Preparation of DMMTA&lt;sup&gt;V&lt;/sup&gt; and DMDTA&lt;sup&gt;V&lt;/sup&gt; Using DMA&lt;sup&gt;V&lt;/sup&gt; for Environmental Applications: Synthesis, Purification, and Confirmation

Lee, Hosub; Kim, Youn Tae; Jeong, Seulki; Yoon, Hoi Soo

doi:10.3791/56603

Cited by 3 publications

(3 citation statements)

References 24 publications

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“…Commercially available arsenite (Riedelde Haen) and pentavalent DMA (Sigma-Aldrich) were used. DMMTA was synthesized according to a protocol by Lee et al 47 IC-ICP-MS analysis detected 2% DMA and 8% DMDTA (±1%) as impurities (Table S1).…”

Section: ■ Introductionmentioning

confidence: 99%

Dimethylmonothioarsenate Is Highly Toxic for Plants and Readily Translocated to Shoots

Pischke

Barozzi

Blanco

et al. 2022

Environ. Sci. Technol.

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Arsenic is one of the most relevant environmental pollutants and human health threats. Several arsenic species occur in soil pore waters. Recently, it was discovered that these include inorganic and organic thioarsenates. Among the latter, dimethylmonothioarsenate (DMMTA) is of particular concern because in mammalian cells, its toxicity was found to exceed even that of arsenite. We investigated DMMTA toxicity for plants in experiments with Arabidopsis thaliana and indeed observed stronger growth inhibition than with arsenite. DMMTA caused a specific, localized deformation of root epidermal cells. Toxicity mechanisms apparently differ from those of arsenite since no accumulation of reactive oxygen species was observed in DMMTA-exposed root tips. Also, there was no contribution of the phytochelatin pathway to the DMMTA detoxification as indicated by exposure experiments with respective mutants and thiol profiling. RNA-seq analysis found strong transcriptome changes dominated by stress-responsive genes. DMMTA was taken up more efficiently than the methylated oxyarsenate dimethylarsenate and highly mobile within plants as revealed by speciation analysis. Shoots showed clear indications of DMMTA toxicity such as anthocyanin accumulation and a decrease in chlorophyll and carotenoid levels. The toxicity and efficient translocation of DMMTA within plants raise important food safety issues.

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Section: ■ Introductionmentioning

confidence: 99%

Dimethylmonothioarsenate Is Highly Toxic for Plants and Readily Translocated to Shoots

Pischke

Barozzi

Blanco

et al. 2022

Environ. Sci. Technol.

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“…To demonstrate the shortcomings of currently used acid-based extractions and the advantage of our method, a comparison with routine nitric acid extraction was done. DMMTA ((CH 3 ) 2 AsS(OH)) was synthesized according to Lee et al 23 Briefly, DMA and Na 2 S•9H 2 O solutions in N 2 -purged deionized water (MQ) were mixed under anoxic conditions and then acidified with concentrated sulfuric acid to achieve a final molar ratio of As:S:H 2 SO 4 = 1:1.6:1.6. After 1 h, the synthesized DMMTA was separated using a liquid−liquid extraction with diethyl ether.…”

Section: ■ Introductionmentioning

confidence: 99%

Detection of Thioarsenates in Rice Grains and Rice Products

Blanco

Kerl

Planer-Friedrich

2021

J. Agric. Food Chem.

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Inorganic and methylated thioarsenates have recently been reported to contribute substantially to arsenic (As) speciation in paddy-soil pore waters. Here, we show that thioarsenates can also accumulate in rice grains and rice products. For their detection, a method was developed using a pepsin–pancreatin enzymatic extraction followed by chromatographic separation at pH 13. From 54 analyzed commercial samples, including white, parboiled and husked rice, puffed rice cakes, and rice flakes, 50 contained dimethylmonothioarsenate (DMMTA) (maximum 25.6 μg kg–1), 18 monothioarsenate (MTA) (maximum 5.6 μg kg–1), 14 dimethyldithioarsenate (DMDTA) (maximum 2.8 μg kg–1), and 5 dithioarsenate (DTA) (maximum 2.3 μg kg–1). Additionally, we show that the commonly used nitric acid extraction transforms MTA to arsenite and DMMTA and DMDTA to dimethylarsenate (DMA). Current food guidelines do not require an analysis of thioarsenates in rice and only limit the contents of inorganic oxyarsenic species (including acid-extraction-transformed MTA), but not DMA (including acid-extraction-transformed DMMTA and DMDTA).

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“…Glassware was soaked in 2% HNO 3 for 2 days, and for sorption experiments, additionally soaked in 2% HCl for 2 days and rinsed with MQ twice before use. Dimethylmonothioarsenate was synthesized following Lee et al 46 (details in Supporting Information). Purity was 91% DMMTA, 7% DMDTA, and 2% DMA.…”

Section: Materials and Standardsmentioning

confidence: 99%

Seasonal Formation of Low-Sorbing Methylthiolated Arsenates Induces Arsenic Mobilization in a Minerotrophic Peatland

Knobloch,

Pham,

Kerl

et al. 2024

Environ. Sci. Technol.

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Peatlands are known sinks for arsenic (As). In the present study, seasonal As mobilization was observed in an acidic, minerotrophic peatland (called Lehstenbach) in late summer, accompanied by a peak in dissolved sulfide (S(-II)). Arsenic speciation revealed the lowest seasonal porewater concentrations of arsenite and arsenate, likely due to As(III)-Sbridging to natural organic matter. Arsenic mobilization was driven by the formation of arsenite-S(-II) colloids and formation of methylthiolated arsenates (up to 59% of the sum of As species) and to a minor extent also of inorganic thioarsenates (6%−30%) and oxymethylated arsenates (5%− 24%). Sorption experiments using a purified model peat, the Lehstenbach peat, natural (to mimic winter conditions) and reacted with S(-II) (to mimic late summer conditions) at acidic and neutral pH confirmed low sorption of methylthiolated arsenates. At acidic pH and in the presence of S(-II), oxymethylated arsenates were completely thiolated. This methylthiolation decreased As sorption up to 10 and 20 times compared with oxymethylated arsenates and arsenite, respectively. At neutral pH, thiolation of monomethylated arsenates was incomplete, and As could be partially retained as oxymethylated arsenates. Dimethylated arsenate was still fully thiolated and highly mobile. Misidentification of methylthiolated arsenates as oxymethylated arsenates might explain previous contradictory reports of methylation decreasing or increasing As mobility.

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Preparation of DMMTA<sup>V</sup> and DMDTA<sup>V</sup> Using DMA<sup>V</sup> for Environmental Applications: Synthesis, Purification, and Confirmation

Cited by 3 publications

References 24 publications

Dimethylmonothioarsenate Is Highly Toxic for Plants and Readily Translocated to Shoots

Dimethylmonothioarsenate Is Highly Toxic for Plants and Readily Translocated to Shoots

Detection of Thioarsenates in Rice Grains and Rice Products

Seasonal Formation of Low-Sorbing Methylthiolated Arsenates Induces Arsenic Mobilization in a Minerotrophic Peatland

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