Electrochemical Determination of Hydroquinone Using a Tyrosinase-Based Cup-Stacked Carbon Nanotube (CSCNT)/Carbon Fiber Felt Composite Electrode

Abstract

This work shows that the cup-stacked carbon nanotube/carbon fiber felt composite electrode (CSCNT/felt) is a promising electronic conductive matrix to develop biosensors. The device was prepared by combining this matrix with the well-studied enzyme tyrosinase. Atomic force microscopy and scanning electron microscopy confirm that tyrosinase remained well dispersed in the whole electrode and completely covered the CSCNT network surface deposited on the surface of each graphitic felt electrode fiber. The studied combination allows preparing a disposable biosensor to determine hydroquinone in water with remarkable selectivity and accuracy when applied in real samples. The limit of detection was 1.4 µM with a wide linear range between 9 and 545 µM. The device presented good reproducibility for construction, with relative error of 2.4% (n = 7). These results confirm that a simple and sensitive device has been constructed to quantify hydroquinone in natural water and that the CSCNT structure is attractive for the immobilization of tyrosinase without functionalization of their walls or the use of surfactants.

Keywords:

• Cup-stacked carbon nanotube/carbon fiber felt composite electrode (CSCNT/felt)
• cyclic voltammetry (CV)
• electrochemistry
• tyrosinase
• phenolics

Additional information

Funding

This study was partly funded by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) – Finance Code 001 – scholarship PNPD (Gomes, W.E.) and Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) – scholarship (Beatto, T.G., and Marcatto, L.C.). Some of the equipment and material used in this work was acquired with a grant from FAPESP (2017/04759-2).