Document Detail

Extraction of fipronil and thiobencarb from anaerobic water samples using solid-phase extraction.
MedLine Citation:
PMID:  16001862     Owner:  NLM     Status:  MEDLINE    
Anaerobic water samples containing levels of soluble Fe(II) may form insoluble Fe(III) particulates that could hinder subsequent extraction and analysis. Solid-phase extraction (SPE) cartridges could become blocked by this material, reducing the volume that can be processed. The ability of ascorbic acid to reduce these Fe(III) colloids and/or to prevent further oxidation of Fe(II) by dissolved oxygen during sampling was investigated and compared to sample stabilization with hydrochloric acid. Ascorbic acid (5%, w/v) proved the most effective treatment because it prevented 95% of the dissolved iron in the sample from precipitating during processing, compared to 40% in untreated samples. The effect of ascorbic acid addition on degradation of 2 rice pesticides, fipronil and thiobencarb, was investigated and compared to degradation rates in water. Pesticide reduction by ascorbic acid over a 3 h period was insignificant compared to the natural degradation occurring in deionized water. While this method was shown to increase sample processing time, it also allowed the processing of large-volume anaerobic water samples (150 mL) that were previously not extractable due to rapid obstruction of the SPE cartridge.
Gregory Doran; Stuart Helliwell; Philip Eberbach
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of AOAC International     Volume:  88     ISSN:  1060-3271     ISO Abbreviation:  J AOAC Int     Publication Date:    2005 May-Jun
Date Detail:
Created Date:  2005-07-08     Completed Date:  2005-09-19     Revised Date:  2008-03-17    
Medline Journal Info:
Nlm Unique ID:  9215446     Medline TA:  J AOAC Int     Country:  United States    
Other Details:
Languages:  eng     Pagination:  854-9     Citation Subset:  IM    
CRC for Sustainable Rice Production, Farrer Centre, School of Agriculture, Charles Sturt University, Wagga Wagga 2678, NSW, Australia.
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MeSH Terms
Ascorbic Acid / analysis
Chromatography, Gas
Dose-Response Relationship, Drug
Herbicides / analysis
Hydrochloric Acid / analysis,  chemistry
Insecticides / analysis
Iron / analysis
Oxygen / analysis,  chemistry
Pesticide Residues / analysis
Pesticides / analysis
Pyrazoles / analysis*
Thiocarbamates / analysis*
Time Factors
Water / analysis*
Water Pollutants, Chemical*
Reg. No./Substance:
0/Colloids; 0/Herbicides; 0/Insecticides; 0/Pesticide Residues; 0/Pesticides; 0/Pyrazoles; 0/Thiocarbamates; 0/Water Pollutants, Chemical; 120068-37-3/fipronil; 28249-77-6/benthiocarb; 50-81-7/Ascorbic Acid; 7439-89-6/Iron; 7647-01-0/Hydrochloric Acid; 7732-18-5/Water; 7782-44-7/Oxygen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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