Novel Ce/Co Metal Organic Frame Work Based Opto-Electrochemical dual mode Sensor for Foodborne Mycotoxin Detection

Abstract

A novel cerium-cobalt metal-organic framework (Ce/Co-PTC-MOF) was designed and employed as a fluorescence quenching sensor for the fast and selective detection of Ochtratoxin A(OTA) in food sample based on Ce redox properties and dual oxidation state. The Ce/Co-PTC-MOF was characterized using X-ray diffraction (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), photoluminescence (PL) spectroscopy, zeta potential measurements, and field emission scanning electron microscopy (FE-SEM) were employed for characterization. The MOF exhibited a hierarchical microstructure with a 3D flower-like morphology composed of ultrathin, interwoven nanosheets with strong negative surface charge. The fluorescence quenching response of Ce/Co-PTC-MOF was optimized by investigating the effects of MOF concentration, sonication time, incubation time, and pH on the quenching efficiency of Rhodamine B (Rh-B). The sensing mechanism was validated through fluorescence emission spectra, demonstrating efficient quenching of Rh-B by Ce/Co- PTC-MOF and significant fluorescence recovery upon the introduction of OTA. A machine learning (ML) approach was employed to enhance the sensor’s analytical capability by modeling the non-linear relationship between fluorescence recovery and OTA concentrations. The sensor exhibited a strong linear response to OTA concentrations ranging from 0.2 to 250 ng/L, with a low limit of detection of 10 pg/ml Electrochemical mode with electroactive surface area increased by nearly twice and electron-transfer kinetics increased at a moderately higher rate as compared to unmodified GCE, Ce/Co-PTC-MOF-modified glassy carbon electrodes (GCEs) generated electrochemical mode products. Surface blocking/passivation controlled the detection mechanism as OTA adsorption at Ce/Co site selectively reduced the difference pulse voltammetry (DPV) peak currents and augmented charge-transfer resistance (Rct) in electrochemical impedance statistica (EIS). The sensor worked on the principle of DPV with the sensitivity of 193.8 mAng-1mL +cm +2 and the detection limit was found as 0.1775 ng/mL, whereas the EIS gave a even lower result with a LOD of 0.20 ng/mL. The selectivity investigations showed the high specificity to the OTA as compared to other mycotoxins and in spiked food sample the maximum recoveries were 99.12 to 102.05 with a low relative standard deviation. According to the obtained results, the Ce/Co-PTC-MOF represents a high-potential multifunctional platform to detect OTA in food safely and without quality concerns with high sensitivity and selectivity as well as practicably, suitable in foods quality control