Abstract：
Acid extraction is commonly used to analyze arsenic species in rice. During the extraction process, spiked monomethylarsonic acid (MMA) is often transformed into different compounds. A similar phenomenon is observed in the arsenic speciation analysis of seafood. To identify these compounds, we analyzed a previously prepared extract using liquid chromatography-time-of-flight/mass spectrometry in differential analysis and liquid chromatography-inductively coupled plasma-MS. The compound was identified as monomethylmonothioarsonic acid (MMMTA), a thioarsenical, which is estimated to be more cytotoxic than MMA. As MMMTA was readily produced by bubbling hydrogen sulfide through MMA, this suggests that MMA reacts with sulfur in rice during the extraction process. Our data also suggested that dimethylarsinic acid could be transformed into another compound, although the generation rate was low. For reliable arsenic speciation analyses, the transformation of arsenic compounds during extraction must be avoided. This study demonstrates that arsenic compounds can be transformed by dilute acid extraction.
摘要：
酸提取通常用于分析大米中的砷物种。在提取过程中,掺加的单甲基arsonic酸（MMA）通常转化为不同的化合物。在海鲜的砷形态分析中观察到类似的现象。为了识别这些化合物，我们使用液相色谱-飞行时间/质谱法在差异分析和液相色谱-电感耦合等离子体-MS中分析了先前制备的提取物。该化合物被鉴定为单甲基单硫代磷酸(MMMTA)，硫砷，估计比MMA更具细胞毒性。由于MMMTA很容易通过将硫化氢鼓泡通过MMA来生产，这表明MMA在提取过程中与大米中的硫发生反应。我们的数据还表明，二甲基arsinic酸可以转化为另一种化合物，虽然生成率很低。对于可靠的砷形态分析，必须避免萃取过程中砷化合物的转化。这项研究表明，砷化合物可以通过稀酸萃取转化。
