The aqueous-phase reaction of dimethylarsinc acid (DMAs(V)) with NaBH₄ (THB) was studied under non-analytical conditions (1000 μg/mL As, 0.1 M HCl, 1% NaBH₄) with the aim of identifying intermediates and reaction products. The use of direct analysis in real time (DART) with high-resolution mass spectrometry (HRMS), in combination with two different chemical vapor generation systems, allowed the identification of some species not detected by GC-MS such as Me₂As–AsMe–AsMe₂ and the arsonium species [Me₃As–AsMe₂]⁺ and [Me₂As–AsMe₂–AsMe₂]⁺. Many other methylated species of arsenic containing up to four arsenic atoms have been observed. Unfortunately, the oxidation mechanism that took place in the DART source interfered with the identification of some of those species formed in solution following THB reduction. The species identified by DART-HRMS, together with those previously identified by GC-MS (Me₂AsH, Me₂AsOH, Me₃As, Me₃AsO, Me₂AsAsMeH, Me₂AsAsMe₂, and Me₂As–O–AsMe₂)‚ enabled the formulation of hypotheses on the possible reaction pathways and revealed an aqueous-phase reactivity of DMAs(V) which could not be explained on the basis of current knowledge.

在非分析条件（1000μg/ mL As，0.1 M HCl，1％NaBH ₄）的非分析条件下研究了二甲基砷酸（DMAs（V））与NaBH ₄（THB）的水相反应，目的是鉴定中间体和反应产物。结合两种不同的化学气相生成系统，结合使用高分辨率实时质谱（HRMS）和实时实时直接分析（DART），可以鉴定GC-MS未检测到的某些物种，例如Me ₂ As–AsMe –AsMe ₂和砷物种[Me ₃ As–AsMe ₂ ] ⁺和[Me ₂ As–AsMe ₂ –AsMe ₂ ] ⁺。已经观察到许多其他甲基化的砷，最多包含四个砷原子。不幸的是，在DART源中发生的氧化机理干扰了THB还原后溶液中形成的某些物种的鉴定。通过DART-HRMS识别的物种，以及之前通过GC-MS识别的物种（Me ₂ AsH，Me ₂ AsOH，Me ₃ As，Me ₃ AsO，Me ₂ AsAsMeH，Me ₂ AsAsMe ₂和Me ₂ As–O– AsMe ₂）使得能够在可能的反应路径上提出假设，并揭示了DMAs（V）的水相反应性，而这在目前的知识基础上是无法解释的。