Determination of Diethylstilbestrol in Environmental Water Based on Co(II)-Sensitized Electrochemical Sensing

In this research, a simple electrochemical sensor (c-MWCNTs/Nafion/GCE) was prepared by carboxylated multi-walled carbon nanotube, perfluorosulfonic acid polymer and glassy carbon electrode using drop coating method, and based on the obvious sensitization effect on the redox peak current of diethylstilbestrol (DES) in the presence of Co 2+ , a new electrochemical sensing method for the determination of DES in water was established. In a buffered solution of 0.2 mol l −1 NaH 2 PO 4 -Na 2 HPO 4 at pH = 7.0, differential pulse voltammetry (DPV) was used when the Co 2+ concentration was 20 μ mol l −1 . Under the optimized conditions of −0.2 ∼ −0.4 V (vs SCE), −0.2 V enrichment potential, and 120 s enrichment time, the concentration of DES showed a good linear relationship with the peak current over the range of 0.3 to 90 μ mol l −1 , and the detection limit(S/N = 3) was 0.01 μ mol l −1 . The actual water sample was detected, and the recovery was between 89.17% and 101.23%. This method had the characteristics of simple operation, low analysis cost and fast analysis speed, and had the potential application value of detecting DES in environmental water. It is proposed to use Co 2+ as a sensitizer to significantly improve the sensitivity of c-MWCNTs/Nafion/GCE for the determination of DES. Based on the stable complex formed by Co 2+ and diethylstilbestrol (DES), it can increase the adsorption amount of diethylstilbestrol on the electrode surface.