DETERMINATION OF CHOLESTEROL AND CHOLESTEROL ESTER WITH NOVEL ENZYME MICROSENSORS

Citation
J. Motonaka et Lr. Faulkner, DETERMINATION OF CHOLESTEROL AND CHOLESTEROL ESTER WITH NOVEL ENZYME MICROSENSORS, Analytical chemistry, 65(22), 1993, pp. 3258-3261
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry Analytical
Journal title
ISSN journal
0003-2700
Volume
65
Issue
22
Year of publication
1993
Pages
3258 - 3261
Database
ISI
SICI code
0003-2700(1993)65:22<3258:DOCACE>2.0.ZU;2-8
Abstract
Enzyme microsensors using cholesterol oxidase (EC 1.1.3.6) and cholest erol esterase (EC 3.1.1.13) were developed for measuring cholesterol a nd cholesterol ester. The platinum microsensors (platinum diameter, 50 mum) were etched in hot aqua regia to create a cavity at their tip. A porous composite material prepared from acetylene black and Teflon em ulsion was packed into this cavity and the redox mediator [Os(bpy)3](P F6)2 was monitored by cyclic voltammetry in the potential range of 200 -900 mV. The microsensors were dipped overnight in buffer solution con taining the desired enzyme to immobilize it on the tip by adsorption. Calibration curves for measurements of cholesterol and cholesterol est er, the effects of pH, temperature, and concomitant compounds, the lif etime of the microsensors, and their availability for measuring choles terol and cholesterol ester in urine were examined. Under optimal cond itions, the response of the sensors was linear in concentration ranges of 5 muM-0.47 mM cholesterol and 2 muM-1.00 mM cholesterol ester.