Sensitive Voltammetric Determination of Ticlopidine in Pharmaceuticals Employing a Multi-Walled Carbon Nanotubes Paste Electrode

A sensitive analytical procedure has been developed for the determination of ticlopidine using a multi-walled carbon nanotubes paste electrode (MWCNTsPE). Direct oxidation of analyte was observed by cyclic voltammetry as evidenced by the presence of well-shaped irreversible peak at 1.05 V vs Ag/AgCl (3.0 mol L–1 KCl) in Britton-Robinson buffer solution (pH 5.0). The use of this electrode has been found to influence the electrochemical determination by presenting a higher intensity of oxidation current for ticlopidine and also a lower detection limit. Using differential pulse voltammetric modality, the obtained analytical curve was linear for ticlopidine concentration ranging from 0.75 to 20 µmol L–1, with detection limit of 0.10 µmol L–1. The proposed method was successfully used to determination of ticlopidine in pharmaceuticals, with satisfying results. In order to indicate that the method is of potential application in biological fluids adequate recovery results were obtained for the determination of ticlopidine in synthetic urine sample. DOI: http://dx.doi.org/10.17807/orbital.v8i3.83

HOW TO MAKE THE VIRTUAL ENVIRONMENT INTERESTING DURING THE COVID-19 PANDEMIC? / COMO TORNAR O AMBIENTE VIRTUAL INTERESSANTE DURANTE A PANDEMIA DE COVID-19?

Unexpectedly, social distancing became a rule, forcing schools and universities to introduce an emergency remote education. The information and communication technologies (ICTs) are being used in many cases only as a way of transmitting content, reducing its potential to promote interaction between users, contextualization to daily life, and failing to make the student a protagonist in their learning process. In this sense, knowing and handling the available tools is essential in the current moment of education. Thus, in order to perform a brief review and at the same time point out ways to research or use technological resources in teaching, this article reports, albeit modestly, some of the tools that can be used for teaching Chemistry at different levels and educational modalities of this science. For this task, several easily accessible resources were selected to bring ways of instigating and making remote classes more interesting in Chemistry learning

Biomimetic polymers in analytical chemistry. Part 2: applications of MIP (Molecularly Imprinted Polymers) in the development of chemical sensors

The aim of this paper is the description of the strategies and advances in the use of MIP in the development of chemical sensors. MIP has been considered an emerging technology, which allows the synthesis of materials that can mimic some highly specific natural receptors such as antibodies and enzymes. In recent years a great number of publications have demonstrated a growth in their use as sensing phases in the construction of sensors . Thus, the MIP technology became very attractive as a promising analytical tool for the development of sensors.10871101Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Removal of Cd(II), Pb(II) and Cr(III) from water using modifed residues of Anacardium occidentale L

The pollution of water has been one of the greatest problems faced by the modern society, due to industrialization and urban growth. Rivers, lakes and seas have been continually suffering from the rising concentration of various pollutants, especially toxic elements. This study aimed to evaluate the use of cashew nut shell (Anacardium occidentale) (CNS), after chemical modification with H2O2, H2SO4 and NaOH, as an new and renewable adsorbent material, for the removal of metals Cd2+, Pb2+ and Cr3+ in aqueous medium. The adsorbents were characterized by its chemical constitution, structure, infrared spectroscopy, morphology, by means of scanning electron microscopy, determination of the point of zero charge, thermogravimetrical analysis and porosimetry assessments. Tests were conducted to determine the optimal conditions (pH vs. adsorbent mass) for adsorption, by means of multivariate analysis using a central composite design. The adsorption kinetics was evaluated by models of pseudo-first order, pseudo-second order, Elovich and intraparticle diffusion, while adsorption isotherms were linearized by Langmuir, Freundlich and Dubinin–Radushkevich. The effect of initial concentration, temperature and desorption was also performed. The adsorbents exhibited irregular, spongy and heterogeneous structure. FTIR analysis confirms the presence of hydroxyl, aliphatic, phenolic and carboxylic acid groups, which are favorable adsorption characteristics. The pHPZC of adsorbent is 4.35, 2.50 e 6.92, respectively, for CNS H2O2, H2SO4 and NaOH. The optimum adsorption conditions were as follows: pH 5.0; relation of adsorbent mass/volume of water: 4 g L−1; 40 min of contact time for reaching the equilibration. Results suggest the predominance of chemisorption of Cd2+ and Cr3+. Most of biosorbents exhibited good fit by Langmuir and Freundlich, suggesting the occurrence of adsorption on mono- and multilayers. The adsorbents of cashew nut shell exhibited high removal efficiency of Cd, Pb and Cr from watersTo Capes and CNPq for the funding of this researchS

Use of Co-Products from the Processing of Cassava for the Development of Adsorbent Materials Aiming Metal Removal

Nowadays the contamination of water resources by the most varied pollutants have been accelerated. Technologies of decontamination of water are too costly, however, the development of low cost adsorbents, have proven to be efficient, promising and cheap alternatives for this purpose. The use of adsorbents from cassava residues has shown great potential for use as an adsorbent. The productive chain of this crop involves the production and processing of its roots, generating a large volume of solid waste. Aiming the sustainability of production systems, productive chains should optimize the production of cassava barks residues, since these do not present significant uses or benefit. In this scenario, this chapter gathers information from the literature on the use of solid waste from the cassava agroindustry and its use as adsorbents, aiming the removal of toxic metals, as well as their potential for the treatment of other contaminants. Several authors have demonstrated through studies the potentiality of the use of agroindustrial cassava residues as adsorbents. Because of a range of characteristics observed these adsorbents present viability for large-scale use, being in very similar to activated carbon. Thus, the use of these adsorbent materials represents an extremely viable and sustainable alternative

Caracterização físico-química e perfil da composição em ácidos graxos de salsichas do tipo comum

Caracterização físico-química e perfil da composição em ácidos graxos foram realizadas em salsichas do tipo comum, das principais marcas do Brasil. Análises de colesterol e ésteres metílicos de ácidos graxos foram determinados por cromatografia gasosa com coluna capilar. Salsichas do tipo comum apresentaram teor de lipídios entre 11,02% para a amostra B e 21,94% para a amostra A. O teor de colesterol foi de 37,61 para C, 47,95 para B, 49,91 para A e 68,00 para D, em mg/100g. A maioria dos ácidos graxos detectados foram os monoinsaturados, sendo o ácido oléico o de maior percentual com valores entre 39,27% para B a 49,15% para A. Em seguida foram detectados os ácidos graxos saturados com o ácido palmítico em maior quantidade com teores entre 21,10% e 26,24% para B e D, respectivamente. As salsichas das amostras B e A apresentaram os maiores teores de ácidos graxos polinsaturados e menores quantidades de ácidos graxos saturados

Polímeros impressos com íons: fundamentos, estratégias de preparo e aplicações em química analítica

Chemical imprinting technology has been widely used as a valuable tool in selective recognition of a given target analyte (molecule or metal ion), yielding a notable advance in the development of new analytical protocols. Since their discovery, molecularly imprinted polymers (MIPs) have been extensively studied with excellent reviews published. However, studies involving ion imprinted polymers (IIPs), in which metal ions are recognized in the presence of closely related inorganic ions, remain scarce. Thus, this review involved a survey of different synthetic approaches for preparing ion imprinted adsorbents and their application for the development of solid phase extraction methods, metal ion sensors (electrodes and optodes) and selective membranes

Determination of Cu2+ and Zn2+ in Flaxseed Flour by FAAS and DPASV using Different Sample Treatments

The performance of three conventional treatments, including microwave-assisted acid digestion (MWAD), ultrasoundassisted extraction (UAE) and dry method (DAM) for determination of Cu2+ and Zn2+ in flaxseed meal, was evaluated. Quantification was performed by flame atomic absorption spectrometry (FAAS) and differential pulse anode stripping voltammetry (DPASV). TheMWAD treatment was performed with both concentrated HNO3 (CA) and diluted acid (DA). The concentration of Cu2+ was determined by FAAS and DPASV, by different treatments, ranging from 14.4-26.0 μg g−1 and 8.5-17.9 μg g−1, respectively. The concentration of Zn2+ was possible only by FAAS (28.7-77.4 μg g−1). The highest concentrations were obtained using MWAD. The DAM showed values similar to MWAD for Cu2+, however, for Zn2+ it showed the lowest concentrations. UAE, in turn, showed low concentrations of Zn2+ in relation to MWAD, but similar results to MWAD-DA for Cu2+ in a sample with low fat content. Therefore, both the choice of treatment and the quantification technique play a crucial role in metal determination