Sensitive simultaneous determination of diethylstilbestrol and bisphenol A based on Bi_2WO_6 nanoplates modified carbon paste electrode

摘要

Bi_2WO_6 nanoplates were hydrothermally prepared and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The synthesized Bi_2WO_6 nanoplates were then used to fabricate modified carbon paste electrode (Bi_2WO_6-CPE) by a simple rubbing method. The result of electrochemical impedance spectroscopy indicated electron transfer resistance of the Bi_2WO_6-CPE was reduced vastly compared with CPE. In the meantime, cyclic voltammetry experiment demonstrated the Bi_2WO_6 nanoplates could accelerate the rate of electron transfer for the electrochemical reaction of diethylstilbestrol (DES) and bisphenol A (BPA) on the electrode. Moreover, the as-prepared electrode exhibited good selectivity toward simultaneous determination of DES and BPA with a rather low detection limit. By using differential pulse voltammetry (DPV) method, low detection limits of 15 nM (S/N = 3) and 20 nM (S/N = 3) for DES and BPA were obtained, with the linear calibration curves over the concentration range 50-2100 nM and 70-1300 nM, respectively. In addition, the proposed sensor was applied for the determination of analytes in spiked milk samples extracted from milk powder.