No abstract

This study describes a fast and simple methodology for the preparation of Cerium (III) Hexacyanoferrate (II) (CeHCF) nanoparticles (NPs). The NPs were characterized by fourier transform infrared (FTIR), x‐ray diffraction (XRD), scanning electron microscopy (SEM) and cyclic voltammetry (CV). The CeHCF cyclic voltammogram indicate a well‐defined redox pair assigned as Fe2+/Fe3+ in the presence of cerium (III), with a formal potential of Eθ′=0.29 V (v=100 mV s−1, KNO3; 1.0 mol/L, pH 7.0). The carbon paste electrode modified with CeHCF (CeHCF‐CPE) was applied to the catalytic electrooxidation of dopamine applying Differential Pulse Voltammetry (DPV). DPV showed linear response at two concentration ranges, from 9.0×10−7 to 8.0×10−6 and 9.0×10−6 to 1.0×10−4 mol/L, with an LOD of 1.9×10−7 and 1.0×10−5 mol/L, respectively. The CeHCF‐CPE exhibited selectivity against substances commonly found in biological samples, with redox potentials close to that of dopamine, such as urea and ascorbic acid (AA). Subsequently the CeHCF‐CPE was successfully applied to the detection of dopamine in simulated urine samples, with recovery percentages ranging between 99 and 103%.

The present study describes the simple and fast preparation of Cerium (III) hexacyanoferrate (II) (CeHCF) solid nanoparticles at three different water/formamide (%) ratios used as solvent (v/v) (100:0, 80:20, 0:100). CeHCF nanoparticles (Nps) were characterized by fourier transform infrared pectroscopy (FTIR), x‐ray diffraction (XRD), scanning electron microscopy (SEM), zeta potential and cyclic voltammetry (CV). Electrodes modified with CeHCF presented a well‐defined redox pair with formal potential (Eo′) of approximately 0.29 V (vs. Ag/AgCl(sat) attributed to the Fe2 +/Fe3+ redox pair in the presence of cerium (III)). The Nps in the three systems investigates, presents a random size distribution to different surface, where most were distributed between 20 and 160 nm. Considering the three investigated systems, only CeHCF‐1 (100:0) was sensitive to L‐dopamine, presenting a linear signal region as a function of L‐dopamine concentrations, with a limit of detection (LD) of 0.125 mmol L−1, limit of quantification (LQ) of 0.419 mmol L−1 and amperometric sensitivity (S) of 148.16 μA mmol L−1.

The herb Equisetum arvense is an herbaceous plant, commonly known as horsetail and as a medicinal plant. Its therapeutic resource is diffused intensely in the urban environment as an alternative or complementary form to allopathic medicines, therefore it is an important theme focused on medicine and popular health. In this context, the focus of the present work was to characterize the product of the tea from a manipulation form made by specialized pharmacy (M) and other natural product banking (B). The two horsetails were extracted in aqueous medium since this is the form in which the material is absorbed by the organisms. The M and B lyophilized products were preliminary characterized by infrared spectroscopy (FTIR), visible ultraviolet (Uv-vis), scanning electron microscopy (SEM) and X-ray dispersive energy (EDX). The resulting biomass adsorption (wastes) were applied in the cupric ions adsorption and the maximum adsorption capacity (Nfmax of M and B horsetail were 4.4x10-4 mol g-1 and 2.6x10-4 mol g-1 respectively.