Ultrasensitive label-free electrochemical immunosensor based on PVA-co-PE nanofibrous membrane for the detection of chloramphenicol residues in milk

An ultrasensitive label-free amperometric immunosensor for the detection of chloramphenicol (CAP) residues in milk has been developed by using a screen-printed carbon electrode laminated with a layer of poly (vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membrane that is covalently immobilized with a CAP antibody (anti-CAP). The performance of the PVA-co-PE nanofiber membrane (PVA-co-PE NFM) on the electrode was compared with a PVA-co-PE casted membrane (PVA-co-PE CM), necessary fabrication steps and performance of the sensors were investigated by electrochemical impedance spectroscopy (EIS). The application of the PVA-co-PE NFM decreased the electron-transfer-resistance by about 4 times compared with a conventional PVA-co-PE casted membrane. Under the optimal conditions, the established immunosensor exhibited high sensitivity for determination of CAP in a range 0.01–10 ng mL−1, with a limit of detection of 0.0047 ng mL−1. In addition to the good selectivity, reusability and stability over time, the prepared immunosensor was successfully used in the detection of CAP in milk samples without any pretreatment. [Display omitted] •First electrochemical immunosensor report of chloramphenicol based on PVA-co-PE.•High sensitivity was achieved using nanofibrous membrane.•Label free detection platform with broad dynamic range.•The proposed sensor exhibited excellent specificity against chloramphenicol and successfully applied to real samples.•Potential application for future on-site detection.