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An Alkaline Oxidation Method for Determination of Total Arsenic and Selenium in Sewage Sludges
Author(s) -
Zhu Baojin,
Tabatabai M. A.
Publication year - 1995
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1995.00472425002400040011x
Subject(s) - chemistry , arsenic , sewage sludge , sewage , atomic absorption spectroscopy , selenium , environmental chemistry , extraction (chemistry) , alkali metal , digestion (alchemy) , chromatography , environmental science , environmental engineering , organic chemistry , physics , quantum mechanics
A simple and precise method was developed for determination of total As and Se in sewage sludges by using hydride‐generation atomic absorption spectrometry (HGAAS). It involves boiling a 50‐mg sample with sodium hypobromite (NaOBr) solution to dryness in a sand bath (260–280°C), extraction of the As and Se in the digest with 1.25 M H 2 SO 4 , and determination of these elements by HGAAS after reducing As(V) and Se(VI) to As(III) and Se(IV), respectively. The proposed method gives quantitative recovery of As and Se in standard reference materials (96–103%) and of these elements added to sewage sludges (95–100%). The average results of As (9.8 mg/kg) and Se (7.5 mg/kg) in 12 sewage sludges determined by the proposed digestion method agreed closely with those obtained by the acid digestion methods recommended by USGS and USEPA. Tests with 13 metals indicated that, at the concentrations expected in sewage sludges, none of the metals interfered with determination of As and Se by the proposed method. A single operator can complete analysis of one of the elements in 40 samples in a normal working day, or both elements in 1.5 d.