Química
URI permanente para esta coleçãohttps://solaris.ufnt.edu.br/handle/123456789/56
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27 resultados
Resultados da Pesquisa
Item QUESTÕES SOCIOCIENTÍFICAS EM TEXTOS DE DIVULGAÇÃO DA CIÊNCIA: CONTRIBUIÇÕES PARA A EDUCAÇÃO CIENTÍFICA(2025-07-03) ALVES, Walisson DamasioThis research investigated the presence of socioscientific issues (SSIs) in popular science texts (SCTs) and their contributions to scientific education training. Based on a qualitative approach and grounded in content analysis, ten popular science texts published in the journal Ciência Hoje were examined. These texts address themes involving moral, environmental, ethical, political and social dilemmas that are configured as Socioscientific Issues of global relevance, thus indicating texts with formative potential for scientific education. Thus, the analysis of the presence of SCIs in these texts indicated that the relationship between SCTs and SSIs is based on three fundamental formative dimensions: the development of critical and politicized reading, the mobilization of scientific concepts and the stimulation of informed decision-making. These dimensions, when articulated, can favor the formation of subjects capable of understanding science as a social practice, and of looking critically at the development and application of S&T.Item PERCEPÇÕES DAS ESTRATÉGIAS DE LEITURA EM TEXTOS DE DIVULGAÇÃO CIENTÍFICA NA FORMAÇÃO INICIAL DE PROFESSORES(2025-07-01) SILVA, Thauane Maria Pereira daThis study aimed to understand the perceptions of Chemistry teachers, both in initial and continuing education, regarding the use of reading strategies applied to popular science texts. The research was motivated by the need to include, in teacher education programs, activities that value reading as a formative practice, focusing on the development of reflective educators capable of understanding the reality in which they are inserted. A qualitative methodological approach was adopted, supported by quantitative data. The study involved the development of a popular science text entitled An Invisible Science: Black Scientists and Their Scientific and Social Contributions in the Field of Chemistry, accompanied by a guided reading script based on the reading strategies proposed by Isabel Solé (1998), structured in three stages: before, during, and after reading. This material was applied in a short course during the II Academic Week of Chemistry at the Federal University of Northern Tocantins (UFNT), with the participation of ten undergraduate students. After the activity, a questionnaire with open and closed questions was administered. The data were analyzed using content analysis, as proposed by Bardin (2016), and organized into five a priori categories. The main results indicated that the reading of popular science texts, mediated by well-structured strategies, was perceived as a useful resource to support content comprehension, promote reflection, and encourage engagement with the topics addressed. Additionally, it allowed participants not only to access scientific content but also to critically reflect on the historical, social, and epistemological contexts of scientific production and the Black representation in Chemistry. The limited familiarity reported by students regarding the strategies used highlights a gap still present in teacher education programs, which are mostly based on technical and non-dialogical approaches. It was concluded, therefore, that the applied reading script proved to be effective in both fostering discussions about the themes presented in the popular science text and broadening the perspectives of student teachers regarding teaching and the formative role of this type of text in science education.Item CARACTERIZAÇÃO ESPECTROSCOPICA, CROMATOGRÁFICA E COMPOSIÇÃO NUTRICIONAL DO ALHO-PORÓ (Allium sp.)(2025-07-03) CONCEIÇÃO, Pedro Rian Barros daLeek is a plant with origins associated with the region near the Mediterranean Sea, with a strong introduction into the European continent. The plant is generally classified as Allium porrum L., Allium ampeloprasum L., or Allium ampeloprasum var. porrum L. Used for various applications throughout history, this vegetable belongs to the same family as garlic and onion (Amaryllidaceae). This study aimed to carry out the chemical and nutritional characterization of a plant traditionally known as leek (Allium sp.) in the northern region of the state of Tocantins. The analyzed variety comes from a family farming system in the municipality of Bielândia – TO, and was cultivated in the nursery of the agronomy program at Centro Universitário Tocantinense Presidente Antônio Carlos (UNITPAC), located in the city of Araguaína – TO. Part of the physicochemical analyses was performed based on the dry matter of the foliage, allowing for the determination of ash (0.65%), moisture (96.13%), nitrogen (4.42%), and protein (27.59%). The contents of calcium (215 mg/100g), magnesium (119 mg/100g), phosphorus (502 mg/100g), sodium (79.55 mg/100g), and potassium (7.71 mg/100g) were also measured. The remaining analyses were conducted using instrumental techniques such as Fourier-transform infrared spectroscopy (FTIR) and headspace solid-phase microextraction followed by gas chromatography–mass spectrometry (HS-SPME/GC-MS). The characterization performed using the HS-SPME/GC-MS technique enabled the precise identification of 32 volatile organic compounds (VOCs) in the oil and leaves of the plant. Among the major compounds, methyl 2-propenyl disulfide, diallyl disulfide, and diallyl sulfide stood out, showing the highest areas percentages and possessing functional activities widely reported in the literature. Based on the results obtained, the leek variety studied in this work stands out as a nutritious, functional, and health-promoting food alternative for the population of northern Tocantins.Item DETERMINAÇÃO DO PERFIL QUÍMICO POR GC-MS E HPLC-DAD DE UMA NOVA CERVEJA FERMENTADA POR GRÃOS DE KEFIR E SUA COMPARAÇÃO À CERVEJA CONVENCIONAL(2022-11-22) ALMEIDA, Natália FerreiraBeer is one of the oldest and most widely consumed beverages in the world, It has a complex chemical composition characterized by amino acids, carbohydrates, minerals, and vitamins. The beverage also contributes to prevent a number of health-related problems, in addition to the constant search for innovations in the brewing industry. When combined with the nutritional and medicinal benefits of Kefir, the beverage has anti-inflammatory and anti-ulcerogenic activities. Based on this, the present work sought to analyze the chemical profile of a new beer fermented by Kefir grains by GC-MS and HPLC-DAD and make the comparison with conventional beer. For the study, three hind of beer samples were produced, one conventional, one fermented with Kefir grains at room temperature and another at controlled temperature, in order to verify the chemical composition of each one. The beers with Kefir had lower alcohol content than the conventional Barley Wine, being respectively 7.3% and 8.9%. The extraction of the compounds was done by HS-SPME, which proved to be very promising because it is a simple and sensitive technique that does not use solvents. Thirteen compounds were identified in the Kefir, being acetoin and acetic acid the most abundant. Similarly, 18 compounds were found in the beer, being ethanol, ethyl acetate, isopentyl alcohol and isopentyl acetate the most abundant. However, the conventional beer presented 4 fewer compounds compared to those with Kefir, showing that the probiotic beers have a richer chemical profile. By extraction of the fractions by SPE, it was found that the beers had hydrophilic compounds, highlighting the style of beer adopted, and the presence of phenolic compounds such as flavonoids, including rutin and quercetin. It was verified that despite the difference in the yeast used, the chromatographic profiles were very similar, i.e., even changing the form of fermentation the same product, beer, was obtained. Finally, by means of statistical analysis, PCA, HCA and PLS-DA, it was found that the beers fermented with Kefir grains had greater similarity between them than with conventional beer.Item EDUCAÇÃO ESPECIAL INCLUSIVA NO ENSINO DE QUÍMICA: UMA ANÁLISE DOS ANAIS DO ENEQ (2014-2024)(2025-06-16) ROCHA, Leiliane CassianoThis study aims to understand what the articles published over the last ten years (2014–2024) in the proceedings of ENEQ (National Meeting on Chemistry Education) say about Inclusive Special Education in Chemistry Teaching in basic education. It focuses on discussing the inclusion of students with special educational needs in basic education, with an emphasis on Chemistry teaching. It concludes that inclusive special education still represents a major challenge for Brazilian education, due to a series of interconnected factors. Although there have been legal and regulatory advances — such as the National Policy on Special Education from the Perspective of Inclusive Education and the Brazilian Law of Inclusion (Law No. 13.146/2015) — the effective implementation of these guidelines faces both structural and cultural barriers.Many schools are still not adequately prepared to receive students with disabilities, whether due to the lack of physical accessibility, the scarcity of appropriate pedagogical resources, or the absence of trained professionals. In addition, there is a significant lack of continuing education for teachers and other education professionals, which compromises the quality of inclusion.We believe that inclusion, in order to be effective, requires more than just the physical presence of the student in the regular classroom; it demands differentiated methodologies, adapted assessments, and a welcoming school culture — all of which are still far from being a reality in most public institutions.Thus, we hope that the data and reflections resulting from this investigation can support more effective public policies, contribute to the continuing education of teachers, and promote the creation of more accessible school environments. These should aim to establish effective conditions for the participation of people with disabilities in social and labor activities, thereby expanding their ways of engaging with knowledge.Item DETERMINAÇÃO DO PERFIL QUÍMICO VOLÁTIL DO BOLDO CHILENO (Peumus boldus Molina) E DO BOLDO BRASILEIRO (Plectranthus barbatus Andrews) POR HS-SPME/GC-MS(2025-06-27) SILVA, Karen Leticia Gomes daCommonly confused in both popular and scientific contexts due to similarities in their nomenclatures and traditional uses, the Brazilian and Chilean boldo species exhibit relevant chemical differences. These distinctions highlight the importance of investigating their chemical composition, particularly through systematic studies that allow for clear differentiation. In this context, the present study aimed to determine the volatile chemical profile of Peumus boldus Molina (Chilean boldo) and Plectranthus barbatus Andrews (Brazilian boldo) using the HS-SPME/GC-MS technique with a polydimethylsiloxane (PDMS) fiber. GC-MS analyses enabled the identification of 60 volatile organic compounds (VOCs), with 32 detected in P. boldus and 28 in P. barbatus, mainly comprising constituents from the monoterpene and sesquiterpene classes. The major compounds identified in P. boldus were 1,8- cineole (19.16%), trans-ascaridole (18.96%), and β-oplopenone (11.64%). Furthermore, this species exhibited 44.38% of oxygenated compounds and 19.57% of hydrocarbons. In contrast, P. barbatus was characterized by α-selinene (23.20%), (E)-caryophyllene (19.58%), and α- copaene (13.64%), with a predominance of hydrocarbon sesquiterpenes (83.68%). In summary, the study individually characterized the volatile chemical profiles of P. boldus and P. barbatus, providing relevant data to support future comparative investigations, especially in light of the recurring conceptual confusion surrounding the use of these species.Item Perfil químico do chá verde (camellia sinensis): identificação da cafeína e dos compostos voláteis por hplc-dad, gc-ms e ftir(Universidade Federal do Norte do Tocantins, 2024) CARVALHO, Erik almeidaEspecificamente, os chás vêm sendo amplamente reconhecidos como a segunda bebida mais consumida atualmente, apresentando fontes significativas de cafeína e compostos fenólicos, que possuem alta atividade antioxidante. Os compostos antioxidantes são substâncias que agem diminuindo os efeitos ocasionados pelos radicais livres e dentre outros compostos antioxidantes. A cafeína é um alcaloide, que pertence ao grupo das metilxantinas, também denominado como 1,3,7-trimetilxantina, que pode ser ou ainda, trimetildioxipurina. Além disso, a cafeína está presente em diversas plantas: folhas, sementes, raízes, cascas e alguns alimentos. O presente trabalho propôs-se analisar e identificar os compostos presentes em amostra de chá verde e cafeína presente no chá verde e chá preto através das técnicas (Headspace Solid Phase Microextraction/Gas Chromatography–Mass Spectrometry), HPLC-DAD (High Performance Liquid Chromatography-Diode Array Detector) e FTIR (Fourier Transform Infrared Spectroscopy). Sendo assim, os resultados mostraram-se promissores em relação a caracterização e investigação dos compostos voláteis e cafeína. A análise por GC-MS foi satisfatória, pois possibilitou analisar os compostos voláteis presente no chá verde, bem como a análise por HPLC-DAD, que evidenciaram a absorção da cafeína no UV com pico máximo de absorção em 262 nm e 268 nm. As análises por FTIR permitiram identificar e evidenciar a similaridade entre bandas de absorção do extrato de chá verde e extrato de chá preto em relação aos grupos funcionais presentes. Este estudo representou uma proposta simples e acessível para a identificação dos compostos voláteis no chá verde e caracterização da cafeína no chá verde e preto, com perspectiva para futuras aplicações em larga escala.Item Otimização e Validação do Método QuEChERS-CG/EM para Análise de Dieldrin em Peixe.(Universidade Federal do Norte do Tocantins, 2025) SOUSA, Sérgio williams ferreiraApós a síntese dos organoclorados, no período da Segunda Guerra Mundial, houve uma aplicação em larga escala devido a diversos incentivos de uso, pois apresentavam alta eficácia no extermínio de pragas em plantações e vetores de doenças, como malária e dengue, em que países tropicais, incluindo o Brasil, sofriam com epidemias. Porém, não eram conhecidos os efeitos secundários que vinham a afetar a fauna e a flora, pois os organoclorados sofrem biotransformações para moléculas bioacumuláveis promotoras de diversos cânceres e distúrbios no sistema endócrino. Hoje estão na classe de produtos altamente perigosos, tornando-se banidos globalmente devido à estabilidade molecular dos organoclorados, que proporciona contaminações até os dias de hoje e em diversos lugares do mundo. Logo, podem ser encontrados nos tecidos adiposos de diversos seres, principalmente os aquáticos, sendo os peixes uma das principais formas de alimento ao homem. Diante disso, é justificada a otimização e validação de um método que possa identificar e quantificar o organoclorado dieldrin em matriz de peixe utilizando o QuEChERS junto à técnica de cromatografia a gás acoplada ao espectrômetro de massas. A otimização nas configurações dos parâmetros da corrida cromatográfica resultou em um tempo de retenção do dieldrin aceitável. Conseguinte da plotagem da curva de calibração, com dieldrin em acetonitrila junto à sobreposição da matriz, comprovando o efeito matriz de -21% que é proporcionado pela variedade de compostos complexos orgânicos presentes na amostra. A plotagem ainda mostra que valores acima do valor de LQ de 50 μg L-1 podem ser a faixa linear de trabalho com alta confiança, devido às práticas serem realizadas e validadas pelas normas dispostas pela ANVISA.Item Estudo e análise dos voláteis das folhas de Nim por clevenger e cg-em(Universidade Federal do Norte do Tocantins, 2023) MONTEIRO, elder silva pazA árvore nim (Azadirachtina indica A. Juss) é popularmente conhecida por suas propriedades medicinais, terapêuticas, farmacológicas, biocontroladora, antisséptica, cicatrizante e imunoestimulante, devido a presença de compostos orgânicos pertencentes à várias classes químicas com atividades biológicas. Devido a estes atributos, o nim possui grande potencial econômico e tem sido utilizada em todo o mundo. No presente trabalho, realizou-se a extração e caracterização química do óleo das folhas de nim coletadas na Universidade Federal do Norte do Tocantins (UFNT), Campus Cimba, localizada em Araguaína, Tocantins. Para extração do óleo foi empregado o sistema Clevenger, já para a concentração e caracterização dos voláteis utilizou-se o método HS-MEFS/CG-EM. O rendimento médio obtido do óleo foi de 0,3 g. Comparando-se com do óleo de sementes de nim este rendimento é inferior, entretanto para as análises realizadas foi satisfatória. Um total de 52 compostos voláteis foram detectados, sendo que destes, cinco tiveram sua identificação confirmadas pelo índice de Kovats: acetato de etila, 96,3 %; (E)-1(Prop-1-eno-1-il) -3-propiltrisufano, 76,6 %; n-hexano, 62,7 %; 2,4-hexenol Z, 68,9 %; 2-metil, 2-ciclopenteno 6 %. Alguns voláteis tiveram suas bioatividades reportadas e correspondem com os benefícios conhecidos do nim. Desse modo, considera-se esses constituintes químicos parte do efeito sinérgico da planta.Item DO LABORATÓRIO DE PEQUISA PARA A SOCIEDADE: Democratização da ciência por meio da produção de texto de divulgação científica.(Universidade Federal do Norte do Tocantins, 2024) ALMEIDA, Martha cristina deAs pesquisas científicas desenvolvidas nas universidades brasileiras, apesar de serem socialmente relevantes, raramente estão disponíveis para o livre acesso do público em geral em uma linguagem acessível. Considerando essa problemática, o presente trabalho tem como objetivo produzir um texto de divulgação científica (TDC) a partir de uma pesquisa científica realizada no laboratório de físico-química e no âmbito do projeto de pesquisa “Análises Físico-Químicas e Microbiológicas da Água Utilizada para Consumo no Município de Araguaína e Região” vinculado à Universidade Federal do Norte do Tocantins – UFNT. Para tanto foram delimitadas categorias indicadas na literatura que caracterizam um bom texto de divulgação científica. O texto produzido indica potencialidades para o ensino de Química, para a aproximação entre os jovens e a Ciência por meio de uma linguagem clara e dialógica e abre caminhos para consolidar parcerias entre cientistas e divulgadores da Ciência.
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