Impedance Immunsensor Based on Interdigitated Array Microelectrode and its Experiment Parameter Optimization

This article accounts for a novel impedance immunosensor based on the specificity reaction of the antigen-antibody and the sensitivity of the interdigitated array microelectrode (IDAM) for the determination of chlorpyrifos residues. The basic knowledge of immunoassay was in relation to its IDAM electrode surface modification, antibody immobilization, bovine serum albumin (BSA) blocking and sample detection. The SPA was dropped onto the surface of IDAM electrode and used for binding antibody Fc fragments. The BSA was employed to block the possible remaining active sites avoiding any nonspecific adsorption. Target chlorpyrifos was then captured by the immobilized antibody, resulting in a change in the impedance of the IDAM microelectrode surface. In this article, the volume of the reagents was micro upgraded. The antibodies, SPA and BSA were 30 μL, the chlorpyrifos sample and detection solution were 50 μL. The advantages of the immunosensor were exhibited in its better specificity, stability, selectivity and regeneration. The proposed method was proven to be a feasible quantitative method for chlorpyrifos analysis in vegetables and fruits.