Fabrication of an efficient hydroquinone biosensor with laccase immobilized on multiwalled carbon nanotubes

Hydroquinone is a phenolic compound commonly found in the raw materials and finished products of various chemical industries. Its widespread usage carries significant risks to aquatic and human life and the environment as well. A laccase biosensor was developed here to determine hydroquinone concentration in water resources. In the present study, the screen-printed electrode of the biosensor was coated with a solution of polyvinyl alcohol containing carboxyl functionalised multiwalled carbon nanotubes (MWCNTs). Laccase extracted from the fungus Trametes versicolor was immobilised on MWCNTs using glutaraldehyde. This strategy showed excellent stability, sensitivity, and selectivity, yielding a quick response time of only 10 sec. The electrode surface at different stages of the preparation was characterized using scanning electron microscopy (SEM). The optimized linear range for the bioelectrode spans from 50 µM to 1100 µM. The detection limit achieved with the electrode is 5 µM to 1700 µM. The biosensor detected hydroquinone successfully in real samples, including tap water, sewage water, spiked tap water and spiked sewage water. Further, this biosensor while offering a cost-effective, portable device, establishes the efficiency of carboxyl-functionalised MWCNTs in polyvinyl alcohol as matrix for the design of a variety of biosensors.