Novo Sensor de Pasta de Carbono Modificado com CuO para Detecção de 17β-estradiol em Amostras de Urina e Manteiga

This work reports the voltammetric determination of 17 β-estradiol using a new sensor on carbon paste modified with CuO(CuO/CPE). 17 β-estradiolis a endocrine disruptor, that has attracted high attention due to causing incidence of cancer and tumors[1]. CuO is a promising material due to its high electrochemical activity, low cost, non-toxic and easy preparationon a nanometric or microsco picscale [2]. The CuO was synthesized by Pechini method andwas characterized by X-ray diffraction, scanning electron microscopy, energy-dispersive spectrum, Fourier Transform Infraredand Raman Spectroscopy. The analysis confirmed the formation of single phase CuO with characteristic vibrational mode of Cu–O and the SEM analysis showed that CuO were synthetized in form of microparticles. Modified carbon paste was prepared by hand mixing of graphite powder, Nujol oil and CuO. The mixture was grinded thoroughly in an agate mortar and pestle for 20 minutes till homogeneous paste was obtained. The electrochemical behavior of17 β-estradiolonCuO/CPE in 0.1 mol L‒1B-R buffer (pH 8.0) was studied by cyclic voltammetry (CV). A single oxidation peak at +0.45 V was observed, characterizing an irreversible process. The CVvoltammogramsdemonstrated that the carbon paste electrode modified with CuO displayed much higher electrocatalytic activityin the 17 β-estradioloxidation reaction than the carbon paste electrode without modification.The calibration curve was obtained by square wave voltammetry. Under the optimized experimental conditions the linear range was obtained to be 0.06 to0.80μmol L‒1(R2= 0.998) with detection limit of 0.021 μmol L‒1. Satisfactory results were obtained for 17 β-estradiol analyses inhuman urine and butter milk samples with excellent recovery values within 95–106%. Several kinds of interfering chemicals were investigated to evaluate the selectivity of the CuO/CPE sensor. The proposed electrochemical sensor was offeredh igh reproducibility, stability, selectivity, fast response, low cost and the potential possibility for practical application for the quantification of 17 β-estradiol.