Programa de Pós-graduação em Química

URI Permanente desta comunidade

http://200.137.215.59/tede/handle/tde/268

Navegar

Agora exibindo 1 - 20 de 81

Calixarenos como plataforma de luminóforos e de co-cristalização com nutracêuticos
(Universidade Federal de Goiás, 2024-08-15) Alvarenga, Meiry Edivirges; Martins, Felipe Terra; http://lattes.cnpq.br/0466799995060671; Martins, Felipe Terra; Gomes, Danielle Cangussu De Castro; Doriguetto, Antonio Carlos; Araújo Neto, João Honorato de; Santos Júnior, Sauli Dos
Calixarenes are notable macrocyclic compounds characterized by a variable number of phenolic units linked by methylene bridges. They possess a series of advantageous features, making them an ideal choice for diverse applications. Their ease of large-scale production from low-cost precursors, coupled with their chemical and thermal stability, as well as the ease of functionalization, elevate calixarenes to the status of highly versatile platforms. They can be utilized in the development of a broad range of materials with potential applications in technological and pharmacological areas. Based on the host-guest properties of calixarenes and the high efficiency of aminopyrazine as a blue light emitter, this research focused on the investigation of two calixarene-pyrazinamide hybrids. The primary goal was to combine hosting capabilities and light emission in a single molecular structure. Two compounds yielded three luminescent crystalline forms, whose structures and optical properties could be correlated. One of them crystallized in two forms, non-solvated and a DMF solvate, while the other, without t-butyl substitutions, formed three conformers with DMF. Variations in molecular substitution affected the conformation of the structures, influencing the coplanarity and conformational profile of the phenolic rings. Under an excitation of 388 nm, both emitted light in the 400-550 nm range, peaking at around 500 nm, but with low quantum efficiency. The low efficiency was attributed to the presence of DMF and π...π stacking interactions. Another aim of this research was to explore the use of calix[4]tube in forming cocrystals with resveratrol, an active nutraceutical known for its potential antibacterial, antioxidant, antiinflammatory, and anticarcinogenic benefits, yet with low aqueous solubility. This work represents the first successful attempt to form a neutral-state resveratrol cocrystal, doubling its water solubility. In summary, this study signifies a significant advancement in using calixarenes as molecular bases for luminophores and in the crystallization of the nutraceutical resveratrol. The employed process proved commercially viable, underlining the immense potential of these methods for future applications in technological and pharmaceutical fields. Therefore, the research focuses on the synthesis of calixarene hybrids with light-emitting properties and the development of cocrystals to enhance the solubility of pharmaceutical compounds, demonstrating the versatility of calixarenes in various areas of chemistry.
Meso-tetra-(piridil)-porfirinas com complexos periféricos de paládio: busca por novos compostos com ação fotodinâmica
(Universidade Federal de Goiás, 2020-12-16) Alves, Kamilla Moraes; Batista, Alzir Azevedo; http://lattes.cnpq.br/6469642481998660; Gonçalves, Pablo José; http://lattes.cnpq.br/0515343409614452; Martins, Felipe Terra; Iglesias, Bernardo Almeida; Gonçalves, Pablo José; Batista, Alzir Azevedo
The present dissertation had as objective at the synthesis of new photosensitizing compounds for use in Photodynamic Therapy through the modification of meso-tetra (4-pyridyl) porphyrin (TPyP). For that, phosphine binders containing palladium atoms were inserted: 1,2-bis(diphenylphosphine)ethane (dppe), 1,3-bis(diphenylphosphine) propane (dppp), 1,4-bis(diphenylphosphine)butane (dppb) and 1,1'-bis (diphenylphosphine)ferrocene (dppf), dating in porphyrins: {TPyP[PdCl(dppe)]4}(PF6)4, {TPyP[PdCl(dppp)]4}(PF6)4, {TPyP[PdCl(dppb)]4}(PF6)4 e {TPyP[PdCl(dppf)]4}(PF6)4, respectively. After synthesis, structural characterization was performed using infrared spectroscopic techniques (FTIR), elementar analysis and 1H, 13C{1H} e 31P{1H} nuclear magnetic resonance (NMR). X-ray diffraction (XRD) was used to prove a structure for obtaining monocrystal porphyrin {TPyP[PdCl(dppb)]4}BF4. Through spectroscopicUV-Vis absorption, fluorescent emission and flash-photolysis techniques, it was possible to determine the lipophilicity of the molar absorption coefficients (), the lifetime of the triplet state and the fluorescence (Φf) and oxygen production quantum singlet (ΦΔ). In addition, an interaction with DNA was evaluated through spectrophotometric titration and viscosity. Finally, phototoxicity and cytotoxicity in the tumor cell line MDA-MB231 and healthy HACAT were evaluated. Biological tests were performed on two cell lines: MDA-MB231 and MCF-10A. The experiments were carried out in the dark and in the presence of irradiation, to determine the photodynamic efficiency of the synthesized compounds. The porphyrin-derived complexes exhibited IC50 values similar to that presented by cisplatin, in the MDA-MB231 breast cell, however, with respect to the non-tumoral breast cell, MCF-10A, they were more cytotoxic than the commercial drug, so that the selectivity index values were much lower for porphyrins than that presented by cisplatin.
Ensino de química afrocentrado: a contribuição africana para o desenvolvimento tecnológico do país
(Universidade Federal de Goiás, 2021-08-20) Alvino, Antônio César Batista; Benite, Anna Maria Canavarro; http://lattes.cnpq.br/8433607360245647; Benite, Anna Maria Canavarro; Souza, Aparecido Ribeiro de; Aguiar, Vinícius Gomes de; Silva, Juvan Pereira da; Bonifácio, Viviane Gomes
This investigation dealt with the implementation of Law n. 10.639/03 in teaching chemistry, high school, which originated this thesis that aimed to answer the question: is it possible to teach chemical contents from the historicity, cultural and epistemic context of an African matrix? For such, a subject entitled Experimental Chemistry was created. What works the chemical contents from the thematic axes: Sugarcane cycle in Brazil; Gold cycle (mining) in Brazil; Origin and production of soap: African technology in Brazilian education – making ash soap and African matrix science: racism in science education, which explored the chemical contents in line with historicity, cultural heritage, technological and epistemic of African peoples and peoples of African descent voluntarily or involuntarily dispersed throughout the world, the study had elements of a participant research, it was, therefore, an educational activity that aimed at the physical and mental emancipation of black youth. We emphasize that this text will present an afrocentered and afrocentric methodological approach. For this reason I print an analysis based on an African center in the analysis of the results. The total corpus of analysis consists of the planning of Pedagogical Interventions (PI) and transcription of classes from audio and video recordings of arguments produced by students produced in classes, 60 students aged between 14 and 22 were actors in this investigation. The data obtained were grouped into 11 extracts that dealt with racial prejudice, racism in science education, anti-discrimination policies, racial discrimination in the media and employment, African matrix technologies, quilombos, chemical reactions, redox reactions, osmosis, polarity and solubility of materials, in the analyzes we printed an African methodological conception of the data and a problematic education perspective of Freire (1979, 1995, 2005) and Francismo Jr (2010), in which we take into account that education in communication (SODRÉ, 2012). The results indicate that there is a possibility to teach chemical contents in a pluralist perspective, which values the view of colonized peoples, hidden in chemical education by epistemic racism.
Síntese, avaliação do potencial antitumoral in vitro e docking molecular de novas imino - chalconas candidatas a inibidoras de CDK2
(Universidade Federal de Goiás, 2022-02-11) Anjos, Murilo Machado dos; Alonso, Christian Gonçalves; http://lattes.cnpq.br/7285754665946583; Oliveira, Guilherme Roberto de; http://lattes.cnpq.br/8239498431579015; Oliveira, Guilherme Roberto de; Chagas, Rafael Pavão das; Gomes, Marcelo do Nascimento; Costa, Maísa Borges; Pérez, Caridad Noda
The search for new active compounds is a line of research widely studied in the area of organic chemistry. Within this niche, computational tools, such as molecular docking, gain great importance for shortening and being able to assertively predict the discoveries of new drugs, as well as the repositioning of these. Among the classes of natural products that receive enormous attention in this field, the chalcones and their derivatives stand out, as they have diverse applicability and have an attractive structural scafford for structural modifications. The objective of this work was the synthesis of derivatives of chalcones, evaluation of the profile of tumor inhibition against the cell lines SNB-19 (Glioblastoma), PC-3 (Prostate), HCT-116 (Colon) and HL-60 (leukemia) and the search for biological targets for the synthesized products, with the purpose of applying the molecular docking process. Seven compounds were synthesized with yields ranging from 25% to 43%, where 5 of these were not published (M1, M4, M5, M6 and M7). The synthesized imino chalcones were tested in vitro against the four cancer cell lines showing an inhibition profile above 75% for all lines, especially the HL-60 line where all compounds showed an inhibition profile above 99%. Compound M4 had the lowest IC50 value, 5.5 µM, for the HL-60 strain. The identification of molecular targets was performed using the PharmMapper platform, where two possible targets were identified, these being the proteins DAPK3 and CDK2. The docking process was validated using the redcoking of the co-crystallization ligands, with the parameters previously defined, where the validity of the process was demonstrated, noting a mean square deviation (RMSD) value close to the crystallographic data, both smaller than 2 Å, where the value found for CDK2 was 0.099 Å. The docking results indicate that the imino-chalcones had a higher affinity for the CDK2 protein, where the compound M4 had the best affinity value (-10.0 Kcal/mol), interacting with some key residues of the CDK2 enzyme by hydrogen bonding with Leu83 and π-anion with Asp145. The ADME profile shows that imino-chalcones have good gastrointestinal absorption, with the exception of compounds M1 and M3. The compounds inhibit CYP3A4, with the exception of M1, in addition to being substrated from p-glycoprotein (Pg-p), minus M2, indicating that an optimization of the structures is necessary to improve their ADME properties.
Desenvolvimento do método de extração por eletromembrana para análise de ácidos naftênicos em água produzida por espectrometria de massas de ultra-alta resolução
(Universidade Federal de Goiás, 2021-07-20) Araújo, Giovanna Lopes de; Chaves, Andréa Rodrigues; http://lattes.cnpq.br/6064014965252121; Vaz, Boniek Gontijo; http://lattes.cnpq.br/7814534710550639; Vaz, Boniek Gontijo; Chaves, Andréa Rodrigues; Coltro, Wendell Karlos Tomazelli; Nascentes, Clésia Cristina
Miniaturized techniques are better alternatives than traditional sample preparation techniques. They use simpler and more direct approaches, reducing the waste generated at the end of the process. Innovatively, these techniques can be applied to create more eco-friendly routine methodologies that contribute to analytical chemistry. This work develops a methodology using Electromembrane Extraction (EME) for the extraction of carboxylic acids, called Naphthenic Acids (NAs). These toxic species are found in Produced Water (PW), an effluent from the petroleum industry. Comparing it to other miniaturized techniques, it obtains better recoveries and shorter extraction times with EME, due to the application of the electric field. The applicability of the EME technique is explored here for the first time in a matrix such as PW. For this, an adaptation of the traditional methodology was carried out, using the hollow fiber membrane in a “U” shape. The conditions that demonstrated the best performance for EME-UHRMS was the 1-decanol as an organic solvent in SLM, pH of 10, five minutes of extraction applying 200 V, and a ratio of 1:4 of matrix and buffer. A migration analysis of some analytes through the membrane was also performed, observing relationships between the Log P and ion mobility. The analytical performance of EME-UHRMS was evaluated for three standards of NAs, obtaining calibration curves with R2> 0.98. LODs and LOQs were between 0.12 to 0.20 μg mL-1 and 0.40 and 0.67 μg mL-1, respectively, generating a huge influence on the matrix of the research data. The relative recovery of the technique is 75% and 111%, adequate values for the EME methodology used. Finally, EME-UHRMS was effectively applied in the produced water sample, demonstrating a more homogeneous extraction of the analytes when compared to the ones obtained by the classical Liquid-Liquid Extraction (LLE) technique.
Geração de compostos químicos de interesse via pirólise lenta da microalga spirulina platensis
(Universidade Federal de Goiás, 2021-02-25) Arruda, Ketley Costa Rocha; Andrade, Laiane Alves de; http://lattes.cnpq.br/6777831109573242; Ostroski, Indianara Conceição; http://lattes.cnpq.br/9689394915288313; Ostroski, Indianara Conceição; Andrade, Laiane Alves de; Alonso, Christian Gonçalves; Borél, Lidja Dahiane Menezes Santos
Investigations on the use of microalgae biomass, converted by pyrolysis, to replace fossil fuels have increased over the past decade. However, bio-oil contains oxygenated and nitrogenous compounds that prevent its direct application. Although prejudicial to biofuel, nitrogenous compounds could be separated and used for other applications, such as in the production of fine chemicals. Therefore, the potential of the highly proteinaceous biomass Spirulina platensis was evaluated to identify the optimum conditions for the production of high added-value nitrogenous compounds in liquid fraction via slow pyrolysis. Thus, in this work, the effects of operational conditions mass load, temperature, and heating rate on the liquid yield and the formation of nitrogenous compounds were evaluated using Experimental Design and Response Surface Methodology (RSM) techniques. An optimization study was performed through the use of Differential Evolution methodology (DE) to determine the operating conditions that maximize the liquid yield. After the pyrolysis process, extraction and adsorption routes were evaluated as potential processes for the separation of nitrogenous compounds. The experimental results indicated that bio-oil produced from slow pyrolysis of Spirulina platensis is a promising source for the generation of nitrogenous compounds, with a maximum of 90.64% of the compounds identified by gas chromatography – mass spectrometry (GC-MS) at mass conditions of 3.75 g, temperature 450 °C and heating rate of 1.7 ° C min-1. The results showed that operating conditions, especially the heating rate, significantly impacted both the liquid yield and the formation of these compounds. From the experimental test at optimal conditions (1.78 g, 556 °C and 10.48 °C m-1) a maximum liquid yield of 64.59% was obtained. The experimental values showed good agreement with the corresponding predicted values, with an error of less than 10%. The extraction with phosphoric acid showed to be a promising route to selectively separate the classes of compound, having remained cyclic compounds in the heavy phase and non-cyclic compounds in the light phase. While adsorption using activated carbon from coconut shell chemically treated with phosphoric acid (FAAC) was favorable in the selective separation of nitrogen compounds, especially the class of amides.
Cerumenolomic applied to Veterinary Medicine for the diagnosis of intoxication and of the metabolic profile of animals
(Universidade Federal de Goiás, 2019-08-08) Barbosa, João Marcos Gonçalves; Antoniosi Filho, Nelson Roberto; http://lattes.cnpq.br/5982964870999454; Antoniosi Filho, Nelson Roberto; Fiovavanti, Maria Clorinda Soares; Oliveira, Anselmo Elcana de
Medicina veterinária é uma das atividades mais antigas da história humana. O desenvolvimento de novos métodos em ciência veterinária é de grande urgência devido a sua importância em garantir o bem-estar animal, o qual é determinante para a economia global, principalmente em relação aos animais de pecuária. Sendo assim, o desenvolvimento de métodos que permitam uma análise de uma maneira rápida, efetiva, de grande acurácia, indolor e não-invasiva é extremamente importante. Nesta dissertação, um método é apresentado – aqui chamado por cerumenolômica- empregando os metabólitos orgânicos voláteis (MOVs) exalados pelo cerúmen (cera de ouvido) como um potencial biofluido que pode ser útil em ciência veterinária para aplicação em pesquisa em animais de pecuária. Amostras de cerúmen de raças brasileiras de bovinos e ovelhas foram coletadas na Escola de Veterinária e Zootecnia da Universidade Federal de Goiás (EVZ-UFG) e foram analisadas em um Cromatógrafo a Gás acoplado a um Espectrômetro de Massas por injeção de amostra via Headspace (CG-EM/HS) e, por fim, os dados dos cromatogramas foram submetidos à ferramentas de estatística multivariada. A cerumenolômica permitiu a identificação de 133 MOVs das classes orgânicas polares e apolares como os compostos emitidos por esses animais quando eles se encontram saudáveis. Além disso, com o objetivo de demostrar e testar a eficiência da análise, a cerumenolômica foi aplicada para o diagnóstico de intoxicação bovina por Stryphnodendron spp., uma árvore comum no Pantanal e no Cerrado brasileiro. A cerumenolômica demostrou alta eficiência na descriminação das amostras intoxicadas e não intoxicadas usando dois biomarcadores: 9-Tetradecen-1-ol e 2-Octildecanol. Em resumo, o método cerumenolômico descrito aqui surge como uma ferramenta em potencial para ser aplicado em medicina veterinária.
Investiga menina: estudos sobre a parceria colaborativa entre o movimento social e a universidade como estratégia de divulgação científica
(Universidade Federal de Goiás, 2020-10-02) Bastos, Morgana Abranches; Benite, Anna Maria Canavarro; http://lattes.cnpq.br/8433607360245647; Benite, Anna Maria Canavarro; Gonçalves, Eliane; Amauro, Nicéa Quintino
The history of science has always been told from the point of view of white men. The scientific and technological achievements are considered to have been developed only by Europeans, and this distorted view contributes to the maintenance of homogenizing stereotypes and to justify the inferiority of non-whites and women. We understand that black women are part of this history, but they have been invisible and excluded over the centuries, a fact that reflects in our reality so that the representation of black women in scientific and technological activities is almost nonexistent, denouncing the confluence of racism with sexism. This research is a participant research. Our results show that the partnership between the university and the social movement around cultural experiences can be an alternative to demystify the sciences as an exclusively male, white and laboratory activity. They also show the importance of valuing and highlighting the contributions of black women to our science and society. The results allow us to conclude that the media play an important role in conveying deformed stereotypes of science, but should also be used to reverse this situation. And that is why we use social networks, important means to bring people together as a strategy to promote the visibility of black scientists and the dissemination of their work. On the other hand, the science produced in our country comes mostly from within public universities, and these universities must communicate with the general population, which pays taxes and maintains them, and the knowledge produced by them must aim at improving people's lives.
Estudo da inserção de grafeno em catalisadores de PtSn para a oxidação de etanol
(Universidade Federal de Goiás, 2022-02-21) Bastos, Tarso Leandro; Colmati Junior, Flavio; http://lattes.cnpq.br/0231242349462585; Colmati Junior, Flávio; Ciapina, Eduardo Gonçalves; Martins, Paulo Roberto
Fuel cells are portable electrochemical converters that generate electricity using renewable fuels and can act as high-efficiency energy sources. When fed with ethanol, they lose performance due to electrode poisoning. To mitigate this problem, noble metals are used in the electrodes in addition to the addition of elements to the electrocatalysts, increasing the production cost while the problem persists. Thus, this study seeks to increase the efficiency of ethanol oxidation by modifying the carbon support with graphene, where the metallic phase is anchored, and to verify its influence on the general catalysis process. Electrocatalysts with carbon-graphene hybrid support were synthesized in different proportions, and a physical mixture of graphene with the carbon-supported electrocatalyst was prepared. Hybrid supported electrocatalysts showed higher electrochemical activity and stability in ethanol oxidation compared to carbon supported electrocatalyst, with an increase of 132% in alkaline medium. In the physical mixture, the addition of graphene generated a 10% decrease in the amount of metallic phase needed, obtaining the same performance as the pure electrocatalyst. While in acidic medium, in addition to the 10% decrease, the physical mixture exhibited a much superior performance to the pure electrocatalyst. The results showed that the influence of graphene depends on its interaction with the electrocatalyst, while promoting an increase in the performance of ethanol oxidation.
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.
Oral squamous cell carcinoma lipid differentiation in gingiva tissue by mass spectrometry
(Universidade Federal de Goiás, 2022-09-23) Bernardo, Ricardo Alves; Chaves, Andréa Rodrigues; http://lattes.cnpq.br/6064014965252121; Chaves, Andréa Rodrigues; Janfelt, Christian; Porcari, Andréia de Melo; Lima, Eliana Martins; Coltro, Wendell Karlos Tomazelli
Oral squamous cell carcinoma (OSCC) is the most common oral cavity cancer, responsible for 90% of all cancers in the head-neck region, except for non-melanoma skin cancer. A fast, accurate, and cheap diagnosis is required to detect the presence of OSCC in the preliminary stages providing better chances of success in cancer treatment. In general, the diagnosis is performed using proteomics and histological data. However, lipids play a key role in cellular metabolism. Therefore, understanding the lipid differentiation between healthy and cancer tissues could be important to predict biomarkers candidates and improve the diagnosis system. Furthermore, a new methodology for simultaneous RNA and lipid extraction using TRIzol® solution was developed, and the lipid profile in both sample groups was studied. The samples stored in TRIzol® solution were homogenized and submitted to liquid-liquid microextraction (LLME) using chloroform as an extractive solvent. Therefore, the organic phase was collected and submitted to the Bligh &Dyer extraction. The simultaneous RNA and lipid extraction was validated according to the parameters described by the Brazilian Nation Health Surveillance Agency. An analytical curve of tissue in methanol and another one of tissue in TRIzol® solution were performed for method evaluation. The sample solutions were spiked with different concentrations of PC 17:0/17:0 standard solution, and caffeine-(trimethyl-13C) was used as the internal standard and directly infused into the mass spectrometer on positive ion mode. Intra-day and inter-day precision, accuracy, absolute recovery, and matrix effect were evaluated in three concentration levels in replicate (n=5). Limits of detection and quantification were estimated in the order of ng mL-1 with good linearity (r² >0.99), precision and accuracy (<15%), and absolute recovery values ranging from 90 to 110%. The mass spectra were submitted to the Global Natural Product Social Network (GNPS) platform for peak annotation. The partial least-square discriminant analysis (PLS-DA) was performed in all samples clustering the healthy samples and separating them from the cancer ones. The PLS-DA revealed that 15 lipids were responsible for describing the healthy group in the positive ion mode, while 8 lipids described the cancer one. In the negative ion mode, 10 lipids described the healthy group, while 10 lipids described the cancer one. Furthermore, cryosections of gingiva tissue (healthy and cancer ones) with 10 µm thickness were analyzed by matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to investigate which lipids pointed by the PLS-DA delimit the cancer region. The MALDI-MSI analyses showed that the lipids responsible for OSCC group classification are more abundant in the cancer tissue compared to the healthy one. The extraction methodology reported here, and the MALDI-MSI as confirmation technique are adequate for classification of OSCC samples regarding lipid content.
Cloridrato de naltrexona: estabilidade de polimorfos hidratados e avaliação da degradação em condições ácidas e básicas
(Universidade Federal de Goiás, 2019-04-30) Borges, Karolina de Oliveira Gonçalves; Carvalho, Jesiel Freitas; http://lattes.cnpq.br/5841291496427516; Oliveira, Cecília Maria Alves de; http://lattes.cnpq.br/3152041311943092; Oliveira, Cecília Maria Alves de; Carvalho, Jesiel Freitas; Martins, Felipe Terra; Kato, Lucília
In this work, it was studied the crystalline stability, and the chemical degradation profile, of the drug CNTX, purchased by compounding pharmacy. Initially, CNTX was characterized by XRD, NMR of 1H and 13C, FTIR, HPLC-MS and TG-DTA techniques. By XRD analysis and refinement by the Rietveld method -using comparison with data reported in the Cambridge Structural Database System (CSDS) – it was not possible the identification of IFA crystalline structure; which was recrystallized in aqueous solution. The CNTX tetrahydrate structure formation, in an aqueous medium, was confirmed by the XRD and TG-DTA data. The crystalline stability of CNTX tetrahydrate was evaluated by XRD analysis through measurements carried out in a nitrogen atmosphere. The experiment showed the conversion of the tetrahydrate structure to the anhydrous CNTX structure after 15 minutes. The characterization of the crystalline phase by XRD leads to the identification of the CNTX dihydrate in the pharmaceutical formulation analyses. Besides, experiments on the crystalline stability of naltrexone hydrochloride present in the formulation over one year, showed that the dihydrate structure remained unchanged. Aiming to perform studies with naltrexone in the form of a free base, the formulation was subjected to acid-base treatment followed by ethyl acetate extraction. After solvent removal, the crystals obtained were analyzed by single-crystal XDR method and identified as two novel crystalline forms of the naltrexone solvates: the ethyl acetate, and the diethyl ether solvate. Regarding the chemical degradation study, naltrexone hydrochloride was subjected to degradation conditions in hydrolytic medium (0.1 M HCl and 0.1M NaOH), followed with LC-MS analysis for the final aqueous solution. In basic medium solution, it was possible to observe the drug degradation and impurity formation in an oxidized form, reported per European Pharmacopoeia as impurity G or F.
Estudo de degradação forçada e de compatibilidade do ciprofibrato com excipientes farmacêuticos
(Universidade Federal de Goiás, 2022-08-31) Brito, Camila Cíntia Sousa Melo; Leles, Maria Inês Gonçalves; http://lattes.cnpq.br/1614912440064013; Leles, Maria Inês Gonçalves; Siqueira, Adriano Buzutti de; Chaves, Andrea Rodrigues; Ionashiro, Elias Yuki; Ribeiro, Elton Brito
Ciprofibrate-CPF is a hypolipidemic that promotes the reduction of serum levels of cholesterol and triglycerides by stimulating activated nuclear receptors for peroxisome proliferation-alpha-PPAR-α. In this work, the stability of CPF was studied using forced degradation and compatibility studies. The Active Pharmaceutical Ingredient-API (SQC) was characterized by Thermogravimetric Analysis/Derivative Thermogravimetric AnalysisTGA/DTGA, Differrential Scanning Calorimetry-DSC, Differrential Scanning Calorimetry coupled to the Photovisual system-DSC-Photovisual, Absorption spectroscopy in the mid-infrared region with Fourier Transform-FTIR, Nuclear Magnetic Resonance-RMN, Powder X-ray Diffractometry-DRXP, High Resolution Mass Spectrometry-EMAR and High Performance Liquid Chromatography coupled with Diode Array Detector and High Resolution Mass Spectrometry-CLAE/DAD/EMAR. The forced degradation study was carried out for CPF (SQC) under the following conditions: acid hydrolysis, basic hydrolysis, oxidative and thermal at 70 °C 240 hours using EMAR and CLAE/DAD/EMAR. The compatibility study between the CPF and the excipients was carried out by preparing binary mixtures in the proportions 50:50 and 92:08 (m/m), where the isolated components (CPF (SQT) and excipients), Simulated Excipients Sample-ASE (excipients) and the binary mixtures (CPF-excipient or CPF-excipients) were analyzed by TGA/DTGA, DSC, DSC-Photovisual, FTIR, and DRXP. The EMAR and CLAE/DAD/EMAR results suggested the degradation of CPF when subjected to basic hydrolysis, with some degradation products previously reported in the literature being observed and a new product identified. In the other exposure conditions, the CPF remained stable. The DSC technique suggested signs of interaction between the CPF and the excipients (Sodium Starch Glycolate-AGS, Sodium Lauryl Sulfate-LSS, Silicon Dioxide-DOS and Hydrogenated Vegetable OilOVH) when prepared in a proportion 50:50 (m/m) and between CPF and the excipient (OVH) in a proportion (92:08 m /m). However, the FTIR and DRXP techniques did not confirm the sings of interaction observed in the DSC, except when DOS was used at 50%. The compatibility study indicated the use of the CPF-ASE binary mixture in the proportion 50:50 (m/m) as a candidate for pre-formulation.
Estudo do efeito da distância de migração secundária do óleo na composição de compostos nitrogenados por FT-ICR MS
(Universidade Federal de Goiás, 2021-07-21) Brito, Talita Pinheiro de; Vaz, Boniek Gontijo; http://lattes.cnpq.br/7814534710550639; Vaz, Boniek Gontijo; Cruz, Georgiana Feitosa da; Severino, Vanessa Gisele Pasqualotto
Crude oil is a complex mixture containing a variety of organic species, with hydrocarbons constituting the most abundant fraction of this matrix, and a small number of polar constituents and some metals. Among the polar constituents, nitrogenous compounds have been widely used in geochemical studies. The distance traveled by the crude oil from the source kitchen to the reservoir is an important parameter in the search for new oil accumulations. For this type of information, reliable and robust molecular markers are desirable to estimate the distance migrated by crude oil. In the present work, Fourier transform ion cyclotron resonance mass spectrometry coupled to the electrospray in negative mode was used in the chemical characterization of nitrogenous compounds in 14 oil samples from three different Brazilian fields (C, H and G). Heteroatomic compounds classes detected in the samples were N, N2, NO, NO2, NS, O, and O2. It was found that the average molecular mass (AMM) for each DBE value of nitrogen compounds (N) can be used as an indicator of oil migration distance within a Brazilian basin. Moreover, a correlation of relative abundance of three carbon atom ranges of alkyl-carbazoles (C12-C20, C21-C29, C30+) and benzocarbazoles (C16-C20, C21-C29, C30+) revealed enrichment or depletion of these species based on their degree of alkylation which can be associated to the polarity of these species and consequently to their chemical fractionation along the petroleum migration. Finally, ratios (C31+/C30-) calculated between of relative abundance of carbazoles and benzocarbazoles divided by two groups of carbon atom numbers show a potential to estimate oil migration distance as their values become higher in petroleum samples collected furthest from the source kitchen. The results obtained indicating the potentiality of using it as new parameters to access secondary migration crude oil distance.
Desenvolvimento de metodologia para avaliação de ácidos graxos em amostras de sêmen humano para fins de estudo de fertilidade
(Universidade Federal de Goiás, 2022-02-22) Bueno, Amanda Cardoso; Chaves, Andrea Rodrigues; http://lattes.cnpq.br/6064014965252121; Chaves, Andrea Rodrigues; Sorgi, Carlos Arterio; Antoniosi Filho, Nelson Roberto
Infertility has been the subject of studies by several researchers around the world, in this field, the influence of diet has been one of the factors evaluated. In women, the cell responsible for reproduction is the egg, for men, it is the sperm, present in human semen, which is a complex matrix, which contains proteins, amino acids, lipids, among other compounds. A semen, with desirable qualities, needs to demonstrate good concentration, morphology, vitality and motility of the sperm present. The lipids present in the composition, especially the fatty acids, such as omegas 3, 6 and 9, help in the structuring of cell membranes, making them more resistant, also acting in the improvement of motility. Thus, in partnership with the Department of Biomedicine of the Federal University of Jataí (UFJ), under number 3,792,715 of the ethics committee of the Federal University of Goiás (UFG), this work proposes to evaluate possible relationships between seminal quality and ingestion of baru nut, typical food of the cerrado region of Goiás. For analytical purposes, the Mass Spectrometry (MS) technique was used, this is a technique subject to the presence of endogenous compounds of the complex matrix, such as semen. Therefore, the sample preparation step for analysis is extremely important. The miniaturized sample preparation technique, disposable pippete extraction (DPX), was evaluated in terms of cleaning the sample and extracting the analytes of interest. In order to increase the selectivity of the technique, a DPX extractor phase, developed by our research group, was applied to extract fatty acids from human semen, followed by analysis by direct infusion in the mass spectrometer. The parameters with direct influence on the efficiency of the DPX technique were optimized. The results showed greater extraction efficiency for 700 μL of semen sample aspirated/dispensed for 7 cycles, followed by desorption, using 1000 μL of acetonitrile in just 1 cycle. For comparison purposes, the samples were also analyzed with sample preparation performed by the adapted Bligh & Dyer method, followed by direct infusion in high resolution mass spectrometry. The method developed was submitted to the evaluation of selectivity, matrix effect, calibration curve, precision and accuracy, following the current legislation for bioassays, RDC 27/2012, drafted and supervised by the National Health Surveillance Agency (ANVISA).
Estudos sobre a educação para as relações étnico-raciais na formação de professores de química: a experiência do Coletivo Ciata
(Universidade Federal de Goiás, 2018-01-21) Camargo, Marysson Jonas Rodrigues; Benite, Anna Maria Canavarro; http://lattes.cnpq.br/8433607360245647; Benite, Anna Maria Canavarro; Cunha Júnior, Henrique Antunes; Dias, Luciene de Oliveira
Although overcome in the theories of natural sciences, the concept of race, as an attribute built socially in time and space, still works as a parameter for allocation of people in the social structure and many data could represent this statement, such as one young black man is murdered in Brazil every twenty-three minutes. Affirmative action comes with a strategy to combat racism and can be put into practice in all spheres of civil society, because it mainly aims to undo the social structure that drives black people to underprivileged economic and symbolic positions. Affirmative action policies in addition to recognizing racism, discrimination and all the ills suffered by the black community, are moving towards the real transformation of this situation, which means putting black men, black women, white men, white women and all racial groups in equality and dignity through their differences. This study presents an affirmative action aiming to discuss and reflect on the following question: how can education for ethnic-racial relations be included in teaching chemistry? This research was constructed under the epistemological approach of Afrocentricity, in which the people from Africa and the diaspora must be the center of the study of social phenomena, therefore protagonists of their own history. The work was developed by the bias of action-research in two cycles in subjects planned and performed by the Ciata Collective. The speech shifts obtained by film recording and, subsequently, transcribed were analyzed, in each cycle, through the reference analysis of the conversation. Our results show that planning and executing a Chemistry class thinking about the epistemic displacement demanded knowledge that was suppressed from our curriculum in the initial formation, which demanded, therefore, research and in-service training of both students and teacher. The chemistry teacher deals with a real school that is a reflection of the society in which it is inserted, so the training of this professional should prepare him/her to also understand the phenomenon of racism in school and know how to act when it comes to his/her work environment.
Avaliação de sorvente MIP em sistema de microextração hifenado ao HPLC-DAD, para determinação de taninos condensados em amostras de casca de jabuticaba (Myrciaria cauliflora)
(Universidade Federal de Goiás, 2022-02-21) Cardoso, Alessandra Timóteo; Chaves, Andrea Rodrigues; http://lattes.cnpq.br/6064014965252121; Chaves, Andrea Rodrigues; Faria, Anizio Marcio de; Martins, Gabriel Rocha
Jabuticaba (Myrciaria cauliflora) is a fruit widely consumed in Brazil and of great nutritional importance. Among the compounds of this fruit are the condensed tannins, which have already been widely investigated regarding their chemical, biological and pharmaceutical properties, which makes the extraction and isolation of these compounds of great economic and environmental importance. According to the literature, the extraction of tannins from jabuticaba for isolation in separation techniques has been carried out by conventional methods such as solid phase extraction (SPE). However, these techniques have a limited selectivity, in addition, a high volume of solventes is necessary, which consequently generates a large amount of waste. Thus, it is necessary to research more selective and ecologically correct methods. Thus, the present work proposed the development and optimization of an online extraction method based on molecularly imprinted polymers (MIP) used in a capillary column for the isolation and identification of condensed tannins in jabuticaba peel. Therefore, catechin was used as a template molecule for MIP and non-imprinted polymer (NIP) was synthesized for comparison studies. The sorbent characterization was performed using scanning electron microscopy (SEM), nitrogen desorption and adsorption analysis, transmission electron microscopy (TEM), infrared spectroscopy (FTIR), thermogravimetry (TG) and diffraction X-ray (XRD). The data obtained with the characterization of the phase showed similarity with the literature, regarding to the possibility of applying these materials as an extractor phase in liquid chromatography with diode array detector(HPLC-DAD). When evaluating the applicability of the column filled with the molecularly printed polymer in HPLC-DAD, it was noted that it presented good results for the extraction of catechin, especially when compared to the non-imprinted polymer. The results of the method optimization indicated that the mobile phase flow of 20 µL min-1 and injection volume of 40 µL were the best in terms of asymmetry and peak resolution, in addition to maintaining the extraction efficiency, decreasing the generation of organic residues. On the other hand, the figures of merit evaluated showed greater selectivity in the MIP in relation to the NIP for catechin, coefficients of variation from 2.6 to 7.3% between extractions, indicating excellent reproducibility of the columns and preconcentration factor of the MIP phase of 5.14%. Regarding the reuse capacity of the columns, a value of relative standard deviation of 3.83% was found, indicating that the columns can be used more than 40 times without losing the extraction efficiency, which is consistent with the result obtained for the memory effect, in which the solvent chromatogram showed no peaks at the same retention time for catechin. The quantification of tannins condensed in the matrix using the vanillin method by the UV-vis spectrum at 500 nm, indicated a content of 59.1 µg mL-1 of the compounds present in jabuticaba's aqueous extracts based on the standard curve of catechin constructed in the concentrations of 0.01 to 1 mg mL-1, which showed relevance in terms of the choice of this matrix. Furthermore, the analyzes performed by HPLC-DAD for the real samples showed efficiency of the MIP column for catechin extraction, eliminating the interferents and concentrating the analyte.
Síntese e avaliação fotofísica de xantonas para sensores luminescentes
(Universidade Federal de Goiás, 2023-02-28) Castilho, Nathália Santos; Coelho, Felipe Lange; http://lattes.cnpq.br/2304463718940575; Severino, Vanessa Gisele Pasqualotto; http://lattes.cnpq.br/0286065758729632; Severino, Vanessa Gisele Pasqualotto; Coelho, Felipe Lange; Kato, Lucilia; Lima, Dênis Pires de
Organic compounds that have in their structure an abundance of π electrons, rigidity and unsaturation occupy a prominent position in photophysical research. The compound 2-(2'-hydroxyphenyl) benzazole, known as cyclobenzazole, is widely studied in photophysics due to its fluorescence emission by the existence of the ESIPT mechanism. In this way, the luminescence of xanthones has been considered, since they present structural similarity with the cyclobenzazole. By synthesizing functional xanthones, new structures may have wide application, such as for fluorescent sensors. In this study, three 1-hydroxy-9H-xanthen-9-one derivatives (1,3-dihydroxy-9H-xanthen-9-one, 1,3-dihydroxy-4-nitro-9H-xanthen-9-one, one and 4-amino-1,3-dihydroxy-9H-xanthen-9-one) were synthesized and evaluated their photophysical properties, as well as the fluorescence emission mechanism of such compounds. In the photophysical evaluation, solutions with dichloromethane, ethanol and acetonitrile were used, at a concentration of 10-3 M. When measuring the maximum absorption of the compounds in the three types of solvents, it was verified that there was no significant variation, since there was no interaction between them. In the emissions, different interactions of the compounds with the employed solvents suggested the existence of a keto-enol equilibrium and the possible ESIPT mechanism, which would explain the fluorescence emission. The synthesis of the compound 5-hydroxy-2-(2-hydroxyphenyl)-6H-xanthen-[4, 3-d]-oxazol-6-one, derived from xanthone and with the benzazole ring in its structure, was developed, still requiring optimizations in the process. However, it was observed that at basic pH the structure emits a significant amount of fluorescence and can be used as a sensor. Therefore, new studies are suggested for a more in-depth photophysical evaluation and expansion of the chemical applicability of the synthesized structures.
Reação de Claisen-Schmidt catalisada por carvões ativados de origem vegetal
(Universidade Federal de Goiás, 2020-03-27) Catharin, Caroline Winter; Chaves, Andréa Rodrigues; http://lattes.cnpq.br/6064014965252121; Noda Pérez, Caridad; http://lattes.cnpq.br/8518548259609686; Noda Pérez, Caridad; Ostroski, Indianara Conceição; Oliveira, Sérgio Botelho de; Henriques, Cristiane Assumpção; Rosseto, Renato
Claisen-Schmidt reaction allows chalcones synthesis, which present biological activity of great interest, as anticancer, by acid or basic catalysis. Activated carbons were prepared with vegetable biomass from domestic or industrial waste, as pequi external mesocarp and shells, coffee grounds and malt bagasse by dehydration with sulfuric acid (98%), washed with distilled water until pH 4 and dried. A portion of prepared carbons were subjected to an alkaline treatment with NaOH 2 mol/L solution and washed with distilled water to pH 8 and dried. Additionally, activated carbons from babassu powdered and granulated, obtained by the industrial process of physical activation, were submitted to the same alkaline treatment. Carbons were characterized by scanning electron microscopy (SEM), thermogravimetry (TG), differential thermal analysis (DTA), textural analysis, infrared spectroscopy (FT-IR), X-rays diffraction (XRD), CHNS elemental analysis and determination of acid and basic sites by the Boehm method. The prepared carbons were tested as catalysts on Claisen-Schmidt condensation reaction between Acetophenone and 4-nitrobenzaldehyde using methanol as solvent at room temperature for 24 h. The conversion of acetophenone was evaluated on HPLC. The highest conversion among carbons produced by dehydration was obtained for coffee grounds carbon with basic characteristics, 64.19%. Among carbons with acid characteristics, the best conversion was 61.70%, for carbon obtained from pequi shell. The reuse test of the activated carbon from pequi shell with acidic characteristics for the reaction under study provided a conversion of 46.50%. Among the industrial carbons, the best was the granulated, achieving conversion of 69.26%. The kinetic study of Claisen-Schmidt reaction was carried out with treated industrial granular carbon, as it showed a higher conversion than the pulverized one and less operational difficulties in a continuous reactor. The reaction kinetics of second global order and the rate constants were determined at 35°C and 50°C. The activation energy calculated for this reaction was 18.91 kJ/mol. The conversion in a fixed bed continuous reactor for 1:1 molar ratio of reactants, with acetophenone and 4-nitrobenzaldehyde initial concentration of 0.05 mol/L, achieved 60.23% in 10 min with ascending flow, for a period of 90 min. Another reaction of aldol condensation was evaluated with NaOH-treated granulated babassu catalyst to obtain (1E,4E)-1-(4-nitrophenyl)-5-(2,6,6-trimethyl-1-ciclohexen-1-yl)-1,4-pentadien-3-one. The reaction was conducted between 3 mmol of β-ionone and 2.5 mmol of 4-nitrobenzaldehyde at 27°C and 55°C. After only 1 h of reaction at 55°C the conversion achieved over 4-nitrobenzaldehyde was 63.95%, while at 27°C it was 28.87%. The specific speed constants and activation energy obtained for the reaction demonstrated the production of this compound is strongly affected by temperature. After 4.5 h of reaction the yield achieved was 82%, indicating a great potential for activated carbons from vegetable source in heterogeneous catalysis.
Tecnologia supercrítica aplicada ao tratamento de águas contaminadas por fármacos
(Universidade Federal de Goiás, 2022-04-29) Dias, Isabela Milhomem; Alonso, Christian Gonçalves; http://lattes.cnpq.br/7285754665946583; Alonso, Christian Gonçalves; Silva, Fábio Moreira da; Freitas, Fernanda Ferreira; Sgobbi, Lívia Flório; Coltro, Wendell Karlos Tomazelli
The growth of the world population has led to the increased disposal of pharmaceutical products in the environment. Also, a wide variety of drugs used for the prevention and treatment of diseases have a low metabolic rate in humans and are often released into the environment in their unaltered form. These contaminants may offer potential risks to human health and the ecosystem. As a consequence, water is one of the most affected parts, because it is involved in various human activities. Currently, there are several processes used in water treatment, which use physical, chemical, and biological methods to remove pollutants from wastewater. However, methods of wastewater treatment have not demonstrated efficiency for the complete degradation of these compounds, or they are often impractical to treat a large volume of residues. With regard to the need to effectively treat these pollutants, this study presents the investigation of the supercritical water oxidation (SCWO) process applied in the treatment of aqueous residues contaminated with pharmaceuticals using a continuous flow reactor. For this purpose, it was investigated the degradation of amoxicillin in industrial pharmaceutical effluent, antibiotics, anxiolytics/antidepressants, and antihypertensive/cardiovascular drugs in an aqueous solution. Reaction tests were separated by therapeutic classes. In that way, a total of 20 drugs were evaluated. For all four scenarios related to each pharmaceutical class, the conditions of temperature, flow rate, and H2O2 concentration were optimized to maximize the total organic carbono removal rate (%RCOT). In the degradation of industrial effluent contaminated with amoxicillin, both temperature and flow parameters had the greatest effect on the %RCOT of the liquid phase, whose maximum value reached was 60.1%. In the gaseous product, the formation of H2, CO2, and CH4 stood out with a total volumetric flow of 6.45 mL/min. In the degradation of 6 antibiotics in an aqueous solution, the temperature was the most significant effect to achieve a %RCOT of 64.1%. The gaseous product, mostly H2 and CO2, had a total volumetric flow rate of 18 mL/min, a value almost 3 times greater than the feed flow rate. During the degradation of 5 anxiolytic/antidepressant contaminants, both parameters of temperature and H2O2 concentration had the greatest impact on %RCOT (85.9%). The total gas flow rate was 11 mL/min and, once again, among the 6 gases determined in the gaseous product, H2 and CO2 were more relevant. In the treatment of cardiovascular/antihypertensive drugs, the maximum %RCOT achieved was 92.1%, and both temperature and H2O2 concentration parameters had the greatest influence on this response. CO2 (98%) was the major constituent of the gas composition that had a total volumetric flow of 26.3 mL/min, which corresponds to twice the feed flow rate used. Briefly, for most of the four scenarios studied, the optimized conditions of temperature, flow rate, and H2O2 concentration were approximately 692°C, 6.6 mL/min, and 292% (m/m), respectively. With an exception in the cardiovascular/antihypertensive degradation condition that occurred at a lower temperature (601°C), intermediate flow rate (13.3 mL/min), and low H2O2 concentration (65%; m/m). Furthermore, for all cases evaluated, most of the limits recommended by national and international legislation regulating water quality were met. In the toxicity essays, exposure to the microcrustaceans Artemia salina revealed toxicity for some treated samples. The lethal concentration, in %(v/v), to kill 50% of the population (LC50) were approximately 12%, 555%, 32%, and 4% for industrial effluent with amoxicillin, and for all aqueous solution with antibiotics drugs, anxiolytic/antidepressant drugs, and cardiovascular/antihypertensive drugs, respectively. Given that, the SCWO technology applied to the treatment of wastewater contaminated with drugs revealed simultaneously, high oxidative power of organic matter and production of valuable energy gases, such as H2, methane, and synthesis gas. The toxicity of some molecules produced is a challenging issue to be addressed. However, due to the high oxidative power, volume and speed of waste processing, the positive contributions of SCWO in the treatment of aqueous waste are undeniable.

Navegar

Navegando Programa de Pós-graduação em Química por Por tipo de Acesso "Attribution-NonCommercial-NoDerivatives 4.0 International"

Resultados por página

Opções de Ordenação