A highly sensitive electrochemical immunosensor based on electrospun nanocomposite for the detection of parathion

For monitoring of the residual of parathion pesticide in food, herein, a sensitive and reliable electrochemical immunosensor based on cross-linked polyvinyl alcohol/citric acid nanofiber membrane (PVA/CA NFM) and horseradish peroxidase labeled anti-parathion nanobody was constructed. Firstly, the cross-linked PVA/CA NFM with extra-high surface area and uniform morphology was prepared and characterized. Then, the immunosensor was assembled and its analytical performances were evaluated. It exhibited high specificity and sensitivity to parathion with the liner range and limit of detection being 0.01–100 ng/mL and 2.26 pg/mL, respectively. Moreover, the biosensor kept almost 75% of its initial activity after regenerating 4 times, and remained 85% after 9 weeks of storage. Finally, the average recoveries from food samples were 96.20%–114.61% with the coefficient of variation being 1.06%–5.28%, which was correlate well with UPLC (R 2  = 0.9964). Therefore, the sensor was demonstrated to be a feasible alternative for sensitive assay of parathion.