Electrochemical bisphenol A sensor based on exfoliated Ni_2Al-layered double hydroxide nanosheets modified electrode

摘要

In the present work, the ultxathin exfoliated Ni_2Al layered double hydroxide (ELDH) nanosheets were prepared by using L-asparagine as pre-intercalator in aqueous medium. The transmission electron microscopy and atomic force microscopy images displayed that ELDH nanosheets had lost the original hexagon of hydrotalcite with about 200 nm lateral size and less than 3 nm thickness. Then a sensitive electrochemical sensor was fabricated for bisphenol A (BPA) detection based on ELDH modified glassy carbon electrode with aid of film-forming agent chitosan. The proposed sensor showed an efficient elec-trocatalytic performance on the oxidation of BPA with the enhanced oxidation response and the lowered oxidation overpotential (0.489 V). Differential pulse voltammetry (DPV) was employed for the determination of BPA with a wide linear range from 0.02 to 1.51 μM. The detection limit was calculated as 6.8 nM (S/N=3). The resultant sensor exhibited good reproducibility, selectivity and acceptable stability due to the contribution of the more active sites and the large surface area from ELDH nanosheets. Additionally, the concentrations of BPA in milk samples were analyzed by this developed method with an acceptable result.