MWCNTs-PEI composites-based electrochemical sensor for sensitive detection of bisphenol A

Bisphenol A (BPA), an important widely used industrial material, could emulate or disrupt the endogenous estrogen. This work presents a simple and convenient electrochemical differential pulse voltammetry (DPV) method for sensitively determining BPA via the fabricated sensor basing MWCNTs-PEI nanocomposites. Scanning electron microscopy (SEM) and Zeta potential measurements have been employed to characterize the morphology and surface modification of the nanocomposites. Electrochemical behaviors of BPA on MWCNTs-PEI modified electrode were investigated. The experimental parameters, such as accumulation potential, accumulation time and pH, have been optimized. Under the optimal conditions, the constructed sensor showed a wide linear range from 10 nM to 50 μM, low detection limit of 3.3 nM BPA (S/N = 3), good stability and reproducibility, which could be attributed to that the presence of MWCNTs promotes fast electron-transfer, and polyethylenimine (PEI) provides a positively charged surface for favorably loading a large amount of BPA. Furthermore, this proposed sensor was successfully demonstrated for the detection of BPA in the real milk samples.