Dimethyl arsenic

Odanake et al. [1] have reported the application of gas chromatography with multiple ion detection after hydride generation with sodium borohydride to the determination of mono and dimethyl arsenic compounds, trimethyl arsenic oxide and inorganic arsenic in soil and sediments. Recoveries in spiking experiments were 100-102% (mono and dimethyl arsenic compounds and inorganic arsenic) and 72% (trimethyl arsenic oxide). 

Eilippova, M. Duerksen-Hughes, P. J. Inorganic and Dimethylated Arsenic Species Induce Cellular p53. Chem. Res. Toxicol. 2003, 16, 423-431. 

Yamanaka, K., Hasegawa, A., Sawamura, R. and Okada, S. (1989) Dimethylated arsenics induce DNA strand breaks in lung via the production of active oxygen in mice. Biochemical and Biophysical Research Communications, 165(1), 43-50. 

The anti-plant agents favoured in Vietnam were 2,4-dichlorophenoxy-acetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), dimethyl-arsenic acid (cacodylic add) and 4-amnito-3,5,6-trichloropicolinic acid (picloram). The formulation in which they were used is set out in Table 5.1. 

Dimethyl arsenic acid yields predominantly dimethylarsine, while methylarsonic acid yields predominantly methylarsine and trimethylarsine oxide yields predominantly trimethylarsine. 

Sample type Description Source Total arsenic(III) and arsenic(V) As(III) As(V) Methyl arsenic Dimethyl arsenic... 

Methylated arsenic is also found in compounds in which arsenic replaces phosphorus of natural biomolecules. Several arsenic-containing ribofuranosides have been identified in brown kelp . The dimethylated arsenic is linked to the C-4 of ribose by a methylene bridge. 

A similar result was obtained from an experiment in which another food chain (phytoplankton C. vulgaris-graieT Moina sp.-carnivorous guppy Poecilia sp. adult) was examined. Figure 4 shows the relative concentration of arsenic species accumulated and demonstrates that the relative concentration of dimethyl arsenic and trimethyl arsenic compounds dramatically increased successively with an elevation in the trophic level. 

Arsenic has also been shown to cross the placenta in pregnant women. Much of the arsenic was in the form of dimethyl arsenic, suggesting that there is an increase in methylation during pregnancy. 

Figure 11.5. Chromatogram of 100 gg each of As(IU), DMAA (dimethyl arsenic acid), MMAA (monomethyl arsenic acid), As(V) species for standard test of species in drinking water, by standard IC and ICP-MS detection. Column ANl (Cetac Technologies, Omaha, NE). Eluent 2 mM PBS/0.2 mM EDTA, pH 6.0 at 1 mL/min. Chromatography courtesy of T. Matsuda, HP-Japan, 1999.

Sample digestion must yield 80% or greater recovery of added (dimethyl arsenic acid) and 90% or greater recovery of added As(III), As(V). 

Trivalent monomethylated and dimethylated arsenic species have also been reported in lake water (58,68,69). These arsenicals are probably methylarsonous acid and dimethylarsinous acid, although their precise chemical structures in natural waters have not been demonstrated. Most analytical methods for determining arsenic species in water samples convert the original arsenic species into volatile hydrides, which then serve as the analytes. Since the trivalent methylated arsenicals generate the same analyte as their respective pentavalent analogues, they must be separated before the hydride generation step so that they can be determined independently. Solvent extraction has been used to effect this separation (58). Possibly, the presence of these trivalent methylated arsenicals has been underestimated because few studies include a solvent separation step. However, in one smdy at least, dimethylarsenic in estuarine and coastal waters, as determined by hydride generation techniques, was shown to be present solely as the pentavalent dimethylarsinate species in three out of the four samples tested (50). 

Lipid arsenic compounds also occur in marine animals (34,110). The compounds originally present in the lipid fraction were subjected to base and/or acid hydrolysis, and the water-soluble products identified by HPLC-ICPMS. In this way, phosphatidylarsenocholine (see Fig. 2, compound 18) and a phosphatidyl-arsenosugar (see Fig. 2, compound 5) were identified in the digestive gland of lobster (34), and evidence was presented for the presence of lipids containing arsenocholine and dimethylated arsenic moieties in shark tissues (110). 

K Hanaoka, W Goessler, K Yoshida, Y Fujitaka, T Kaise, KJ Irgolic. Arseno-choline- and dimethylated arsenic-containing lipids in starspotted shark Mustelus manazo. Appl Organomet Chem 13 765-770, 1999. 

Arsenic concentrations in hair and nails have been used as indicators of exposure to inorganic arsenic (112,113,121,122). However, arsenic in hair might be influenced by surface contamination via dust, water, soaps, and shampoos. Data on arsenic speciation in hair and nails is sparse. Only two studies reported the presence of dimethylated arsenic species in hair and nails (119,120). 

Surface waters are exposed to sunlight and the atmosphere, which support the growth of photosynthetic organisms. Nutrient-like behavior of arsenic (i.e., surface depletion in its total concentration) has been observed in surface seawater (23) and in some lakes (24), though, in other cases, surface depletions were not observed (25-28). The occurrence of arsenic in the (thermodynamically unstable) +III oxidation state and of monomethylated and dimethylated arsenic species in oxic surface waters has been attributed to the activity of phytoplankton (25-27,29). 

Synonyms CAS 75-60-5 agent blue BOLLSEYE CHEXMATE dimethyl arsenic acid ERASE SALVO Cadmium... 

Arsenite, arsenate, dimethyl arsenic acid in 4 min EKC WATER Ground water FASI 10 mmol L phosphate buffer, 0.35 mmol L" TTAB (pH 9.0) UV, 185 nm 0.1-0.5 mgL 234... 

Sodium 0,0-di-(methylamyl) dithiophosphate. See Sodium di-(methylamyl) dithiophosphate Sodium dimethyl arsenate Sodium dimethylarsinate Sodium dimethylarsonate. See Sodium cacodylate... 

Reverse-phase CIS column Determination of arsenite [As(III)], dimethyl arsenic add, monomethyl arsenic and arsenate [As(V)J in Chinese brake fern by ion-pair reverse-phase UPLC-inductively coupled plasma (ICP) MS [69]... 

Arsenic can be found in two primary forms organic and inorganic. Organic species of As are mainly found in food, such as shellfish, and include forms as monomethyl arsenic acid (MMAA), dimethyl arsenic acid (DMAA) and arseno-sugars. Inorganic arsenic (i-As) occurs in two valence states, arsenite (As(III)) and arsenate (As(V)). In natural waters, As(III) species consist primarily of arsenious acid (H3ASO3) and As(V) species is predominantly present as H2AsO and HAsO ... 

Reproductive system Environmental arsenic exposure can impair male fertility. A case-control study in China concluded that elevated inorganic arsenate (Asi(V)) exposure is associated with arsenic-induced male infertility. The mechanism of toxicity by arsenic species may involve oxidative stress and sexual hormone disruption measured by biomarkers including acylcamitines, aspartic acid and hydroxyestrone, which were negatively associated with infertility, and uridine and methylxanthine, which were positively associated [44 ]. Arsenic exposme is also correlated to a decrease in human semen quality as reported in a reproductive-age Chinese cohort. The study demonstrated significant association of dimethyl arsenic species (DMA) concentration with low sperm concentrations [45 -]. 

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