Abstract
Ochratoxin A (OTA) is among the most important mycotoxins classified as potential risks to human health and food safety. In this work, a novel label-free electrochemical immunosensor has been proposed for the quantitative detection of OTA, based on a two-step strategy for the fabrication of the immunosensor. This involved coating of a carbon felt (CF) electrode with palladium nanoparticles (PdNPs) using atomic layer deposition (ALD), followed by the grafting of the anti-OTA antibodies onto the nanocomposite structure using a carbodiimide functional group via a cross linkage route. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) have been employed for the characterization of the immunosensor properties. The fabricated BSA/anti-OTA/PdNPs/CF immunosensor showed outstanding electrochemical performance towards the detection of OTA in spiked coffee samples. At the optimal working conditions, the linear detection range of the developed immunosensor was from 0.5-20 ng mL(-1) (R-2 = 0.996) with a low detection limit of 0.096 ng mL(-1), making it applicable to the screening of OTA in food products. In addition, the sensor was highly selective to OTA in the presence of interfering compounds and revealed stability of up to three weeks, opening up prospects for the molecular sensing community and paving a new route for quality control in the food industry.