Synthesis of gold nanocubes/PEI-wrinkled CoSe2 nanomaterials and its application in electrochemical immunosensors for detection of dipropyl phthalate

Abstract

CoSe2 nanosheet materials with a wrinkled sheet structure and large surface area were synthesized via a simple hydrothermal method. Then polyethyleneimine (PEI) was used to functionalize wrinkled CoSe2 (w-CoSe2) to make gold nanocubes (AuNCs) uniformly anchored onto the surface of PEI-w-CoSe2 via Au–N bonds. And its application in electrochemical immunosensors for the detection of dipropyl phthalate (DPrP) was studied. The obtained material was characterized by the Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy. The effective surface area and conductivity of the electrode were enhanced by the introduction of AuNCs/PEI-w-CoSe2 nanocomposite. Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were used to characterize the performance of immunosensor. After DPrP binds to antibodies via the antigen–antibody interaction, [Fe(CN)6]3-/4- was used as a signal probe to monitor the change of oxidation current of different DPrP concentrations. Under optimal conditions, the electrochemical responses of the prepared immunosensor were linear when the DPrP concentrations ranged from 1 × 10−11 to 1 × 10−5 mol·L−1, with a detection limit of 1.39 × 10−12 mol·L−1. The coefficient of determination (R2) is 0.995, indicating that the degree of fitting is good. Besides, the constructed immunosensor exhibited acceptable reproducibility, selectivity, and stability. Therefore, it may be found that the composite material has good application prospects in the electrochemical sensors field.