Poly(Neutral Red)/Cholesterol Oxidase Modified Carbon Film Electrode for Cholesterol Biosensing

Abstract

New amperometric cholesterol oxidase (ChOx) based enzyme biosensors for cholesterol have been developed. The enzyme was immobilised with and without glutaraldehyde cross-linking on top of carbon film electrodes modified with redox mediators. Mediators tested were: poly(neutral red) (PNR), Prussian blue and cobalt hexacyanoferrates. Amperometric detection of cholesterol showed that PNR/ChOx modified electrodes exhibited the best characteristics; under optimised conditions cholesterol was determined at -0.4V vs. SCE with a detection limit of 1.9μM. The biosensors showed good reproducibility and stability and only a small influence from potential interferents in food. Analyses of cholesterol in egg yolk were successfully performed. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.