Selenium Speciation of Soil/Sediment Determined with Sequential Extractions and Hydride Generation Atomic Absorption Spectrophotometry
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- 作者：Dean A. Martens and Donald L. Suarez
- 刊名：Environmental Science & Technology
- 出版年：1997
- 出版时间：January 1997
- 年：1997
- 卷：31
- 期：1
- 页码：133 - 139
- 全文大小：217K
- 年卷期：v.31,no.1(January 1997)
- ISSN：1520-5851
文摘
Understanding the speciation of the multioxidation statesof selenium is vital to predicting the mineralization,mobilization, and toxicity of the trace element in naturalsystems. A sequential extraction scheme (SES) wasdevelopedfor identification of Se oxidation states that firstemployed0.1 M (pH 7.0)K2HPO4-KH2PO4(P-buffer) to releasesoluble selenate (Se+VI) and selenide(Se-II) and ligand-exchangeable selenite (Se+IV). The second stepinvolvedoxidation of organic materials with 0.1 MK2S2O8 (90 
C)to release Se-II and Se+IVassociated or occluded with organicmatter. The final step used HNO3 (90 C) tosolubilizeinsoluble Se remaining in the sample. The solubilizedSecompounds were speciated by a selective hydridegeneration atomic absorption spectrophotometry technique.Accuracy of the developed SES method (96-103%recovery)was verified by use of prepared Se compounds of knownspeciation, NIST standard reference materials, andexistingseleniferous soils. The average precision (relativestandarddeviation) for the P-buffer extraction ranged from 5.5 to7.7% (n = 12); the precision of the persulfate extractionrangedfrom 2.6 to 8.4% (n = 12); and the precision of thenitricacid extraction ranged from 2.8 to 7.4% (n = 12) forthree soilsextracted at four different time periods. The methodwasapplied to analyze Se species in seleniferous plant, soil,and sediment samples.
C)to release Se-II and Se+IVassociated or occluded with organicmatter. The final step used HNO3 (90 C) tosolubilizeinsoluble Se remaining in the sample. The solubilizedSecompounds were speciated by a selective hydridegeneration atomic absorption spectrophotometry technique.Accuracy of the developed SES method (96-103%recovery)was verified by use of prepared Se compounds of knownspeciation, NIST standard reference materials, andexistingseleniferous soils. The average precision (relativestandarddeviation) for the P-buffer extraction ranged from 5.5 to7.7% (n = 12); the precision of the persulfate extractionrangedfrom 2.6 to 8.4% (n = 12); and the precision of thenitricacid extraction ranged from 2.8 to 7.4% (n = 12) forthree soilsextracted at four different time periods. The methodwasapplied to analyze Se species in seleniferous plant, soil,and sediment samples.