title: Influence of sulfide (S2-) on preservation and speciation of inorganic arsenic in drinking water.
abstract: 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.
authors.affiliation: Department of Civil and Environmental Engineering, University of Houston, N 107 Engineering Building 1 Houston, TX 77204-4003, USA. gsamanta@mail.uh.edu
authors.forename: Gautam
authors.initials: G
authors.lastname: Samanta
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Clifford
mesh_terms: D000327:Adsorption; D001148:Arsenamide / Q000032:analysis / Q000737:chemistry; D001151:Arsenic / Q000032:analysis* / Q000737:chemistry; D001152:Arsenicals / Q000737:chemistry / Q000494:pharmacology; D011232:Chemical Precipitation; D004305:Dose-Response Relationship, Drug; D004784:Environmental Monitoring / Q000379:methods*; D010084:Oxidation-Reduction; D010472:Perchlorates / Q000737:chemistry; D012116:Resins, Plant / Q000737:chemistry; D017670:Sodium Compounds / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry* / Q000494:pharmacology; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
chemical_list: D001152:Arsenicals; D010472:Perchlorates; D012116:Resins, Plant; D017670:Sodium Compounds; D013440:Sulfides; D014874:Water Pollutants, Chemical; C045816:arsenic trisulfide; C031068:sodium perchlorate; D001151:Arsenic; D001148:Arsenamide