity of such organoarsenothio(y)l compounds.
Co-reporter:Helle Rüsz Hansen, Andrea Raab and Jörg Feldmann
Journal of Analytical Atomic Spectrometry 2003 vol. 18(Issue 5) pp:474-479
Publication Date(Web):10 Apr 2003
DOI:10.1039/B301686B
Here we report a new arsenic metabolite found in sheep’s urine after arsenosugar ingestion identified by the parallel use of HPLC-ICP-MS and HPLC-ESI-MS. The two methods together provide an excellent tool for identification of novel arsenic compounds in body fluids and extracts. Besides the previously reported major arsenic metabolite dimethylarsinic acid (DMA(V)) and the minor dimethylarsinoylethanol (DMAE), here we identify the second most abundant metabolite as dimethylarsinoylacetate (DMAA). The pH dependent retention behaviour of all three arsenic compounds was studied on an anion-exchange column in the pH range 3–8.5. This is the first time DMAA has been reported as a metabolite in urine after arsenosugar ingestion.
Co-reporter:Shya Devalla and;Jörg Feldmann
Applied Organometallic Chemistry 2003 Volume 17(Issue 12) pp:
Publication Date(Web):5 NOV 2003
DOI:10.1002/aoc.550
This work is part of an ongoing research study towards an understanding of the complete metabolism of arsenosugars in mammalian organisms when ingesting seaweed, using the North Ronaldsay (NR) sheep as a model organism. We focus on the analysis of only those arsenic species bound to the lipids of the feed (Laminaria digitata), faeces and the tissues of the NR sheep using a novel enzymatic hydrolytic method that is simple and reliable. This rare breed of sheep, found in the remote Orkney Islands in the north of Scotland, live the entire year on the beaches and eat seaweed that is washed ashore (up to 3 kg daily).
Previous studies on arsenic fractionation in muscle, kidney and liver tissues revealed that most of the arsenic is concentrated in the fat fractions of these tissues (muscle fat: 61%; liver fat: 66%; kidney fat: 25%) rather than in the non-lipid fractions. Hence, this study was undertaken in order to determine the arsenic species bound to lipids in the muscle, kidney and faeces of NR sheep and to compare these with the arsenic species bound to the lipids of the L. digitata consumed.
The enzymatic hydrolytic procedure has been successfully employed for the first time to cleave the arsenic species cleanly from the rest of the lipid structure. This makes the arsenic species water soluble and enables their direct determination by high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry. Dimethylarsinic acid (DMA(V)) and monomethylarsonic acid (MA(V)) were found to be the major hydrolysed arsenic species bound to the kidney and muscle lipids, whereas arsenosugar-1 was found to be the major hydrolysed arsenic species in L. digitata lipids. On the other hand, DMA(V) was found to be the major arsenical obtained after the enzymatic hydrolysis of the faeces lipids. These results seem to suggest that both direct absorption and biotransformation of the absorbed organoarsenicals are the likely reasons for their occurrence and accumulation in the NR sheep tissues. Copyright © 2003 John Wiley & Sons, Ltd.
Co-reporter:Andrea Raab;David R. Genney;Andrew A. Meharg;Jörg Feldmann
Applied Organometallic Chemistry 2003 Volume 17(Issue 9) pp:
Publication Date(Web):31 JUL 2003
DOI:10.1002/aoc.488
Sheep on the island of North Ronaldsay (Orkney, UK) feed mostly on seaweed, which contains high concentrations of dimethylated arsenoribosides. Wool of these sheep contains dimethylated, monomethylated and inorganic arsenic, in addition to unidentified arsenic species in unbound and complexed form. Chromatographic techniques using different separation mechanisms and detectors enabled us to identify five arsenic species in water extracts of wool. The wool contained 5.2 ± 2.3 µg arsenic per gram wool. About 80% of the arsenic in wool was extracted by boiling the wool with water. The main species is dimethylarsenic, which accounted for about 75 to 85%, monomethylated arsenic at about 5% and the rest is inorganic arsenic. Depending on the separation method and condition, the chromatographic recovery of arsenic species was between 45% for the anion exchange column, 68% for the size exclusion chromatography (SEC) and 82% for the cation exchange column. The SEC revealed the occurrence of two unknown arsenic compounds, of which one was probably a high molecular mass species. Since chromatographic recovery can be improved by either treating the extract with CuCl/HCl (CAT: 90%) or longer storage of the sample (CAT: 105%), in particular for methylated arsenic species, it can be assumed that labile arsenic–protein-like coordination species occur in the extract, which cannot be speciated with conventional chromatographic methods. It is clear from our study of sheep wool that there can be different kinds of ‘hidden’ arsenic in biological matrices, depending on the extraction, separation and detection methods used. Hidden species can be defined as species that are not recordable by the detection system, not extractable or do not elute from chromatographic columns. Copyright © 2003 John Wiley & Sons, Ltd.
Co-reporter:Linda A. Murray;Andrea Raab;Iain L. Marr;Jörg Feldmann
Applied Organometallic Chemistry 2003 Volume 17(Issue 9) pp:
Publication Date(Web):31 JUL 2003
DOI:10.1002/aoc.498
Chlorella vulgaris was cultivated in a growth medium containing arsenate concentration of <0.01, 10, 100 and 1000 mg l−1. Illumination was carried out in 12 h cycles for 5 days. The health status of the culture was monitored by continuous pH and dissolved oxygen (DO) readings. Destructive sampling was used for the determination of biomass, chlorophyll, total arsenic and arsenic species. The chlorophyll a content, the DO and pH cycles were not significantly different for the different arsenate concentrations in the culture. In contrast, biomass production was significantly (p < 0.05) increased for the arsenic(V) treatment at 1000 mg l−1 compared with 100 mg l−1.
The arsenic concentration in the algae increased with the arsenate concentration in the culture. However, the bioconcentration factor decreased a hundred-fold with increase of arsenate from the background level to 1000 mg l−1. The arsenic species were identified by using strong anion-exchange high-performance liquid chromatography–inductively coupled plasma mass spectrometry analysis after methanol/water (1 : 1) extraction. The majority (87–100%) of the extractable arsenic was still arsenate; arsenite was found to be between 1 and 6% of total extractable arsenic in the algae. In addition to dimethylarsinic acid, one unknown arsenical (almost co-eluting with methylarsonic acid) and three different arsenosugars have been identified for the first time in C. vulgaris growing in a culture containing a mixture of antibiotics and believed to be axenic. The transformation to arsenosugars in the algae is not dependent on the arsenate concentration in the culture and varies between 0.2 and 5% of total accumulated arsenic. Although no microbiological tests for bacterial contamination were made, this study supports the hypothesis that algae, and not associated bacteria, produce the arsenosugars. Copyright © 2003 John Wiley & Sons, Ltd.
Co-reporter:Jörg Feldmann, Andrew Kindness and Paul Ek
Journal of Analytical Atomic Spectrometry 2002 vol. 17(Issue 8) pp:813-818
Publication Date(Web):08 Jul 2002
DOI:10.1039/B201960D
A cryogenically cooled ablation cell enables the direct analysis of thin sections from fresh soft tissue samples, such as liver or kidney, for trace elements using laser ablation ICP-MS. We show here, for the first time, that reproducibilities of about 2–6% can be achieved if the tissue sample can be ablated at a temperature below −60 °C. All ablation and detection parameters, such as energy, spot size, focus, fire frequency and integration time at the ICP-TOF-MS, were optimised. A calibration method using three different tissue samples (sheep kidney, pig liver and sheep liver), from which the bulk element concentrations were determined, was validated with CRM Pig Liver (LGC 7112), which was pressed and frozen in the form of a thin slice. Good recoveries (86–124% for the certified values) were achieved for Cd (0.31 mg kg−1; 0.25 ± 0.04 certified), Cu (101 mg kg−1;
117 ± 8 certified), Zn (43.0 mg kg−1; 43.0 ± 2.7 certified) and Mo (1.8 mg kg−1; ∼1 indicative value). Therefore this CRM can be used for the quantification of other tissues with similar C-content using a one-point calibration. Detection limits in the lower µg kg−1 range (Cd: 15 µg kg−1, Cu: 50 µg kg−1, Zn: 20 µg kg−1, Mo: 10 µg kg−1 and Pb: 2 µg kg−1) were determined based on 3σ of the blank signal with a spatial resolution of less than 200 μm. Using the CRM Pig Liver, it was shown that the use of an internal standard (13C) can account for fluctuations in the ablated material during a line scan. Instead of 12% RSD without internal standard, the stability of the signal was improved using the normalized signal (5.2%)
compared to 2.5–3.5% precision when a NIST 610 Glass standard was ablated. Hence, LA coupled to ICP-MS with a cryogenically cooled ablation chamber is the ideal technique for 2D mapping of trace elements in soft tissues. Depending on the concentration of element present, it may be possible to determine trace elements directly in tissue samples at a spatial resolution of <20 µm.
Co-reporter:Donald E. Macphee, Iain L. Marr and Jörg Feldmann
Environmental Science: Nano 2002 vol. 4(Issue 6) pp:108N-111N
Publication Date(Web):2002/11/26
DOI:10.1039/B209061A
Co-reporter:Andrea Raab, Helle R Hansen, Liuying Zhuang, Jörg Feldmann
Talanta 2002 Volume 58(Issue 1) pp:67-76
Publication Date(Web):16 August 2002
DOI:10.1016/S0039-9140(02)00257-6
Wool or hair fibre is a metabolically dead material after it has left the epidermis. During growth the fibre in the root is a metabolically very active organ, which is highly influenced by the health status of the living being. Arsenic is one of the elements that is easily taken up by the cells of the root and stored in the fibre afterwards. Here we show that arsenic can quantitatively be extracted by boiling the wool fibre or hair in water. The high intake of arsenic species by the sheep of North Ronaldsay (the seaweed-eating sheep) leads to a high arsenic concentration in wool (mean 5.2±2.3 μg g−1). The wool of lambs of these sheep, which are not exposed to seaweed, contains about 10 times less arsenic, which is still elevated compared to uncontaminated wool. The arsenic species identified in wool extract are arsenite (As(III)), arsenate (As(V)), monomethylarsonic acid (MMA(V)) and monomethylarsonious acid (MMA(III)) as minor species. The major species is dimethylated arsenic DMA in its tri- and pentavalent form (dimethylarsinous acid (DMA(III)) and dimethylarsinic acid (DMA(V))) accounting for 85% of the specified arsenic in the wool which reflects the amount of dimethylated species (i.e. the arsenoribofuranosides) taken up by seaweed being the main food source of the sheep. However, there are unknown arsenic species in the extract, which are not eluting from a strong anion exchange column. In vitro incubation experiments with this kind of wool showed that it has reducing properties but no demethylation was recorded. The absorption ability of the wool for methylated arsenic species is negligible, while inorganic arsenic is easier to be absorbed in the fibre (11–17%). This means that the species integrity is only guaranteed in terms of the degree of methylation but not in terms of their redox status.
Co-reporter:Jörg Feldmann, Laurent Naëls and Karsten Haas
Journal of Analytical Atomic Spectrometry 2001 vol. 16(Issue 9) pp:1040-1043
Publication Date(Web):11 Jun 2001
DOI:10.1039/B102580P
A cryotrapping GC-ICP-MS method for the determination of volatile metal compounds (VOMs) in gases from anaerobic environments has been developed. The major gases CH4 and CO2 have to be separated from the less volatile metal compounds. The inert capillary cryo-trap was submerged in liquid nitrogen or in a dry-ice/acetone slush, the latter preventing the condensation of CH4 but not CO2 and water. Cartridges filled with 4–5 g of NaOH were installed in front of the cryotrap in order to eliminate water and especially CO2 before the cryogenic preconcentration step of the VOMs. The cryo-trap was hyphenated to a capillary GC-ICP-MS, which directly enabled multielemental speciation of the VOMs in the gas samples. The effect of CO2 in the gas sample on the ICP-MS was monitored by a continuous internal standard (an added indium solution of 10 ng mL−1). The
reproducibility of the retention time and intensities as well as the recovery rates for VOMs were investigated using an in-house gas standard containing AsH3, MeAsH2, Me2AsH, Me3As, SbH3, MeSbH2, Me2SbH, Me3Sb, SnH4, MeSnH3, Me2SnH2, Me3SnH, BuSnH3 in N2 and in a N2–CH4–CO2 mixture. The stannane standards showed recovery rates of about 90%, while the different arsenic standards recorded recovery rates between 80 and 90%. Care has to be taken if antimony species have to be measured since their recovery rates vary between 30 and 75%, due to a chemical reaction with NaOH, which consequently reduces the volatility of the compounds and hence no memory effect can be identified originating from the NaOH cartridge.
Co-reporter:Gudrun Przygoda;Jörg Feldmann;William R. Cullen
Applied Organometallic Chemistry 2001 Volume 15(Issue 6) pp:
Publication Date(Web):10 MAY 2001
DOI:10.1002/aoc.126
We have reviewed the case of residents of Styria, Austria, who are reported to have consumed large quantities of arsenic oxide (300–400 mg per dose) and remained in good health.
Co-reporter:Jörg Feldmann;Eva M. Krupp;Dietmar Glindemann;Alfred V. Hirner;William R. Cullen
Applied Organometallic Chemistry 1999 Volume 13(Issue 10) pp:
Publication Date(Web):8 SEP 1999
DOI:10.1002/(SICI)1099-0739(199910)13:10<739::AID-AOC925>3.0.CO;2-Z
Biomethylation of metals and metalloids of Group 14 and 15 metals such as tin, lead and arsenic takes place in the environment, but information about methylated bismuth compounds is rather limited, although bismuth compounds are used widely in alloys, cosmetics and pharmaceutical products.
Cryotrapping gas chromatography and hydride generation gas chromatography coupled with an ICP–MS as a bismuth-selective detector were used to determine volatile bismuth compounds in landfill and in sewage gas, as well as non-volatile methylated compounds in water and sediment samples.
One volatile bismuth compound could be determined in gaseous samples; it was identified as Me3Bi (TMB) by element-specific detection (ICP-MS, m/z 209), matching the retention time with a TMB standard. The molecular structure was recently confirmed by gas-chromatographic fractionation with MS–ion trap detection (electron impact). Among other volatile metal compounds, TMB is a major component in the gases of sewage sludge digesters: concentrations of up to 25 µ<?tf="PS2B61">g m−3 have been measured at eight sewage treatment plants. The concentration in landfill gas was approximately one order of magnitude lower.
In laboratory experiments, fermentors containing an anaerobic culture from a clean pond sludge were mixed with contaminated soil from four different industrial areas. After an incubation time of two weeks at 30 °C in the dark, TMB was detected in the headspace of all the samples. The volatilization rate of bismuth did not correlate with the total amount of bismuth in the sediments or with the available fraction after acid digestion following hydride generation. Some evidence was obtained for the occurrence of methylated bismuth compounds in water samples and in sediments. Copyright © 1999 John Wiley & Sons, Ltd.
Co-reporter:Fatai Adigun Aborode, Andrea Raab, Matthias Voigt, Leticia Malta Costa, ... Joerg Feldmann
Journal of Environmental Sciences (November 2016) Volume 49() pp:150-161
Publication Date(Web):1 November 2016
DOI:10.1016/j.jes.2016.08.009
We investigated the role of glutathione (GSH) and phytochelatins (PCs) on the detoxification of selenite using Arabidopsis thaliana. The wild-type (WT) of Arabidopsis thaliana and its mutants (glutathione deficient Cad 2–1 and phytochelatins deficient Cad 1–3) were separately exposed to varying concentrations of selenite and arsenate and jointly to both toxicants to determine their sensitivities. The results of the study revealed that, the mutants were about 20-fold more sensitive to arsenate than the WT, an indication that the GSH and PCs affect arsenate detoxification. On the contrary, the WT and both mutants showed a similar level of sensitivity to selenite, an indication that the GSH and PCs do not significantly affect selenite detoxification. However, the WT is about 8 times more sensitive to selenite than to arsenate, and the mutants were more resistant to selenite than arsenate by a factor of 2. This could not be explained by the accumulation of both elements in roots and shoots in exposure experiments. The co-exposure of the WT indicates a synergistic effect with regards to toxicity since selenite did not induce PCs but arsenic and selenium compete in their PC binding as revealed by speciation analysis of the root extracts using HPLC–ICP–MS/ESI–MS. In the absence of PCs an antagonistic effect has been detected which might suggest indirectly that the formation of Se glutathione complex prevent the formation of detrimental selenopeptides. This study, therefore, revealed that PC and GSH have only a subordinate role in the detoxification of selenite.Download high-res image (275KB)Download full-size image
Co-reporter:
Analytical Methods (2009-Present) 2014 - vol. 6(Issue 14) pp:NaN5396-5396
Publication Date(Web):2014/03/24
DOI:10.1039/C4AY00423J
The inorganic arsenic (iAs) concentration was measured in 44 rice product samples, covering a wide range, using both hydride generation (HG) ICP-MS and HPLC-ICP-MS. Linear regression showed good linearity (R2 of 0.99) with a slope close to 1 (0.969 ± 0.015) and similar sensitivity showing that HPLC can robustly be replaced by a simple HG system, shortening the measurement time and resulting in easier data treatment as no manual integration of peaks is necessary. With upcoming regulations on the iAs concentration in rice in the EU, it is important that regulators do not prescribe only one standard method since it excludes new instrumental developments.
Co-reporter:Adrien Mestrot, Britta Planer-Friedrich and Jörg Feldmann
Environmental Science: Nano 2013 - vol. 15(Issue 9) pp:NaN1651-1651
Publication Date(Web):2013/06/07
DOI:10.1039/C3EM00105A
It has been known for over a hundred years that microorganisms can produce volatile arsenic (As) species, termed “arsines”. However, this topic has received relatively little attention compared to As behaviour in soils and biotransformation through the trophic level in the marine and terrestrial environment. We believe this is due to long-standing misconceptions regarding volatile As stability and transport as well as an absence, until recently, of appropriate sampling methods. First and foremost, an attempt is made to unify arsines' designations, notations and formulas, taking into account all the different terms used in the literature. Then, the stability of As volatile species is discussed and new analytical developments are explored. Further, the special cases of diffuse low-level emissions (e.g. soil and sediment biovolatilisation), and point sources with high-level emissions (geothermal environments, landfills, and natural gas) are comprehensively reviewed. In each case, future possible areas of research and unknown mechanisms are identified and their importance towards the global As biogeochemical cycle is explored. This review gathers new information regarding mechanisms, stability, transport and sampling of the very elusive arsines and shows that more research should be conducted on this important process.
Co-reporter:Chris Newcombe;Andrea Raab;Paul N. Williams;Claire Deacon;Parvez I. Haris;Andrew A. Meharg;Jörg Feldmann
Environmental Science: Nano 2010 - vol. 12(Issue 4) pp:
Publication Date(Web):2010/04/09
DOI:10.1039/B921588C
Arsenobetaine has always been referred to as a non-toxic but readily bioavailable compound and the available data would suggest that it is neither metabolised by nor accumulated in humans. Here this study investigates the urine of five volunteers on an arsenobetaine exclusive diet for twelve days and shows that arsenobetaine was consistently excreted by three of the five volunteers. From the expected elimination pattern of arsenobetaine in rodents, no significant amount of arsenobetaine should have been detectable after 5 days of the trial period. The arsenobetaine concentration found in the urine was constant after 5 days and varied between 0.2 and 12.2 µg As per L for three of the volunteers. Contrary to the established belief that arsenobetaine is neither accumulated nor generated by humans, the presented results would suggest that either accumulated arsenobetaine in the tissues is slowly released over time or that arsenobetaine is a human metabolite of dimethylarsinic acid or inorganic arsenic from the trial food, or both. Either possibility is intriguing and raises fundamental questions about human arsenic metabolism and the toxicological and environmental inertness of arsenobetaine.
Co-reporter:M. Kalle Uroic, Eva M. Krupp, Charlie Johnson and Jörg Feldmann
Environmental Science: Nano 2009 - vol. 11(Issue 12) pp:NaN2230-2230
Publication Date(Web):2009/09/25
DOI:10.1039/B913322D
Volatile arsenic compounds in natural gas, existing in the form of trimethylarsine (TMAs), have been determined using gas cryo-trapping gas chromatography coupled to inductively coupled plasma-mass spectrometry (CT-GC-ICP-MS). The results from a number of different gas wells revealed a huge concentration spread ranging from below the detection limit of 0.2 up to 1800 µg/m3 TMAs (as As) in the gas. Due to the toxicity and corrosive nature of these arsines, they need near real time monitoring via a method that can easily be implemented on site, i.e. during gas exploitation. Here, we introduce a novel method which utilises silver nitrate impregnated silica gel tubes for quantitative chemotrapping of trimethylarsine (TMAs) from a natural gas matrix. Subsequent elution with hot nitric acid followed by online photo-oxidation hydride generation atomic fluorescence spectrometry (HG-AFS) is used for the determination of TMAs gas standards in nitrogen and natural gas samples, respectively. The chemotrapping method was validated using CT-GC-ICP-MS as a reference method. The recovery of arsenic from nitrogen or natural gas matrix ranged from 85 to 113% for a range of 20 to 2000 ng As. Trapping efficiency was >98%, from the methods LOD of 20 ng to 4.8 µg (absolute amount As) with sample sizes of 0.02 and 2 L gas. Method performance was established by comparing the results obtained for eight natural gas samples containing between 1 and 140 µg As/m3 with those achieved by the reference method (CT-GC-ICP-MS).
Co-reporter:Éderson R. Pereira, Johannes F. Kopp, Andrea Raab, Eva M. Krupp, Javier del Campo Menoyo, Eduardo Carasek, Bernhard Welz and Jörg Feldmann
Journal of Analytical Atomic Spectrometry 2016 - vol. 31(Issue 9) pp:NaN1845-1845
Publication Date(Web):2016/06/29
DOI:10.1039/C6JA00162A
This study describes the identification and quantification of five new arsenolipids present in raw marine fish oil extracted mainly from Peruvian anchoveta (Engraulis ringens). The arsenolipids accumulated on bentonite, which has been used to clean-up raw fish oils in an industrial process for producing commercial fish oil rich in omega-3 fatty acids. The bentonite, which adsorbed the arsenolipids efficiently from the raw fish oil was extracted with different solvents and subsequently cleaned up by normal phase chromatography, which fractionated all absorbed compounds according to polarity. The arsenic containing fatty acids (AsFA) and arsenic containing hydrocarbons (AsHC) were determined using a separation by reverse phase high performance liquid chromatography coupled online to inductively coupled plasma mass spectrometry (RP-HPLC-ICP-MS) for quantification and simultaneously to electrospray ionization mass spectrometry (ESI-MS) for identification. A mixture of methanol/chloroform (1:2 v/v) was sufficient for the extraction of the majority of the adsorbed arsenic species (129 μg g−1 As bentonite). The pre-concentration using the adsorbent with subsequent fractionation made it possible to identify minor arsenolipids especially in the polar methanol fraction. Besides two major arsenic containing hydrocarbons (AsHC332 and AsHC360) three new arsenic containing medium chain fatty acids (As-MCFA) of molecular mass 250, 278, 292 and two new arsenic containing long chain fatty acids (As-LCFA) of mass 306 and 320 could be identified although their concentrations were as low as 0.004 μg g−1 As bentonite. The significance of MCFA is that these compounds usually occur not as free fatty acids but are conjugated to glycerol forming triglycerides. Confirmation of this hypothesis is given in the fact that a methanol extract which was directly analyzed without any clean up procedure did only contain traces of As-LCFA and no As-MCFA but the same concentration of the more inert AsHCs, which are not expected to be conjugated to other organic compounds. This highlights that a successful pre-concentration and clean up procedure is essential to determine traces of minor arsenolipids but it does not provide a guarantee for the integrity of all arsenolipid species.
Co-reporter:Dagmar S. Urgast, Gillian C. Adams, Andrea Raab and Jörg Feldmann
Environmental Science: Nano 2010 - vol. 12(Issue 5) pp:NaN1132-1132
Publication Date(Web):2010/02/22
DOI:10.1039/B924351H
European whelks (Buccinum undatum) have shown to accumulate high levels of arsenic. Since the accumulation process is not well understood it is necessary to gain information about the geographical variability of the arsenic concentration in them. Here we show that the mean arsenic concentrations of the whelks are site specific and vary by a factor of 3.5 in ten different geographical locations. At fishing grounds where whelks exhibited low arsenic concentrations the arsenic concentration increased linearly with size, whereas the whelks with high arsenic levels from a different location showed no correlation. Although the overall arsenic concentration in the whelks differed between 45 and 655 mg kg−1 d.w., the inorganic arsenic concentration did not exceed 0.4 mg kg−1 d.w. The main arsenic compound is arsenobetaine, which is widely considered as non-toxic. The exposure to toxic inorganic arsenic when eating whelks cannot be estimated from their size or their total arsenic concentration.
Co-reporter:Ronit Jakob, Anja Roth, Karsten Haas, Eva M. Krupp, Andrea Raab, Patricia Smichowski, Darío Gómez and Jörg Feldmann
Environmental Science: Nano 2010 - vol. 12(Issue 2) pp:NaN416-416
Publication Date(Web):2009/11/17
DOI:10.1039/B915867G
Biovolatilisation of arsenic as their arsines in the form of AsH3, and mono-, di and trimethylarsine has often been determined under laboratory conditions. Although environmental point sources such as landfill sites or hot springs have been characterised, only limited knowledge is available on how widespread the formation of volatile methylated arsenic compounds are in the environment. Here we studied the atmospheric stability of the different arsines and quantified their oxidation products in atmospheric particulate matter (PM10) in two locations in Argentina. The atmospheric half-life of the arsines range from 19 weeks for AsH3 to 2 d for trimethylarsine (TMAs) at 20 °C in the dark, while during simulated daytime conditions the stability is reduced for all arsines and in particular for the methylated arsines by three orders of magnitude which suggests that TMAs can only be dispersed at night. At both locations the arsenic concentration was in all samples below 1 ng As m−3, which is considered as rural background for arsenic. The oxidation products, i.e. methylarsonate (MA), dimethylarsinate (DMA) and trimethylarsine oxide (TMAO) were identified by using HPLC-ICP-MS/ES-MS in more than 90% of the 49 PM10 samples taken from 8 sampling points at the two geographically different locations. TMAO was the predominate organoarsenicals in both locations (66 and 69%, respectively) while DMA was determined to be between 13 and 19% of all organoarsenicals at the two locations. The concentration of the organoarsenicals ranged from 4 to 60 pg As as TMAO m−3, while the maximum concentration for DMA and MA were 16 and 6 pg As m−3, respectively. No difference in terms of the concentration or distribution of the organoarsenicals in the PM10 samples was identified as significant. Since the two locations were different in climate and industrial impact and sampled in different seasons, these data suggest that methylated arsenicals do occur as background chemicals in the environment. Due to the low atmospheric stability of the methylated arsines, it is suggested that biovolatilization of arsenic as methylated arsines is a widespread phenomenon. More studies however are necessary to identify the major sources and determine the flux of the volatilization process in order to determine whether or not the process has environmental significance.
Co-reporter:Zhiwei Qin, Andrea Raab, Eva Krupp, Hai Deng and Jörg Feldmann
Journal of Analytical Atomic Spectrometry 2013 - vol. 28(Issue 6) pp:NaN882-882
Publication Date(Web):2013/03/28
DOI:10.1039/C3JA50086A
The lack of specific fluorine detection at trace levels hampers the screening of microorganisms which can form novel fluorometabolites. So far only target analysis by ESI-MS using accurate mass and certain fragmentation or preconcentration and clean-up procedures has been used to perform 19F and 13C/1H NMR for the identification of novel fluorocompounds. Here we demonstrate that the analysis of complex media from microorganism cultures can be screened using a set of HPLC separations which are coupled parallel to CS-MAS as a fluorine specific detector and the ESI-MS as the molecular detection. This makes it possible to identify fluorine containing species without prior knowledge of the compounds and the use of clean up procedures. Here specifically we identify traces of a fluorometabolite (5′-fluoro-5′-deoxy-adenosine, 5′-FDA) in complex media of Streptomyces cattleya without preconcentration and target analysis.
Co-reporter:Dagmar S. Urgast and Jörg Feldmann
Journal of Analytical Atomic Spectrometry 2013 - vol. 28(Issue 9) pp:NaN1371-1371
Publication Date(Web):2013/05/21
DOI:10.1039/C3JA50058F
This article describes the advantages and possibilities of using LA-ICP-MS for isotope ratio measurements, briefly comparing quadrupole, sector-field and multi-collector systems. It also discusses problems and limitations of the respective set-ups. A special focus lies on biological samples from stable isotope tracer experiments and on spatially resolved isotope ratio measurements including imaging of isotope ratios. The article explores if there are valid reasons why until now almost no one used LA-ICP-MS to image isotope ratios. It wants to encourage the ICP-MS community to realise the potential of using LA-ICP-MS for isotope ratio measurements in biological samples and to hopefully spur further developments and applications.
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