Programa de Pós-graduação em Química

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Abordagem dos princípios da Química Verde por meio do lúdico na formação ambiental de profissionais da química
(Universidade Federal de Goiás, 2018-05-28) Costa, Mariângela Célia Souza; Mesquita, Nyuara Araújo da Silva; http://lattes.cnpq.br/6971106875143413; Echeverría, Agustina Rosa; Brito, Núbia Natália de
The environmental questions have been put forward for discussion in the formation of Chemistry professionals since the 20th Century’s end and the 21st Century’s beginning. In this context, the Green Chemistry (GC), even though is a recent perspective for the chemists’ professional formation, needs to be inserted in the formative discussions extent of students and industrial chemists. Even though it comes as an evaluation aspect in the chemists formation, being even a requested content in the Student Performance Nation Exam (SPNE), there are still gaps regarding the theme’s insertion throughout the graduation. Considering such aspect, this research aimed at making a documentary survey from the Chemistry Course Pedagogical Projects (CPP) in the state of Goias to identify the Green Chemistry theme’s presence in the referred pedagogical proposals. Beyond that, it was proposed the theme insertion in the Chemistry students’ formation by a playful activity carried out in a Chemistry Jury format about the GC and its 12 principles. The methodology adopted in this second moment, of Chemistry Jury development, was the research- action which involves various phases such as problem investigation, action planning, development and process evaluation. From the data collected three analysis categories emerged. The first has a relation with the appropriation of the concepts involved in the 12 principles by the students, the second refers to the characters’ representation process by the students, and the third category relates to the GC in the critical environmental education perspective and the students’ simplistic view. In the face of the analysis made in this research it is inferred that the insertion of the GC theme is necessary, and its principles from the critical environmental education in the Chemistry students’ formation as well as the Chemistry Jury appears as teaching strategies that make the theme discussion possible with everyone’s participation in a classroom giving voice to the students and putting them as protagonists in the teaching and learning process.
Abordagens para análise de n-nitrosaminas em medicamentos utilizando DPX-LC-MS e DART-MS
(Universidade Federal de Goiás, 2023-12-19) Batista Junior, Almir Custodio; Chaves, Andréa Rodrigues; http://lattes.cnpq.br/6064014965252121; Chaves, Andréa Rodrigues; Coltro, Wendell Karlos Tomazelli; Freitas, Carla Santos de
N-Nitrosamines (NAs) are molecules characterized by a deprotonated amine group linked to a nitroso group, usually formed through the reaction of secondary or tertiary amines with nitrosating agents. NAs are commonly found as impurities in various products, such as processed foods and cosmetics. These molecules are the subject of study due to their potential mutagenic and carcinogenic properties. In 2018, NAs were discovered in medicines containing the active ingredient valsartan. In sartan medicines, the occurrence of NAs was initially linked to the synthesis of the active pharmaceutical ingredient (API), as the reaction medium may contain precursor amines for NAs, as well as a nitrosating agent. Through more in-depth studies, it has been confirmed that the degradation of the API or its interaction with the packaging material could lead to the formation of NAs. These discoveries prompted global regulatory agencies to establish guiding principles regarding the presence and maximum allowable concentrations of these molecules in such medicines. Aiming to assess the content of NAs in medicines, efficient and sensitive analytical methods have been developed. The challenge in analyzing NAs in medicines lies in the low concentration of these analytes, as they are found in this matrix in the order of ng of N-nitrosamine per mg of the medicines. The literature presents various chromatographic methods coupled with mass spectrometry (MS) applied in such analyses. Both liquid chromatography (LC) and gas chromatography (GC) techniques provide sensitive and selective methods for the analysis of NAs in medicines. However, LC methods have advantages over GC as it allows the analysis of thermally unstable and non-volatile compounds. Due to the presence of the API in the sample and the low concentration of these impurities, the determination of NAs can be compromised by various factors, such as matrix effects, carryover effects, and the compromise and contamination of the LC-MS system. Thus, the sample preparation step proves to be important, aiming at the extraction, purification, and pre-concentration of NAs. Additionally, advances in mass spectrometry have led to the development of ambient ionization techniques designed to analyze samples that are either unprocessed or minimally modified in their native environment. These techniques enable the analysis of samples in situ, often in a non-destructive manner. Another important factor currently is the adaptation of analysis protocols with sustainable principles advocated by green chemistry, which aim to reduce the use of solvents and samples, minimize risks, decrease energy consumption, and reduce waste generation. Therefore, the present study introduces new approaches to the analysis of NAs in medicines that have not yet been explored in the literature. Chapter I demonstrates the use of a miniaturized sample preparation technique for the separation and pre-concentration of NAs in medicines followed by LC-MS analysis. Conversely, Chapter II presents the application of an ambient ionization technique coupled with mass spectrometry for the assessment and quantification of NAs in medicines.
O acidente radiológico de Goiânia e seus desdobramentos nos currículos da licenciatura em Química em Goiás: uma leitura freireana
(Universidade Federal de Goiás, 2021-11-02) Nunes, Luclécia Dias; Mesquita, Nyuara Araújo da Silva; http://lattes.cnpq.br/6971106875143413; Mesquita, Nyuara Araújo da Silva; Soares, Marlon Herbert Flora Barbosa; Silva Filho, Juvenal Carolino da; Genovese, Cinthia Letícia de Carvalho Roversi
In Goiânia, in 1987, a radiological accident occurred with a Cesium 137 source, which could have been avoided if those involved had basic knowledge about some symbols related to the scientific context and to Radioactivity, which highlights the role of the school and teachers with regard to scientific literacy. Thus, this research sought to understand the relationship between the theme Radioactivity and scientific literacy, in the formation of Chemistry teachers, in the state of Goiás and the possible implications for their teaching performance. For this, a reading of the radiological was made from the Freireana perspective, seeking to understand the social relations that emerged in the context of the actions imbricated in the history of the accident. We also analyzed the PPC for degrees in Chemistry offered by the IES in the state and questionnaires sent to basic education teachers, in order to identify whether the courses include the theme Radioactivity and the accident in focus, so that we can understand, in terms of teacher training and action, the obliterating reflexes of the (non)approach to the Radioactivity theme in initial training for a pedagogical practice that considers scientific literacy as a (trans)forming element. In the analytical process, two a priori categories were used: the formation of Chemistry teachers in the state of Goiás and scientific literacy; and the approach of Radioactivity in the training of Chemistry teachers and na emerging category: the influences of initial training in relation to the theme Radioactivity in the teaching performace of Chemistry teachers in basic education. As a theoretical interlocutor for this tese and for data analysis, we used the theoretical framework from Paulo Freire. By analyzing the first category, we see that in the PPC there is evidence that the IES are conducting the training of undergraduates in Chemistry through the bias of scientific literacy, as all documents bring elements that indicate a pedagogical proposal that seeks to train teachers through a critical and reflective considering elements that characterize the formation for citizenship. In the processo of analyzing the second category, it was observed that of the 16 IES that offer the degree course in Chemistry, nine PPC have disciplines that somehow address the theme Radioactivity, three PPC have specific disciplines on the theme, but only one explicit in its menu that will address nuclear accidents. The analysis of the questionnaries showed that the teachers either did not study on the theme, or studied it superficially and the accident was little discussed, which reverberated in their teaching performance. Thus, what we infer from the analyzed documents was that, although there are indications that guide the reader initially to glimpse that the undersgraduate are being trained in the perspective of being prepared to, in their future teaching action, act as Chemistry teachers, who literate their students scientifically, the work as a whole shows that this training will most likely not be achieved in relation to the theme Radioactivity. Because, in general, teachers trained in Chemistry at the IES in the state of Goiás do not have opportunities to learn and discuss Radioactivity content and, specially the accident with Cesium 137, therefore, they are not prepared to scientifically literate education students basic in relation to theme Radioactivity.
Adsorção e fotodegradação de corantes, amarelo crepúsculo e azul brilhante, para tratamento de efluentes de indústrias alimentícias
(Universidade Federal de Goiás, 2013-04-26) Sá, Fernando Pereira de; Nunes, Liliane Magalhães; http://lattes.cnpq.br/6591210839894513; Nunes, Liliane Magalhães; Colmati Júnior, Flávio; Monteiro Júnior, Oyrton Azevedo de Castro; Seolatto, Araceli Aparecida; Borges, Elisangela Cardoso de Lima
Effluents that are discarded by food industry are important sources of water pollution, as they may contain high concentrations of organic matter and intense color. We used the technique of design of experiments to evaluate the influence of some variables in the study of adsorption of food colors, sunset yellow and brilliant blue. The “batch” method was used to assess the effects of variaable: contact time, pH0 and concentration of the adsorbate in the adsorption process of colors in hydroxide double layered system CaAl-LDH-NO3. The LDH was synthesized by coprecipitation at pH variable and characterized by X-ray diffraction, infrared spectroscopy, electron microscopy scanning thermogravimetric analysis, zeta potential, surface area and pore volume. adsorption assays were performed as a function of contact time, pH0, dye concentration and temperature. Results showed that the pH affects the surface charge of the adsorbent and the degree of dissociation of the anionic dyes. Among the initial pHs (4 and 10) for sunset yellow and (6 and 10) to brilliant blue, as the pH0 increases, decreases the amount of dye removed. Langmuir equation was that more adequately described the equilibrium data, obtaining a maximum adsorption of 398.41 mg/g for sunset yellow and 108.23 mg/g for brilliant blue. In the process of photodegradation by direct photolysis using ultraviolet radiation, the efficiency of decolourisation percentages reached 98 % for the yellow dye twilight and 97 % to bright blue. The absorbance spectra for two samples of colorants showed a decrease of characteristic absorption bands of these materials throughout the irradiation time. The photodegradation was also performed on solid after adsorption, the visually observable discoloration of the material and confirming the degradation process by XRD. Adsorption, and photodegradation were effective also in the treatment of synthetic effluent (mixture the dyes sunset yellow and brilliant blue), presenting virtually the same kinetics observed for removing discoloration of dyes individually.
Água em condição supercrítica: uma tecnologia versátil para o tratamento de efluentes industriais e produção de hidrogênio
(Universidade Federal de Goiás, 2021-03-26) Ribeiro, Thiago Soares Silva; Oliveira, Sérgio Botelho de; http://lattes.cnpq.br/3447406257464639; Alonso, Christian; http://lattes.cnpq.br/7285754665946583; Oliveira, Sérgio Botelho de; Aranda , Donato Alexandre Gomes; Cardozo Filho, Lúcio; Antoniosi Filho, Nelson Roberto; Oliveira, Guilherme Roberto de
Industrial processes bring with them an important concern: the correct management of waste generated, whether solid, liquid or gaseous. Among the various types of industrial wastewater, those generated in pharmaceutical industries that produce hormonal drugs or in biodiesel producing plants stand out for their polluting potential and high organic load, respectively. Therefore, it is essential to perform the appropriate treatment of these industrial wastewater, which does not occur in many of the conventional processes used in wastewater treatment stations (WTS). In this scenario that the objective of this work was to treat samples of hormonal (synthetic (EHS) and industrial (EHI)) wastewater, in addition to samples of wastewater from a biodiesel producing plant (EPB) using the process with supercritical water (SCWP), in a continuous flow reactor in the absence of catalysts, aiming at the degradation of contaminants and obtaining hydrogen gas, syngas and other fuel gases. The use of samples with such a different chemical composition is justified by the intention to evaluate the versatility of the wastewater treatment via SCWP for both environmental and energy purposes. The liquid phase was characterized by the determination of physical-chemical parameters such as total organic carbon (TOC), Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD), Oils and Greases (OG), pH, nitrogen compounds, metals, among others, in addition to high performance liquid chromatography (HPLC), for EHS samples, mass spectrometry (EM), and phytotoxicity tests with cucumber seeds (Cucumis sativus). The gas phase was characterized by gas chromatography (GC). Regarding the reduction of TOC, it was possible to reduce between 80% and 90% of TOC in the EHS samples for most of the feed flow rate conditions evaluated at 700 °C and for the EHI samples the maximum value of 89 was obtained, 6% reduction in TOC at the highest temperature evaluated. In EPB samples, the maximum TOC reduction value reached was 98.8%. The other physical-chemical parameters analyzed point to the same trend: the higher the temperature and the spatial time, the greater the efficiency of the process in relation to the reduction of physical-chemical parameters. The phytotoxicity tests against cucumber seeds, indicate a significant reduction in the toxic effect of the chemical compounds present in the initial samples, in treatments from 600 °C. The results of mass spectrometry point to the predominance of esters and fatty acids in both samples analyzed. The characterization of the gases showed that the production of hydrogen gas stands out among the other gases, and the amount produced in the treatment of EPB samples (885.9 NmL(H2)/mL (powered EPB)) indicates several possibilities of using this gas in industrial processes such as Ammonia Production, Production of new compounds via Fischer-Tropsch process, Fuel cells, Burning as fuel, Hydrotreated vegetable oil (HVO) manufacturing processes, Power-to-X technologies (PtX). In view of the results, it is possible to infer that the treatment of organic contaminants via SCWP is quite promising for both energy and environmental purposes.
Alcaloides de Psychotria capitata Ruiz & Pav. (Rubiaceae): determinação estrutural e atividade biológica
(Universidade Federal de Goiás, 2014-10-09) Wakui, Vinícius Galvão; Oliveira, Cecilia Maria Alves de; Kato, Lucilia; http://lattes.cnpq.br/1362891438631386; Kato, Lucilia; Oliveira, Cecilia Maria Alves de; Severino, Richele Priscila; Santos, Suzana da Costa
Regarding that Psychotria species are described as sources of alkaloids, mainly β-carboline type with potential biological activity, this work focused on the phytochemical study of Psychotria capitata Ruiz & Pav. (Rubiaceae) leaves with widely occurrence on Cerrado Biome. The study of this specie led to the isolation and structural elucidation of the alkaloids: bufotenine and bufotenine-N-oxide and coumarin iso-scopelletin. These alkaloids were found mostly in all studied fractions. Furthermore, two alkaloids were identified in misture: 6-hydroxide-2-methyl-1,2,3,4-tetrahydro-β- carboline and 7-carboxyl-2-methyl-dihydro-β-carbolinium. Last one is novel alkaloid which however still in structural elucidation. Additionally, considering the great bioactive potential of indol alkaloids, particularly those found in Psychotria species regarding to central nervous system biological activity, we have submitted fractions and isolated compounds of P. capitata to in vitro evaluation with monoamineoxidases MAO-A and MAO-B as bio targets. These biological essays was realized in collaboration with research group of FF/UFRGS that develops studies searching for enzymatic inhibitors involved in neurodegenerative disease such as Parkinson´s disease and Alzheimer. Thus, search of compounds that interact with cholinesterase (AChE and BCHE) and monoamineoxidases (MAO-A and MAO-B) enzymes are important to the comprehension of neurochemical bases of these diseases. The alkaloidal fractions of P. capitata (10 mg/mL) showed inhibition rates between 60 and 89 %, which demonstrate the potential of these fractions. Bufotenine showed selective inhibiton (89 μM) to MAO-A, while bufotenine-Noxide didn´t showed inhibition to none of the enzymes. Therefore, this work contributes to the study of the species of Rubiaceae family, confirming the great potential of this family as source of indol alkaloids with a β- carboline nucleous, which show biological activity of great interest.
Alcaloides indólicos das partes aéreas de psychotria sp.(rubiaceae) e síntese de tiohidantoínas e tioureias derivadas de aminoácidos e do r-(+)-limoneno
(Universidade Federal de Goiás, 2013-05-03) Moraes, Aline Pereira; Oliveira , Cecília Maria Alves de; http://lattes.cnpq.br/3152041311943092; Oliveira, Cecília Maria Alves de; Fátima, Angelo de; Queiroz Jùnior, Luiz Henrique Keng
The use of natural products and their synthetic derivatives has been a relevant strategy in the development of novel medicines. Phytochemical studies and synthesis of natural-product-based libraries are primordial in the search for therapeutic agents. Previous phytochemical studies of genus Psychotria (Rubiaceae) have resulted in the identification of polypyrrolidine indole and monoterpenoid indole alkaloids, which present a broad range of biological activities, such as antifungal and inhibition of monoamine oxidases (MAOs) A e B, that are related to neurodegenerative diseases. This study aims to evaluate the phytochemical composition of the aerial parts of Psychotria sp. collected in Brazilian Cerrado. Fractionation of the crude extract by column chromatography on silica gel and Sephadex led to isolation of three known indole alkaloids: bahienoside A, desoxycordifoline and desoxycordifolinic acid. Additionally, thiohydantoins and thioureas were synthesized from amino acids and R- (+)-limonene, in order to assess the cooperative effect of indole nucleus combined with terpene, thiourea and thiohydantoin units. Preliminary tests showed that desoxycordifoline, hydantoin (20) and thiohydantoin necrostatin-1 (14) inhibit the enzyme MAO-A higher than 80% at concentrations of 175 mM, 100 mM, 386 mM, respectively. Also, the polar extracts of the leaves of Psychotria sp. showed antioxidant activity with IC50 < 50 mg.mL-1 measured by DPPH free radical scavenging assay.
Amplificação isotérmica de DNA mediada por loop (LAMP) em microchip de poliéster-toner
(Universidade Federal de Goiás, 2016-10-07) Oliveira, Kezia Gomes de; Bailão, Alexandre Melo; http://lattes.cnpq.br/5415221996976886; Duarte, Gabriela Rodrigues Mendes; http://lattes.cnpq.br/9005971441891787; Duarte, Gabriela Rodrigues Mendes; Carrilho, Emanuel; Coltro, Wendell Karlos Tomazelli; Bailão, Alexandre Melo
The several advantages of miniaturization of DNA amplification and coupling with sample preparation and detection steps on the same chip are well known. Currently, most miniaturized systems for nucleic acids analysis are based on polymerase chain reaction (PCR). PCR amplification requires precise temperature control, switching between heating and cooling solution in three specific temperatures. Therefore, the adaptation of PCR for microchip is relatively complex and presents some limitations particularly for use in remote locations. Without the need for heating cycles, isothermal microsystems for DNA amplification can be designed to be simple and low energy consumption and hence can overlap the portable PCR detection systems. The loop-mediated isothermal amplification (LAMP) is a novel technique which has emerged as a simple and fast tool for DNA amplification which can be used for the detection and identification of several pathogens. The LAMP using Bst DNA polymerase enzyme which is an enzyme having strand displacement activity and uses a set of four primers designed from six individual segments of the sequence to be amplified. In this study, we developed a simple and rapid LAMP reaction for the E. coli malB gene amplification in the reaction was thermally controlled with a thermoblock for 60 minutes at 66 ° C. The PeT microdevices demonstrated compatibility with all reagents used in the LAMP and the success of the isothermal amplification was observed by agarose gel electrophoresis, yielding detectable amount amplicons as few as starting with 1 copy of DNA. Moreover, the success of the nucleic acid amplification reaction was evaluated by visual detection of the amplicons in the microchip by the use of fluorescent DNA intercalators, which yielded fluorescence in positive reactions. The LAMP in PeT microdevice is a simple and inexpensive method, that allowed a rapid detection (62 minutes) of E. coli. Because of simple operation and without the need for sophisticated instrumentation, LAMP held in microchip PeT has proven to be a valuable tool for molecular diagnostics, with great potential for applications in point-of-care.
Análise computacional da solvatação do diclofenaco e interações da melatonina com radical hidroxila: abordagens via dinâmica molecular e teoria do funcional da densidade
(Universidade Federal de Goiás, 2024-11-14) Rodrigues, Allane Catharina Carvalhaes; Oliveira, Heibbe Cristhian Benedito de; http://lattes.cnpq.br/5995553993631378; Oliveira, Heibbe Cristhian Benedito de; Perez, Caridad Noda; Borges, Leonardo Luiz; Gargano, Ricardo; Lima, Igo Torres
Computational chemistry represents an understanding of chemistry as the manifestation of the behavior of atoms and molecules. This active research field, spanning over a decade, employs mathematical techniques and algorithms to model and simulate chemical influences. The application of computational chemistry is crucial in material design, drug development, and the comprehension of biological processes. Analyzing solute-solvent interactions underscores the importance of physicochemical properties in chemical research, whereas the investigation of free radical elimination is essential for physiological balance. Within this context, the proposed study aims to comprehend the mechanisms of hydroxyl radical removal by melatonin and evaluate the aqueous solvation process of diclofenac through molecular modeling, employing Car-Parrinello and Born-Oppenheimer molecular dynamics, in addition to Density Functional Theory. Results from the dynamics of reactions between the •OH radical and melatonin provide a detailed understanding of various involved conditions, emphasizing the crucial influence of variables such as speed, temperature, and attack direction. The reaction with the hydrogen bonded to the nitrogen of the indole group (called H22) is the more favorable. Energy profiles and rate constants support H22 as the most likely path, providing comprehensive insights into the kinetic and thermodynamic characteristics of the interactions. Our findings regarding diclofenac solubility in water highlight the formation of important intermolecular hydrogen bonds between the atoms of diclofenac with water molecules (OH⋯Owater and CO⋯Hwater). The OH⋯Owater bond is exceptionally strong, similar a covalent bond. Additionally, we observe intramolecular hydrogen bonds in the diclofenac molecule (NH⋯OH e NH⋯Cl) and weaker interactions involving CH⋯Cl. Remarkably, diclofenac protonation contributes to molecular rigidity, hindering future hydrogen bonds with adjacent water molecules, directly impacting molecule solubility. Advancements in this field promise to enrich fundamental chemistry understanding and drive practical advancements in various areas, such as pharmacology, molecular biology, and industrial chemistry.
Análise de imagens para a determinação de parâmetros de cinética química
(Universidade Federal de Goiás, 2024-05-31) Oliveira, Isabella Moura e; Oliveira, Anselmo Elcana de; http://lattes.cnpq.br/0369339073291948; Oliveira, Anselmo Elcana de; Guimarães, Freddy Fernandes; Coelho, Clarimar José
A low-cost experimental apparatus was built from a video capture device (smartphone) and a lighting box. This system was used to determine the rate constant of fading of Phenolphthalein in NaOH (pH > 10) using video analysis. All computational development was carried out using free software. The analytical methodology developed is statistically equivalent to the determination made by the reference spectrophotometric method (λ = 550 nm). A case study using categorization was designed to evaluate the use of video analysis methodology as a teaching tool in a class on the Experimental Physical Chemistry course. The results obtained reinforce that the methodology developed showed good agreement between the results obtained in the classroom and those in the literature. There was also a positive interest among students in the alternative approach, highlighting the practicality and mobility offered by the new methodology. In other words, this methodology can also be effective in teaching laboratories, especially as a low-cost alternative to the use of UV/Vis spectrophotometers.
Análise de íons inorgânicos em resíduos de explosão utilizando microssistemas eletroforéticos
(Universidade Federal de Goiás, 2018-08-01) Pinheiro, Kemilly Mara Pires; Coltro, Wendell Karlos Tomazelli; http://lattes.cnpq.br/8302650734477213; Coltro, Wendell Karlos Tomazelli; Rosseto, Renato; lonashiro, Elias Yuki
This study describes the development of an analytical methodology based on the use of microchip electrophoresis (MSE) devices integrated with capacitively coupled contactless conductivity detection (C4D) for the separation and detection of inorganic anions in post-blast explosive residues. The best separation condition was achieved using a running buffer composed of 35 mmol L-1 lactic acid, 10 mmol L-1 histidine and 0.070 mmol L-1 cetyl(trimethyl ammonium) bromide. For C4D measurements, the highest sensitivity was obtained applying a 700 kHz sinusoidal wave with excitation voltage of 20 Vpp. The separation of Cl-, NO3-, NO2-, SO42-, ClO4- and ClO3- was performed within ca. 150 s with baseline resolution and efficiencies between 4.4x104 and 1.7x105 plates/m. The found limits of detection ranged between 2.5 and 9.5 μmol L-1. Also, excellent repeatability was obtained, with relative standard deviation lower than 0.8%, 8.8% and 13.5% for the injection time, for the intensity and the peak areas, respectively. Lastly, real samples of post-blast explosive residues were analyzed on the MSE-C4D devices obtaining successfully the determination of Cl-, NO3- and SO42-. The achieved concentration values varied between 2301,610 µg g-1 for Cl-, 805,490 µg g-1 for NO3- and 1453,270 µg g-1 for SO42-. It was also possible to compare the anionic profile of residues of an improved explosive device and a commercial explosive emulsion, confirming the improved explosive device composition, based on ammonium nitrate fuel oil (ANFO). The approach reported herein has provided short analysis time, instrumental simplicity, good analytical performance and low cost. Furthermore, the MSE-C4D devices emerge as a powerful and portable analytical platform for on-site analysis demonstrating to be a promising tool for the crime scene investigation.
Análise de síntons intermoleculares de bases N-heterocíclicas e suas correlações com propriedades óticas
(Universidade Federal de Goiás, 2021-12-17) Valdo, Ana Karoline Silva Mendanha; Martins, Felipe Terra; http://lattes.cnpq.br/0466799995060671; Martins, Felipe Terra; Guimarães, Freddy Fernandes; Nakahata, Douglas Hideki; Santana, Ricardo Costa de; Araujo Neto, João Honorato de
One of the aims of crystal engineering is the analysis of synthons. The understanding of synthons formation allows modifying them to obtain chemical and physical properties of interest. Among those properties, structure dependents, are optical and electronic properties. The second harmonic generation (SHG) is one example of nonlinear optics phenomena and has a great potential aaplication. In this area, several organic compounds, such as nitrogenous aromatic ones, show SHG. Although robust synthons exist, their modification is delicate, since various parameters induce their formation. Moreover, the SHG has a requirement of inversion center absence in the structure. In this context, guiding structure to specific symmetries are still a crystallographic hard task. In this work the synthons of monoprotonated nitrogenous aromatic compounds salts were analyzed. The salts were synthesized throughout the reaction of nitrogenous compounds (dissolved in isopropanol) with organic and inorganic acids. The used compounds belong to the classes of pyrimidines and pyrazines. After the synthesis, the acidified solutions were submitted to crystallization using the slow evaporation technique. The single crystals had their X-Ray Diffraction data collected. Yet, reflectance diffuse spectroscopy data were collected for some samples. Further, calculations of electronic structure to obtain geometric optimization and spectra absorption data were performed. These calculations were done with density functional theory (and time-dependent density functional theory), with the functional M06-2X or B3LYP and the base 6-31G** or Def2-TZV. In this study fifteen unpublished structures were obtained, among which only one was solved in a noncentrosymmetic space group. The analyses of synthons in all structures revealed two tendencies. The first was observed for the structures obtained from 2-aminopyrazine. In those structures, the protonation of 2-aminopyrazine nitrogen (from aromatic ring) not depended on exclusively of 𝑝𝑘𝑎 from compounds, but also has relation with the final synthons. Accordingly, it was possible to noted that not only a chemical propriety dictates the protonation in the formation of a crystalline medium. Beyond that, the energy of finals intra and intermolecular interactions were essential to understand this result. The other tendency was verified for the compound derived of 2-aminopyrazine substituted by halogen atoms in the aromatic ring, in which, the synthons for the aromatic compounds with or without halogen atoms were the same. Thus, it was observed that a structural modification as an insertion of a halogen atom did not alter the interactions pattern in aromatic compounds. Regarding the physical properties, the direct band gap value for some nitrogenous compound was determined experimentally. Finally, we related the approximationof theoretical and experimental data on electronic transition with the energy of synthons or interactions for a set of atoms present in the structures. For some data, we observed that the greater the stability of the interactions involved, the closer were the theoretical data to the experimental one for the electronic transitions. However, this did not extend to all datasets analyzed in this work.
Análise Ecotoxicológica e Química da Estação de Tratamento de Efluentes de uma Indústria de Laticínios em Goiás
(Universidade Federal de Goiás, 2011-08-26) Machado, Victor Vinicius Batista; Tavares, Maria Gizelda de Oliveira; http://lattes.cnpq.br/0066533047918329; Leles, Maria Inês Goncalves; http://lattes.cnpq.br/1614912440064013; Coltro, Wendell Karlos Tomazelli Coltro; http://lattes.cnpq.br/8302650734477213; Brait, Carlos Henrique Hoff; http://lattes.cnpq.br/8443681172569310
The dairy industries represent one of the most important sectors for the economy of Goiás. The intense industrialization, together with the lack of specialized labor, means that these industries generally produce without any concern for the waste generated. Besides solid waste, these industries generate effluents with high levels of pollution that can affect the water and soil quality, in water bodies into which they flow. Faced with this scenario, the need arose to carry out a study of the risks inherent to this type of effluent, both from a physical-chemical and ecotoxicological point of view. For this purpose, acute toxicity studies were carried out with the Zebrafish (Danio rerio), to evaluate the toxicity of the effluents in pre-defined points of the Wastewater Treatment Plant (WTP) analyzed (points A, D and F). To evaluate the efficiency of the WTP, some physical-chemical parameters were measured (pH, conductivity, cloudiness, BOD, COD, TS, OG among others), and a chemical analysis was carried out of the metals Zn, Cd, Cu and Pb. To determine the solid residues in the effluent, thermogravimetric analyses were performed. Through mathematical models, the efficiency of the WTP was evaluated in terms of the parameters measured, which throughout the treatment process, proved inefficient, presenting mainly negative values. The tests of acute toxicity carried out with the test organisms in contact with the effluent from the dairy effluent, collected in various points of the plant, enabled the LC50 to be calculated, which indicated a moderate to high toxicity of the effluents analyzed.
Análise multiparamétrica da qualidade dos frutos, mostos e vinhos de jabuticaba
(Universidade Federal de Goiás, 2012-06-28) FORTES, Gilmara Aparecida Corrêa; SANTOS, Suzana da Costa; http://lattes.cnpq.br/7811945085200334
Chemical parameters were monitored during the jabuticaba s development, fermentation and ageing of its wine, by quantitative 1H NMR, spectrophotometric assays and standard methods of analysis. Data collected were analysed by variance (ANOVA), principal components (PCA), hierarchical cluster (HCA) and canonical correlation analyses (CCA). Jabuticaba s development was analysed in order to identify the optimal harvest period for winemaking. Total acidity decreased 70.5%, whereas reducing sugars increased about threefold in pulps up until the full ripe stage. Anthocyanin levels underwent a sharp increase in the skins reaching 22.0 mg/g at complete maturation. Tannins and total phenols showed no significant differences in their levels between ripe and full ripe stages. The PCA and HCA distinguished two sample groups, the first comprised of samples from the first four days of fermentation characterized by high levels of fructose, glucose, anthocianins and colour intensity (19.90 g/kg; 36.95 g/kg; 177.88 mg/L and 8.6). The second cluster consisted of samples from days 5 to 14 with higher levels of ethanol, glycerol, methanol, acetic acid (75.02; 3.13; 0.19 and 0.99 g/kg), hue and pH (1.25 and 3.49). The canonical correlation analysis confirmed the influence of alcohols (ethanol, methanol and glycerol), organic acids (citric, succinic and acetic acids), pH and titratable acidity on the extraction and stability of anthocyanins and copigments. Three clusters were identified by the multivariate statistical analysis of red wine samples from 2001 to 2010. Cluster I, wines from 2001, 2002, 2003 and 2006, was characterized by chemical age 1 and 3, hue (1.02; 0.89; 1.83), acetaldehyde and alcohols (0.04 and 0.24 g/L). The wines from 2005, 2007 and 2008 formed the second cluster and presented the lowest content of superior alcohols (0.14 g/L). The third cluster was comprised by wines from 2009 and 2010, which contained higher levels of methanol, acetic and latic acids (0.12; 1.24; 0.35 g/L), and the highest pH (3.96). The canonical correlation analysis revealed that chemical age 1, 2 and 3 correlate negatively with anthocyanins, pH and titratable acidity, confirming the importance of pH and acidity in the anthocyanins stability and polimerization.
Aplicação da tecnologia supercrítica no tratamento de resíduos plásticos presentes em amostras de água
(Universidade Federal de Goiás, 2023-12-21) Viana , Júlio Cezar Vieira; Alonso, Christian Gonçalves; http://lattes.cnpq.br/7285754665946583; Alonso, Christian Gonçalves; Montel, Adão Lincon Bezerra; Silva, Donizete Xavier da; Oliveira, Heibbe Cristhian Benedito de; Brito, Nubia Natalia de
Phthalic acid esters (PAEs) and bisphenol A (BPA) are plastic waste classified as emerging organic contaminants that can harm biota and human health. These residues arise as a result of the fragmentation of plastics into their monomers or the leaching of compounds used as plasticizers, such as BPA and DEP. In addition to contaminants of emerging concern, these compounds are also classified as endocrine disruptors (EDCs), interacting with estrogen receptors and causing harm to human health and the environment. Even with the availability of physical and chemical wastewater treatment methods, classical treatment methods for these compounds have proven not to be efficient in removing these refractory compounds. Therefore, the objective of this work was to use supercritical water oxidation (OASC) technology to investigate the degradation of BPA and DEP plastic waste in aqueous samples. The variables flow rate, temperature, concentration of oxidizing agent (H2O2) and homogeneous and heterogeneous catalyst, such as Cu(NO3)2 and metallic copper wire, respectively were used as parameters for the tests. Metallic copper was also used in the form of a wire together with H2O2. After treatment using OASC Total organic carbon (TOC) removal efficiencies were found to increase linearly with increasing temperature in the range of 400°C to 700°C for all tests with BPA and DEP. For all tests carried out, the best efficiency in removing total organic carbon (TOC) for BPA was achieved at a temperature of 700°C, oxidant concentration of 60 mM and flow rate of 10 mL.min-1 , reaching 91% of removal. For DEP, the best removal efficiency was achieved at a temperature of 700°C, oxidant concentration of 23 mM and flow rate of 10 mL.min-1, achieving 85% removal. Gas chromatography analysis was carried out for the gaseous components and revealed the presence of hydrogen, carbon dioxide, ethane, ethylene, methane and carbon monoxide gases. The analysis of the liquid fraction for BPA samples in the best treatment condition was carried out using liquid chromatography coupled to mass spectrometry and revealed the presence of the intermediate 2-phenyl2-propanol as the main degradation product. The liquid fraction for DEP samples in the best treatment condition was performed by gas chromatography coupled to mass spectrometry and revealed the presence of aliphatic chain hydrocarbons, such as decosane, triacontane, tetracosane and eicosane as the main degradation products. Therefore, the use of supercritical technology proved to be an efficient method for treating aqueous samples containing BPA and DEP.
Aplicação de métodos quimiométricos em estudos de bioequivalência do antibiótico amoxicilina
(Universidade Federal de Goiás, 2008-02-28) Ramos, Douglas Rodrigues; Souza, Paulo Sérgio de; http://lattes.cnpq.br/0834231763464061; Souza, Paulo Sérgio de; Garrote, Clévia Ferreira Duarte; Coelho, Clarimar José
The generic medicines have brought to the national population a higher possibility to access the treatment with medication, the competition stimulation and the medicine exchange insertion, in which the reference formulation can be substituted by the generic medicine, without any harm to the treatment. ANVISA (National Agency of Sanitary Surveillance) regulates this national market, demanding the bioequivalence confirmation between test and reference medicines. Therefore, in a period of six years, those studies have been performed and several generic medicines have been liberated to commercialization. However, the exchange confirmation among the several generic and reference medication are still difficult to observe due to the complexity of the values obtained. The chemometrics analysis decreases the sample space of the complex data which allows samples similarity observation as well as their classification in distinct groups. For that, Principal Components Analysis (PCA) and the Hierarchical Cluster Analysis (HCA) have been used. With these techniques an n-dimension space statistics have been evaluated for a bi-dimension of six amoxicillin bioequivalence studies as capsules and suspensions and therefore, classified them in groups in accordance with the similarity of the formulations pharmacokinetic profiles, which has allowed the medicine exchange observation. The chemometrics applications in pharmacokinetic data differentiated the pharmaceuticals forms capsule and suspensions, of absorption and elimination parameters allowing the exchange avaliations of formulations showing been useful in research laboratories or by regulatories agency for the quality monitoring of the medicine.
Aplicação de métodos quimiométricos para a classificação de águas minerais comercializadas em Goiânia-GO
(Universidade Federal de Goiás, 2010-08-27) BORGES FILHO, Dorivan; SOUZA, Paulo Sérgio de; http://lattes.cnpq.br/0834231763464061
Aplicação de técnicas multivariadas em espectros de infravermelho para a determinação de teores totais de carbono, oxigênio e hidrogênio em amostras de biomassas e biocarvões
(Universidade Federal de Goiás, 2015-06-19) Borges, Yuri Araújo; Guimarães, Freddy Fernandes; http://lattes.cnpq.br/6780812627526129; Guimarães, Freddy Fernandes; Souza, Patterson Patrìcio de; Oliveira, Anselmo Elcana de
(Sem resumo em outra língua)
Aplicações bionalíticas do imageamento químico por técnicas de ionização ambiente de espectrometria de massas: DESI e LAESI
(Universidade Federal de Goiás, 2020-03-20) Vasconcelos, Géssica Adriana; Vaz, Boniek Gontijo; http://lattes.cnpq.br/7814534710550639; Vaz, Boniek Gontijo; Kato, Lucília; Severino, Vanessa Gisele Pasqualotto; Romão, Wanderson; Martins, Aline Maria Araújo
Recent advances in mass spectrometry allowed the study of samples with little or no sample preparation. Among these techniques, Desorption Electrospray (DESI) and Laser Electrospray Ionization (LAESI) has gained popularity for their ability to generate chemical images and the use of a laser to study samples under ambient conditions respectively. New DESI users may face several operational problems due to the lack of a literature describing a detailed protocol on how to work with this technique. Although there is a rich literature on DESI, scientific articles always present a brief description of how the experiments were carried out. Thus, the objective of chapter 1 was to present a simple protocol on how to perform imaging experiments by DESIMS. This chapter describes how to optimize the spot, geometric parameters and how to perform an image acquisition. The main application of the DESI imaging technique is in the medical-clinical area. Numerous researchers have investigated the chemical signatures of tumors and cancers for biomarkers that can not only assist on their identification, but also in the development of new treatments for patients. However, there are several clinical areas that have not been much explored by this technology, such as diseases caused by restricted blood flow to the brain. Models of blood flow reduction are often used in mice to simulate stroke that affects humans. Thus, chapter 2 presents the results obtained from the DESI-MS evaluation of the brain of animals after 1, 3 and 7 days after ischemia induction. 2D chemical images were generated for the most abundant ions and PSL-DA statistical analysis was used to verify the most relevant molecular species for this model. Chapter 3 presents the use of LAESI-MS technology in the study of cyanobacteria that commonly produce toxins. The chosen species are known to cause damage to aquatic bodies due to their extensive proliferation in a short period of time. The metabolic profile of each species was investigated, and statistic tools were used to observe the degree of separation between the cyanobacteria species studied. In addition, ion mobility data were used in order to increase molecular coverage and confidence in the identification of species of interest.
Aplicações da cromatografia líquida e espectrometria de massas na análise de contaminantes em amostras de leite bovino e arroz para fins de controle de qualidade e segurança em alimentos
(Universidade Federal de Goiás, 2024-03-28) Soares, Daniel de Almeida; Chaves, Andréa Rodrigues; http://lattes.cnpq.br/6064014965252121; Chaves, Andréa Rodrigues; Rezende, Cintia Silva Minafra e; Lima, Leomir Aires Silva de; Alves, Maria Isabel Ribeiro; Brito, Nubia Natalia De
The present study uses liquid chromatography and mass spectrometry approaches as tools for identifying and quantifying contaminants in foods, such as rice and bovine milk. For the sake of comprehension, this study is divided into four stages: 1) Development of an LC-MS methodology for quantifying the antibiotic ceftiofur in bovine milk samples; 2) Determination of bisphenols (A and S) in long-life milk and its respective packaging by Paper Spray Ionization (PSI-MS); 3) Development of a methodology for determining herbicides in rice (Oryza sativa) samples using the miniaturized hollow fiber liquid phase microextraction sample preparation technique (HF-LPME) with electrospray ionization analysis (ESI-MS); 4) Chemometric analysis comparing rice samples contaminated with fungicides and not contaminated from direct analysis by ESI-MS. In step 1, to determine ceftiofur in milk samples, a liquidliquid extraction (ELL) method was developed followed by analysis of the extracts by LC-MS. The main variables associated with the extraction process were optimized and the figures of merit: linearity, limit of detection and quantification (LOD and LOQ), precision and recovery were evaluated. The method presented LOQ 0.80 ng.mL-1 , inter-day precision of less than 7.3% and recovery greater than 94%. Milk samples obtained from cows subjected to antibiotic application were analyzed for the purpose of evaluating the antibiotic elimination profile in the milk samples. In part 2, it was possible to develop a rapid method for analyzing bisphenols (BPA and BPS) in longlife milk samples and their respective packaging using ambient mass spectrometry using the PSI-MS technique. The method was optimized and the figures of merit linearity, precision, accuracy, LOQ and LOD were evaluated, all of which were within the parameters required by national legislation. The bisphenols under study were detected in all samples (packaging and milk) and in only one sample the BPA content was above 10 ng.mL-1 (maximum residue limit) and for BPS the majority of samples presented levels above the same concentration. In milk, a content of up to 150 ng.mL1 for BPA and an average content of 60 ng.mL-1 for BPS was obtained. The results of this study were published in the journal Food Chemistry (qualis A1). In chapter 3, the use of the miniaturized HF-LPME sample preparation technique followed by ESI ionization mass spectrometry analysis for the determination of herbicides in rice is presented. The main parameters relating to the sample preparation method were optimized, with the use of a two-phase system resulting in shorter extraction times. However, in a three-phase system, with the donor phase at pH 1.7 and the acceptor phase at pH 12, extraction was favored for all analytes. The ionic strength was evaluated by adding salt to the donor solution and did not favor extraction. Therefore, the three-phase system presented a better response to the analytes and the method should have its figures of merit evaluated using the optimized HF-LPME/ESI-MS method. The fourth chapter presents a metabolomic analysis followed by chemometric treatment of data obtained by ESI-MS analysis on rice extract samples using positive and negative modes. A comparison of samples was carried out in 4 different matrices (rice husk, grain with husk, polished grain without husk and unpolished grain without husk). The samples evaluated were divided into two groups: contaminated with fungicides and not contaminated. The data obtained made it possible to separate them into classes using treatments using principal component analysis (PCA). In ESI(-) mode, the data were better explained by PCA Without normalization (89.1%) and also by Quantile Normalization (90%). The negative mode better explains the dissimilarity between the contaminated and uncontaminated rice groups.

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