Tyrosinase biosensor for benzoic acid inhibition-based determination with the use of a flow-batch monosegmented sequential injection system

Amperometric tyrosinase based biosensor for benzoic acid determination with the use of a flow-batch monosegmented sequential injection system is proposed. The functioning of the biosensor is based on the inhibition effect of benzoic acid on the biocatalytic activity of tyrosinase, polyphenol oxidase. In the biosensor, tyrosinase is entrapped in titania gel modified with multiwalled carbon nanotubes (MWCNT) and Nation. The procedure of optimization of experimental conditions affecting the biosensor response, as well as its analytical characteristics and results of the approach verification using synthetic samples and a reference material are presented. The developed biosensor exhibits linear range up to 2.46 mu M, good sensitivity toward benzoic acid (1.06 mu A mu M-1) and low detection limit (0.03 mu M). The approach has been applied to benzoic acid determination in a real beverage sample giving the result consistent with that obtained using the HPLC method. (C) 2011 Elsevier B.V. All rights reserved.