Mestrado em Química (IQ)

URI Permanente para esta coleção


Submissões Recentes

Agora exibindo 1 - 20 de 213
  • Item
    Análise de íons inorgânicos em resíduos de explosão utilizando microssistemas eletroforéticos
    (Universidade Federal de Goiás, 2018-08-01) Pinheiro, Kemilly Mara Pires; Coltro, Wendell Karlos Tomazelli;; Coltro, Wendell Karlos Tomazelli; Rosseto, Renato; lonashiro, Elias Yuki
    This study describes the development of an analytical methodology based on the use of microchip electrophoresis (MSE) devices integrated with capacitively coupled contactless conductivity detection (C4D) for the separation and detection of inorganic anions in post-blast explosive residues. The best separation condition was achieved using a running buffer composed of 35 mmol L-1 lactic acid, 10 mmol L-1 histidine and 0.070 mmol L-1 cetyl(trimethyl ammonium) bromide. For C4D measurements, the highest sensitivity was obtained applying a 700 kHz sinusoidal wave with excitation voltage of 20 Vpp. The separation of Cl-, NO3-, NO2-, SO42-, ClO4- and ClO3- was performed within ca. 150 s with baseline resolution and efficiencies between 4.4x104 and 1.7x105 plates/m. The found limits of detection ranged between 2.5 and 9.5 μmol L-1. Also, excellent repeatability was obtained, with relative standard deviation lower than 0.8%, 8.8% and 13.5% for the injection time, for the intensity and the peak areas, respectively. Lastly, real samples of post-blast explosive residues were analyzed on the MSE-C4D devices obtaining successfully the determination of Cl-, NO3- and SO42-. The achieved concentration values varied between 2301,610 µg g-1 for Cl-, 805,490 µg g-1 for NO3- and 1453,270 µg g-1 for SO42-. It was also possible to compare the anionic profile of residues of an improved explosive device and a commercial explosive emulsion, confirming the improved explosive device composition, based on ammonium nitrate fuel oil (ANFO). The approach reported herein has provided short analysis time, instrumental simplicity, good analytical performance and low cost. Furthermore, the MSE-C4D devices emerge as a powerful and portable analytical platform for on-site analysis demonstrating to be a promising tool for the crime scene investigation.
  • Item
    Determinação de escopolamina e butilescopolamina em amostras de bebidas, urina e comprimidos de Buscopan® usando microssistemas eletroforéticos
    (Universidade Federal de Goiás, 2023-08-08) Santos, Hellen Inácia dos; Coltro, Wendell Karlos Tomazelli;; Coltro, Wendell Karlos Tomazelli; Jesus, Dosil Pereira de; Chaves, Andréa Rodrigues
    The number of cases in which scopolamine (SCO) was used for both recreational and predatory purposes has increased dramatically in recent decades. Linked to this, there is a concern about obtaining SCO through thermal degradation of butylscopolamine (BSCO) – an active ingredient of Buscopan® – a drug sold without a medical prescription. In this study, mixtures containing SCO and BSCO were separated and detected on a microchip electrophoresis (ME) device with integrated capacitively coupled contactless conductivity detection (C4D) using a running buffer composed of 40 mmol L-1 of butyric acid and 25 mmol L-1 of sodium hydroxide (pH 5.0). The separation was performed within ca. 115 s with a resolution of 1.3 and separation efficiency of 1.4x105 and 1.5x105 theoretical plates m-1 for SCO and BSCO, respectively. The limit of detection was 1.1 μmol L-1 for both species and the developed method revealed satisfactory repeatability with relative standard deviation (RSD) values for forty-eight injections between 4.8 and 9.4% for peak areas and lower than 3.3% for migration times. Furthermore, inter-day precision was evaluated for sixteen injections (a sequence of four injections performed over four days), and RSD values were less than 6.6% for peak areas and 2.2% for migration times. Satisfactory recovery values (95 – 114 %) were obtained for all evaluated beverage samples (cachaça, vodka, whiskey, beer, coke soft drink, and grape juice) as well as for artificial urine samples (95 – 107 %). Finally, the conversion of BSCO into SCO was observed after simple heating procedure of Buscopan® sample (not subject to medical prescription), which was successfully confirmed through analysis by capillary electrophoresis coupled to the mass spectrometry (CE-MS). Based on the reported results, the use of ME-C4D devices has demonstrated a huge potential for applications in the forensic chemistry field.
  • Item
    Enhancing accuracy in predicting optical properties of explicitly solvated systems: a comprehensive approach through long-range separated tuning of RSH functional and sequential QM/MM
    (Universidade Federal de Goiás, 2023-07-31) Matias, Pedro Henrique Ferreira; Oliveira, Heibbe Cristhian Benedito de;; Oliveira, Heibbe Cristhian Benedito de; Ramalho, Teodorico de Castro; Colmati Junior, Flavio
    The properties of molecular systems are generally measured experimentally in solution. In a theoretical context, molecular modeling is done in vacuum, leading to discrepancies when comparing theoretical results with the experimental ones. In light of this, the use of solvation methods become necessary. However, existing methodologies do not allow optimizing the separation parameter of electronic interactions in RSH functionals ω. An approach to combine functional optimization of the functionals with explicitly solvated organic systems, such as para-Nitroaniline and Phenol Blue, was developed by this work. The explicit solvation was performed using the S-QM/MM methodology with ASEC-FEG approximations. The optimization process was performed using the JGAP scheme with a Golden Ratio-based search algorithm to minimize the number of calculations. RSH functionals are noteworthy for improving the description of photoelectronic properties, hence we decided to study such properties. Firstly, electronic excitation and non-linear optical properties calculations were performed for para-nitroaniline to verify the change in photophysical properties with functional optimization. The properties were evaluated as well for Phenol Blue systems, which has well-elucidated optoelectronic properties, to validate the methodology. Finally, the results showed that the proposed methodology is successful in explicit solvation. Photophysical properties were improved by circa 20%, in high polar systems, for para-Nitroaniline and Phenol Blue. NLO Properties for Phenol Blue have an good agreement for first-hyperpolarizability in non-polar and protic-polar systems, and secondhyperpolarizability have the best results in protic-polar systems.
  • Item
    Síntese e avaliação fotofísica de xantonas para sensores luminescentes
    (Universidade Federal de Goiás, 2023-02-28) Castilho, Nathália Santos; Coelho, Felipe Lange;; Severino, Vanessa Gisele Pasqualotto;; 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.
  • Item
    Efeito de solvatação explícita nas propriedades eletrônicas de peptóides fluorescentes via metodologia QM/MM sequencial
    (Universidade Federal de Goiás, 2023-02-23) Souza, Shamon Henrique Feitosa de; Oliveira, Heibbe Cristhian Benedito de;; Oliveira, Heibbe Cristhian Benedito de; Franco Junior, Adolfo; Gargano, Ricardo
    In this work, we investigated the photophysical properties of four recently synthesized peptoids employing Quantum Chemistry calculations. The environment in which the solute is inserted can directly influence its properties, as the interactions of the solute with other molecules directly affect the geometric and electronic structure of the entire system. Therefore, in this work we use explicit solvation methods, in which each solvent molecule is explicitly treated and the total contribution of solvent molecules is included in the system, thus providing a better approximation between theoretical and experimental values. We studied the effect of explicit solvent treatment on the electronic properties of fluorescent peptoids, solvated in five different solvents, through computer simulations using a hybrid methodology (QM/MM). Sequentially to the Monte Carlo calculations (ASEC via DICE program) ab initio quantum calculations were performed in which we used several exchange-correlation functionals in order to identify which is the most suitable for the studied peptoids and analogous systems. The results obtained via theoretical calculations were compared with the experimental results published by Wender et al. (2016). With that, we developed a computational protocol comparable to the experimental values.
  • Item
    Estudo da utilização do óleo de peixe visando à produção de nutracêuticos e biodiesel
    (Universidade Federal de Goiás, 2017-06-05) Oliveira, Ingryd Cristina de; Antoniosi Filho, Nelson Roberto;; Antoniosi Filho, Nelson Roberto; Souza, Carolina Guimarães de; Duarte, Gabriela Rodrigues Mendes
    The use of waste from the fishing industry is emerging worldwide as a sustainable and attractive raw material alternative in environmental, economic and social aspects. Fish oil contains omega-3 polyunsaturated fatty acids (ω3-PUFA), ingredients in the pharmaceutical industry, in the production of nutraceuticals. On the other hand, it also contains saturated fatty acids (SFA), usable in the biodiesel industry. Given this context, the objective of this dissertation was the study of fish oil aiming its fractionation into saturated and unsaturated fatty acids (UFA). In this sense, the extraction and evaluation of oil from Clupea harengus (OR) residues were carried out through physical-chemical, thermal, and chromatographic techniques. Followed by the optimization of the chemical hydrolysis of the oil through 23 factorial design; and obtaining free fatty acids (FFA) using the conditions determined by planning. These FFAs were characterized, and with these results a new strategy of concentration of ω3-PUFA fatty acids was proposed: chemical hydrolysis, followed by crystallization at low temperatures in two steps in the absence of solvents. The research showed that OR has a high content of UFA (71.81%) and ω3-PUFA (17.44%). However, triacylglycerides are difficult to fractionate. The optimal condition for the hydrolysis found is that the catalyst is at 22% m/m; temperature of 90 oC; and reaction time of 2 h. The hydrolysis was effective, with the acidity index increasing from 7.68 mg KOH/g to 172.22 mg KOH/g, and did not significantly affect the UFA content. Two-step crystallization (10 oC and -10 oC) decreased SFA levels by 39.90%, but there was also a decrease in ω3-PUFA of 11.11%. The overall yield was 54% to 60%. The obtained concentrate can be considered a rich source of UFA with a total amount of 83.43%. Among these, 16.17% are ω3-PUFA and 11.78% are EPA + DHA. Thus, the oil extraction, hydrolysis, and characterization procedures were successful. However, the fractionation procedure of free fatty acids at low temperatures needs further studies.
  • Item
    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;; 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.
  • Item
    Comparação de técnicas de extração e caracterização de ácidos naftênicos em águas produzidas
    (Universidade Federal de Goiás, 2022-04-27) Vieira, Michel Moreira de Freitas; Vaz, Boniek Gontijo;; Vaz, Boniek Gontijo; Coltro, Wendell Karlos Tomazelli; Santos, Jandyson Machado
    In the first part of the work, for the purpose of studying the extraction efficiency of NAs in Brazilian PWs, some SPE methodologies were studied for these analytes, established in the literature, in order to perform the comparison and determination of the best methodologies, in order to optimize and adapt them to the analytes of the Brazilian scenario. The stationary phases studied in this first part were: C18, ENV, ENV+, Strata-X and HLB. We proceeded with the extractions by fully replicating the parameters as presented in the literature, in order to be able to compare the solid phase extraction methodologies employed to the same matrix. The analyses were performed on the Q-Exactive Orbitrap ultra-high resolution mass spectrometer, using the electrospray ionization (ESI) source in negative mode. Data processing was performed with Composer and Thanus software. The results obtained indicate that the methodologies of group III, with the solid phases ENV and HLB, showed the highest number of AN species extracted with the three solvents used, hexane (HEX), dichloromethane (DCM) and isopropanol (IPA). The results obtained indicate that the solvent DCM extracted in higher concentrations species with a DBE value of 1, and the solvent methanol extracted in higher concentrations species with a DBE value of 2. Moreover, the solvent hexane presented species with a DBE value of 2 in high concentrations, indicating that these species are eluted by this solvent with greater efficiency. Finally, tests with methodologies using ENV, C18, APS, Strata-X and HLB solid phases were performed in order to determine the optimum solvent volume and optimum sample pH for efficient extraction. The results presented indicate that pH 2 showed the highest recovery results for acidic species. Also, the extractions eluted with 20 mL of dichloromethane, divided into two fractions provided better results in terms of the number of formulas assigned. Another point of note is the fact that acid species were eluted by water during the washing step for the removal of salts from the PW sample, making it necessary to remove this step from the extraction methodologies
  • Item
    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;; 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.
  • Item
    Desenvolvimento de dispositivos eletroquímicos descartáveis para detecção de vitamina D
    (Universidade Federal de Goiás, 2022-03-03) Venancio, Kamylla de Paula; Sgobbi, Lívia Flório;; Sgobbi, Lívia Flório; Chaves, Andrea Rodrigues; Martins, Paulo Roberto
    Vitamin D deficiency and insufficiency is emerging as a public health problem worldwide, which has resulted in a high demand for clinical tests for its detection and quantification. Given this scenario, the development of electrochemical devices is an alternative for the detection of vitamins, due to its simplicity, low cost, miniaturization and portability. In the present project, a disposable electrochemical device was developed to detect vitamin D in its two forms, Ergocalciferol (D2) and Cholecalciferol (D3). For its development, the device underwent a series of optimizations to guarantee its better functioning, which include its manufacturing process, conditions of use, methodologies and techniques used for detections. After manufacturing optimization, solvents, support electrolytes and parameters that conferred better electrochemical responses were investigated, where in such steps it was defined the use of a mixture of 60% ethanol/water and NaClO4, composing the electrolyte solution, together with vitamins D2 and D3. Voltammetric parameters such as potential increment, sweep speed, amplitude and frequency, most suitable for each vitamin, were evaluated, which made it possible to detect the two forms of vitamin D, at potentials between +0.80 V and 1.0 V. The effect of adsorptive polarization was also evaluated, which allowed the displacement of the oxidation potential to lower values. The proposed methodology proved to be a good alternative to commonly known detection methods, despite having problems such as reproducibility, in part related to the manual manufacturing process of the electrodes and the lipophilic character of the analyte. On the other hand, the use of electrodes offers advantages such as fast, simple and cheap analysis. Selectivity studies were also carried out in the presence of other vitamins, observing a decrease in the peak current of vitamin D. The reproducibility of the device can be increased by automating the production of electrodes and the evaluation of other experimental conditions, such as surface treatment using alkaline medium.
  • Item
    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;; 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.
  • Item
    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;; 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).
  • Item
    Síntese, caracterização e comportamento eletroquímico de um hidróxido duplo lamelar baseado em níquel e alumínio como material de eletrodo para sistemas de armazenamento de energia
    (Universidade Federal de Goiás, 2022-02-23) Fonseca, Isabella; Martins, Paulo Roberto;; Martins, Paulo Roberto; Gonçalves, Josué Martins; Colmati Júnior, Flávio
    With each passing year, portable electronic devices such as smartphones and laptops have required increasingly efficient energy storage systems in order to ensure satisfactory performance. Nickel hydroxide, in turn, has been extensively studied and used as an electrode material, where improvements in its electrochemical properties end up becoming a major key point for the construction and development of batteries or supercapacitors that have greater charging efficiency, in addition to low cost and long-life cycle. Thus, in this work, a double lamellar hydroxide containing 90% nickel and 10% aluminum (NiAl-LDH-90:10) was synthesized, characterized and its electrochemical behavior was evaluated. Due to the presence of the diffraction peak (003) located in regions of low angle 2θ, the alpha polymorphic phase was attributed to pure nickel hydroxide (Ni100). The nickel and aluminum LDH nanoparticles, obtained by the modified Tower method, showed manometric dimensions in the order of ~5 nm, confirmed by the TEM technique. Through
  • Item
    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;; 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.
  • Item
    RMN aliada a métodos estatísticos para controle de qualidade de sucos integrais e néctares de laranja
    (Universidade Federal de Goiás, 2021-01-22) Wilhelms, Renan Ziemann; Queiroz Júnior, Luiz Henrique Keng;; Queiroz Júnior, Luiz Henrique Keng; Ferri, Pedro Henrique; Colnago, Luiz Alberto
    Orange integral juice and nectar are highly consumed in the world and like any process is subject to production failures, however, with the use of 1H NMR spectroscopy is possible to identify these non-conformities. The present work aims to evaluate the chemical profile and identify chemical markers that can be used to build prediction models to distinguish integral juice from nectar and integral juice and nectar with and without the addition of apple. With the 1H NMR technique, it was possible to identify chemical markers to distinguish orange integral juice and nectar and the same ones with and without the addition of apple. The quantification of these chemical markers was done using Electronic REference To access In vivo Concentrations (ERETIC2), which were sucrose, α-glucose, β-glucose, malic acid, fructose, dimethylproline (DMP), citric acid, alanine, lactate and ethanol. Among these compounds, DMP stands out as a chemical marker for evaluating juices and nectars with and without apple addiction. The Redundancy Analysis (RDA) was of great importance as a filter for verifying the information on the labels of integral juices and nectars, where two samples with possible adulteration of apple addition were identified. With the results of the RDA, prediction models were constructed using the Orthogonal Projections to the Latent Structure (O-PLS) to differentiate integral juice from nectar and integral juice and nectar with and without the addition of apple. The constructed models were able to distinguish the types of drinks, with a Q2 equal to 0.706 for the integral juice and nectar model and Q2 of 0.681 for integral juice and nectar with and without added apple. Using partial least squares regression (PLS), an orange and apple content prediction model was built with good percentage prediction capacity with an R2 of 0.9989. Using the aforementioned tools, it was possible to develop models to support quality control and adulteration of orange integral juices and nectars.
  • Item
    Dispositivos microfluídicos baseados em fita adesiva dupla face e aplicações no diagnóstico molecular da Covid-19
    (Universidade Federal de Goiás, 2021-07-29) Estrela, Paulo Felipe Neves; Duarte, Gabriela Rodrigues Mendes;; Duarte, Gabriela Rodrigues Mendes; Gomes, Danielle Cangussu de Castro; Rodrigues, Flávia Melo
    Microfluidic devices have shown potential application in several areas of science due to the possibility of integration and automation of steps, reducing time and cost in total analysis. However, due to the laboriousness of the preparation, its use is still discreet. Thus, in the aim to make microfluidic devices accessible, in this study we explore the development of disposable microfluidic devices based on double-sided tape and polyester film (DF-Pe) and we initially demonstrated its use in all stages of molecular diagnosis for COVID-19. Devices based on double-sided adhesive tape were manufactured in two different forms: using a laser cutter or totally free-instrumentation. The DF-Pe microchips developed here exhibited low cost, simplicity, fast fabrication, chemical resistance, versatility for layout changes and biocompatibility. In the DF-Pe microchips, we carried out the isolation of nucleic acids from samples of patients with SARS-CoV-2 infection, using the technique of dynamic solid phase extraction (dSPE) with an efficiency of extraction of 56%, obtaining the RNA at the end of the process suitable to be amplified by RT-qPCR (Reverse Transcription - Quantitative Pol-ymerase Chain Reaction) and RT-LAMP (Reverse Transcription - Loop-Mediated Isother-mal Amplification). We demonstrated a RT-LAMP based assay to detect SARS-CoV-2 di-rectly on microdevices in 30 minutes, also we applied the test to a panel of 40 samples and the results obtained were with 100% concordance with the gold standard method (RT-qPCR). Furthermore, the features of the DF-Pe microdevice were evaluated through the development of passive micromixers that allowed visual detection of the amplification prod-ucts directly on the microdevices. The high simplicity, cost-effective and fast manufacturing of the DF-Pe microdevices, integrated to the simple and quick extraction, amplification and viral detection directly on chip, demonstrates the high potential application of this method in the molecular diagnosis of COVID-19 in resources limited settings.
  • Item
    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;; Vaz, Boniek Gontijo;; 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.
  • Item
    Desenvolvimento de materiais nanoestruturados baseados em hidróxidos mistos de cobalto / manganês para aplicação em dispositivos eletroquímicos de armazenamento de energia
    (Universidade Federal de Goiás, 2021-06-29) Silva, Cristiane Garcia; Martins, Paulo Roberto;; Martins, Paulo Roberto; Sgobbi, Lívia Flório; Gonçalves, Josué Martins
    In recent years, the development of new electrode materials for energy storage devices has been intensified, owing to increasing energy consumption levels, as well as depletion of nonrenewable energy resources. Thus, low-cost electrode materials, easy to obtain, and with excellent electrochemical performance are desirable. In this sense, the cobalt hydroxide has drawn attention due to its structure, morphology, and electrochemical features and then becoming a promising electrode material for energy storage devices. Thus, in this work, cobalt hydroxide and mixed cobalt/manganese hydroxide (in the proportions of Co:Mn 75:25 and 50:50), named respectively as Co-100, CoMn-75:25, and CoMn-50:50, were synthesized using the modified Tower method. Through the X-ray diffraction technique, it was possible to determine that the materials are in the alpha phase since the (003) diffraction peak was found in low angle regions 2θ. In addition, the morphology of the materials was evaluated using transmission electron microscopy, where the images showed that nanoparticles presented spherical shape and an average size of ~5 nm. The CoMn-75:25 and CoMn-50:50 were classified as double hydroxide salt since the metal ions presented the same valence state (+2), determined by X-ray Photoelectron Spectroscopy. The materials were deposited on FTO electrodes using the spin-coating technique and the electrochemical behavior of the modified electrodes was evaluated cyclic voltammetry, galvanostatic charge/discharge curves and electrochemical impedance spectroscopy. Through electrochemical studies, it was possible to determine that the energy storage mechanism is of the extrinsic intercalation pseudocapacitance type, due to the nanostructured of the materials. It was observed that the Epa, related to the Co+2/Co+3 redox process, was shifted to more negative potentials and there was an increase in ipa intensity for CoMn-75:25 and CoMn-50:50, as a consequence of the isomorphic substitution of Co2+ by Mn2+ ions in the crystal lattice of Co-100. Besides, the CoMn-75:25 showed a specific capacitance two and a half fold higher (677.0 F g-1) than Co-100 (268.7 F g-1). Also, the CoMn-75:25 presented a capacitance retention of 70.64% even after 5000 galvanostatic charge/discharge cycles. Finally, the electrochemical impedance spectroscopy studies (Nyquist diagram and Bode phase) confirmed that the electrode materials present a pseudocapacitive signature.
  • Item
    Interferências do contexto de conflitos entre ciência e religiosidade no ensino de Química
    (Universidade Federal de Goiás, 2021-03-05) Leite, Robert Ramos; Soares, Márlon Herbert Flora Barbosa;; Martins, Tatiana Duque; Ribeiro, Marcus Eduardo Maciel; Soares, Marlon Herbert Flora Barbosa
    We record this work with the main purpose of analyzing how a context of conflict between science and religiosity occurs, in the Teaching of Chemistry, which will be consequences of situations arising from the daily classroom. We conducted the research using two methodologies: interview and questionnaires. This first thought with three religious representatives, on themes that can build a conflict situation, their arguments and opinions about possible interferences of the scientific teaching in the religious and other contributions to the curbing of similar conflicts. In this paper we comment on some opinions and discuss how the religious perspective can interfere in teaching. The questionnaires were taken to undergraduate chemistry students, aiming at research to identify some methodological approaches in the conflict situation, applied in two institutes, IF Goiano - Campus Iporá and IFMT - Campus Primavera do Leste, including a total of 27 participants, from final. Also, even high school students, seeking to know their contributions, the application of these questionnaires was carried out in a public school in Iporá, CEJA Dom Bosco, including a total of 140 participating students. It is interesting that a large part of those surveyed keep their arguments condensed into three biases, one in defense of the religious teaching profession, the other maintaining the scientific teaching profession, in addition to these, which avoids conflict. Of the religious representatives we know in similarities an agreement in maintain the facility for dialogue between magistrates. From chemistry graduates, not far from high school students, we see rooted Christian attitudes, which are summed up in the option of not working on the situation of the conflict that happens.
  • Item
    SPYN: desenvolvimento e aplicações de um novo software para estudos de cristalografia por RMN
    (Universidade Federal de Goiás, 2021-01-15) Silva, Jefferson Richard Dias da; Queiroz Júnior, Luiz Henrique Keng;; Queiroz Júnior, Luiz Henrique Keng; Ferreira, Vinicius Sousa; Colnago, Luiz Alberto
    Resumo em língua estrangeira: The results obtained by NMR-es are difficult to understand due to several factors such as: anisotropy, dipolar coupling and the need for high sample rotations. Thus, NMR-es has a certain dependence on theoretical calculations of the chemical shielding tensors for crossing with the experimental data. In this work, a graphic and intuitive software was developed to assist in NMR crystallography studies - the SPYN platform, in addition to structural aspects through quantum chemistry calculations. The four forms of lamivudines were elucidated experimentally by NMR-es, the calculations of the shielding tensors for both GIAO and GIPAW methods were with low error in relation to the experimental chemical shifts which shows the low values of average and median error , in addition the high correlation of Pearson and Kendall explain the coherence between theoretical and experimental chemical shifts. The calculations of QTAIM and NBO were performed using theory and basis set M062X/6-311 ++g** and showed all intra- and intermolecular interactions, as well as the relationship of the interatomic distance with the hydrogen bonding force. QTAIM has shown that there are interactions of hydrogen with sulfur for \textbf{C} and \textbf{D} structures, which in general are long bonds 3,41 $\AA$ and 2,80 $\AA$ respectively. We hope that the SPYN application can help the scientific community to make the calculation of chemical shielding tensors, conformational search and calculation of the boltzmann distribution easily and also that structural studies on lamivudine cocrystals help to develop new drugs.