Programa de Pós-graduação em Química

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Aplicações de espectrometria de massas ambiente em metabolômica clínica
(Universidade Federal de Goiás, 2019-12-07) Andrade, Thais Pontes Pereira Mendes de; Vaz, Boniek Gontijo; http://lattes.cnpq.br/7814534710550639; Vaz, Boniek Gontijo; Chaves, Andrea Rodrigues; Duarte, Gabriela Rodrigues Mendes; Gil, Eric de Souza; Pinto, Mauro Cunha Xavier
Most clinical biofluids studies are based on plasma/serum and urine, which are more free and representative models of general metabolism. Each of these fluids has a unique matrix, comprising different levels of proteins and metabolites. Therefore, it is important to optimize sample preparation and analytical methods to achieve comprehensive coverage of the analytes present in these samples. In this context, Ambient Mass Spectrometry (AMS) arises, which is a family of desorption and ionization techniques that have revolutionized the way of obtaining ions in mass spectrometry. These techniques share the ability to generate ions in the gas phase directly from untreated samples, reducing or virtually eliminating analyte extraction and prior separation. Substrate Electrospray Ionization are ionization techniques in AMS, which comprise, for example, Paper spray ionization (PSI) and Probe electrospray ionization (PESI). In this study, two analytical approaches are proposed in clinical metabolomics using PSI and, also, the development of a new Substrate Electrospray Ionization. The first approach is the use of a paper coated by a molecularly printed polymer (MIP) as a substrate for PSI in metabolite analysis: dopamine, sarcosine and butyric acid in artificial urine. This new substrate was highly selective for the desired targets, in addition to minimizing the effects of common ion suppression on PSI. In addition, calibration curves with R2> 0.99 and limits of detection (LOD) and quantification (LOQ) in the ppb range were obtained. In addition, success was obtained when using this technique for the analysis of dopamine in a real sample. In the second approach, PSI was combined with a chemometric approach called Interval-successive projections algorithm linear discriminant analysis (iSPA-LDA) to detect lipid biomarkers of cervical cancer using unprepared blood plasma lipids. A total of 86 blood plasma samples from different women were collected, including 37 cancer controls and 49 healthy controls, where 8 lipids were found as possible biomarkers with an overall precision of 77%. The results show the potential of PSI associated with multivariate analysis as a complementary tool for the screening or diagnosis of cervical. It is the application of PSI in plasma samples in a non-targeted lipidic approach, with the objective of discovering biomarkers of cervical cancer. The final approach was to use graphite as a substrate for ESI. The effect of voltage, probe angle and sample volume were evaluated. The ionization capacity of several analytes, including a protein, has also been evaluated, and creatinine quantification tests have been performed on real urine samples. The ESI graphite technique was optimized and obtained excellent ionization of the analytes, not presenting ionic suppression. It was possible to determine the amount of creatinine present in the samples tested and all were within the established limits. In addition, the technique was employed in mouse brain analysis and through these analyzes combined with Principal Component Analysis (PCA) it was possible to differentiate different regions of the brain and separate the samples in male and female. With this, the graphite ESI technique proved very efficient to be used in metabolomic approaches.
Síntese e caracterização de novos complexos de maleatos de íons lantanídeos trivalentes (La3+, Ce3+, Pr3+, Nd3+, Sm3+, Tb3+ e Er3+)
(Universidade Federal de Goiás, 2020-07) Costa, Bruna de Araújo; Leles, Maria Inês Gonçalves; http://lattes.cnpq.br/1614912440064013; Arruda, Andrea Fernandes; Alves, Maria Isabel Ribeiro; Ionashiro, Elias Yuki; Siqueira, Adriana de Paula Cardoso; Leles, Maria Inês Gonçalves
New complexes of lanthanides maleates were synthesized by the stoichiometric reaction between maleic acid and lanthanides hydroxycarbonates. The complexes were evaluated by a variety of techniques such as thermogravimetry and derivative thermogravimetry (TGA/DTG), differential scanning calorimetry (DSC), simultaneous TGA-DSC, DSC photovisual (microscope coupled to DSC), Fourier transform infrared spectroscopy (FTIR), evolved gas analysis (EGA) using TGA-FTIR and power x-ray powder diffraction (PXRD). The results of the analysis of these compounds provide information related to the such as stoichiometry, thermal stability, degree of hydration, hydration enthalpies, the main evolved gases during pyrolysis, the coordination mode between metal and ligand and the PXRD results. This detailed study intends to contribute to the area of synthesis of lanthanide compounds, motivating the elaboration of other syntheses, survey of more properties of these compounds or future applications with different functionalities.
Fabricação e caracterização de eletrodos flexíveis visando o desenvolvimento de sensores vestíveis e sistemas microfluídicos integrados
(Universidade Federal de Goiás, 2020-08-28) Dias, Anderson Almeida; Sgobbi, Lívia Flório; http://lattes.cnpq.br/0051559038460460; Coltro, Wendell Karlos Tomazelli; http://lattes.cnpq.br/8302650734477213; Coltro, Wendell Karlos Tomazelli; Takeuchi , Regina Massako; Bertotti , Mauro; Santhiago , Murilo; Martins , Paulo Roberto
The fabrication of electrodes based on graphite and polymers has been attracting the attention of the scientific community due to some advantages, such as flexibility, facility to assemble, low cost, the possibility of wearable sensors development, and integration with microfluidic systems. Nonetheless, most fabrication processes are not environmentally friendly manufacturing, because of the use of toxic reagents. This study describes an alternative method for the fabrication of the flexible electrodes by solid-solid deposition and hot compression using plastic substrates and graphite powder, without the aid of hazardous chemicals. The electrodes were produced by applying hot pressure over the graphite powder the thermal lamination sheet. The manufacturing process for these electrodes has advantages such as low cost (about 1 unit = 0.03 Brazilian real), mechanical resistance, and versatility. The electrodes were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Raman spectroscopy, and scanning electron microscopy. These devices exhibited good current repeatability in CV for different electrodes verified by ANOVA statistical analysis. As proof of concept, the modified electrodes with bismuth were integrated into a 3D device and used for zinc analysis in sweat real samples. The modified electrodes showed linearity in a wide concentration range between 50 and 2000 ppb of Zinc (R² = 0.996) and low detection limit (4.31 ppb). The obtained results for the real samples revealed statistical agreement with the reference method (atomic absorption spectroscopy). Besides, the electrodes were integrated into a microfluidic device (µDPE-plastic microdevice with electrochemical detection) which was incorporated together through a 3D printed platform. Preliminary analyzes performed using a redox probe as model showed repeatability with a standard deviation between injections in the range of 2 and 11% and repeatability between µDPEs verified by ANOVA statistical analysis. The devices exhibited low cost (1 unit = 0.05 Brazilian real), analytical frequency of approximately 75 injections per hour, and the use of low volumes of 10 µL. The 3D platform was also accomplished at a low cost (1 unit = 2.50 Brazilian real) and proved to be essential for good repeatability between injections.
Sinterização, caracterização e estudo das propriedades dielétricas de cerâmicas de TiO2 co-dopadas com íons Nb5+, Al3+ e Cr3+
(Universidade Federal de Goiás, 2020-05-06) Lira, Stéfane Oliveira de; Franco Júnior, Adolfo; http://lattes.cnpq.br/0187547195548392; Franco Junior, Adolfo; Gonçalves, Pablo José; Araújo, Olacir Alves
Dielectric ceramics free of lead presents great interest to the scientific community due its low toxicity or absence of it. In this work, ceramic materials of aluminum, chromium and niobium doped titanium dioxide (TiO2) Ti0,995[Nb1,33(AlxCr1-x)0,66]0,005O2 with x assuming the values of 1; 0,7; 0,5; 0,3; 0,1 in mols. Such materials were obtained through solid state reaction with uniaxial and isostatic cold pressing and sintering maximum temperature of 1500 °C. Structural, optics and electrics characterization were realized via Apparent density (rap), X-Ray diffraction (XRD), Fourier transform infrared (FTIR), Ultraviolet–visible spectroscopy (UV-Vis), Raman spectroscopy and Dielectric permittivity and Impedance spectroscopy. These caracterizations indicated the formation of the tetragonal rutile phase with no spurious phases and all the samples presented 97 to 99% densification. FTIR, UV-Vis and Raman measurements confirmed the tetragonal rutile crystalline phase by means of characteristic vibrational bands, in addition to allowing the observation of the increase in defects and the reduction of the band gap with doping. The dielectric permittivity and impedance measurements prove the presence of Colossal permittivity effect (e’ ~ 106) for all the samples, increasing dielectric constant with doping. The samples high permittivity was atrtibuted to the presence of electron confinement in complex clusters of defects and the presence of potencial barriers in grain boundary.
Desenvolvimento e caracterização de métodos alternativos para prototipagem de dispositivos microfluídicos em poli(metil metacrilato) (PMMA)
(Universidade Federal de Goiás, 2020-08-26) Lobo Júnior, Eulício de Oliveira; Coltro, Wendell Karlos Tomazelli; http://lattes.cnpq.br/8302650734477213; Coltro, Wendell Karlos Tomazelli; Rubio, Mario Ricardo Gongora; Silva, José Alberto Fracassi da; Piccin, Evandro; Duarte, Gabriela Rodrigues Mendes
This thesis describes an unconventional and economical soft embossing process for the production of poly (methyl methacrylate) (PMMA) microfluidic devices. This process was developed in order to meet the demand of researchers interested in producing and developing their own microfluidic systems with the desired configurations. Basically, for the production of these devices, the microfluidic structure of interest was photographed on a poly (vinyl acetate) film (PVAc) deposited on a glass surface to produce a primary mold. Then this mold was used to produce a secondary embossed mold of hardened PDMS (S-PDMS), which was obtained by increasing the proportion of curing agent / monomer (1: 5) followed by thermal aging in an oven (200 ºC for 24 h). Then the S-PDMS mold was used to mold the microfluidic devices in PMMA via soft embossing at (220-230 ºC) and followed by thermal sealing at 140 ºC. Both the molding and sealing processes were carried out using metal clips to perform pressure. The proposed protocol ensured the molding of PMMA devices with excellent fidelity (> 94%). With the developed technique, electrophoretic microsystems (MSE), micro-drop generator devices and microwell plates were produced. These devices have been tested in the respective analytical techniques showing promising results. Specifically, to test the MSE a model mixture containing inorganic cations was used, and in a systematic comparison, the analytical performance obtained did not differ significantly from a commercial PMMA MSE. With micro-drop generator device micro-drops were produced in a rate of 60 micro-drops per minute (setting the flow rate at 100µL / h) with a size of 322 ± 6 μm. Electrophoretic separations and microdroplet generation were monitored using a capacitively coupled non- contact conductometric detection system or C4D. For the positioning of the C4D electrodes in the devices, a cavity was produced that allowed the electrodes to be positioned just 100 µm away from the microfluidic channels. Colorimetric glucose assays were performed on the plate containing microwells and a detection limit of 9.0 µmol L-1 was obtained. The results obtained for two artificial serum samples showed agreement with the label concentrations. An economical protocol for the production of PMMA thin film was also developed, which was applied for the production of MSEs and a microdroplet generating device, containing integrated electrodes with a distance of only 25 µm from the microfluidic channels. This strategy has the potential to improve detection limits with C4D in manufactured devices. In addition, an automated process was developed using a mini-drill (CNC) bench for the production of FIA device (flow injection analysis) with amperometric detection. Preliminary results with this device demonstrate the potential for applications such as the determination of metal ions in solution as well as the determination of carbohydrates in biological samples. The microfabrication process developed is capable of producing structures with minimum dimensions of width and height of the order of 30 µm. Thus, this thesis presents economic processes for the production of microfluidic devices with the potential for bioanalytical, environmental, forensic applications, among others. The microfabrication process uses low cost materials whose development was directed to be carried out in almost any research or even teaching laboratory of chemistry or biology. Additionally, despite using relatively simple technologies, the microfabrication process developed has the potential to achieve quality compatible with conventional microfabrication processes.
Síntese de carbonatos cíclicos a partir de CO2 e epóxidos catalisada por complexos metálicos com ligantes benzotiazois
(Universidade Federal de Goiás, 2020-02-14) Mata, Álvaro Farias Arruda da; Chagas, Rafael Pavão das; http://lattes.cnpq.br/9712618482518275; Chagas, Rafael Pavão das; Milani, Jorge Luiz Sônego; Castro, Danielle Cangussu de
Carbon dioxide is an abundant and renewable source of carbon, which can be used to replace fossil resources in the synthesis of various substances. This work aims to develop a catalytic system, using complexes with benzothiazole-derived ligands, for the synthesis of cyclic carbonates by the chemical fixation of CO2 by reaction with epoxides. The ligands 2-(2-hydroxyphenyl)-benzothiazole (L1) and 2-(2-pyridyl)-benzothiazole (L2) were used in the synthesis of eight complexes with the metals Zn(II) (7a and 8a), Co(II) (7b and 8b), Ni(II) (7c and 8c) and Mn(II) (7d and 8d). The synthesized compounds were characterized by nuclear magnetic resonance, elemental analysis, infrared and UV-vis absorption spectroscopy and thermal analysis. Initially, all complexes were active catalysts in the cycloaddition reaction between CO2 and propylene oxide for the production of the respective cyclic carbonate with high selectivity and conversions of 15% to 48%, under high pressure conditions. Under the same conditions, the control experiment converted only 2% of the epoxide. The catalytic system with complex Zn(L1)2 (8a) was the most active, so this complex was used in the optimization of the reaction by evaluating the following parameters: pressure, time, temperature, catalyst load and type of cocatalyst. The optimum condition was used in reactions with different epoxides, producing the respective cyclic carbonates with high conversion values. This is the first work to report a catalytic system that uses complexes with benzothiazole ligands for the synthesis of cyclic carbonates from CO2 and epoxides, demonstrating its efficiency in the chemical fixation of CO2.
Desenvolvimento de dispositivos analíticos em plataformas de papel para análises volumétricas
(Universidade Federal de Goiás, 2020-09-04) Nogueira, Sandro Alves; Coltro, Wendell Karlos Tomazelli; http://lattes.cnpq.br/8302650734477213; Coltro, Wendell Karlos Tomazelli; Souza, Aparecido Ribeiro de; Petruci, João Flávio da Silveira; Soares, Marlon Herbert Flora Barbosa; Rocha, Fábio Rodrigo Piovezani
This thesis demonstrates the development of acid-base, redox, complexometric and precipitation titrations on paper-based analytical devices (PADs) with and without the instruments such as smartphones for applications in chemical, biological, forensic, and quality control areas. The titrations in PADs present a performance similar to the classic methods using less reagents and generating less residues in a simpler platform and easier to prepared platform. The layout of the PADs was designed using a graphic software and subsequently printed on paper substrate through wax printing method. Prior to use, PADs were heated to melt the wax and create hydrophobic barriers. The acid-base titration in PAD was performed using a natural indicator prepared based on jabuticaba bark extract. Successive aliquots of titrant were added inside circular zones and the digital image was captured between each addition. The concentrations of acetic acid were determined in vinegar samples and the achieved values presented a difference between 5 and 8% when compared to conventional volumetric method. Redox titration was realized in a PAD composed of three zones folded like an origami, which were use to add the required reagents. The device was sealed with an adhesive tape at the bottom layer and successive aliquots of titrant were added to the sampling zone. The alcohol concentration was determined visually without the need for applications or software to process the color intensity. A linear behavior was observed for the concentration range from 0 to 50% (R2 = 0.992 and LOD = 2.1%). The proposed method was used to determine the alcohol content in seized whiskey samples from different brands. A total of 73% of the tested samples were correctly classified as adulterated. Redox titration was also evaluated to determine sodium hypochlorite in bleach obtaining a difference lower than 2% in comparison with the conventional method. For complexometric titration, it is necessary to use a buffer solution (pH 10) prepared with the mixture of sodium tetraborate and sodium hydroxide using eriochrome black T as an indicator and EDTA to complex the sample cation. All reagents were added in the PAD and allowed to dry prior to use. The distance of the red color formed by the cation complexation reaction was proportional to the analyte concentration. A linear behavior was observed in the concentration range between 7 and 250 mg / L of CaCO3 (R2 = 0.985 and LOD 10.74 mg / L of CaCO3). The distance-based complexometric assay was applied to determine the water hardness and calcium concentration in powdered milk sample. Finally, precipitation titration was performed on PADs by adding silver nitrate with the aid of a dropper and potassium chromate by immersing the device. After drying, the sample was added to the application zone and the concentration of chloride ions in samples of artificial saliva and physiological saline solution was obtained by measuring the distance resulting of the generated white precipitate. In the absence of any displacement, the color intensity was analyzed by a cell phone application. The linear range observed for chloride ion varied from 0.10 to 1.00% (R2 = 0.990 and LOD = 0.2%) for distance-based measurements and from 0.02 to 0.20% (R2 = 0.944 and LOD = 0.036%) for the color intensity recorded by the App. The methods proposed in this thesis did not differ significantly from classical titrations at 95% confidence level. The preparation of paper devices for titrations is simple, fast, and inexpensive. In addition, they are portable and do not require sophisticated instruments. Thus, the paper-based titrations open new perspectives for teaching analytical chemistry at all levels.
A língua(gem) como constitutiva da (re)elaboração conceitual: um estudo a partir da educação Química de surdos
(Universidade Federal de Goiás, 2020-03-31) Pereira, Lidiane de Lemos Soares; Benite, Anna Maria Canavarro; http://lattes.cnpq.br/8433607360245647; Benite, Anna Maria Canavarro; Machado, Andréa Horta; Pires, Edna Misseno; Preuss, Elena Ortiz; Mesquita, Nyuara Araújo da Silva
In accordance with the Dialectical Historical Materialism and substantiated on Marxist bases, such as Vigotski's Sociocultural Theory, and Language in the perspective of Bakhtin's Circle, this thesis is a participating research and assumed as a proposition that the meanings and senses elaborated by deaf students in chemistry classes, in a bilingual environment, are directly related to the intermediation of knowledge provided by the translators and interpreters of Libras/Portuguese, so that we express this relationship from the approach of the concept of Chemical Transformation. We analyzed the discursive interactions established during a didactic sequence, carried out in the second semester of 2016, at the Federal Institute of Education, Science and Technology of Goiás - Câmpus Anápolis. In all, eight pedagogical interventions were carried out that dealt with the concept of “Chemical Transformations”. Thirteen deaf students enrolled in the State and Federal Education Network of the city of Anápolis participated in the study, and of these, six allowed us to perform an analysis of their bilingual profiles by applying a Language History Questionnaire. The data collection instrument used was video recording, which took place from two different cameras. All pedagogical interventions went through a process of translation and transcription, and the data generated were analyzed from the Dialogic Discourse Analysis. Our results indicate that the education of the deaf is multifaceted and crossed by several singularities. Our participants, like most deaf children of hearing parents, had late access to Libras, which led to differences in their development compared to listeners of the same age. Our results also showed that our participants presented different dominances in both languages (Libras and Portuguese), and therefore different bilingual profiles. The discursive interactions during the didactic sequence allowed to analyze the ways in which the speech that circulates in the bilingual environment constitutes the elaboration of meanings and senses, both for TILS and for deaf students, so that it was explained that access to chemical thinking by of these individuals goes through processes of intermediation of dialogical relations, starting from the figure of TILS, permeated by conflicts in the negotiation of meanings and senses. However, we emphasize the importance of approaching the three levels of chemical knowledge as a way to enhance the access of deaf students to a chemical thought.
Os poderes das super-heroínas: possibilidade de discussão de conceitos científicos com estudantes do ensino médio
(Universidade Federal de Goiás, 2020-04-22) Pinto, Pollyana de Godoy; Soares, Márlon Herbert Flora Barbosa; http://lattes.cnpq.br/9698540158266610; Soares, Márlon Herbert Flora Barbosa; Mota, Rejane Dias Pereira; Mesquita, Nyuara Araújo Da Silva
This work highlights the process of investigation of science present in the powers of super heroines, by students of public high school in Goiás. Also emphasizing the evolution of the female presence in superhero films, which establishes the encouragement in women in more diverse spaces. The objective of this work was to verify if there was a possibility to relate the fictional powers contained in the characters with formal science. Also, to analyze the scientific level to which these students belonged. The work was carried out in a state college in the metropolitan region of Goiânia with four high school classes, the first two years, a second year and a third year. In total 122 students participated in the work. The students chose eleven super heroines, within the criteria that they themselves defined. They conducted research on the disciplines that best explained their powers, produced written works and oral presentations. The level of approximation between students' previous concepts and scientific concepts in the explanation of powers was evaluated. The results show that the strategy was satisfactory, since 58% of the concepts investigated by the students had a level of approximation with the scientific concept. The data show us that there was involvement and perspective from the students, and that this theme, guarantees motivation allowing a more pleasant science teaching to students.
Síntese, caracterização e propriedades magnéticas de complexos homo e heterobimetálicos com o ligante 2,2-difeniletil (oxamato)
(Universidade Federal de Goiás, 2020-01-31) Prado, Joice Ferreira do; Gomes, Danielle Cangussu de Castro; http://lattes.cnpq.br/5709288358367849; Chagas, Rafael Pavão das; Martins, Paulo Roberto; Quintino, Michelle Pereira; Souza, Aparecido Ribeiro de; Gomes, Danielle Cangussu de Castro
Initially, studies were carried out regarding the syntheses and characterizations of the oxamate ligand (EtH2dipea) and two new precursors [Me4N]2[Cu(dipea)2] and [Bu4N]2[Cu(dipea)2]. For preliminary studies, the synthesis and characterization of the lanthanide complexes (Dy, Eu, Gd, and Tb were also addressed. Taking as a starting element the precursor [Bu4N]2[Cu(dipea)2], were obtained from three new complexes heterobimetallics: {[CoCu(dipea)2]}n, {[NiCu(dipea)2]}n e {[MnCu(dipea)2]}n, which studies on the magnetic properties were carried out. These complexes exhibited ferromagnetic behavior with critical temperature 11.5 k for {[CoCu(dipea)2]}n, 3.92 k for {[NiCu(dipea)2]}n and 23.1 k for {[MnCu(dipea)2]}n. All the compounds obtained in this work were characterized by means of melting point, elemental analysis, vibrational spectroscopy in the infrared region and solubility. The EtH2dipea ligand was also characterized by nuclear magnetic resonance for hydrogen (RMN-1H) and carbon (RMN-13C) and mass spectrometry. For the precursors [Me4N]2[Cu(dipea)2] and [Bu4N]2[Cu(dipea)2]), thermal analysis was also used (TG and DTA) and monocrystal X-ray diffraction. For complexes with lanthanides [Me4N]3[Dy(dipea)3], [Me4N]3[Eu(dipea)3], [Me4N]3[Gd(dipea)3] and [Me4N]3[Tb(dipea)3] optical emission spectrometry with inductively coupled plasma, absorption spectroscopy in the ultraviolet and visible region and thermal analysis (TG and DTA) were also performed. And for the heterobimetallic complexes {[CoCu(dipea)2]}n, {[NiCu(dipea)2]}n e {[MnCu(dipea)2]}n atomic absorption spectrophotometry, absorption spectroscopy in the ultraviolet, visible and thermal analysis (TG and DTA) and powder X-ray diffraction
Viabilidade da utilização do óleo de baru na síntese de poliuretanas
(Universidade Federal de Goiás, 2020-01-24) Rosa, Gabriel Marques; Lião, Luciano Morais; http://lattes.cnpq.br/2647529909397336; Liao, Luciano Morais; Souza, Aparecido Ribeiro de; Braghiroli, Rodrigo; Oliveira, Gerlon De Almeida Ribeiro; Alves, Eliane Santana Fernandes
In this work, the feasibility of using oil extracted from baru seeds in the synthesis of polyurethanes was studied. From raw seeds purchased from traders in the city of Iporá located in the state of Goiás, the oil was extracted and in order to study the polyol obtained, a factorial design 22 was carried out, changing the synthesis conditions. The bio-polyols obtained were then characterized via Acidity Index (IA), Hydroxyl Index (IOH), Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), Differential Scanning Calorimetry (DSC) and Gravimetry Term (TG). It was possible to observe that baru oil polyols were synthesized in all studied conditions, obtaining different levels of hydroxylation, diversifying its use. The preparation of the polymeric materials involved polyaddition reactions of a polyol (Baru biopolyols obtained under different synthesis conditions) and an isocyanate (TDI, mixture of isomers). The formation of polyurethanes was confirmed by Infrared Spectroscopy with Fourier Transform, where all samples had hydrogen bonds in the NH groups of the polyurethane, the low frequency (around approximately 3370 cm-1) evidences hydrogen bonds between the rigid and flexible. The DSC results demonstrated that there is an increase in Tg for polyurethanes synthesized with more hydroxylated bio-polyols, thus producing more rigid polyurethanes. SEM analyzes revealed polyurethanes with different morphologies, the presence of heterogeneous shapes and sizes on the polymer surfaces. Therefore, the results obtained demonstrated that the synthesis conditions generate polyols with different degrees of hydroxylation resulting in polyurethanes with different characteristics.
Vulnerabilidade de aquíferos e urbanização no entorno de cemitérios: o caso da cidade de Valparaíso de Goiás
(Universidade Federal de Goiás, 2020-02-27) Saba, Elias Divino; Oliveira, Anselmo Elcana de; http://lattes.cnpq.br/0369339073291948; Oliveira, Anselmo Elcana de; Oliveira, Sérgio Botelho de; Cavalcante, André Luis Brasil; Chaves, Andréa Rodrigues; Alves, Maria Isabel Ribeiro
This study evaluated the influence of decomposition of deposited bodies in Jardim Metropolitano Cemetery, Valparaiso, Goiás, and the consequent formation of necrochorume on groundwater and local soils. Data collection took place from 2007 to 2018. During this follow-up period three monitoring wells were monitored within the cemetery area whose parameters alkalinity, pH, dissolved oxygen, conductivity, color, hardness, turbidity, iron content, total dissolved solids, chemical oxygen demand, biological oxygen demand and groundwater microbiological. According to the obtained results, the median values of the physicochemical parameters are not above the allowed by the Brazilian legislation. Redundancy Analysis (RDA), employed by the CANOCO software, made it possible to identify the most relevant physicochemical parameters at the collection sites and in the years 2007 to 2018, allowing to differentiate and classify the water samples. Thus, it was possible to correlate the results of chemical, chemical and microbiological, and identify the sites most conducive to contamination, concluding that there was influence of the cemetery on changes in the potability indices of aquifers, but within the normative limits used. This is due to the region's soil, which being a later tropical soil, is able to purify or necrochorume before reaching the aquifer. Pollution in artesian wells used by the population near the cemetery was found to be caused by poor conditioning and dumping of waste and effluents.
Desenvolvimento e acoplamento por deslizamento vertical de dispositivos microfluídicos colorimétricos e eletroquímicos baseados em papel usando suporte impresso em 3D para detecção multiplexada de metais
(Universidade Federal de Goiás, 2020-02-17) Silva Neto, Habdias de Araujo; Coltro, Wendell Karlos Tomazelli; http://lattes.cnpq.br/8302650734477213; Coltro, Wendell Karlos Tomazelli; Paixão, Thiago Regis Longo César da; Chaves, Andréa Rodrigues
As the world population increases at a rate of 80 million per year, this behavior requires an increase on demand for essential resources such as food, fuel and fiber, causing agribusiness companies to intensify the exploitation of natural resources. However, they negatively affect the environmental compartments of the region, such as fluvial systems with metal pollutants. Thus, various analytical methods have been reported to detect and quantify metals in environmental samples, such as atomic absorption spectroscopy, coupled plasma mass spectrometry and coupled plasma atomic emission spectrometry. However, these detection systems require a long training time and high financial investment, which make research on environmental pollutants in developing countries difficult. Here, we report for the first time the integration of a paper-based electrochemical and colorimetric device (ePAD and μPAD) through vertical sliding coupling on three-dimensional printed support for multiplexed detection of Zn, Cd, Pb, Fe, Ni and Cu in a water sample from the Meia Ponte River. It was possible to manufacture 90 μPADs and 140 ePADs using a chromatographic and vegetal paper, respectively. In addition, the cost price of the device was c.a. 0.03 USD (R$ 0,1), considering the paper, conductive inks, and plastic material. The combination of the electrochemical and colorimetric detection methods of the proposed analytical system did not statistically interfere with the signal of simultaneous detection of metals (significance level <95%), enabling the multiplexed detection of six metals.During the proof-of-concept, the method showed a fast analysis time (10 min), good analytical frequency (36 analyzes per hour) and detection limits were 1.46 (Zn), 1.26 (Cd) and 0.51 (Pb ) μg L-1 for electrochemical detection and 0.14 (Fe), 0.33 (Ni) and 0.15 (Cu) mg L-1 (colorimetric detection). Furthermore, the proposed method successfully demonstrated the detection of metals in Meia Ponte River water samples (range 16 to 786 μg L-1), in the recovery studies (76 to 121%) and when compared with the atomic absorption spectroscopy method (significance level of 95%). Thus, the integration of ePAD and μPAD by vertical sliding was efficient for multiplexed analysis of heavy metals and can be exploited to monitor metallic pollutants in industrial process residues, by environmental inspection agencies and in river water samples.
O Jogo e a teoria do processamento da informação no ensino de geometria molecular
(Universidade Federal de Goiás, 2020-04-28) Silva, Cleberson Souza da; Soares, Márlon Herbert Flora Barbosa; http://lattes.cnpq.br/9698540158266610; Soares, Márlon Herbert Flora Barbosa; Eichler , Marcelo Leandro; Santos , Jane Darley Alves dos
This research developed and evaluated a game based on the Theory of Information Processing, particularly, on the Computational Theory of Mind with the objective of enabling the learning of concepts related to Molecular Geometry. The Theory of Information Processing is a descriptive model that explains how the human mind processes the information it receives, thus, the Computational Theory of Mind is a type of Theory of Information Processing that lists concepts such as symbol, input, output and processing for explain the processing of information in the mental structure of individuals. In this dissertation, based on the Computational Theory of Mind, a board and card game called: GeomeQuímica, which has in its scope themes such as: Molecular Geometry, Polarities of Molecules and Angle of Bond. The main idea of this dissertation was that from the elaborated game it was possible to provide an adequate process of construction of the knowledge of concepts related to Molecular Geometry. For this, this research was characterized as a qualitative case study. It is important to highlight that in a qualitative research, the researcher does not remain distant from his object of study, on the contrary, he is within the field of analysis trying to capture the meanings of the phenomena he is studying. Thus, the author of this dissertation, and a teacher at a public school of Basic Education located in the city of Luziânia in the state of Goiás in Brazil, invited his students from two classes of the first grade of High School to participate in the aforementioned game. In one class, students participated in the game from an application perspective in which it was considered Didactic and in the other as Pedagogical. Didactic Game is that game that the teacher usually uses to reinforce content that he has already taught. On the other hand, the Pedagogical Game is one that students participate before they have even studied about the subject addressed, in order to learn from the game. While the students participated in the game, their speeches were recorded using audio and video, and later transcribed and analyzed using the Content Analysis technique. The students' speeches generated the following five categories of analysis: Doubts involving the Operation and the Rules of the Game; Evaluation; Mathematical concepts; Chemical Concepts and Associative Networks. From these categories it was possible to perceive that during the game the students presented typical characteristics of the game as pleasure, fun and little competitiveness. We infer, through the analysis of the categories, that when the students participated in GeomeQuímica acting as Didactic Game, it managed to enable a greater learning of the concepts covered. On the other hand, GeomeQuímica acting as a Pedagogical Game was able to favor learning from error, which is often not done by schools. Thus, it was possible to approximate the most relevant concepts of the Computational Theory of Mind with the concepts of Piaget's Genetic Epistemology as: symbol corresponding to scheme; assimilation input; output the accommodation and processing the equilibration.
Estudos sobre a formação de professores de química numa disciplina experimental com abordagem cultural diaspórica
(Universidade Federal de Goiás, 2020-03-05) Silva, Juvan Pereira da; Benite, Anna Maria Canavarro; http://lattes.cnpq.br/8433607360245647; Benite, Anna Maria Canavarro; Silva, Juvenal Carolino da; Silva, Petronilha Beatriz Gonçalves e; Aguiar, Vinícius Gomes de; Mesquita, Nyuara Araújo da Silva
This research that dealt with the implementation of law 10639/03 and the fulfillment of Resolution CNE / CP 01/2004 and Opinion CNE / CP 03/2004 in the teaching of chemistry, originated this which had the following objectives: a) to answer the question: is is it possible to train chemistry teachers in an experimental discipline with a diasporic cultural approach? b) Investigate a conceptual appropriation in this experimental discipline as a possibility of implementing Law 10639/03 in science / chemistry teaching at a higher level; c) evaluate, during this conceptual appropriation, present in the speeches of the research participants the three levels of aspects of scientific knowledge - theoretical, phenomenological and representational - proposed by Mortimer and collaborators (2000). In order to achieve these objectives, we created two experimental disciplines at the Chemistry Institute of UFG, to collect data for research. The study had elements of participatory research; therefore, it was an educational activity of research and social action. The term “participant suggests the controversial insertion of a researcher formed by the socio-cultural life of a close or distant person, who, in turn, is invited to participate in the investigation as an informant, collaborator or interlocutor. The total corpus of analysis was formed by the transcription of 45.75h from audio and video recordings of the speeches produced by the subjects of the investigation. The data obtained were grouped by units of meaning and analyzed with elements of Bakhtin Discourse Analysis technique. The choice of this data analysis technique meant an undertaking in trying to explain and understand “how the meaning of a text is constructed and how that text is articulated with the history and the society that produced it. In the subjects taught during the research, for each topic contained in the menu, diasporic cultural and scientific conceptual approaches were carried out. Thus chemical concepts involving chemical reactions with Fe and Ni, synthesis of a ferrite, stability of complexes in solution, chelate effect, were contextualized with the following cultural approaches: legacy of the African blacksmith and his descendants in the fields of arts, mining and religion and the African heritage in Goiás, namely the Congadas. These diasporic conceptual and cultural approaches were carried out with the subjects: the chemistry of iron and the role of the African blacksmith in Central African societies and in colonial Brazil and the African, indigenous and Portuguese cultural heritage in the mining regions of the state of Goiás contained in course menus. Concepts of density and viscosity, fatty acids and phytochemistry, were intertwined with the cultural approach on the importance of oil palm in the formation and maintenance of Afro-Brazilian culture of African peoples, communities, traditional knowledge and religions. The subjects in the menus that gave rise to these two approaches were: the chemistry of and in oil palm, its importance in religions of African origin and in Afro-Brazilian cuisine and an ethnobotanical approach to plants used in religions of African origin. In the topic of archeology in Africa and its techniques, the analytical techniques used in so-called archeometry were discussed, which help to retell the history of the African continent. The cultural approach in this topic was dairy farming practiced by African peoples about five thousand years before the Christian era and the chemical reactions that were contextualized in these approaches were those that prove some frauds carried out on milk for human consumption. Finally, the studies of noble metal chemistry, the use of Pd and Pt in devices to control air quality, the school curriculum x curriculum in action, were contextualized with the apartheid experienced by the South African peoples in the years 1946 until 1995.
Estudo da remoção do pesticida metomil em efluentes simulados por biossorção em bagaço de laranja residual
(Universidade Federal de Goiás, 2020-01-30) Zimmer, Thiago Ruiz; Teles, Helder Lopes; http://lattes.cnpq.br/5902911518497333; Seolatto, Araceli Aparecida; http://lattes.cnpq.br/1495882445078650; Seolatto, Araceli Aparecida; Teles, Helder Lopes; Freitas, Fernanada Ferreira; Alonso, Christian Gonçalves; Ostroski, Indianara Conceição
This work consisted of studying the use of residual orange pomace from the juice processing industry as an adsorbent for the removal of methomyl, an extremely toxic carbamate pesticide, prepared in the laboratory as a synthetic aqueous solution to simulate the washing effluent of equipment used in activities spraying. Initially, the biosorbent biomass was subjected to surface characterization by means of scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). From the images obtained by SEM it was possible to observe many irregularities on the surface of the adsorbent particles, however it was not possible to visualize macro or micro pores, denoting little porous particles. The study of the spectrograms obtained by FTIR revealed the presence of hydroxyl, carbonyl and carboxylic groups on the surface of the adsorbent particles. The biosorption tests were carried out in three stages. The first stage consisted of batch tests. The kinetics, the isotherm and the effects of pH and solid/liquid ratio (R) were evaluated, using the Central Rotational Composite Design 22 (DCCR 22), on the adsorption capacity of metomil in orange pomace particles (q). The second stage consisted of biosorption tests in pilot columns of 1 cm in diameter and fixed bed of orange bagasse of 30 cm, operated in continuous upward flow. In this step, the effects of flow (1, 5 and 10 mL) and the initial concentration of the affluent solution (20 and 50 mg.L−1) on the process were evaluated. Finally, the third step consisted of scaling up the biosorption column. Two systems were evaluated, System 1, consisting of two tubes 100 mm in diameter, one bed of 50 cm high orange pomace followed by a bed of foam 100 cm high, and System 2, consisting of three tubes 100 mm in diameter, being a bed of “gravel 2” 100 cm high, followed by a bed of orange pomace 100 cm high, followed by per 100 cm high foam bed, both operated in continuous upward flow. During the operation of System 1, elementary analysis was performed by fluorescence spectroscopy with total X-ray reflection (TXRF), of samples of affluent and effluent solutions, in order to qualitatively and quantitatively assess which elements had the greatest influence on the biosorption process of metomil in orange pomace. In batch tests, a better fit was obtained for the pseudo-second order kinetic model (R2 = 0.949), concluding that the chemisorption was the controlling step of the process. The Langmuir isotherm model fitted better to the experimental data (R2 = 0.989) confirming the adsorption in monolayers, without interaction between the adsorbate molecules. The statistical study of the effects of pH and the solid/liquid ratio (R) on the adsorption capacity of methomyl in the orange pomace particles resulted in higher values of adsorption capacity (q = 3.73 and q = 3.43 mg.g−1), obtained at pH 6.0 and 4.5 with R values equal to 0.017 and 0.015 (g.mL−1), respectively. Thus, it was concluded that there was greater adsorption in tests containing a greater mass of adsorbent at slightly acidic pH. The study of the effects of the flow and the initial concentration on the biosorption of methomel in orange pomace carried out in the columns on a pilot scale demonstrated that the increase in flow increased the mass transfer rate and, consequently, the biosorption capacity of the bed, however it took to faster bed saturation, with steeper rupture curves. On the other hand, in the tests with lower flow, the adsorvate had a longer time of contact with the biosorbent particles resulting in greater removal of the pesticide. The increase in the concentration of the solution fed to the column resulted in a greater driving force in the mass transfer process and, consequently, in a greater biosorption capacity of the bed. The two full-scale treatment systems, System 1 and System 2, achieved removal of 57.88% and 50.53%, respectively, noting that the adsorption technology for the treatment of effluents contaminated with the metomil pesticide proved to be quite promising. The elementary analysis, by TXRF, showed that the leaching, mainly of Ca2+ and K+ salts, may have caused the vacancy of active sites, providing increased removal of methomyl by adsorption in the adsorbent particles of residual orange bagasse.

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