Ultrathin Layered Vanadyl Phosphate Nanosheets as an Ultrasensitive Electrochemical Sensor for Dihydroxybenzene Isomers in Biological and Environmental Matrices

The electrochemical detection of dihydroxybenzene isomers (DHBIs) in body fluids is needed for the early detection of diseases and hazardous chemicals with high sensitivity and selectivity. This study focuses on the synthesis and characterization of layered ultrathin vanadyl phosphate (VOPO4) nanosheets and explores their potential as efficient electrochemical sensors for the rapid and simultaneous detection of two important dihydroxybenzene isomers (DHBIs): hydroquinone (Hydr) and catechol (Ctc). The phase identification, structural, and morphological studies of the VOPO4 nanostructures were confirmed by powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, Brunauer–Emmet–Teller method, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. VOPO4 nanosheets (VPO NSs) offer unique properties, including high surface area, excellent electrical conductivity, and abundant active sites, making them promising candidates for improving sensor performance. The fabricated carbon-based screen-printed electrode was employed for the simultaneous detection of Hydr and Ctc by using differential pulse voltammetry and cyclic voltammetry. The sensitivity, selectivity, and stability of the developed sensor in various environmental samples and biological matrices were evaluated. This sensor demonstrated outstandingly low detection limits of 0.11 nM for Hydr and 0.69 nM for Ctc, along with a wide linear range of 0.05–120 for both analytes. This study aims to address the limitations of current DHBI detection methods and provide a more reliable and efficient tool for clinical diagnosis and environmental analyses.