Wang Suiling, Mulligan Catherine N
Department of Building, Civil and Environmental Engineering, Concordia University, 1455 de Maisonneuve Boulevard W., EV6.187, Montreal, Quebec, Canada H3G 1M8.
Environ Int. 2008 Aug;34(6):867-79. doi: 10.1016/j.envint.2007.11.005. Epub 2008 Mar 4.
Accurate determination of individual arsenic species is critical because the toxicology, mobility, and adsorptivity of arsenic vary substantially with its chemical forms and oxidation states. Separation techniques together with techniques for chemical identification make it possible to determine the combinational forms and oxidation states of arsenic in solid phases. Selective sequential extraction is often employed to determine operationally defined fractions, but it has a poor precision and selectivity. Direct methods, based on X-ray techniques and vibrational spectroscopy, have been developed to analyze the valence, local coordination, protonation, and other properties of arsenic in solid phases. Extensive research studies in the literature have been performed to elucidate the interfacial reactions between inorganic arsenic and solid surfaces of sulfides, and Fe, Al, and Mn (hydro)oxides. Outer-sphere and inner-sphere complex (monodentate mononuclear, bidentate mononuclear, and bidentate binuclear complex) models have been proposed to interpret the sorption mechanisms. The nature of the surface complexes has been inspected by spectroscopic methods but remains controversial. This paper focuses on the recent advancement in arsenic speciation in solid phases and covers relevant methodological, analytical and modeling aspects. The identification of arsenic species in natural materials, however, is complicated by the presence of multiple species, and the applications of instrumental methods are usually limited due to their comparatively high detection limits. Development of advanced in-situ methods with high sensitivity, therefore, is required.
准确测定单个砷物种至关重要，因为砷的毒理学、迁移率和吸附性会因其化学形态和氧化态的不同而有很大差异。分离技术与化学鉴定技术相结合，使得确定固相砷的组合形态和氧化态成为可能。选择性连续提取法常被用于测定操作定义的组分，但该方法的精密度和选择性较差。基于X射线技术和振动光谱的直接方法已被开发出来，用于分析固相砷的价态、局部配位、质子化及其他性质。文献中已开展了大量研究，以阐明无机砷与硫化物、铁、铝和锰（氢）氧化物的固体表面之间的界面反应。已提出外层和内层配合物（单齿单核、双齿单核和双齿双核配合物）模型来解释吸附机制。表面配合物的性质已通过光谱方法进行了研究，但仍存在争议。本文重点关注固相砷形态分析的最新进展，并涵盖相关的方法学、分析和建模方面。然而，由于天然材料中存在多种砷物种，其砷物种的鉴定变得复杂，并且由于仪器方法的检测限相对较高，其应用通常受到限制。因此，需要开发具有高灵敏度的先进原位方法。
