COMPOSITE GLUCOSE BIOSENSOR BASED ON SCREEN-PRINTED ELECTRODES BULK MODIFIED WITH PRUSSIAN BLUE AND GLUCOSE OXIDASE

ABSTRACT

Biosensors for glucose based on glucose oxidase (GOx) and Prussian Blue (PB) bulk modified carbon screen-printed electrodes were developed. PB was made chemically by the reaction of FeCl₃ with K₄[Fe(CN)₆]. The resulting powder, obtained by forced crystallisation induced by acetone, was dried and activated at 150°C for 10 h. PB and GOx microparticles (<38 µm) were prepared and mixed with carbon ink in different ratios. The electrode has been optimised with respect to the lowest limit of detection achieved. The lowest LOD values were at 5% PB-8%GOx-SPE and 7% PB-12%GOx-SPE. The first electrode has been taken as optimal and investigated. The highest response was observed at 0 V vs. Ag/AgCl in the pH interval 6–8. Cross-linking with glutaraldehyde improved the sensitivity by 40% as well as the stability. The final glucose biosensor exhibited LOD of 0.2 mM, linear range up to 4 mM,of 5.3 mM, and the sensitivity of 880 ± 20 nA mM⁻¹ cm⁻². The biosensor was totally insensitive to oxygen, ascorbate, urate, and paracetamol.

Keywords:

• Prussian Blue
• Doped screen-printed electrode
• Biosensors
• Glucose oxidase
• Mediator

ACKNOWLEDGMENT

This work was supported by European Union, project ERBIC15-CT98-0906.