Detection of Benzoic Acid by an Amperometric Inhibitor Biosensor Based on Mushroom Tissue Homogenate

Mustafa Kemal Sezgintürk*, Tüge Göktuğ and Erhan Dinçkaya

Ege University, Faculty of Science, Biochemistry Department 35100, Bornova-Ïzmir, Turkey

Article history:
Received February 2, 2005
Accepted September 22, 2005

Keywords:
benzoic acid, inhibitor biosensors, polyphenol oxidases, food additives, Clark-type oxygen electrode

Summary:
An amperometric benzoic acid-sensing inhibitor biosensor was prepared by immobilizing mushroom (Agaricus bisporus) tissue homogenate on a Clark-type oxygen electrode. The effects of the quantity of mushroom tissue homogenate, the quantity of gelatin and the effect of the crosslinking agent glutaraldehyde percent on the biosensor were studied. The optimum concentration of phenol used as substrate was 200
μM. The bioanalytical properties of the proposed biosensor, such as dependence of the biosensor response on the pH value and the temperature, were investigated. The biosensor responded linearly to benzoic acid in a concentration range of 25–100
μM. Standard deviation (s.d.) was ±0.49
μM for 7 successive determinations at a concentration of 75
μM. The inhibitor biosensor based on mushroom tissue homogenate was applied for the determination of benzoic acid in fizzy lemonade, some fruits and groundwater samples. Results were compared to those obtained using AOAC method, showing a good agreement.

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