Samanta Gautam, Clifford Dennis A
Department of Civil and Environmental Engineering, University of Houston, N 107 Engineering Building 1 Houston, TX 77204-4003, USA.
Chemosphere. 2006 Oct;65(5):847-53. doi: 10.1016/j.chemosphere.2006.03.023. Epub 2006 Apr 27.
Generally, H2SO4, HNO3, HCl or the combination of ethylenediaminetetraacetate with acetic acid (EDTA-HAc) have been used to preserve arsenite and arsenate species prior to analysis. When these acidic preservatives are added in sulfidic water, instantaneous precipitation of poorly crystalline orpiment, As2S3(am), occurs, thereby lowering the total arsenic, As(Tot), analysis. A new method for the determination of As(Tot) was developed in which acid-preserved sulfidic water samples were oxidized with NaOCl, converting As2S3(am) and thioarsenic species to arsenate. A new method was also developed for the separation of uncharged arsenite and charged thioarsenic species in fresh, unpreserved sulfidic water by adsorbing the charged thioarsenic species while allowing uncharged arsenite to pass through a strong-base resin unhindered. The adsorbed thioarsenic species could be eluted efficiently with 0.16 M NaOCl solution.
一般来说，在分析之前，硫酸、硝酸、盐酸或乙二胺四乙酸与乙酸的组合（EDTA-HAc）已被用于保存亚砷酸盐和砷酸盐物种。当这些酸性防腐剂添加到含硫水中时，会立即形成结晶性较差的雌黄（As2S3(am)）沉淀，从而降低总砷（As(Tot)）的分析结果。开发了一种测定As(Tot)的新方法，其中用次氯酸钠氧化经酸保存的含硫水样，将As2S3(am)和硫代砷物种转化为砷酸盐。还开发了一种新方法，通过吸附带电的硫代砷物种，同时让不带电的亚砷酸盐不受阻碍地通过强碱树脂，来分离新鲜的、未保存的含硫水中不带电的亚砷酸盐和带电的硫代砷物种。吸附的硫代砷物种可用0.16 M次氯酸钠溶液有效洗脱。
