Document Detail

Total inorganic arsenic detection in real water samples using anodic stripping voltammetry and a gold-coated diamond thin-film electrode.
MedLine Citation:
PMID:  17531818     Owner:  NLM     Status:  MEDLINE    
An accurate method for total inorganic arsenic determination in real water samples was developed using differential pulse anodic stripping voltammetry (DPASV) and a Au-coated boron-doped diamond thin-film electrode. Keys to the method are the use of a conducting diamond platform and solid phase extraction for sample preparation. In the method, the As(III) present in the sample is first detected by DPASV. The As(V) present is then reduced to As(III) by reaction with Na2SO3 and this is followed by a second detection of As(III) by DPASV. Interfering metal ions (e.g., Cu(II)) that cause decreased electrode response sensitivity for arsenic in real samples are removed by solid phase extraction as part of the sample preparation. For example, Cu(II) caused a 30% decrease in the As stripping peak current at a solution concentration ratio of 3:1 (Cu(II)/As(III)). This loss was mitigated by passage of the solution through a Chelex 100 cation exchange resin. After passage, only a 5% As stripping current response loss was seen. The effect of organic matter on the Au-coated diamond electrode response for As(III) was also evaluated. Humic acid at a 5 ppm concentration caused only a 9% decrease in the As stripping peak charge for Au-coated diamond. By comparison, a 50% response decrease was observed for Au foil. Clearly, the chemical properties of the diamond surface in the vicinity of the metal deposits inhibit molecular adsorption on at least some of the Au surface. The method provided reproducible and accurate results for total inorganic arsenic in two contaminated water samples provided by the U.S. Bureau of Reclamation. The total inorganic As concentration in the two samples, quantified by the standard addition method, was 23.2+/-2.9 ppb for UV plant influent water and 16.4+/-0.9 ppb for Well 119 water (n=4). These values differed from the specified concentrations by less than 4%.
Yang Song; Greg M Swain
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2007-04-24
Journal Detail:
Title:  Analytica chimica acta     Volume:  593     ISSN:  1873-4324     ISO Abbreviation:  Anal. Chim. Acta     Publication Date:  2007 Jun 
Date Detail:
Created Date:  2007-05-28     Completed Date:  2007-06-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0370534     Medline TA:  Anal Chim Acta     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  7-12     Citation Subset:  IM    
Department of Chemistry, Michigan State University, East Lansing, MI 48824-1322, United States.
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MeSH Terms
Arsenic / analysis*
Diamond / chemistry
Electrochemistry / methods*
Gold / chemistry
Humic Substances / adverse effects
Water Pollutants, Chemical / analysis*
Reg. No./Substance:
0/Humic Substances; 0/Water Pollutants, Chemical; 7440-38-2/Arsenic; 7440-57-5/Gold; 7782-40-3/Diamond

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