Establishment and application of a method for the detection of ochratoxin A based on screen-printed electrodes and diazo- functionalised immunosensors

Abstract

Abstract Ochratoxin A is a toxic metabolite commonly found in cereals and animal feeds, causing not only economic losses in the trade of agricultural products, but also potential hazards to human health. In this study, An electrochemical immunosensor for the rapid detection of OTA using anti-OTA antibodies and diazonium-functionalized screen-printed electrodes was proposed. 4-aminobenzoic acid was attached to the electrode surface, followed by activation of the carboxyl groups on the electrode surface with carbodiimide, and finally the antibody was attached to the diazo layer. Subsequently, bovine serum protein (BSA) was used as a sealer to prevent the non-specific antigen from binding to the antibody. The performance of the sensors was evaluated by cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry. The sensor has high specificity and sensitivity, and good linear responses in the range of 20–200 ng/mL, limit of detection of 0.5 ng/mL, and good recoveries of 90.54–100.92% in in spiked samples were obtained. The sensor can be stored at 4℃ for half a month and has high stability, with current response variation of no more than 4.62%.