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Electrochemical sensors to quantify concentrations of emerging pollutants have attracted great attention from the industry and scientific community. Nanomaterials such as carbon black have been applied in sensors to identify substances that are toxic to the environment and human health due to their excellent electroanalytical properties. The aim of the study was to develop a novel electrochemical sensor for the endocrine disruptor hormone determination. To our knowledge, for the first time the synthesis of material based on carbon black containing immobilized palladium nanoparticles, with the application for the hormone ethinylestradiol, is reported in the literature. The material was synthesized, characterized, and applied to the determination in tap water and human urine of the synthetic hormone 17α‐ethinylestradiol (EE2), which is currently considered an emerging pollutant. The morphology, structure and electrochemical performance of the sensors were characterized by scanning electron microscopy (SEM) and cyclic voltammetry (CV). Differential pulse voltammetry (DPV) in sodium phosphate buffer solution at pH 5.0 allowed the generation of a method to quantify the concentration of 17α‐ethinylestradiol in a linear range of 0.5–119.0 μmol L−1, obtaining 81.0 nmol L−1 of calculated limit of detection (LOD). The system was efficient in detecting 17α‐ethinylestradiol in real urine samples and showed no interferences for ascorbic acid, uric acid, progesterone, and dopamine. It is noteworthy that the results obtained showed good recovery values, considering that the urine samples were not previously treated or pre‐concentrated, which suggests the development of an electrochemical sensor that works in situ and in real time to monitor relevant substances in the control clinical and environmental, with the possibility of point‐of‐care analyses. [ABSTRACT FROM AUTHOR]

The nanocomposite material bismuth vanadate and reduced graphene oxide BiVO4/rGO was prepared and deposited onto a fluorine‐doped tin oxide glass surface for application of a photoelectrochemical sensor for the determination of sodium diclofenac in urine samples. This drug is considered as an emergent pollutant because of its ecotoxicological risk when discarded in wastewater. Electrochemistry Impedance Spectroscopy experiments shown that the rGO contributed to the efficiency of the DCF electro‐oxidization and, under irradiation, the resistance in the charge transfer in the work electrode decreased. The sensor presented photocurrent responses during the diclofenac electro‐oxidation under visible light irradiation, with a linear concentration range from 9.6×10−9 mol L−1 to 9.2×10−6 mol L−1 and a LOD of 4.2×10−9 mol L−1. The presence of the drug in urine was successfully determined by recovery in spiked samples. [ABSTRACT FROM AUTHOR]

A novel material for the electrochemical determination of endocrine disruptors using a composite based on graphene oxide modified with cadmium telluride quantum dots has been evaluated. The morphology, structure and electrochemical performance of the composite electrodes were characterised by transmission electron microscopy, dynamic light scattering, UV-visible absorption spectra, fluorescence spectra, Raman spectra and cyclic voltammetry. The dynamic light scattering, transmission electronic microscopy and spectrophotometric measurements all showed good distribution of the quantum dots with a small particle size. The electrochemical measurements demonstrated the high performance of the composite response in the presence of a light source. Differential pulse voltammetry allowed the development of a method to determine 17β-estradiol levels in the range from 0.2 to 4.0 μmol L−1 with a detection limit of 2.8 nmol L−1 (0.76 μg L−1). [ABSTRACT FROM AUTHOR]