Development of highly sensitive electrochemical biosensor for the detection of hydroquinone using a FAD functionalized fluorapatite/SWCNT hybrid composite modified electrode

Hydroquinone (HQ) is a toxic and carcinogenic substance commonly used in cosmetics, pharmaceuticals, and various industrial applications. In this study, we report the synthesis of a novel composite material consisting of flavin adenine dinucleotide (FAD) functionalized fluorapatite (FA) combined with single-walled carbon nanotubes (SWCNTs) (FAD/FA/SWCNT). This composite was prepared through a mechanochemical method using dimethyl sulfoxide (DMSO) as the dispersing solvent. The resulting composite was then applied on to a glassy carbon electrode (GCE) for the electrochemical detection of hydroquinone (HQ). The structural morphology and phase of the nanocomposite were characterized using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and UV-visible spectroscopy. Electrochemical techniques, including cyclic voltammetry and amperometry, were employed to evaluate the electrochemical performance of the surface-modified electrode for hydroquinone (HQ) detection. The FAD/FA/SWCNT biosensor exhibited a redox peak at -0.45 V in a 0.1 M phosphate buffer solution (PBS, pH 7.4) under blank conditions. The composite demonstrated remarkable catalytic activity, showing an increased current signal in response to HQ detection. The sensor displayed a linear response range from 0.005 μM to 258.2 μM for HQ, with a limit of detection (LOD) of 2.70 nM. Furthermore, the FAD/FA/SWCNT biosensor successfully detected HQ in spiked water samples, achieving high recovery rates between 100.4% and 103.0%, highlighting its potential for real-world applications.