Document Detail

Graphite-teflon composite bienzyme electrodes for the determination of cholesterol in reversed micelles. Application to food samples.
MedLine Citation:
PMID:  11305650     Owner:  NLM     Status:  MEDLINE    
A bienzyme amperometric composite biosensor for the determination of free and total cholesterol in food samples is reported. Cholesterol oxidase and horseradish peroxidase, together with potassium ferrocyanide as a mediator, are incorporated into a graphite-70% Teflon matrix. The compatibility of this biosensor design with predominantly nonaqueous media allows the use of reversed micelles as working medium. The reversed micelles are formed with ethyl acetate as continuous phase (in which cholesterol is soluble), a 4% final concentration of 0.05 mol L(-1) phosphate buffer solution, pH 7.4, as dispersed phase, and 0.1 mol L(-1) AOT as emulsifying agent. Studies on the repeatability of the amperometric response obtained at +0.10 V, with and without regeneration of the electrode surface by polishing, on the useful lifetime of one single biosensor and on the reproducibility in the fabrication of different pellets illustrate the robustness of the biosensor design. Determination of free and total cholesterol in food samples such as butter, lard, and egg yoke was carried out, and the obtained results were advantageously compared with those provided by using a commercial Boehringer test kit.
N Peña; G Ruiz; A J Reviejo; J M Pingarrón
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Analytical chemistry     Volume:  73     ISSN:  0003-2700     ISO Abbreviation:  Anal. Chem.     Publication Date:  2001 Mar 
Date Detail:
Created Date:  2001-04-17     Completed Date:  2001-05-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370536     Medline TA:  Anal Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1190-5     Citation Subset:  IM    
Department of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, Spain.
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MeSH Terms
Biosensing Techniques*
Cholesterol / analysis*
Food Analysis / instrumentation*
Reg. No./Substance:
0/Micelles; 57-88-5/Cholesterol; 7782-42-5/Graphite; 9002-84-0/Polytetrafluoroethylene

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