Intake of different chemical species of dietary arsenic by the japanese,and their blood and urinary arsenic levels

We calculated the intake of each chemical species of dietary arsenic by typical Japanese, and determined urinary and blood levels of each chemical species of arsenic. The mean total arsenic intake by 35 volunteers was 195±235 (15.8-1039) μg As day^?1, composed of 76% trimethylated arsenic (TMA), 17.3% inorganic arsenic (As_i), 5.8% dimethylated arsenic (DMA), and 0.8% monomethylated arsenic (MA): the intake of TMA was the largest of all the measured species. Intake of As_i characteristically and invariably occurred in each meal. Of the intake of As_i, 45-75% was methylated in vivo to form MA and DMA, and excreted in these forms into urine. The mean measured urinary total arsenic level in 56 healthy volunteers was 129±92.0 μg As dm^?3, composed of 64.6% TMA, 26.7% DMA, 6.7% As_i and 2.2% MA. The mean blood total arsenic level in the 56 volunteers was 0.73±0.57 μg dl^?1, composed of 73% TMA, 14% DMA and 9.6% As_i. The urinary TMA levels proved to be significantly correlated with the whole-blood TMA levels (r = 0.376; P<0.01).     

Samarium Polyarsenides Derived from Nanoscale Arsenic

Zintl phases of arsenic and molecular compounds containing Zintl‐type polyarsenide ions are of fundamental interest in basic and applied sciences. Unfortunately, the most obvious and reactive arsenic source for the preparation of defined molecular polyarsenide compounds, yellow arsenic As₄, is very inconvenient to prepare and neither storable in pure form nor easy to handle. Herein, we present the synthesis and reactivity of elemental As⁰ nanoparticles (As⁰_Nano, d=7.2±1.8 nm), which were successfully utilized as a reactive arsenic source in reductive f‐element chemistry. Starting from [Cp*₂Sm] (Cp*=η⁵‐C₅Me₅), the samarium polyarsenide complexes [(Cp*₂Sm)₂(μ‐η²:η²‐As₂)] and [(Cp*₂Sm)₄As₈] were obtained from As⁰_nano, thereby generating the largest molecular polyarsenide of the f‐elements and circumventing the use of As₄ in preparative chemistry.     

A feasibility study on oxidation state of arsenic in cut tobacco,mainstream cigarette smoke and cigarette ash by X-ray absorption spectroscopy

This work describes the application of synchrotron-based X-ray Absorption Near-Edge Structure spectroscopy to study the oxidation state of arsenic in cigarette mainstream smoke, cut tobacco and cigarette ash. The level of arsenic in the total particulate matter of the smoke is approximately 1 ppm for the standard research reference cigarette 2R4F and its replacement 3R4F. Smoke particulate samples collected by a conventional glass-fiber membrane (commercially known as Cambridge filter pad) and a jet-impaction method were analyzed and compared. In addition smoke particulate samples were aged either at ambient temperature or at 195 K. X-ray Absorption Near-Edge Structure spectroscopy results revealed that the cut tobacco powder and cigarette ash contained almost exclusively As^V. The smoke particulate samples however contained a mixture of As^III and As^V. The As^V in the smoke particulate was reduced to As^III upon aging. Stabilizing the smoke particulate matter at 195 K by solid CO₂ slowed down this aging reaction and revealed a higher percentage of As^V. This behavior is consistent with the redox properties of the arsenic species and the smoke particulate matrix.     

Reactivity in the System Copper/Arsenic/Sulfur II. The Formation of CuAsS, (Lautite)

The reaction pathways during the synthesis of CuAsS have been studied with the DTA in the range 25 — 810 °C with a heating rate of 10 K/min. Educts, intermediates, and products were characterized by X‐ray diffraction at room and elevated temperatures. Educts were the corresponding elements and the binary compounds As₄S₄, As₂S₃, Cu_3—xAs, Cu_5—δAs₂, Cu₂S, and CuS. The 13 examined educt mixtures can be divided into four groups specified by their thermal effects observed during the reaction. Mixtures of group I contain copper arsenides and arsenic sulfides, those of group II and III arsenic and copper sulfides, and arsenic sulfides and copper, respectively. Group IV includes mixtures showing individual reactions. In all cases the reaction to CuAsS proceeds stepwise. The reaction is not completed at 574 °C, the decomposition temperature of CuAsS, because the product is still associated with Cu_12+xAs_4+yS₁₃ , As, and to a lesser amount with Cu_1.81S. Nevertheless, a consecutive run in which the samples were heated above the liquidus temperature shows no exothermic reaction effect. When the mixtures were cooled at 10 K/min after the runs, no CuAsS was found in the X‐ray experiments. Only Cu_12+xAs_4+yS₁₃ and As were then observed.     

CpPEt2As4—An Organic‐Substituted As4 Butterfly Compound

Cp^PEt₂As₄ (Cp^PEt=C₅(4‐EtC₆H₄)₅) ( 1 ) is synthesized by the reaction of Cp^PEt. radicals with yellow arsenic (As₄). In solution an equilibrium of the starting materials and the product is found. However, 1 can be isolated and stored in the solid state without decomposition. As₄ can be easily released from 1 under thermal or photochemical conditions. From powder samples of Cp^PEt₂As₄, yellow arsenic can be sublimed under rather mild conditions (T=125 °C). A similar behavior for the P₄‐releasing agent was determined for the related phosphorus compound Cp^BIG₂P₄ ( 2 ; Cp^BIG=C₅(4‐nBuC₆H₄)₅). DFT calculations show the importance of dispersion forces for the stability of the products.     

The detection of preservatives in wood with pyrocatechol violet

The detection ot As⁺⁵, BO₃^-3. Cu⁺², Cr⁺³, Cr⁺⁶, Zn⁺², and F^- in treated wood with Pyrocatechol Violet is described.Es wird eine Method vorgeschlagen zum Nachweis von As⁺⁵, BO₃^-3, Cu⁺², Cr⁺³, Cr⁺³, Zn⁺² and F^- in imprägniertem Holz unter Verwendung von Pyrocatechol Violet.     

Arsenic speciation: HPLC followed by ICP-MS or INAA

Sensitivities for the measurement of four arsenic species, As^III, As^V, monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), in environmental waters and rice extracts by a new neutron activation analysis (NAA) method using pre-separation of the species by liquid chromatography were determined. A manual fraction collection was used to isolate the species, followed by instrumental neutron activation analysis procedures. The sensitivities determined for arsenic species in the samples varied from 1.21 to 1.47 ng per vial or about 30 μg·L⁻¹ in sample solutions which translates to about 900 ng arsenic per gram of rice for our HPLC-NAA experiments.     

The Autoxidation of Triaryl Trithioarsenites, (ArS)3As: Evidence for Binding and Activation of Triplet Dioxygen by Arsenic(III)

Triaryl trithioarsenites, (ArS)₃As, are oxidized by air to As ₂ O ₃ and ArSSAr. In two cases the parent “thiol” (pyrid-2-thione and 1-hydroxypyrid-2-thione) is coproduced. The oxidation, in nonprotic solvents, is favored by electron-withdrawing groups at the para position of the phenyl group. The products obtained in nonprotic solvents were rationalized by assuming that the binding of the triplet dioxygen to arsenic(III) gives a triplet diradical, (ArS) ₃ A?─O─?, or an arsenadioxirane, (ArS) ₃ As(O ₂ ), intermediate, which decomposes after nucleophilic attack by another (ArS) ₃ As molecule. In protic solvents a zwitterion, (ArS) ₃ As⁺─O─O^?, and in the presence of moisture a hydroperoxy arsenic(V) compound, (ArS)₃As(OH)─O─OH, may be intermediates in the air oxidation of some aromatic trithioarsenites. These data tend to indicate that arsenic(III) bound to suitable groups can directly bind dioxygen, a property which may have implications in chemotherapy and carcinogenesis.     

Solution Chemistry of Arsenic Anions in the Presence of Metal Cations

The interaction of arsenic(V) and arsenic(III) oxyanions with metal cations was investigated by potentiometry under temperature and ionic strength conditions approaching those prevailing in natural waters. The selection includes the major metal cations and some other ions of high environmental relevance. Ionic pairs [M(As^VO₄)]^?, [M(HAs^VO₄)] and [M(H₂As^IIIO₃)]⁺ formation is suggested for all +2 metal cations, based on the potentiometric results. These ion-pairs between arsenic anions and other metal cations are hardly ever mentioned or taken into account when arsenic speciation in natural waters is considered. These results provide the basis for studying arsenic speciation in natural aquatic systems, on which environmental fate, bioavailability and toxicity of the element depend. Some extrapolations to the conditions of the natural waters are presented as well as some insights into the adsorption process onto hydrous oxides.     

Preparation and characterization of several II-IV-V2 chalcopyrite single crystals

Single crystals of ZnSiP₂, ZnGeP₂, ZnGeP_1.8As_0.2, and ZnGeP_1.6As_0.4 have been grown by several techniques and their electronic and optical properties were compared. For ZnSiP₂ there are marked absorption bands at 10 and 11.5 μm, and at 13 μm for ZnGeP₂. Upon substitution of 10 mole% of arsenic for phosphorus, the latter band does not shift to higher wavelengths. Further substitution of arsenic for phosphorus in ZnGeP₂ showed a weak second band at 9.8 μm.     

Interference of arsenic trioxide on magnesium dependent polymerization of microtubule proteins

Prevention of microtubule polymerization is considered as one of the promising approaches towards inhibition of cell proliferation, especially in treatment of malignancies. Arsenic trioxide, As₂O₃, is being successfully used in the treatment of human lymphoma, while the mechanism of its therapeutic function is still under investigation. Experiments were designed to determine if indeed As₂O₃ interferes with polymerization of nanotube microtubule. Microtubules were extracted from sheep brain and their interaction with arsenic trioxide was examined by spectrometery. Electrical conductometry of 2 mM MgSO₄ solution containing various concentrations of As₂O₃ was studied in order to determine their possible interaction. Transmission electron microscopy was used to show microtubule structure in the presence of arsenic trioxide. Fluorometric characteristics of tubulin dimer were examined in presence of varying concentrations of arsenic trioxide. It is concluded that arsenic trioxide interacts with Mg²⁺ ion around GTPase site of β-tubulin, resulting enhancement of depolymerization of the microtubule polymer.     

Speciation of arsenic in ground water samples: A comparative study of CE-UV, HG-AAS and LC-ICP-MS

The performance of capillary electrophoresis-ultraviolet detector (CE-UV), hydride generation-atomic absorption spectrometry (HG-AAS) and liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) have been compared for the speciation of arsenic (As) in groundwater samples. Two inorganic As species, arsenite (As^III), arsenate (As^V) and one organo species dimethyl arsenic acid (DMA) were mainly considered for this study as these are known to be predominant in water. Under optimal analytical conditions, limits of detection (LD) ranging from 0.10 (As^III, AsT) to 0.19 (DMA) μg/l for HG-AAS, 100 (As^III, DMA) to 500 (As^V) μg/l for CE-UV and 0.1 (DMA, MMA) to 0.2 (As^III, As^V) μg/l for LC-ICP-MS, allowed the determination of the above three species present in these samples. Results obtained by all the three methods are well correlated (r² = 0.996*** for total As) with the precision of <5% R.S.D. except CE-UV. The effect of interfering ions (e.g. Fe²⁺, Fe³⁺, SO₄²⁻ and Cl⁻) commonly found in ground water on separation and estimation of As species were studied and corrected for. Spike recovery was tested and found to be 80-110% at 0.5 μg/l As standard except CE-UV where only 50% of the analyte was recovered. Comparison of these results shows that LC-ICP-MS is the best choice for routine analysis of As species in ground water samples.     

Speciation of arsenic trioxide metabolites in blood cells and plasma of a patient with acute promyelocytic leukemia

Arsenic trioxide (As₂O₃) has been widely accepted as the second-best choice for the treatment of relapsed and refractory acute promyelocytic leukemia (APL) patients. However, a few studies have been conducted on a detailed speciation of As₂O₃ metabolites in blood samples of patients. To clarify the speciation of arsenic, the blood samples were collected at various time points from a patient with APL after remission induction therapy and during consolidation therapy. The total amounts of arsenic in blood cells and plasma, and the plasma concentrations of inorganic arsenic and methylated metabolites were determined by inductively coupled plasma mass spectrometry (ICP-MS) and high-performance liquid chromatography/ICP-MS, respectively. The total amounts of arsenic in the blood cells were 4–10 times higher than those in plasma. Among all arsenic metabolites, the pentavalent arsenate (As^V) in plasma was more readily eliminated. During the drug-withdrawal period, the initial plasma concentrations of trivalent arsenic (As^III) declined more rapidly than those of methylarsonic acid and dimethlyarsinic acid, which are known as the major methylated metabolites of As^III. On the other hand, during the consecutive administration in the consolidation therapy period, the plasma concentrations of total arsenic and arsenic metabolites increased with time. In conclusion, these results may support the idea that methylated metabolites of As₂O₃ contribute to the efficacy of arsenic in APL patients. These results also suggest that detailed studies on the pharmacokinetics as well as the pharmacodynamics of As₂O₃ in the blood cells from APL patients should be carried out to provide an effective treatment protocol. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. Presented at the 4th International Conference on Trace Element Speciation in Biomedical, Nutritional and Environmental Sciences, 25–29 May 2008, Munich-Neuherberg, Germany.     

Simple and selective determination of arsenite and arsenate by electrospray ionization mass spectrometry

Arsenic pollution of public water supplies has been reported in various regions of the world. Recently, some cancer patients are treated with arsenite (As^III); most Japanese people consume seafoods containing large amounts of negligibly toxic arsenic compounds. Some of these arsenic species are metabolized, but some remain intact. For the determination of toxic As^III, a simple, rapid and sensitive method has been developed using electrospray ionization mass spectrometry (ESI-MS). As^III was reacted with a chelating agent, pyrrolidinedithiocarbamate (PDC, C₄H₈NCSS^-) and tripyrrolidinedithiocarbamate-arsine, As(PDC)₃, extracted with methyl isobutyl ketone (MIBK). A 1 μL aliquot of MIBK layer was directly injected into ESI-MS instrument without chromatographic separation, and was detected within 1 min. Arsenate (As^V) was reduced to As^III with thiosulfate, and then the total inorganic As was quantified as As^III. This method was validated for the analysis of urine samples. The limit of detection of As was 0.22 μg L⁻¹ using 10 μL of sample solution, and it is far below the permissible limit of As in drinking water, 10 μg L⁻¹, recommended by the WHO. Results were obtained in < 10 min with a linear calibration range of 1-100 μg L⁻¹. Several organic arsenic compounds in urine did not interfere with As^III detection, and the inorganic As in the reference materials SRM 2670a and 1643e were quantified after the reduction of As^V to As^III.     

Investigation of the substitution at the anionic positions BaT<Subscript>2</Subscript>As<Subscript>2</Subscript> (T = Fe,Ni) superconductors

The possibilities of electron/hole doping of two ternary arsenides, BaFe₂As₂ and BaNi₂As₂, via partial substitution at the arsenic position by 16 and 14 group elements, have been studied. While no substitution has been observed for chalcogens, BaFe₂As₂ incorporates Sb, Si, and Ge at the As site; BaNi₂As₂ incorporates Sb, Ge, Sn, and Pb. The observed results can be tentatively explained suggesting that 14 group elements are incorporated into the BaT₂As₂ structures as X^6? ₂ dumbbells.     

High-temperature laser Raman spectroscopic study on mixtures of arsenic and sulphur vapours

The gas-phase laser Raman spectra of arsenic and sulphur mixed vapours are investigated as a function of composition and temperature up to 800 °C. The various S_n species dominate the spectra of the sulphur rich mixtures. In the arsenic rich mixtures the results suggest the presence of As₄, As₄S₃, As₄S₄ and As₂S₂ in the vapour.     

Stability of arsenic peptides in plant extracts: off-line versus on-line parallel elemental and molecular mass spectrometric detection for liquid chromatographic separation

The instability of metal and metalloid complexes during analytical processes has always been an issue of an uncertainty regarding their speciation in plant extracts. Two different speciation protocols were compared regarding the analysis of arsenic phytochelatin (As^IIIPC) complexes in fresh plant material. As the final step for separation/detection both methods used RP-HPLC simultaneously coupled to ICP-MS and ES-MS. However, one method was the often used off-line approach using two-dimensional separation, i.e. a pre-cleaning step using size-exclusion chromatography with subsequent fraction collection and freeze-drying prior to the analysis using RP-HPLC–ICP-MS and/or ES-MS. This approach revealed that less than 2% of the total arsenic was bound to peptides such as phytochelatins in the root extract of an arsenate exposed Thunbergia alata, whereas the direct on-line method showed that 83% of arsenic was bound to peptides, mainly as As^IIIPC₃ and (GS)As^IIIPC₂. Key analytical factors were identified which destabilise the As^IIIPCs. The low pH of the mobile phase (0.1% formic acid) using RP-HPLC–ICP-MS/ES-MS stabilises the arsenic peptide complexes in the plant extract as well as the free peptide concentration, as shown by the kinetic disintegration study of the model compound As^III(GS)₃ at pH 2.2 and 3.8. But only short half-lives of only a few hours were determined for the arsenic glutathione complex. Although As^IIIPC₃ showed a ten times higher half-life (23 h) in a plant extract, the pre-cleaning step with subsequent fractionation in a mobile phase of pH 5.6 contributes to the destabilisation of the arsenic peptides in the off-line method. Furthermore, it was found that during a freeze-drying process more than 90% of an As^IIIPC₃ complex and smaller free peptides such as PC₂ and PC₃ can be lost. Although the two-dimensional off-line method has been used successfully for other metal complexes, it is concluded here that the fractionation and the subsequent freeze-drying were responsible for the loss of arsenic phytochelatin complexes during the analysis. Hence, the on-line HPLC–ICP-MS/ES-MS is the preferred method for such unstable peptide complexes. Since freeze-drying has been found to be undesirable for sample storage other methods for sample handling needed to be investigated. Hence, the storage of the fresh plant at low temperature was tested. We can report for the first time a storage method which successfully conserves the integrity of the labile arsenic phytochelatin complexes: quantitative recovery of As^IIIPC₃ in a formic acid extract of a Thunbergia alata exposed for 24 h to 1 mg As^v L⁻¹ was found when the fresh plant was stored for 21 days at 193 K. Figure On-line HPLC–ICP-MS/ES-MS (bottom) is the preferred method for MS determination of unstable arsenic peptide complexes in plant extracts, since this avoids fractionation and subsequent freeze-drying that are responsible for loss of arsenic phytochelatin complexes in the 2D off-line method (top) Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Arsenic pentafluoride equilibria in anhydrous hydrogen fluoride

Earlier work has indicated that arsenic pentafluoride when dissolved in anhydrous HF is present largely as the anion As₂F₁₁^-, particularly temperatures much below ambient. Raman spectra and conductance measurements are used here to show that, at and near room temperature, there are significant concentrations of molecular AsF₅, AsF₆^- and As₂F₁₁^-in equilibrium and that on reduction of temperature, As₂F₁₁^- is formed at the expense of AsF₅ and AsF₆^-. The implications of the Lewis acid and oxidant strengths of AsF₅ are discussed as affecting synthetic procedures in anhydrous HF.     

Hydrothermal synthesis and structures of organic–inorganic hybrid solids based on arsenic-vanadate building blocks

Four novel organic–inorganic hybrid arsenic-vanadate complexes, [Cu(phen)][(As^VO₄)(V^V ₃O₇)(H₂O)] (1), [Cu(en)₂]₂[As₈V₁₄O₄₂(H₂O)]?·?2.5H₂O (2), [M(1,10-phen)₃]₂[As₈V₁₄O₄₂(H₂O)_0.5]?·?0.5H₂O (M?=?Mn, 3, Cd, 4) (1,10-phen?=?1,10-phenanthroline) have been hydrothermally synthesized for the first time and characterized by elemental analyses, XPS spectra, EPR spectra, IR spectra, TG analyses and single crystal X-ray diffraction. The structure of compound 1 consists of arsenic vanadate ribbons coordinated by the [Cu(phen)]²⁺ complex, while compounds 2 to 4 possess a spherical [As₈ ^IIIV₁₄ ^IVO₄₂]^4? cage with H₂O molecules encapsulated. The unexpected preparation 1 and the synthesis of compounds 2 to 4 on the basis of same polyoxoanion structures show that the pH value of the reaction plays a crucial role in controlling the basic architectures.     

Heats of immersion of amorphous As2S3, As2S5 and As2Se3 in organic liquids

The heats of immersion of hydrophobic, amorphous arsenic chalcogenides have been measured in several organic liquids. For hexane, butanol, butylchloride and nitropropane, the heats of immersion with As₂S₃, As₂S₅ and As₂Se₃ showed linear dependences on the dipole moment of the wetting liquid molecule. From the results the average values of the electrostatic field strength were calculated to be 0.29 × 10⁵, 0.31 × 10⁵, and 0.57 × 10⁵ e.s.u. cm^?2. The heats of immersional wetting of As₂S₃ and As₂Se₃ in n-alkanols linearly increased with an increase of n, the number of carbon atoms in C_nH_2n+1OH. The contributions due to polarization of the liquid molecule by the electrostatic field of the solid surface, due to the dispersion force and due to the interaction between the dipole moment of the liquid with the electrostatic field of the solid were calculated by applying the additivity of intermolecular forces. The result showed that the dispersion force was the dominant contribution to the interaction in As chalcogenides-n-alkanol systems.