Amperometric Glucose Biosensors Based on Glassy Carbon and SWCNT‐Modified Glassy Carbon Electrodes

Abstract Different carbonaceous materials, such as single‐walled carbon nanotubes (SWCNTs) and glassy carbon submitted to an electrochemical activation at +1.80 V (vs. SCE) for 900 s, have been used with the aim of comparing their performances in the development of enzyme electrodes. Commercial SWCNTs have been pretreated with 2.2 M HNO3 for 20 h prior to use. The utility of activated GC as promising material for amperometric oxidase‐based biosensors has been confirmed. With glucose oxidase (GOx) as a model enzyme, glucose was efficiently detected up to 1 mM without the use of a mediator. Both electrodes operated in stirred solutions of 0.1 M phosphate buffer (pH 5.5), containing dissolved oxygen, at a potential of −0.40 V vs. SCE. Although the performances of the two carbonaceous materials were comparable, the biosensors based on activated GC were characterized by a practically unchanged response 40 days after the fabrication, a better signal to noise ratio, and a little worse sensitivity. In addition, the preparation procedure of such biosensors was more simple, rapid and reproducible.