Dual mode competitive electrochemical immunoassay for dibutyl phthalate detection based on PEI functionalized nitrogen doped graphene-CoSe2/gold nanowires and thionine-Au@Pt core-shell

In this work, a sensitive dual mode competitive electrochemical immunosensor based on differential pulse voltammetry (DPV) and square wave voltammetry (SWV) response modes for quantitative determination of dibutyl phthalate (DBP) was successfully established. According to diethylenetriamine (DETA) assisted hydrothermal strategy, a novel N-doped graphene/CoSe 2 nanobelt composite was prepared. Afterwards, PEI functionalized NG-CoSe 2 and gold nanowires (AuNWs) were further compounded as a preliminary signal amplification platform for immunosensor. Thionine (Thi)-loaded [email protected] and secondary antibody (Ab 2 ) connected as a signal label. The immobilized coating antigen DBP-BSA and the DBP compete for limited antibody binding sites. The concentration of DBP can be determined by DPV detect the Thi signal loaded on the [email protected] 2 label. It can also be determined by SWV mode to detect the current generated by the reaction system of H 2 O 2 and o-phenylenediamine (o-PD) catalyzed by [email protected] with peroxidase like properties. Under optimum conditions, the linear ranges of the DPV and SWV modes were 1 pg mL −1 ∼1 μg mL −1 . And LOD were 0.486 pg mL -1 (DPV) and 0.711 pg mL -1 (SWV), respectively. Besides, it exhibited outstanding selectivity, reproducibility, stability and can be used for sensitive detection of DBP in real samples.