Perušković, Danica S., Stevanović, Nikola R., Kovačević, Gordana, Stanković, Dalibor, Lolić, Aleksandar, Baošić, Rada, Perušković, Danica S., Stevanović, Nikola R., Kovačević, Gordana, Stanković, Dalibor, Lolić, Aleksandar, and Baošić, Rada
A new glucose biosensor for selective and sensitive determination of glucose in beverage samples was developed. A copper complex with a Schiff base, N,N’-bis(acetylacetonato) propylenediimine, was used as a mediator. It was mixed with glucose oxidase (GOx) and prepared as carbon paste electrode (CPE). Cyclic voltammetry was used for electrochemical measurements. The biosensor showed improved sensitivity when enzyme mediator ratio was 1 : 5, and working pH was 6.6 in 0.1 M phosphate buffer. The linear response of the biosensor for glucose concentration was in the range from 0.5 to 10 mM, with low detection limit of 0.36 mM (calculated as 3 s/n) and sensitivity of 0.16 μA/mM. The reproducibility of the biosensor, calculated as relative standard deviation, was 1.9% for 6 intra-day measurements. Biosensor was stored at +4 °C between experiments, and it was stable during 14 days after the preparation. The developed biosensor was applied on determination of glucose in commercial beverages (apple and cherry juice) and obtained results showed good agreement with the reference method.