Voltammetric determination of 17β-estradiol in human urine and buttermilk samples using a simple copper(II) oxide-modified carbon paste electrode

This paper reports the voltammetric determination of 17 beta-estradiol in urine and buttermilk samples using a simple detector based on a carbon paste electrode (CPE) modified with copper(II) oxide (CuO). The CuO was obtained by the Pechini method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive (EDS), Fourier transform infrared (FTIR), and Raman spectroscopies. Cyclic voltammetry (CV) and square-wave voltammetry (SWV) demonstrated that the CuO-modified carbon paste electrode (CuO/CPE detector) displayed much higher electrocatalytic activity in the 17 beta-estradiol oxidation reaction than the CPE without modification, exhibiting a low detection limit of 21.0 nmol L-1 with a wide linear range from 60.0 to 800.0 nmol L-1 (R = 0.998). Satisfactory results were obtained for the determination of 17 beta-estradiol in human urine and buttermilk samples. The proposed electrochemical detector offers high repeatability, stability, fast response, low cost, and potential for practical application in the quantification of this hormone.