Determination of arsenic and selenium in environmental samples by flow-injection hydride generation atomic absorption spectrometry

✍ Scribed by Chris C.Y. Chan; Ram S. Sadana

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 571 KB
• Volume: 270
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/0003-2670(92)80112-k

✦ Synopsis

Flow-injection analysis is applied to sample introduction in conjunction with automated hydride generation and AAS for the determination of As and Se in environmental samples such as soil, vegetation, waters, sediments, and industrial wastes. A large sample loop was used to provide high sensitivities with an absorbance of 0.4 for 10 ng ml-1 for both As and Se. The samples, except waters, are digested with a mixture of nitric, sulfuric, and perchloric acids. Se 6+ in the digested solutions is pre-reduced to Se 4+ by exothermic reaction in 6-8 M HCI solution, and As 5+ to As 3+ by reacting with KI. The analyte is then converted to hydride by NaBH 4 in an automated hydride generation system. The evolved hydride is carried through to a heated quartz tube by a stream of argon, and the atomic absorption of the analyte is measured. 1,10-Phenanthroline is used as masking agent to control interferences from Cu and Ni on Se. The detection limits for both As and Se are 0.3 ng ml-1, equivalent to 75 ng g-~ in solid sample. Precision is 2.6% R.S.D. Results for standard reference materials agree closely with the certified values.