Biosensor based on MXene-Y2O3 composite for ultrasensitive detection of catechol in water samples

Phenolic compounds are considered to be major environmental pollutants because of their toxicity and hazard on the marine ecosystem and human health even at low concentrations. An ultrasensitive biosensor was fabricated by immobilizing polyphenol oxidase into a composite of transition metal carbides (MXene)-yttrium oxide (Y 2 O 3 ) for the detection of catechol in environmental water bodies. The morphology and electrochemical performance of the as-prepared biosensors were investigated using scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV), respectively. Under the optimal pH value and applied potential, the biosensor exhibited a linear response range from 0.04 to 3.2 µM (R 2 = 0.9974) with an excellent sensitivity of 2294.8 mA·M −1 . The limit of detection (LOD) was found to be 7 nM (S/N = 3) with acceptable repeatability and reproducibility. The interference from ascorbic acid, uric acid, CuSO 4 , MgSO 4 , FeCl 3 , CaCl 2 , and ZnSO 4 was also investigated. The proposed biosensor was used for the determination of trace catechol in real water samples with satisfactory results compared with that of HPLC. The construction of MXene-Y 2 O 3 composite is expected to be a platform for immobilizing enzymes to prepare versatile electrochemical biosensors.