Accessibility / Report Error
Química Nova, Volume: 46, Issue: 10, Published: 2023
  • PANORAMA ATUAL E PERSPECTIVAS PARA 2024 Editorial

    Machado, Giovanna; David, Jorge M.; Morgon, Nelson H.
  • PHYSICO-CHEMICAL CHARACTERIZATION OF HONEYS AND POLLENS OF STINGLESS BEES OF THE SPECIES Melipona flavolineata AND Melipona fasciculata. Artigo

    Oliveira, Emily Vitória dos Santos; Vasconcelos, Giovana Kathelly Costa; Silva, Josyane Brasil da; Silva, Elen Vanessa Costa da

    Abstract in Portuguese:

    This study aimed to analyze the physicochemical characteristics of honey and pollen of two different species of stingless bees Melipona flavolineata and Melipona fasciculata from different regions in the State of Pará, the two totally different localities, Mosqueiro Island and Castanhal municipality, different climate and vegetation directly influence the quality and characteristics of these raw materials. The honey and pollen samples were collected and stored in hermetically sealed pots, the honey was kept at room temperature and the pollen at a freezing temperature of -12 °C to -15 °C, the analyzes were carried out in the laboratory of the Universidade do Estado do Pará - Campus Castanhal. For physicochemical characterization of honey, moisture, acidity, pH, ash, insoluble solids, HMF reducing sugar, total and apparent sucrose, HMF and color were performed. For the physicochemical characterization of the pollen, moisture, ash, protein, acidity, reducing and total sugars were analyzed. Regarding the honey collected in the meliponario of the municipality of Castanhal, they obtained different results from the honey collected in Mosqueiro, even being of the same species. In the pollen collected from the stingless bees of the meliponario located on the island of Mosqueiro, there were high levels of lipids, the results of proteins obtained from the pollen of Castanhal were high, unlike the pollen of the island of Mosqueiro.
  • MULTIVARIATE ANALYSIS AND MULTIPLE FACTORIAL MODELING IN THE CLASSIFICATION OF PERUVIAN HONEYS FROM BAJO MAYO, SAN MARTIN, PERU. Artigo

    Grosso, Guillermo Salamanca; Tangarife, Mónica Patricia Osorio; Franco, Anderson Guarnizo

    Abstract in Spanish:

    Honey is a natural product made mainly from the nectar of flowers; its final quality depends on its botanical and geographical origin. The variability is wide even for honey from the same region. The botanical and geographical origin of honey is still difficult to determine, so it is increasingly necessary to standardize analysis protocols that contribute to the verification of the quality of this important product of the beehive. The physicochemical and sensory properties of fifteen samples of honey from the Mayo River basin, Department of San Martin (Peru) have been evaluated, taking as reference the physicochemical parameters of color, the chromaticity of the CIELab system, pH, free acidity, total sugars, humidity, ash, electrical conductivity, density, and water activity. Additionally, the sensory attributes and intrinsic properties of the honey samples have been related to their classification through a Neuronal Probabilistic Network system, cluster analysis, discriminant, multiple factorial, and PLS-PATH, which have allowed the differentiation and classification of the honey, according to their geographical origin under three categories associated to the Pfund scale in amber, light amber, and extra light amber.
  • PYROLIGNEOUS ACIDS OF COCONUT SHELL, BLACK WATTLE AND EUCALYPTUS: PHYSICAL-CHEMICAL CHARACTERIZATION AND IN VITRO EVALUATION AS POTENTIAL UREASE INHIBITORS Artigo

    Cândido, Núbia Rangel; Modolo, Luzia Valentina; Pasa, Vânya Márcia Duarte; Fátima, Ângelo de

    Abstract in Portuguese:

    The increase in food production to meet the demand of the world’s growing population is largely conditioned by the efficiency of agricultural fertilizers. The development of relatively low-cost urease inhibitors and more environmentally friendly ones is a challenge for agriculture, especially because urea is the most used nitrogen fertilizer globally. The pyroligneous acid (PA), a by-product of wood charcoal production, stimulates plant growth, increases crop productivity, improves microbial metabolism, and induces plant tolerance to (a)biotic stresses. This work investigated the in vitro urease inhibitory potential of tree PAs of distinct plant biomass origin and production process. Coconut (Cocus nucifera) shell PA showed the highest urease inhibitory activity, followed by black wattle (Acacia mearnsii) PA and eucalyptus (Eucalyptus urograndis, a hybrid of Eucalyptus grandis and Eucalyptus urophylla). The same sequence was observed for the content of phenols and humic substances (humic acids + fulvic acids). This fact probably justifies the greater inhibitory activity, since both humic substances and some phenols normally present in PA, such as hydroquinone, have already been reported in the literature as urease inhibitors. The results are promising in terms of urease inhibition by PA samples, especially due to its low cost, biodegradability, non-toxicity, high solubility in water, and beneficial effects on plant development.
  • APPLICATION OF PAPER SPRAY IONIZATION MASS SPECTROMETRY AND RELATED TECHNIQUES IN THE DIRECT ANALYSIS OF BIOLOGICAL MATRICES FOR DETECTION OF DRUGS - A REVIEW Revisão

    Allochio Filho, João Francisco; Pires, Bruna Carneiro; Santos, Nayara A.; Dionisio, Sara Joaquina Inocencio; Conceição, Nathália dos S.; Feu, Amanda Eiriz; Borges, Warley de Souza; Lacerda Jr., Valdemar; Romão, Wanderson

    Abstract in Portuguese:

    In recent years, technological development in analytical instrumentation has progressed vigorously, which has allowed the evolution of analytical techniques that play an indispensable role within society, highlighting mass spectrometry. Parallel to the technological advance of this technique, the development of new ionization methods that are simpler, faster, and allow direct analysis without the need for prior treatment or sample processing is underway. The methods of ambient ionization derived from paper spray have been developing rapidly in current days, mainly in the forensic field, due to the chemical modifications made in the paper substrate and the introduction of new types of organic materials that function as a probe/substrate to collect, store, and ionize the sample, then enabling more efficient and selective analyzes. This review highlights direct analyzes by applying paper spray ionization in the forensic field and some variations of this technique, including Thread Spray Ionization (TSI) when a fabric thread is used; Touch Spray Ionization (TSI), which uses materials such as metallic needles, medical swabs, and wooden sticks; Fiber Spray Ionization (FSI), which applies polymeric fibers as substrates.
  • LIPID-CORE NANOCAPSULES: PREPARATION, CHARACTERIZATION AND BIOLOGICAL APPLICATIONS Artigo

    Dallemole, Danieli R.; Ciocheta, Taiane M.; Frank, Luiza A.; Alves, Aline de C. S.; Zoche, Bárbara P.; Guterres, Silvia S.; Paese, Karina; Pohlmann, Adriana R.

    Abstract in Portuguese:

    Lipid-core nanocapsules (LNCs) are core-shell structures, in which the core is an organogel formed by a solid lipid dispersed in a triglyceride, and the shell is a polymer. Those nanocapsules encapsulate poorly-water soluble drugs by dispersion in the core and/or interaction with the polymer. The core and the shell act as diffusional barriers differenting the LNC from previously developed polymeric nanocapsules containing an oily core and a polymer shell, which unique diffusional barrier is the shell. In this review, we discuss the supramolecular structure, the physico-chemical characterization, including sizing, surface potential, fluorescent labeling strategies, as well as the interfacial reactions in water to coat and functionalise the LNC surface. Different organometallic complexes have been synthesized to decorate the nanocapsules envisaging the treatment of atherosclerosis, cancer, mucopolysaccharidosis I, and hypertension. We also describe the main applications of the nanoformulations in the pharmaceutical, medical, and veterinary fields, including in vitro and in vivo evaluations of toxicity and efficacy.
  • SOLVATOCHROMISM AND THE EMPIRICAL SCALES OF SOLVENT POLARITY: A REVIEW Artigo

    Paczkowski, Ingrid Maliszewski; Campo, Leandra Franciscato

    Abstract in Portuguese:

    The term solvatochromism is used to describe the changes in the optical properties of a dye molecule by influence of the solvent characteristics. Solvatochromic shifts are governed by intermolecular interactions between solute-solvent that can be either electrostatic (non-specific interactions) or chemical (specific interactions). Due to the complexity of these interactions and absence of theoretical models that can explain the specific effects of solvent, different authors have introduced empirical parameters to building more reliable solvent polarity scales. Out of various polarity scales that have arisen from this need, those based on the effect of solvent polarity on the electronic excitation energy of indicator organic dyes are the most prevalent in literature. The use of empirical equations that correlate bathochromic (positive solvatochromism) and hypsochromic (negative solvatochromism) shifts of optical spectra of organic molecules with the polarity of solvent has become essential for understanding solute-solvent interactions. This review article presents main mathematical equations that use linear correlations between macroscopic and/or microscopic polarity functions of solvent with spectroscopic parameters of solute (dye) in construction of solvent polarity scales. In addition, main mathematical models that use solvatochromic shifts to estimate the dipole moment of ground and excited state are discussed.
  • THEMATIC UNITS: POSSIBILITIES FOR THE DEVELOPMENT OF THE PRINCIPLES OF CRITICAL ENVIRONMENTAL EDUCATION Educação

    Ponzoni, Aline Sobierai; Slaviero, André; Passos, Camila Greff; Sirtori, Carla

    Abstract in Portuguese:

    This work qualitatively analyzes the productions resulting from an extension course, developed with 24 teachers in initial and continuing training. This course was constituted by the (re)construction of knowledge related to Environmental Education (EE), in its critical aspect, to promote the debate on socio-environmental problems, allied to the theme of perfluorinated compounds, as a way of inserting these discussions in basic education, through the construction of teaching materials in the format of Thematic Units (TU). Thus, the objective of this study is to analyze the four TU produced by the course participants, in order to classify such productions supported by indicators and parameters of critical environmental education. Thus, it was possible to observe that most productions significantly contemplated these indicators, demonstrating that the activities and discussions developed enabled teachers to build a critical view of socio-environmental issues and perceptions of the possibility of developing them in the school environment.
  • ELABORATION OF A PLAYFUL METHOD FOR CHEMISTRY TEACHING: A GAME BASED ON DYE-SENSITIZED SOLAR CELLS Educação

    Magalhães, Letícia F.; Alves, Rafael B.; Cunha, Letícia R. C.; Rocha, Leonardo A.; Schiavon, Marco A.

    Abstract in Portuguese:

    Considering the current environmental problems associated with the growing world demand for energy arising from development and population growth, the need to diversify energy matrices, such as the implementation of solar energy, is highlighted. Thus, it is important to discuss this topic in the school environment, because when they are introduced from childhood to high school, the probability of this orientation being effective is much greater. In this context, educational games have attracted attention as a teaching tool, combining a fun atmosphere with the improvement of learning. This work aimed the production and application of a game in board format representing a dye-sensitized solar cell (CSSC) as a didactic resource in approaching the content of energy conversion. The game allowed an easy visualization of how the energy conversion process is performed by a CSSC. It was presented during the scientific dissemination event “Café com Ciência”, promoted by the Federal University of São João del-Rei, with good results both in gameplay aspects and in helping to understand the theme. The feedback obtained indicates that the game can be a useful tool for students and educators, reaching all its didactic potential and facilitating learning in the face of complex concepts.
  • APPLICATION OF NAMED REACTIONS IN POLYMER CHEMISTRY TEACHING Educação

    Lu, Dawei; Zou, Xudong; Li, Chaofan; Wang, Zhifeng; Xu, Bojun

    Abstract in English:

    Being an essential component of organic chemistry, named reactions are indispensable in organic synthesis. More and more named reactions have been devised to create unique polymer backbones, which has significantly accelerated the creation of new polymer materials. Yet, the university chemical knowledge system is deficient in relevant introductions. The purpose of this study is to incorporate the specified reactions within the teaching of polymer chemistry. These reactions are divided into six categories: transition metal-catalyzed coupling reactions, condensation reactions, pericyclic reactions, multi-component reactions, free radical reactions, and other reactions. This work methodically covers these six types of reactions, which are critical for polymer backbone synthesis, and presents the practice in teaching. It can assist students to learn polymer chemistry in conjunction with organic chemistry and provide some reference for students and teachers.
  • WILL THERE BE SPACE FOR THE HUMAN IN THE AGE OF IN SILICO CHEMISTRY? Assuntos Gerais

    Candido, Jorge G. de; Loguercio, Rochele de Q.

    Abstract in Portuguese:

    The mobilization of this article/essay is to problematize the impact that new technologies (Artificial Intelligence and Automation) have on the subjects of science, especially in the field of chemistry. In a theoretical analysis, we discuss the potential that smart technologies emerge in our daily lives, in our studies, in our professional activities and in the construction of scientific knowledge itself. In a first analysis, there are three inflections that need to be considered when such technologies fold subjects, spaces, society and that is most innate to human beings: thinking and the construction of knowledge. Thus, the movements that chemistry and its subjects have - and will have - in this emerging (4th) Industrial Revolution are problematized.
Sociedade Brasileira de Química Secretaria Executiva, Av. Prof. Lineu Prestes, 748 - bloco 3 - Superior, 05508-000 São Paulo SP - Brazil, C.P. 26.037 - 05599-970, Tel.: +55 11 3032.2299, Fax: +55 11 3814.3602 - São Paulo - SP - Brazil
E-mail: quimicanova@sbq.org.br