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Walter Goessler - One of the best experts on this subject based on the ideXlab platform.
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accurate quantification and transformation of Arsenic compounds during wet ashing with nitric Acid and microwave assisted heating
Analyst, 2003Co-Authors: Walter Goessler, M. PavkovAbstract:Arsenous Acid, dimethylarsinic Acid (DMA), methylarsonic Acid (MA), Arsenic Acid, arsenobetaine bromide (AB), trimethylarsine oxide (TMAO), arsenocholine iodide (AC), and tetramethylarsonium iodide (TETRA) were heated in a microwave autoclave with nitric Acid to 100–300 °C. The Arsenic compounds in the digests were separated with anion- and cation-exchange chromatography and determined with an inductively coupled plasma mass spectrometer as Arsenic-specific detector. Arsenous Acid was completely oxidized to Arsenic Acid at 100 °C. For a complete oxidation of MA and DMA to Arsenic Acid temperatures >220 °C and >280 °C were necessary. AB decomposed to Arsenic Acid via TMAO. Complete conversion was only obtained after heating the sample for 90 min to 300 °C. For a complete conversion of TMAO similar harsh conditions were necessary. AC was already substantially degraded to TMAO, TETRA and two unknown compounds at 100 °C. The unknown Arsenic compounds were found only in the digests up to 160 °C. Quantitative conversion of AC to Arsenic Acid went also via TMAO. At temperatures above 220 °C TETRA started to convert to TMAO, which then was further converted to Arsenic Acid. To investigate whether the results obtained for the Arsenic standards are transferable to real samples, the certified reference material DORM-2 was also heated in nitric Acid with variable digestion temperatures and times. For an almost complete conversion of the AB present in DORM-2 90 min at 300 °C were necessary. Total organic carbon (TOC) was less <0.2% when DORM-2 was heated at temperatures ≥260 °C for 60 min. UV photo-oxidation of DORM-2 was investigated as an alternative sample decomposition. Only 6% of AB was converted to Arsenic Acid when DORM-2 was irradiated for 2 h at 1000 W. In contrast to microwave heating substantial amounts of MA were observed as degradation product.
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comparison of three methods for the extraction of Arsenic compounds from the nrcc standard reference material dorm 2 and the brown alga hijiki fuziforme
Applied Organometallic Chemistry, 2001Co-Authors: Doris Kuehnelt, Kurt J. Irgolic, Walter GoesslerAbstract:The NRCC standard reference material DORM-2 and the marine brown alga Hijiki fuziforme were extracted with water, methanol/water (9 + 1), and 1.5 M orthophosphoric Acid. The extracts from DORM-2 were analyzed by HPLC–ICP-MS for arsenobetaine, arsenocholine, trimethylarsine oxide, and the tetramethylarsonium cation and the extracts from H. fuziforme for arsenous Acid, Arsenic Acid, dimethylarsinic Acid, methylarsonic Acid, and four arsenoriboses. Almost no differences between the three extractants were observed when DORM-2 was investigated. Only arsenobetaine was slightly better extracted with 1.5 M orthophosphoric Acid or methanol/water (9 + 1) than with water. The sum of all extractable compounds (arsenobetaine, the tetramethylarsonium cation, and a formerly unknown compound recently identified as the trimethyl(2-carboxyethyl)arsonium ion) accounted for 94% of the total Arsenic when 1.5 M orthophosphoric Acid was used, for 92% when methanol/water (9 + 1) was used, and for 87% when water was used. Significant differences in the extraction yields obtained for the alga were observed for Arsenic Acid and one of the arsenoriboses (‘glycerol-ribose’). Orthophosphoric Acid removed twice as much of this ribose from the algal material than water and three times more than methanol/water (9 + 1). Arsenic Acid was 1.2 times better extracted with orthophosphoric Acid than with water and ten times better than with methanol/water (9 + 1). Almost no differences in the extraction yields were found for dimethylarsinic Acid and the other three riboses. Orthophosphoric Acid extracted 76%, water 65%, and methanol/water 33% of the total Arsenic from H. fuziforme. Copyright © 2001 John Wiley & Sons, Ltd.
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determination of arsenosugars in algae with anion exchange chromatography and an inductively coupled plasma mass spectrometer as element specific detector
Fresenius Journal of Analytical Chemistry, 2000Co-Authors: Georg Raber, Kevin A. Francesconi, Kurt J. Irgolic, Walter GoesslerAbstract:The retention behavior of four naturally occurring dimethylarsinoylribosides with -CH2-CHOH-CH2X (X = OH, HO3POCH2CHOHCH2OH, SO3H, OSO3H) as aglycones, of arsenous Acid, Arsenic Acid, methylarsonic Acid, and dimethylarsinic Acid was investigated on a Hamilton PRP-X100 anion-exchange column with aqueous solutions of ammonium dihydrogen phosphate (20 mmol/L) in the pH range of 3.8-9.0 as mobile phase. A HP 4500 inductively coupled plasma mass spectrometer (ICP-MS) served as Arsenic-specific detector. The influence of pH, temperature, and the concentration of methanol in the mobile phase on the retention times of these Arsenic compounds was explored. An aqueous 20 mM ammonium dihydrogen phosphate solution at pH 5.6 at a column temperature of 40 degrees C was considered optimal as it allowed the separation of seven of the Arsenic compounds within 16 min. Only arsenous Acid and the ribose with the glycerol aglycone have overlapping signals with both migrating almost with the solvent front. At a concentration of 0.50 ng As mL(-1) the relative standard deviations (n = 3) of the signal areas of the eight Arsenic compounds was in the range from 3.5 to 8.1%. The linear calibration curves (peak areas) from 0.5 to 10 ng/mL had correlation coefficients > 0.997. Extracts obtained from the brown algae Fucus spiralis and Halidrys siliquosa were chromatographed under the optimized conditions. Both species contained the sulfate riboside as the major Arsenic compound (approximately 55% of total extractable Arsenic) together with the sulfonate- and phosphate riboside. Arsenic Acid was a significant constituent of Halidrys siliquosa (approximately 6.5%), but was not detected in Fucus spiralis.
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Arsenic compounds in terrestrial organisms. IV. Green plants and lichens from an old Arsenic smelter site in Austria
Applied Organometallic Chemistry, 2000Co-Authors: Doris Kuehnelt, Josef Lintschinger, Walter GoesslerAbstract:Two lichens and 12 green plants growing at a former Arsenic roasting facility in Austria were analyzed for total Arsenic by ICP–MS, and for 12 Arsenic compounds (arsenous Acid, Arsenic Acid, dimethylarsinic Acid, methylarsonic Acid, arsenobetaine, arsenocholine, trimethylarsine oxide, the tetramethylarsonium cation and four arsenoriboses) by HPLC–ICP–MS. Total Arsenic concentrations were in the range of 0.27 mg As (kg dry mass)−1 (Vaccinium vitis idaea) to 8.45 mg As (kg dry mass)−1 (Equisetum pratense). Arsenic compounds were extracted with two different extractants [water or methanol/water (9:1)]. Extraction yields achieved with water [7% (Alectoria ochroleuca) to 71% (Equisetum pratense)] were higher than those with methanol/water (9:1) [4% (Alectoria ochroleuca) to 22% (Deschampsia cespitosa)]. The differences were caused mainly by better extraction of inorganic Arsenic (green plants) and an arsenoribose (lichens) by water. Inorganic Arsenic was detected in all extracts. Dimethylarsinic Acid was identified in nine green plants. One of the lichens (Alectoria ochroleuca) contained traces of methylarsonic Acid, and this compound was also detected in nine of the green plants. Arsenobetaine was a major Arsenic compound in extracts of the lichens, but except for traces in the grass Deschampsia cespitosa, it was not detected in the green plants. In contrast to arsenobetaine, trimethylarsine oxide was found in all samples. The tetramethylarsonium cation was identified in the lichen Alectoria ochroleuca and in four green plants. With the exception of the needles of the tree Larix decidua the arsenoribose (2′R)-dimethyl[1-O-(2′,3′-dihydroxypropyl)-5-deoxy-β-D-ribofuranos-5-yl]arsine oxide was identified at the low μg kg−1 level or as a trace in all plants investigated. In the lichens an unknown Arsenic compound, which did not match any of the standard compounds available, was also detected. Arsenocholine and three of the arsenoriboses were not detected in the samples. Copyright © 2000 John Wiley & Sons, Ltd.
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Determination of Arsenic Compounds in Earthworms
Environmental Science & Technology, 1998Co-Authors: Anita Geiszinger, Kevin A. Francesconi, Walter Goessler, Doris Kuehnelt, Walter KosmusAbstract:Earthworms and soil collected from six sites in Styria, Austria, were investigated for total Arsenic concentrations by ICP-MS and for Arsenic compounds by HPLC−ICP-MS. Total Arsenic concentrations ranged from 3.2 to 17.9 mg/kg dry weight in the worms and from 5.0 to 79.7 mg/kg dry weight in the soil samples. There was no strict correlation between the total Arsenic concentrations in the worms and soil. Arsenic compounds were extracted from soil and a freeze-dried earthworm sample with a methanol/water mixture (9:1, v/v). The extracts were evaporated to dryness, redissolved in water, and chromatographed on an anion- and a cation-exchange column. Arsenic compounds were identified by comparison of the retention times with known standards. Only traces of Arsenic Acid could be extracted from the soil with the methanol/water (9:1, v/v) mixture. The major Arsenic compounds detected in the extracts of the earthworms were arsenous Acid and Arsenic Acid. Arsenobetaine was present as a minor constituent, and traces ...
Giwoong Shim - One of the best experts on this subject based on the ideXlab platform.
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comparison of Arsenic Acid with phosphoric Acid in the interaction with a water molecule and an alkali alkaline earth metal cation
Journal of Physical Chemistry A, 2011Co-Authors: Sungwoo Park, Giwoong ShimAbstract:Recently, Wolfe-Simon has discovered a bacterium which is able to survive using Arsenic(V) rather than phosphorus(V) in its DNA. Thus it is important to investigate some important structural and chemical similarities and dissimilarities between phosphate and arsenate. We compared the monohydrated structures and the alkali/alkaline-earth metal (Na+, K+, Mg2+ and Ca2+) complexes of the Arsenic Acid/anions with those of the phosphoric Acid/anions [i.e., HmPO4–(3–m) vs HmAsO4–(3–m) (m = 1–3)]. We carried out geometry optimization along with harmonic frequency calculations using ab initio calculations. Despite the increased van der Waals radius of As, the hydrated structures of both P and As systems show very close similarity (within 0.25 A in the P/As···O(water) distance and within a few kJ/mol in binding energy) because of the increased induction energies by more polar Arsenic Acid/anons and slightly increased dispersion energy by a larger size of the As atom. In the metal complexes, the Arsenic Acid has a s...
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comparison of Arsenic Acid with phosphoric Acid in the interaction with a water molecule and an alkali alkaline earth metal cation
Journal of Physical Chemistry A, 2011Co-Authors: Sungwoo Park, Giwoong Shim, Chang Woo Kim, Ji Hyun Lee, Kwang S KimAbstract:Recently, Wolfe-Simon has discovered a bacterium which is able to survive using Arsenic(V) rather than phosphorus(V) in its DNA. Thus it is important to investigate some important structural and chemical similarities and dissimilarities between phosphate and arsenate. We compared the monohydrated structures and the alkali/alkaline-earth metal (Na(+), K(+), Mg(2+) and Ca(2+)) complexes of the Arsenic Acid/anions with those of the phosphoric Acid/anions [i.e., H(m)PO(4)(-(3-m)) vs H(m)AsO(4)(-(3-m)) (m = 1-3)]. We carried out geometry optimization along with harmonic frequency calculations using ab initio calculations. Despite the increased van der Waals radius of As, the hydrated structures of both P and As systems show very close similarity (within 0.25 A in the P/As···O(water) distance and within a few kJ/mol in binding energy) because of the increased induction energies by more polar Arsenic Acid/anons and slightly increased dispersion energy by a larger size of the As atom. In the metal complexes, the Arsenic Acid has a slightly larger binding distance (by 0.07-1.0 A) and weaker binding energy because the As(V) ion has a slightly larger radius than the P(V) ion, and the electrostatic interaction is the dominating feature in these systems.
Mawrong Lee - One of the best experts on this subject based on the ideXlab platform.
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a novel method of ultrasound assisted dispersive liquid liquid microextraction coupled to liquid chromatography mass spectrometry for the determination of trace organoArsenic compounds in edible oil
Analytica Chimica Acta, 2011Co-Authors: Weixun Wang, Tzungjie Yang, Tingting Jong, Mawrong LeeAbstract:A novel approach, ultrasound-assisted dispersive liquid-liquid microextraction combined with liquid chromatography-mass spectrometry (UA-DLLME with LC-MS) is demonstrated to be quite useful for the determination of trace amounts of organoArsenic compounds in edible oil. The organoArsenic compounds studied include dimethylarsinic Acid (DMA), monomethylarsonic Acid (MMA) and 3-nitro-4-hydroxyphenyl Arsenic Acid (Roxarsone). Orthogonal array experimental design (OAD) was utilized to investigate the parameter space of conditions for UA-DLLME. The optimum conditions were found to be 4 min of ultrasonic extraction using 1.25 mL of mixed solvent with 50 μL of buffer solution. Under these optimal conditions, the linear range was from 10 ng g(-1) to 500 ng g(-1) for DMA and Roxarsone, from 25 ng g(-1) to 500 ng g(-1) for MMA. Limits of detection of DMA, MMA and Roxarsone were 1.0 ng g(-1), 3.0 ng g(-1) and 5.8 ng g(-1), respectively. The precisions and recoveries also were investigated by spiking 3-level concentrations in edible oil. The recoveries obtained were over 89.9% with relative standard deviation (RSD) of 9.6%. The new approach was utilized to successfully detect trace amounts of organoArsenic compounds in various edible oil samples.
Sungwoo Park - One of the best experts on this subject based on the ideXlab platform.
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comparison of Arsenic Acid with phosphoric Acid in the interaction with a water molecule and an alkali alkaline earth metal cation
Journal of Physical Chemistry A, 2011Co-Authors: Sungwoo Park, Giwoong ShimAbstract:Recently, Wolfe-Simon has discovered a bacterium which is able to survive using Arsenic(V) rather than phosphorus(V) in its DNA. Thus it is important to investigate some important structural and chemical similarities and dissimilarities between phosphate and arsenate. We compared the monohydrated structures and the alkali/alkaline-earth metal (Na+, K+, Mg2+ and Ca2+) complexes of the Arsenic Acid/anions with those of the phosphoric Acid/anions [i.e., HmPO4–(3–m) vs HmAsO4–(3–m) (m = 1–3)]. We carried out geometry optimization along with harmonic frequency calculations using ab initio calculations. Despite the increased van der Waals radius of As, the hydrated structures of both P and As systems show very close similarity (within 0.25 A in the P/As···O(water) distance and within a few kJ/mol in binding energy) because of the increased induction energies by more polar Arsenic Acid/anons and slightly increased dispersion energy by a larger size of the As atom. In the metal complexes, the Arsenic Acid has a s...
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comparison of Arsenic Acid with phosphoric Acid in the interaction with a water molecule and an alkali alkaline earth metal cation
Journal of Physical Chemistry A, 2011Co-Authors: Sungwoo Park, Giwoong Shim, Chang Woo Kim, Ji Hyun Lee, Kwang S KimAbstract:Recently, Wolfe-Simon has discovered a bacterium which is able to survive using Arsenic(V) rather than phosphorus(V) in its DNA. Thus it is important to investigate some important structural and chemical similarities and dissimilarities between phosphate and arsenate. We compared the monohydrated structures and the alkali/alkaline-earth metal (Na(+), K(+), Mg(2+) and Ca(2+)) complexes of the Arsenic Acid/anions with those of the phosphoric Acid/anions [i.e., H(m)PO(4)(-(3-m)) vs H(m)AsO(4)(-(3-m)) (m = 1-3)]. We carried out geometry optimization along with harmonic frequency calculations using ab initio calculations. Despite the increased van der Waals radius of As, the hydrated structures of both P and As systems show very close similarity (within 0.25 A in the P/As···O(water) distance and within a few kJ/mol in binding energy) because of the increased induction energies by more polar Arsenic Acid/anons and slightly increased dispersion energy by a larger size of the As atom. In the metal complexes, the Arsenic Acid has a slightly larger binding distance (by 0.07-1.0 A) and weaker binding energy because the As(V) ion has a slightly larger radius than the P(V) ion, and the electrostatic interaction is the dominating feature in these systems.
Masanori Ando - One of the best experts on this subject based on the ideXlab platform.
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high performance liquid chromatography inductively coupled plasma mass spectrometry for speciation of Arsenic compounds in urine
Microchemical Journal, 2000Co-Authors: Gautam Samanta, Uttam Kumar Chowdhury, Badal Kumar Mandal, Dipankar Chakraborti, Chandra N Sekaran, Hiroshi Tokunaga, Masanori AndoAbstract:Abstract Speciation of urinary Arsenic is very important to know the extent of human exposure to inorganic Arsenic and also from toxicity point of view. A high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) system for speciation of arsenite, arsenate, monomethyl arsonic Acid (MMAA), dimethyl Arsenic Acid (DMAA) and arsenobetaine (AB) in a single run in urine samples has been developed. The method is based on anion exchange high performance liquid chromatography (HPLC) coupled on-line to inductively coupled plasma mass spectrometer (ICP-MS). Detection limits for the five Arsenic species in urine samples are between 0.01 and 0.04 μg l −1 . To validate the method, Standard Reference Material, toxic metals in freeze-dried urine SRM 2670 containing both normal and elevated levels of Arsenic have been analyzed for Arsenic species. Our results of Arsenic species in Standard Reference Material SRM 2670 have been compared with the results of seven other laboratories. The method has been applied to determine the Arsenic species in urine samples of two groups of people from two Arsenic-affected villages of two districts, out of the nine affected districts of West Bengal, India. These two groups were using Arsenic-contaminated water a few years ago, but are now supposed to be using safe water for drinking and cooking, as safe sources have been installed. From their urine speciation, the nature of exposure of individuals to Arsenic compound could be predicted. It is concluded that, even though these groups are using safe water, they cannot avoid, from time to time, Arsenic contamination as many water sources of the surrounding areas are Arsenic contaminated.