Doutorado em Química

URI Permanente para esta coleção

http://repositorio.ufes.br/handle/10/17501

Nível: início
Ano de início: 2014
Conceito atual na CAPES: 5
Ato normativo: Homologação da 85ª Reunião do CTC-ES, Parecer CNE/CES nº 163/2005.
Processo nº 23001.000081/2005-56 do Ministério da Educação.
Publicado no DOU 28/07/2005, seção 1, página 11)
Periodicidade de seleção: Anual
Área(s) de concentração: Química
Url do curso: https://quimica.vitoria.ufes.br/pt-br/pos-graduacao/PPGQ/detalhes-do-curso?id=956/a>

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"Utilização da RMN associada a métodos quimiométricos na caracterização de petróleos e derivados"
(Universidade Federal do Espírito Santo, 2016-12-19) Oliveira, Emanuele Catarina da Silva; Cunha Neto, Álvaro; Lacerda Junior, Valdemar; Filgueiras, Paulo Roberto; Menezes, Sonia Maria Cabral de; Chinelatto Júnior, Luiz Silvino
Petroleum products are in general highly complex andconsiderable effort is needed to characterize their chemical and physical properties. Frequently the results of several analyses are urgent and this is compromised by the way the analyses are carried out. Thus, NMR (Nuclear Magnetic Resonance) associated with chemometrics methods have been generating alternative methods to characterize and evaluate physical and chemical properties of petroleum and its derivatives with high precision, reliability and promptitude. Considering its applicability, this work proposes the use of NMR as spectroscopic method and from the integration areas of 1H and 13C NMR’s spectra associated to the chemometric calibration tools (Partial Least Square Method,PLS, and Multiple Linear Regression, MLR) it were determined the following properties in petroleum samples: API gravity, Maximum Pour Point (°C), Cinematic Viscosity (mm2/s at 50°C) and SARA-saturated, aromatic, resins and asphaltenes (%m/m),in order to evaluate the obtained models’ performance. This evaluation was obtained through determination and analyses of the coefficient of determination (R2)of several calculated errors for the calibration and prediction sets. The models were still exposed to statistical tests and their figures of merit calculated. The chemical properties with direct influence on the spectral profile, such as, API gravity, kinematic viscosity and saturated and aromatic contents in SARA models, had generated more robust models and with better predictive capacity, when compared to the models selected for the prediction of the remaining properties, maximum pour point, resins and asphaltenes. A standard recognition tool (partial least squares method with discriminant analysis, PLS-DA) was used to classify petroleum samples into light, medium or heavy oils according to API gravity. In this work, PCA (Principal Component Analysis) models were also constructed aiming the exploratory analysis of a set of spectra of oil derivative samples in order to determine acidity of the original oil considering the structural parameters of the fractions..
Desenvolvimento de novos métodos analíticos em química forense e petroleômica por espectrometria de massas ambiente (Paper Spray) e espectroscopia portátil na região do infravermelho próximo (MICRONIR)
(Universidade Federal do Espírito Santo, 2017-11-30) Domingos, Eloilson; Romão, Wanderson; Ferreira, Ernesto Correa; Ribeiro, Juliano Souza; Filgueiras , Paulo Roberto; Kuster, Ricardo Machado
With the advent of a new family of ionization techniques, ambient mass spectrometry (or ambient MS) was introduced as a simple way of generating ions in MS. Among them, the paper spray ionization (PS-MS) technique has demonstrated to be versatile to solve numerous problems in many areas of science. In this work, the PS-MS technique in the positive ionizationmode (PS(+)-MS) was applied in three subareas of forensic chemistry: drugs of abuse, documentoscopy, and herbal medicines. In the first, the PS(+)MS technique was applied to obtain the chemical profiles of illicit drugs such as drug stamps containing 25I-NBOMe, extracts and leaves of natural cannabinoids (?9-tetrahydrocannabinol) and synthetic cannabinoids (JWH-073; 5F-AKB48; JWH-122; JWH-250; e JWH-210). In all cases, molecules were easily detected in their protonated form ([M + H]+) with resolution of m/?m50%=67,000 and a mass precision <2 ppm. The performance of the PS(+)-MS technique was compared with other sources of ionization: leaf spray (LS-MS) and electrospray (ESI-MS). In addition, a method was developed to quantify a series of illicit drugs (from 1 to 110 ??g L-1, with linearity of R2> 0.99). In documentoscopy, the PS(+)-MS technique was able to successfully obtain the chemical profile of different pens commercially sold in stores. The relative intensity (RII372) of the methylene blue dye was monitored to discriminate crossing pen traces and, to date, questioned documents. The chemical profile of second-generation Brazilian notes of R$ 100.00 (reais) was also explored. The PS(+)-MS technique was able to classify notes into either authentic or counterfeit. Finding that fake samples have a chemical profile similar to the homemade notes of the Deskjet® printer. Finally, PS-MS was applied to verify the authenticity of herbs used for weight loss. Fifteen different herbal medicines were analyzed by PS(+)-MS, substances such as: sibutramine (m/z280), caffeine (m/z195), and glucose (m/z203 [M + Na], m/z219 [M + K] and sucrose (m/z381 [M + K]) were found in samples where they were not listed in the herbal medicine label. In general, the PS(+)-MS technique proved to be an excellent analytical tool in chemistry forensic. A second study developed wasquality control of fuel with the application of the portable micro-spectrometer inthe near infrared region (MICRONIR), which has proven to be an excellent analytical technique in the quality control of several products. In this work, the potential of the MICRONIR in the control of fuel quality was verified. Thus, chemometric models (PLS-Partial Least Squares regression) were developed using near-infrared data acquired in the MICRONIR to determine the amount of biodiesel in Diesel (LOD=0.5wt%; LOQ=1.8 wt%, RMSEP=1.8 wt%); sulfur in Diesel (LOD=2.4 mg L-1; LOQ=8.0 mg L-1, RMSEP=13.2 mg L-1); gasoline, ethanol and methanol in gasoline type C (LODgas=0.55 wt%; LOQgas=1.84 wt%, RMSEPgas=0.81 wt%; LOQgas=2.50 wt%, RMSEPeth=3.81 wt%, LODmet= 0.85 wt% LOQmeth= 2.84 wt%, RMSEPmeth=1.80 wt% ; and water, methanol and ethanol in ethanol hydrated fuel (LODH2O=0.04 wt%; LQH2O=1.29 wt%, RMSEPH2O=1.05 wt%; , LOQmeth=1.73 wt%, RMSEPmeth=2.78 wt%). The proposed method presented high precision and accuracy in all cases, and the results showed that the MICRONIR technique had excellent performance in the control of fuel quality.
Elementos traço em água e sedimento na bacia hidrográfica do Rio Santa Maria da Vitória (ES)
(Universidade Federal do Espírito Santo, 2018-06-27) Salles, Roberta Chechetto; Rodrigues Neto, Renato; Carneiro, Maria Tereza Weitzel Dias; Filgueiras, Paulo Roberto; Athayde, Geisamanda Pedrini Brandão; Sá, Fabian; Lima, Ana Teresa Macas
The population growth leads to an increase in activities related to urbanization and industrialization, which are responsible for increasing trace elements in water sources. These elements present significant toxicity, and may accumulate over decades in the environment, generating risks to human health and ecosystem. In this sense, it is necessary to quantify trace elements in order to evaluate the contamination of the environment and its effects. In this context, this work aims to quantify and evaluate the contamination by trace elements: Fe, Mn, Ni, As, Cd, Cu, Co andPbin samples of water, surface sediment and of the corein the watershed of the river Santa Maria da Vitória. The river basin Santa Maria da Vitória is located in the central region of the Espírito Santo occupying an area of 1.563,3 km2. It is born in the mountain region of the state and includes the municipalities of Santa Maria de Jetibá and Santa Leopoldina, and part of the municipalities of Cariacica, Serra, Vila Velha, Viana and Vitória. In its middle course it suffers two buses, of the reservoirs Rio Bonito and Suíça. Two campaigns were carried out in march and november 2016. In these campaigns, samples of water and surface sediment were collected from the Santa Maria da Vitória river (5 stations) and Rio Bonito (3 stations), Suíça(2 stations) and Duas Bocas (3 stations). In the reservoir, the water samples were collected on the surface and at different depths and in the second campaign, in addition to the water and surface sediment samples, a sediment sample was collected in each of these reservoir. The analytical methodology was evaluated for sensitivity and linearity, accuracy and limits of detection and quantification.The water samples were filtered, acidified and analyzed by ICP-MS for the Mn, Ni, As, Cd, Cu, Co, and Pb elements and by ICP OES for Fe. Sediment, surface and sample samples were digested in and analyzed by ICP-MS for the Ni, As, Cd, Cu, Co and Pb elements and by ICP OES for Fe and Mn. The results obtained for the Santa Mariada Vitória river show the great impact that the stream São Luiz has been suffering through the dumping of different types of tailings from different origins. The results for the water samples and surface sediment of the dams indicate the difference between the river, intermediate and lacustrine zones. By means of the concentration of the trace elements and the dating(Pb210)of the sediment samples from the Rio Bonito reservoir, Suíça and Duas Bocas, an association was made with the historical events occurring at each site.To better interpret the data, the enrichment factor and the PLI and IR pollution parameters were analyzed. In addition, the granulometry and mineralogy of the samples and Pearson's analysis were performed in order to assist in the discussion of the results. The distribution of the elements in the soil is governed by interactions between the elements themselves and the same with attributes such as clay and silt fractions and Fe and Mn oxides, in addition to interaction with organic matter.The studies also indicate that Rio Bonito is in an alert situation, due to the large amount of tailings that are retained in this reservoir, from the rural and industrial activities of Santa Maria Jetibá. The maintenanceof the Suíça reservoir caused a change in the sediment column, compromising the results of this study. Whilefor Duas Bocas, it is clear that the results are a reflection of deforestation and the use of land for agriculturewhich occurred decades ago.
Espectrometria de massas de alta resolução acoplada a espectrometria mobilidade iônica para análise de matrizes complexas
(Universidade Federal do Espírito Santo, 2018-08-16) Tose, Lilian Valadares; Romão, Wanderson; Cunha Neto, Álvaro; Kuster, Ricardo Machado; Aquije, Gloria Maria de Farias Viégas; Lima, Francisco Alberto Fernandez
Mass spectrometry (MS) is a technique able to ionize simple molecules until complex structures, performing efficiently and dynamically with a wide application using high sensitivity and speed of analysis. Although MS hasconsiderable interest in the scientific society, the application of new technologies in the field of complex matrix analysis still is little explored.Inanalyzes of crude oil, paraffin and condensed aromatic standards, the atmospheric solids analysis probe mass spectrometry (ASAP-MS) is a powerful ionization sourceforcharacterization of samples in original form. Initially, two methodologies were used to determine the chemical composition of the samples: (1) using a temperature gradient ranging from 150 to 600 °C at a heating rate of 150 °C.min-1(parafina) or 50 °C.min-1; (2) with a constant temperaturearound350 °C. ASAP(+)-MS ionized crude oil and paraffin, showing a typical petroleum profile in the range of m/z200 -1400 for both samples. This performancecould relateASAP sourceto detection of compounds of high molecular weight (> 1000 Da). In addition, the AC standardswere identifiedin two ionicforms: radicals, [M]+•and protonated cations, [M+H]+, with minimal fragmentation. Therefore, ASAP was efficient for accessing the chemical composition of polar and non-polar compounds.Analysis of the Cannabis sativaL. plant, were doing by ultra-high performance liquid chromatography coupled to travelingwave ionic mass spectrometry (UPLC-TWIMS MS) using electrospray ionization source in both modes, ESI (±). Hashish, marijuana, and parts of the plant Cannabis sativaL. (flower and leaf) were analyzed. Isomeric compounds were identified inacomplex mixture of cannabinoids, mainly ?9-THC, cannabidiol (CBN-C5and Mw= 310 Da), ?9-tetrahydrocannabinolic acid A and B (?9-THCA-C5A/B and Mw= 358 Da) and their isomers. Analizes by ESI-TWIMSMS were identified three isomers, m/z315/313, 311, and 357, while a high selectivity was observedin UPLC-ESI-TOF MS data, identifying more thanfour isomeric compounds in the single ion acquisition mode (SIM).In other study, we evaluated the use of a high resolution mobility analyzer coupled to ultra high resolution mass spectrometry for molecular characterization of dissolved organic matter. The main goal wastovalidate the reproducibility of trapped ion mobility spectrometry (TIMS), the range of applicability and possible challenges during routine analysis.TIMS coupledto TOF MS and FT-ICR MS showed similar 18performance and high reproducibility. For the analysis of complex mixtures, both platforms were able to aquiriedthe main characteristics. However, the increase ofchemical complexity at nominal mass level (m/z> 300-350), only TIMS-FT-ICR MS was able to solve the compositional tendencies of lower Mass spectrometry (MS) is a technique able to ionize simple molecules until complex structures, performing efficiently and dynamically with a wide application using high sensitivity and speed of analysis. Although MS hasconsiderable interest in the scientific society, the application of new technologies in the field of complex matrix analysis still is little explored.Inanalyzes of crude oil, paraffin and condensed aromatic standards, the atmospheric solids analysis probe mass spectrometry (ASAP-MS) is a powerful ionization sourceforcharacterization of samples in original form. Initially, two methodologies were used to determine the chemical composition of the samples: (1) using a temperature gradient ranging from 150 to 600 °C at a heating rate of 150 °C.min-1(parafina) or 50 °C.min-1; (2) with a constant temperaturearound350 °C. ASAP(+)-MS ionized crude oil and paraffin, showing a typical petroleum profile in the range of m/z200 -1400 for both samples. This performancecould relateASAP sourceto detection of compounds of high molecular weight (> 1000 Da). In addition, the AC standardswere identifiedin two ionicforms: radicals, [M]+•and protonated cations, [M+H]+, with minimal fragmentation. Therefore, ASAP was efficient for accessing the chemical composition of polar and non-polar compounds.Analysis of the Cannabis sativaL. plant, were doing by ultra-high performance liquid chromatography coupled to travelingwave ionic mass spectrometry (UPLC-TWIMS MS) using electrospray ionization source in both modes, ESI (±). Hashish, marijuana, and parts of the plant Cannabis sativaL. (flower and leaf) were analyzed. Isomeric compounds were identified inacomplex mixture of cannabinoids, mainly ?9-THC, cannabidiol (CBN-C5and Mw= 310 Da), ?9-tetrahydrocannabinolic acid A and B (?9-THCA-C5A/B and Mw= 358 Da) and their isomers. Analizes by ESI-TWIMSMS were identified three isomers, m/z315/313, 311, and 357, while a high selectivity was observedin UPLC-ESI-TOF MS data, identifying more thanfour isomeric compounds in the single ion acquisition mode (SIM).In other study, we evaluated the use of a high resolution mobility analyzer coupled to ultra high resolution mass spectrometry for molecular characterization of dissolved organic matter. The main goal wastovalidate the reproducibility of trapped ion mobility spectrometry (TIMS), the range of applicability and possible challenges during routine analysis.TIMS coupledto TOF MS and FT-ICR MS showed similar 18performance and high reproducibility. For the analysis of complex mixtures, both platforms were able to aquiriedthe main characteristics. However, the increase ofchemical complexity at nominal mass level (m/z> 300-350), only TIMS-FT-ICR MS was able to solve the compositional tendencies of lower aMass spectrometry (MS) is a technique able to ionize simple molecules until complex structures, performing efficiently and dynamically with a wide application using high sensitivity and speed of analysis. Although MS hasconsiderable interest in the scientific society, the application of new technologies in the field of complex matrix analysis still is little explored.Inanalyzes of crude oil, paraffin and condensed aromatic standards, the atmospheric solids analysis probe mass spectrometry (ASAP-MS) is a powerful ionization sourceforcharacterization of samples in original form. Initially, two methodologies were used to determine the chemical composition of the samples: (1) using a temperature gradient ranging from 150 to 600 °C at a heating rate of 150 °C.min-1(parafina) or 50 °C.min-1; (2) with a constant temperaturearound350 °C. ASAP(+)-MS ionized crude oil and paraffin, showing a typical petroleum profile in the range of m/z200 -1400 for both samples. This performancecould relateASAP sourceto detection of compounds of high molecular weight (> 1000 Da). In addition, the AC standardswere identifiedin two ionicforms: radicals, [M]+•and protonated cations, [M+H]+, with minimal fragmentation. Therefore, ASAP was efficient for accessing the chemical composition of polar and non-polar compounds.Analysis of the Cannabis sativaL. plant, were doing by ultra-high performance liquid chromatography coupled to travelingwave ionic mass spectrometry (UPLC-TWIMS MS) using electrospray ionization source in both modes, ESI (±). Hashish, marijuana, and parts of the plant Cannabis sativaL. (flower and leaf) were analyzed. Isomeric compounds were identified inacomplex mixture of cannabinoids, mainly ?9-THC, cannabidiol (CBN-C5and Mw= 310 Da), ?9-tetrahydrocannabinolic acid A and B (?9-THCA-C5A/B and Mw= 358 Da) and their isomers. Analizes by ESI-TWIMSMS were identified three isomers, m/z315/313, 311, and 357, while a high selectivity was observedin UPLC-ESI-TOF MS data, identifying more thanfour isomeric compounds in the single ion acquisition mode (SIM).In other study, we evaluated the use of a high resolution mobility analyzer coupled to ultra high resolution mass spectrometry for molecular characterization of dissolved organic matter. The main goal wastovalidate the reproducibility of trapped ion mobility spectrometry (TIMS), the range of applicability and possible challenges during routine analysis.TIMS coupledto TOF MS and FT-ICR MS showed similar 18performance and high reproducibility. For the analysis of complex mixtures, both platforms were able to aquiriedthe main characteristics. However, the increase ofchemical complexity at nominal mass level (m/z> 300-350), only TIMS-FT-ICR MS was able to solve the compositional tendencies of lower abundance
Alcaloides dos bulbos das espécies Griffinia gardneriana (Herb.) Ravenna e Habranthus itaobinus Ravenna (amaryllidaceae): perfil químico e propriedades citotóxicas e genotóxicas
(Universidade Federal do Espírito Santo, 2018-08-23) Cole, Eduardo Roberto; Borges, Warley de Souza; Lacerda Junior, Valdemar; Endringer, Denise Coutinho; Santos, Reginaldo Bezerra dos; Kuster, Ricardo Machado; Cunha Neto, Álvaro
The Amaryllidaceae family is widely distributed throughout the world, being considered one of the 20 most important families among which they present alkaloids in their composition, exhibiting antiviral, antimalarial, anticancer and anticholinesterase activities, among others. This work aims to perform a chemical study on alkaloids of Griffinia gardneriana and Habranthus itaobinus bulbs, belonging to this family, to evaluate its cytotoxic and genotoxic properties and the role of caspase-3 as a molecular mediator of apoptosis induced by these compounds. Fractions enriched in alkaloids obtained from G. gardneriana and H. itaobinus bulbs were initially subjected to gas chromatography coupled to mass spectrometry (GC-MS) and then fractionated by different chromatographic techniques, such as molecular exclusion chromatography, column chromatography and preparative thin layer chromatography. The isolation and identification of the alkaloids was done by means of high performance liquid chromatography and mono- and bidimensional nuclear magnetic resonance, in addition to circular dichroism. Studies were carried out to evaluate the cytotoxicity of the enriched fractions by the MTT method using the OVCAR-3, J774 and L929 cell lines. In addition, the in vitro cytotoxicity and genotoxicity of the alkaloids isolated (through the MTT assay and micronucleus test) using tumoral (HepG2, MCF- 7, A549) and normal (L929, CHO-1-15) cell lines. In parallel, a study was developed to evaluate the correlation of the results obtained in the cytotoxicity assays by MTT and cytometry by image analysis. Molecular docking studies were performed to evaluate the free binding energies between the alkaloids isolated with the caspase-3 protein, described in the literature as the probable site of action of these compounds, also being calculated the theoretical inhibition constant, Ki. The GC-MS result of the enriched fractions evidenced the presence of only one alkaloid in G. gardneriana and five in H. itaobinus. Seven alkaloids of Amaryllidaceae, belonging to different type skeletons, all of them already well characterized in the literature, are some common ones to the two species (trisphaeridine and pretazettine), whereas others present only in G. gardneriana (lycorine and sanguinine) or in H. itaobinus (tazettine, 11- hydroxyvitattine and 2-a-7-dimethoxyhomolycorine). All enriched fractions showed cytotoxic action in the tested methods, but for the alkaloids isolated 11-hydroxyvitattine and 2-a-7-dimethoxyhomocolycorine were not cytotoxic, whereas tazettine, trisphaeridine and sanguinine presented activity only against the fibroblastic lineage. Lycorine and pretazettine were 10 to 30 times more cytotoxic than the other alkaloids, being active also for the cancerous lines, exhibiting time-dependent and concentration action, besides being genotoxic and able to promote the apoptosis via caspase-3. This result corroborates the data obtained in the docking studies in which these two compounds were among those with the highest binding affinity values.
Estudo teórico-experimental por RMN para elucidação estrutural de derivados do Cardanol, Homolicorinas e Cicloheptenonas.
(Universidade Federal do Espírito Santo, 2018-08-27) Barbosa, Layla Rosario; Lacerda Júnior, Valdemar; Cunha Neto, Álvaro; Gonçalves, Arlan da Silva; Queiroz Júnior, Luiz Henrique Keng; Morais, Pedro Alves Bezerra
Estudo da ionização de hidrocarbonetos do petróleo por APCI(+)FT-ICR MS.
(Universidade Federal do Espírito Santo, 2018-08-28) Souza, Lindamara Maria de; Romão, Wanderson; Cunha Neto, Álvaro; Kuster, Ricardo Machado; Fleming, Felipe Pereira; Cardoso, Felipe Mauro Rena
Analyzing paraffins/fractions of saturates, is a difficult task because they are apolar compounds, characterizing a challenge to the mass spectrometry. However, Atmospheric Pressure Chemical Ionization (APCI) source has provided higher applicability. In order to understand and apply APCI(+) MS to analyze paraffins with the best performance and correlate the MS results with other techniques, this work was divided into three sections: i) associate the results of paraffin analysis by analytical techniques to the Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) results. In addition, studying the ionization of paraffins in the presence of polyaromatic. ii) Comparing the ionization efficiency of saturated hydrocarbons (HCs), polyaromatic hydrocarbons (PAHs), and fractions of n-paraffins, as a function of different types of nebulizing gases (synthetic air, nitrogen (N2) and helium (He)) at the APCI source; iii) Study the interaction of petroleum paraffin deposition inhibitors by establishing a correlation between rheology and oil-finger cold tests with gas chromatography results and mass spectrometry of the saturated fraction of the same oils. These studies showed good agreement between APCI(+)FT-ICR MS and High-Temperature Gas Chromatography (HTGC) data through the distribution of carbon numbers plots for paraffin samples. Mwvalues could be compared to Nuclear Magnetic Resonance spectroscopy (RMN) results. Comprehensive Two-dimensional Gas Chromatography (GCxGC) and APCI(+)FT-ICR MS indicated the presence of cyclic paraffin in saturated fractions obtained from the SAP (Saturate, Aromatic and Polar) method. It was noted that PAHs at concentrations greater than or equal to 25 ppm suppressed the ionization of paraffins, but at low concentrations of PAHs (up to 15 ppm) it is possible to ionize paraffins. The evaluation of different ion gas source (nebulizer gas) showed, surprisingly, that the synthetic air presented an excellent signal-to-noise ratio and a lower matrix suppression. For the samples of n-paraffin, synthetic air and He presented similar ionization performance by hydride abstraction ([M-H]+). However, He showed lower mass errors and lower number of molecules with heteroatoms when HCS and PAH standards were analyzed. The correlation between cold-finger and rheology results with MS showed that inhibitors that caused viscosity reduction and deposit mass acted on oils with similar paraffin fractions for the composition of cyclic HCs
Síntese, caracterização e aplicações de materiais reciclados a partir de baterias íon-Li exauridas
(Universidade Federal do Espírito Santo, 2018-08-31) Pegoretti, Vitor Cezar Broetto; Freitas, Marcos Benedito José Geraldo de; Lelis, Maria de Fátima Fontes; Ferreira, Rafael de Queiroz; Almeida, Luiz Carlos Pimentel; Profeti, Demetrius
In this work, cobalt is recycled from a spent lithium-ion battery (LIB) to synthetize high-temperature HT-LiCoO2. In the leaching process, the cathode and anode materials are mixed with sulfuric acid and hydrogen peroxide under stirring and heating. The leaching liquor is filtrated to separate the carbon graphite anode. Cobalt hydroxide is precipitated after the addition of potassium hydroxide to the leaching solution. Cobalt hydroxide and lithium carbonate are the precursor materials for the thermal synthesis of HT LiCoO2 at 800 °C for 5 h. Raman spectroscopyconfirmedthe presence of the ??3¯??phase in HTLiCoO2.Transmission electron microscopy (TEM)analysis showed that the synthesized material has microcracks and defects.The electrochemical behavior of the synthesized material is tested by cyclic voltammetry and cycling tests. The results indicate intercalation and de-intercalation of lithium ions into and from the HT LiCoO2structure. The material presents the highest capacity value of 61.5 mAh g–1for discharge time of 4.4 h in the 4thcycle, and 32.5 mAh g–1in the 15thcycle for discharge time of 2 h. HT LiCoO2is also tested as an electrocatalyst for the oxygen evolution reaction (OER). Cyclic voltammetry and chronoamperometry tests show that the evolution of oxygen starts at 0.35 V accompanied by the formation of Co4+ions. The activation free energy of the reaction calculated using Tafel plot is 28.0 kJ mol-1and electrochemical impedance spectroscopy elucidates an equivalent circuit with a transfer charge resistance of 1.55 O, Warburg impedance of 150.3 O, and constant phase elements of 3.50 and 1.35 mF inside the pores and at the double layer, respectively.A green method was evaluated on route B. A cathodeLiCoxNiyMn1-x-yO2type form aspent lithium-ion battery was leached withmalic acid and the synthesis followed by sol–gelmethod. Three compoundswere prepared varying the synthesis time and the amount of lithium in the reaction medium. CNM10-10h material was obtained after 10 h under muffle furnace at 900 °C with Li:(Co+Ni+Mn)ratio of1.1:1.XRD with Rietveld refinementrevealed that the material is composed of64.3% Li0.31Ni0.5Mn0.5O2(??3¯??)and 35.7% Co3O4(??43¯??).SEM imagesshowedthe presence of octahedral Co3O4particles of approximately 1µmand TEM presented nanorods particles attributed to the lithiated phase. Cyclic voltammetry tests confirmed themultifunctional properties of the mixed oxide, which can be used as pseudocapacitor, catalyst,and non-enzymaticelectrochemical sensor for ascorbic acid determination. The synthesizedmaterial had a specific capacitance of 4.6 F g-1at the 1000thvoltammetric cycleat 10 mV s-1, an ascorbic acid sensitivity of 238.4 µA L mmol-1cm-2,and alinear working range of0.5–5 mmolL-1.CNM10-3h and CNM20-3h materials were obtained after 3 h under muffle furnace. The Li:(Co+Ni+Mn) ratio was 1.1:1 on the first material and 1.2:1 on the second one. XRD with Rietveld refinementrevealed that CNM10-3h material is composed by21.8% of Co3O4(??43¯??) and 78.2%of LiCo0,28Ni0,33Mn0,34O2(??3¯??).CNM20-3h is composed by 14.7 % ofCo3O4(??43¯??) and85.3 % ofLi0.94Co0.25Ni0.34Mn0.41O2(??3¯??).The electrochemical behavior of the synthesized materialswas tested by cyclic voltammetry and cycling tests. The results indicate intercalation and de-intercalation of lithium ions into and from thelithiated phase. Charge/discharge tests under C/10 rate realized on CNM10-3h and CNM20-3h presentedthe highest capacity value of 80and 119 mAh g–1onthe 1stcycle, respectively. Prolonged tests realized in 15 cycles only on CNM20-3h showed the capacity of 39,7 mAh g-1on the last cycle and a 9efficiency of 88,8%. Therefore, the recycling routes proposed in this work are efficient for the production of materials with different technological applications
Espectrometria de massas ambiente e tandem na quantificação de drogas de abuso
(Universidade Federal do Espírito Santo, 2018-09-10) Santos, Heloa; Romão, Wanderson; Cunha Neto, Álvaro; Borges, Warley de Souza; Vaz, Boniek Gontijo; França, Hildegardo Seibert
Mass spectrometry (MS) is a powerful tool because has high resolution and specificity for molecules chemical characterization. Initially, paper chromatography was developed using Dragendorff reagent and paper spray ionization mass spectrometry (PS-MS) for quantification. Then, polymers with electrical conductivity (PC) were studied because they are promising in high voltage applied in PS-MS and charging drops formation. Furthermore, PC-coated paper surface can be determinant for analyzes of various analytes, such as: avermectins, bupropion and its metabolites, anesthetics, anxiolytics, hormones, meloxicam, adulterants and drugs of abuse. The emergence of new psychoactive substances (NPS) is worldwide and alarming. Considering this growing market for NPS synthesis, the last part of this study presents a simple direct analysis in real time (DART) method. In Chapter 2, The method presented linearity greater than 0.98 and LODs of 6.51 ?g/mL, 13.53 ?g/mL and 0.35 mg/mL for Cocaína, levamisole and Lidocaína, respectively. Ten samples were quantified by PS(+)-MS and there was not statistically significant difference between PS(+)-MS and gas chromatography with flame ionization detector (GC-FID) at a significance level of 5 %. In Chapter 3, Polypyrrole (PPy), Polyaniline (PAni) or both polymers [Poly (Py-co-Ani)] were synthetized on paper by in situ polymerization. All the analytes were tested by PS (+)-FT-ICR and, in most cases, coated papers showed a higher absolute intensity signal compared to conventional chromatographic paper. The [Poly (Py-co-Ani)] paper showed better results and the linearity of the response was evaluated in Orbitrap (r2> 0.9851). The [Poly (Py-co-Ani)] paper was subjected to the reuse test and, compared to the traditional chromatographic paper, its results are promising for qualitative and quantitative PS-MS analysis. In Chapter 4, preliminary screening with DART-MS accelerates the detection process for 25 compounds among the most prominent classes of NPS, including synthetic cannabinoids and cathinone derivatives. Methanolic extracts were studied by DART(+)-MS/MS and it was efficient for rapid screening and detection of NPS in oral fluid and the herbal material (Turnera diffusa). LC-MS was able to generate MS/MS spectra with adequate linearity and sensitivity. The method was fully validated in the range of 0.01 to 100 ppb. Preliminary result of proposed off-line SPE protocol showed acceptable recoveries for the majority of drugs. Quality control samples were used during the method validation process, and all analytes showed RSD below 20 %
Determinação de propriedade físico-químicas de biodiesel e blendas por RMN de baixo campo e calibração multivariada
(Universidade Federal do Espírito Santo, 2018-11-06) Constantino, André Fazolo; Lacerda Junior, Valdemar; Consalter, Daniel Martelozo; Santos, Reginaldo Bezerra dos; Cunha Neto, Álvaro; Barbosa, Lúcio Leonel
Because the methods specified by regulatory agencies for the determination of the physicochemical properties of biodiesel can be laborious and expensive, the development of alternative methodologies represents a major breakthrough. Thus, low-field nuclear magnetic resonance (NMR) is an advantageous option because it is nondestructive and reduces the cost and time consumption. In this study, the partial least squares (PLS) regression method was used to create models that correlated the decay curves of the Carr–Purcell–Meiboom–Gill (CPMG) signal, Continuous Wave Free Precession (CWFPx-x) orCarr–Purcell Continuous Wave Free Precession (CP-CWFPx-x), obtained fromlow-field NMR equipments(2.2 MHz and 15.0 MHz for 1H), with the kinematic viscosity, specific mass,refractive index and iodine value of biodiesel and their blends. Seventeen oilseeds diversified between edible and non-edible oils were utilized to synthesizethe biodiesel and producebinary blends.Separately, multivariate calibration models were created only with pure biodiesel and blends withcastor bean because these samples showed different tendencies from the others. The best values of root mean square error of prediction (RMSEP) for the kinematic viscosity, specific mass and refractive index were equal to 0.1 mm2/s, 1.9 kg/m3, 0.002 and 15.5 g I2/100 g of sample,respectively, for samples of biodiesel and blends without castor bean and 0.3mm2/s, 1.3kg/m3,0.0003 and 1.9 g I2/100 g of samplefor samples of biodiesel and blends with castor bean. The results reveal that the developed models are very satisfactory to predict the quality parameters of biodiesel and blendswith fairly good efficacy, withthe models created withCPMG andCP-CWFPx-xdata being stood out to those constructedwith CWFPx-xdata. The physicochemical properties were also correlated with the decay curves of seed and oil samples, with the aim of predicting the quality of biodiesel from the analysis of its raw materials. However,the resultswere not very promising, sincethe correlations betweenmeasured physicochemical properties by American Society for Testing and Materials (ASTM) methods and its predicted values from the constructed PLS models resulted in very low coefficients of determination (R2)
Preparação e caracterização do óxido de grafeno funcionalizado com aminas para aplicação em supercapacitadores eletroquímicos
(Universidade Federal do Espírito Santo, 2018-12-17) Caliman, Cristiano Carrareto; Mesquita, Anderson Fuzer; Freitas, Marcos Benedito José Geraldo de; Porto, Arilza de Oliveira; Prado, Adilson Ribeiro; Ribeiro, Marcos Antônio
A simple and direct method using microwave assisted reactions was presented for functionalization of graphene oxide with aromatic and non-aromatic amines, notably dibenzylamine (DBA), para-phenylenediamine (PPD), diisopropylamine (DPA) and piperidine (PA) as well as its subsequent decoration with nickel and cobalt sulfides.The amine-functionalized graphene oxide (GO-amine) materials were characterized using XRD, FTIR, 13C NMR and XPS, METspectroscopic techniques for image characterization and thermogravimetric analysis (TGA).Composites ofamine-functionalized graphene oxide decorated with nickel and cobalt sulfide particles(GO-amine-sulfide) were also characterized by XRD, FTIR, 13C NMR, MET and TGAtechniques.The characterizations confirmed the functionalizationfor all the amines, reaching relatively high concentrations of superficial nitrogen, up to 8.8%.The investigations of electrochemical behavior for GO-amines showed a significant increase in GO ´selectrochemical propertiesafterfunctionalization, exhibiting long cyclic stability and achieving specific capacitance valuesof 290 Fg-1and 260 Fg-1for GO-PA and G-DPA, respectively, confirming its potential application as alternative support material in supercapacitors.Likewise, the electrochemical characterization of the GO-amine-sulfide composites showed an increase in specific capacitance after the addition of metal sulphides, exhibiting values of 397 Fg-1and 380 Fg-1for GO DPA NiS and GO PA CoS respectively.
Investigação sobre materiais híbridos obtidos a partir de óxido de grafeno com incorporação de sílica ou de grupos contendo fósforo
(Universidade Federal do Espírito Santo, 2018-12-18) Vieira, Mariana Arpini; Freitas, Jair Carlos Checon de; Emmerich, Francisco Guilherme; Lacerda Junior, Valdemar; Dalmaschio, Cleocir José; Alves, Klinger Marcos Barbosa; Porto, Arilza de Oliveira
The reduction of graphene oxide (GO), which can be accomplished by the combination of thermal and chemical treatments, leads to the production of a material known as reduced graphene oxide (rGO); this material exhibits good electrical conductivity and, despite the presence of structural defects and chemical heterogeneity, can represent a viable and low-cost alternative to pure graphene in several applications. In the presentwork GO was produced by both Hummers and Tour methodsfrom an Li-ionbattery recycled graphite powder, varying the final content of phosphorusand sulfurby modifying the proportion of the reactants (H2SO4/H3PO4). After centrifugation the materialsweredried and concomitantly lead to thermal reduction under ambient atmosphere and at different temperatures (80, 100 and 150 °C). The products were characterized by X-ray diffraction (XRD), thermogravimetry, solid-state 13C and 31P nuclear magnetic resonance (NMR) and X-ray fluorescence. 13C NMR results show that the treatment of the materials at higher temperatures causes the progressive disappearance of the peaks associated with the oxygenated functional groups, leading to an NMR spectrum dominated by a largeresonance peak associated with sp2hybridized carbon atoms. 31P NMR results indicate that phosphorus is present in rGOsamples in the form of phosphonate groups (with P-C bonds), polyphosphoric acids (present in chains formed by the condensation of phosphate groups) and orthophosphoric acid.Furthermore, it was possible to synthesize rGO samples containing approximately 5% (m/m) of Pand 2% (m/m) of S, as stated by XRF analysis.A method of synthesizing a GO-SiO2hybrid material was also proposed, using the GOsuspension in the synthesis procedure, eliminating the drying step of the GO for its application in the preparation of the hybrid material. Results of solid-state29Si and 13C NMR,SEM, XRD and FT-IR showed that the proposed method allowed the synthesis of hybrids with different silica contents (~ 22and 46%m/m). In addition, the results of XRD, 29Si NMR, FT-IR and TG/DTG indicated the presence of nanostructured or amorphous silica and suggested the interaction of the silica particles with the GO matrixby hydrogen bonds between the silanol groups and the oxygenated functionalities of GO, and by Si-O-C bonds formed from the reaction of the carboxylic acids of the GOwith the silanol groups
DESENVOLVIMENTO DE UM MÉTODO ALTERNATIVO DE DESSALGAÇÃO E DESIDRATAÇÃO DE PETRÓLEOS PESADOS E EXTRAPESADOS
(Universidade Federal do Espírito Santo, 2019-02-15) Sad, Cristina Maria dos Santos; Castro, Eustaquio Vinicius Ribeiro de; https://orcid.org/; http://lattes.cnpq.br/1055263403980509; https://orcid.org/; http://lattes.cnpq.br/; Prado, Adilson Ribeiro; https://orcid.org/; http://lattes.cnpq.br/; Neto, Alvaro Cunha; https://orcid.org/; http://lattes.cnpq.br/7448379486432052; Santana, Hosiberto Batista de; https://orcid.org/; http://lattes.cnpq.br/; Junior, Valdemar Lacerda; https://orcid.org/0000000282575443; http://lattes.cnpq.br/9819471276433138
abstract
Preparação e caracterização de um candidato à material de referência de elementos traço em petróleo
(Universidade Federal do Espírito Santo, 2019-03-28) Marchezi, Thabita Thiciana Bastos; Lima, Maria Tereza Weitzel Dias Carneiro; https://orcid.org/0000-0002-8731-5093; http://lattes.cnpq.br/9989703911201351; https://orcid.org/; http://lattes.cnpq.br/3585702259425999; Nogueira, Ana Rita de Araujo; https://orcid.org/; http://lattes.cnpq.br/7034773971317045; Souza, Jefferson Rodrigues de; https://orcid.org/; http://lattes.cnpq.br/; Athayde, Geisamanda Pedrini Brandao; https://orcid.org/0000-0002-4315-0653; http://lattes.cnpq.br/8037324704189596; Filgueiras, Paulo Roberto; https://orcid.org/0000000326171601; http://lattes.cnpq.br/1907915547207861
Due to the complexity determination of trace elements in crude oil, mainly by multi element techniques, many works have been developed to optimize instrumental parameters and new techniques for preparation and introduction of samples, aiming at improving the sensitivity, precision and accuracy in the measurement. In all cases, it is necessary to use reference materials (RMs) and/or certified reference materials (CRMs) to verify the performance of the new proposed method. However, most reference materials for trace elements in the liquid fuels are matrices like gasoline, diesel oil, fuel oil and lubricating oil. In this work it was developed all the necessary steps for the preparation, characterization and certification of a national crude oil reference material for trace elements following the internationally accepted requirements. Three kilos of crude oil were homogenized under optimized conditions and they were distributed among 115 units containing about 20 g each. The homogeneity of the material was studied in the different units produced. For the short term stability study, a test was performed at different temperatures, ranging from + 4 to + 50 º C, and storage times of 1, 2, 3 and 4. The long-term study was performed for 9 months at the laboratory room temperature (+20 to +26 ºC). The obtained results indicated that the material was homogeneous and stable under the studied conditions. For the statistical evaluation, classical statistical techniques were performed, such as analysis of variance and regression tests and multivariate techniques, as the principal component Analysis (PCA). For the values attributed to the mass fractions (µg g-1), a multi-method in-house approach was used. The combination of the results obtained in the characterization and in the studies of homogeneity and stability allowed to assign values to 5 elements with their respective uncertainties: 2 certified values (Ni and V), 3 reference values (Ba, Na and Sr) and 4 values information (Ca, Mg, Co and Fe).
Reciclagem sustentável do anodo de baterias exauridas deNi-MH: sínteses dos óxidos de níquel e lantanídeos pelos métodosde precipitação seletiva, sol-gel e coprecipitação
(Universidade Federal do Espírito Santo, 2019-04-03) Marins, Antonio Augusto Lopes; Freitas, Marcos Benedito José Geraldo de; Silva Filho, Eloi Alves da; Castro, Eustáquio Vinícius Ribeiro de; Prado, Adilson Ribeiro; Entringer, José Marcos Stelzer
Mecanismo de degradação da Goma Guar submetida a escoamento turbulento
(Universidade Federal do Espírito Santo, 2019-04-16) Motta, Marcus Vinícius Lisboa; Castro, Eustáquio Vinicius Ribeiro de; Silva Filho, Eloi Alves da; Filgueiras, Paulo Roberto; Loureiro, Bruno Venturini; Martins, André Leibsohn
Internal turbulent flows are commonly found in industrial applications in fluid transport. This flow regime is associated with additional energy losses in relation to the laminar flow due to the existence of complex dissipative structures in the flow and to the greater friction suffered by the flow with the internal walls of the pipe. In order to maintain this flow regime, the main flow must supply energy from the pumping unit. Reducing the demand for energy to promote internal turbulent flows can be done by the injection of drag reducing additives, usually polymeric in nature. In the studied condition the polymers undergo mechanical degradation and lose the ability to promote drag reduction over time. Studies indicate that the drag reduction may be related to the flexibility of the polymer and the size of the macromolecules of the additive used, which can interact with the vortices and reduce energy dissipation. In this study, the aqueous solution of the guar gum polysaccharide 400 ppm was subjected to a turbulent flow regime with the objective of monitoring, in an experimental plant, molecular degradation, drag reduction and energy demand. For this purpose, solution samples were removed during two hours of flow and the polysaccharide was isolated for characterization of the degradation. FTIR and NMR spectroscopy suggest that the mechanical degradation occurs with the hydrolysis of the a (1 ? 6) bond of the main chain with (D) -galactose due to the appearance of the carbonyl functional group. Thermal analysis revealed a decrease in the thermal stability of the polysaccharide by the decrease of the polymer chain. Finally, the understanding of this mechanism aims at the use of more efficient polymers in the reduction of drag and the decrease of the demand of energy in pumping processes that use these drag reducing macromolecules. Fourier transform infrared spectroscopy (FTIR), solid state nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and viscosity in diluted solution were analyzed. It was characterized, that the drag reduction efficiency promoted by guar gum is compromised by the polysaccharide undergoes chemical degradation, promoted by mechanical stress. As evidence, the viscosimetric analysis of guar gum showed the reduction of molecular weight in the period. FTIR and NMR spectroscopy suggest that the mechanical degradation occurs with the hydrolysis of the a (1 ? 6) bond of the main chain with (D) -galactose due to the appearance of the carbonyl functional group. Thermal analysis revealed a decrease in the thermal stability of the polysaccharide by the decrease of the polymer chain. Finally, the understanding of this mechanism aims at the use of more efficient polymers in the reduction of drag and the decrease of the demand of energy in pumping processes that use these drag reducing macromolecules.
Avaliação da taxa de corrosão do aço AISI 1020 em petróleo bruto e padrões de ácidos naftênicos
(Universidade Federal do Espírito Santo, 2019-06-07) Dias, Heloisa Pinto; Romao, Wanderson; https://orcid.org/0000000222546683; http://lattes.cnpq.br/9121022613112821; https://orcid.org/; http://lattes.cnpq.br/5071058338667825; Nicolin, Viviane Azambuja Favre; https://orcid.org/0000-0001-6795-1167; http://lattes.cnpq.br/8203456381935461; Prado, Adilson Ribeiro; https://orcid.org/0000-0001-8808-4488; http://lattes.cnpq.br/3085491325255749; Filgueiras, Paulo Roberto; https://orcid.org/0000000326171601; http://lattes.cnpq.br/1907915547207861; Junior, Valdemar Lacerda; https://orcid.org/0000000282575443; http://lattes.cnpq.br/9819471276433138
It is common to use the total acid number (TAN) as a measure of the acidity of a Petroleum. However, naphthenic acids (NAs) vary in their structures and concentrations from one petroleum to another, even when the TAN value remains constant. Daily practice at the refineries has shown that oils with a NAT less than 0.5 mg of KOH·g-1 most often presents an unexpected corrosive behavior. Although naphthenic corrosion has been studied for years, its process is still not completely understood. Thus, the present study investigated the influence of solutions of molecules of linear, cyclic and aromatic NAs, (evaluating the effect of their concentrations, molar mass (Mw), and structural and electronic properties) in the corrosion rate under AISI 1020 steel, through tests at 320 ºC in 24H.The type and extent of corrosion were monitored by characterizing the surface of the specimens by light microscopy (LM), atomic force microscopy (AFM), and scanning electron microscopy (SEM). The results showed that, even when the TAN was below the limit of detection, the value of the observed corrosion rate (CR) was significant, being considered high (TC < 0.19 mm·year-1) by the oil industry. At concentrations ≥ 5000 ppm of benzoic acids (BENA) and stearic (STA), the corrosion rate varied proportionally to the TAN. In addition, there was an inversely proportional correlation between the molar mass (Mw) and the number of aromatic rings of the NAs with their corrosive capacity. It was observed that the NAs standards containing a lower molar volume presented a higher corrosion rate. The images presented by SEM showed changes in the surface of all coupons exposed to NAs solutions, indicating that a protective layer was formed under the surface of the carbon steel coupon. The images by AFM revealed a topographic and phase profile deeply altered by the formation of valleys and peaks and variations in the mechanical properties of the AISI 1020 steel surface. The results obtained in this study are promising and confirm the influence of the electronic structural properties of organic acid molecules under naphthenic corrosion.
Caracterização de asfaltenos e outros derivados do petróleo por ESI(±)FT-ICR MS
(Universidade Federal do Espírito Santo, 2019-06-18) Pinto, Fernanda Endringer; Romao, Wanderson; https://orcid.org/0000000222546683; http://lattes.cnpq.br/9121022613112821; https://orcid.org/0000000223008481; http://lattes.cnpq.br/2271664099284682; Cardoso, Felipe Mauro Rena; https://orcid.org/0000-0002-2300-8481; http://lattes.cnpq.br/7445086243070619; Cunha Neto, Alvaro ; https://orcid.org/0000-0002-1814-6214; http://lattes.cnpq.br/7448379486432052; Junior, Valdemar Lacerda; https://orcid.org/0000000282575443; http://lattes.cnpq.br/9819471276433138; Souza, Lindamara Maria de
Positive and negative ion-mode electrospray (ESI(±)) technique coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) preferably provides ionization of polar constituents with ultra-high resolution and mass accuracy. The purpose of this research was to characterize asphaltenes and vacuum gasoil (VGO) by ESI(±)FT-ICR MS. Three asphaltenes subfractions obtained from precipitation with different n-hexane/crude oil ratios (3.5V, 3.5–6V, and 6–40V), and three subfractions obtained from adsorption onto CaCO3 (non-adsorbed, adsorbed, and irreversibly adsorbed), besides the original asphaltenes were analyzed. With the data generated from the ESI(±), solubility parameters (δ) were calculated. ESI(±) data showed that polar compounds species with lower carbon numbers were mainly found for the irreversibly adsorbed subfraction, while the subfraction 6-40V presented a more aromatic profile than of remaining subfractions. The δ obtained from the ESI(+) results showed an overlapping of Nx species indicating that subfractions produced in n-hexane had a lower tendency to precipitate in hydrocarbons in relation to subfractions produced onto CaCO3. The last presented a shift to higher δ for both ionization modes ESI(±), indicating that the fractionation onto CaCO3 was able to produce more distinct subfractions, with different δ, aromaticity, and polarity. The VGO samples consisted of VGO original and VGO treated with clay and silica obtain from breakthrough curves on two temperature levels (80 and 150 °C) and different rupture times (from 60 to 420 min). ESI(±) analyses of GOV and their fractions indicated that the removal of nitrogen compounds by the clay adsorbent was enhanced when the temperature was higher (150 °C). Conversely, silica has shown a rich adsorption capacity at moderate temperatures (80 °C). This result corroborates the existence of two different adsorption mechanisms. The clay adsorption mechanism is likely a chemisorption process, while the silica adsorption mechanism is related to physisorption. Both processes displayed better performance in short rupture times, for example, at 60 min. Class distribution showed a preferential removal of N[H] and N2[H] compounds with low carbon numbers (< C26) for ESI(+). However, the ESI(−) data showed that, although adsorbents, such as clay, present acid sites and selectively adsorb basic nitrogen species, a great reduction of non-basic nitrogen species, such as carbazole and its analogues, is clearly observed mainly for VGO samples treated with clay at 150 °C and with silica at 80 and 150 °C. The application of ESI (±) FT-ICR MS in the analysis of petroleum and derivatives facilitated the specific comparison of compounds between the samples, due to the ability of the equipment to monitor thousands of species present in the oil, with a high precision and mass resolution, as well a promise tool in the determination of different reaction mechanisms.
Quimiometria associada à espectroscopia no infravermelho na previsão da eficiência de sequestrantes de H2S e supressores de poeira de minério de ferro
(Universidade Federal do Espírito Santo, 2019-06-27) Moncioso, Natalia de Aquino Portela; Silva Filho, Eloi Alves da ; https://orcid.org/0000-0002-9306-7882; http://lattes.cnpq.br/8259708288584235; https://orcid.org/0000-0003-3823-7356; http://lattes.cnpq.br/6260991079860492; Motta, Marcus Vinicius Lisboa; https://orcid.org/0000-0002-3801-4366; http://lattes.cnpq.br/0764912059341298; Filgueiras, Paulo Roberto; https://orcid.org/0000000326171601; http://lattes.cnpq.br/1907915547207861; Rocha, Julia Tristao do Carmo; https://orcid.org/; http://lattes.cnpq.br/6899104555589459; Dalmaschio, Cleocir Jose; https://orcid.org/0000000237735786; http://lattes.cnpq.br/5209978120430790; Castro, Eustaquio Vinicius Ribeiro de; http://lattes.cnpq.br/1055263403980509
The emission of particulate matter from the iron ore stockpiles is one of the concerns of the mining industry. In addition to the possible environmental and health damages, iron ore being the raw material for the steelmaking process is the economic problem. Sprinkling commercial water-soluble dust suppressants is a method of reducing or eliminating dust emission from ore stockpiles. Dust suppressants are aqueous solutions, sprayed on the surface of the ores, and there are several types available commercially. Already in crude oil exploration, the problems caused by the presence of H2S in oil production are diverse and comprehensive. In the petroleum industry several methods are used to remove this gas, with the use of commercial H2S scavengers being one of the most commonly used alternatives. There are a variety of commercial products known as H2S scavengers, which makes studies necessary to choose these products. In this thesis a methodology for evaluating the performance of commercial dust suppressors in iron ore storage stacks using the wind tunnel was studied. In addition, two performance prediction tests were proposed: for commercial H2S scavengers in oil and for commercial iron ore dust suppressants and using multivariate analysis of the infrared (IR) spectra in the middle region, considering that only one variable does not respond to the prediction of the performance of the samples, and associating bands in the IV evidenced in the graph of the loadings. The efficiency prediction test of H2S scavengers in capturing the sulfide in petroleum provided the estimation of the efficiency of the samples with 84% accuracy. It has been found that nitrogenous and extreme pH scavengers have a tendency to capture a greater amount of sulfide in the petroleum. In the test of prediction of the efficiency of the ore dust suppressors it was possible to discriminate samples with potential dust suppression with 86% accuracy. The high performance suppressors presented the hydrophobicity index of the IV bands at 2926/3300 cm-1 lower than 0.333.
Qualidade química de suco de uva comercial, perfil químico de bananas e açaí juçara e atividade quimiopreventiva de câncer de extratos de bananas
(Universidade Federal do Espírito Santo, 2019-06-27) Oliveira, Bruno Gomes de; Endringer, Denise Coutinho; Romão, Wanderson; Costa, Helber Barcellos da; Filgueiras, Paulo Roberto; Cunha Neto, Álvaro; Ventura, José Aires
Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT ICR-MS) allied to electrospray ionization (ESI) is a powerful tool for chemical analysis. In this work, a methodology was developed for the identification and quantification of grape juice with apple juiceadulteration. Anunivariate and two multivariate calibration models (PLS and MRL) were developed. The three models presented results with good precision and accuracy. Eleven samples of commercial whole grape juice were tested. Of these eleven samples, two of them presented apple juice content of approximately 24% m/m and the other nine juices investigated they either did not contain apple juice or had a content below the limit of quantification.In addition, using the ESI(-) FT ICR-MS, it was possible to study the glycidic and phenolic profile of bananas of the Pacovan, Ambrosia, Vitória, Japira, Prata Comum and Tropical varieties at four maturation stages. It was possible to observe the increase of the carbohydrate content in the fruits, during maturation. The Prata (Japira, Vitória, PrataComum and Pacovan) bananas had a monosaccharide content higher than the disaccharide content. Conversely, Gros Michel (Ambrosia) and Maçã(Tropical) had a higher disaccharide content than the monosaccharide content. The polyphenolic profile of these samples indicated a predominance of flavonoids and cinnamic acids, of which 20 polyphenols were detected, for example: epicatechin, hexoside ferulic acid, caffeic acid derivative, gallic acid derivative, proanthocyanidin and quercetin deoxyhexosehexoside.The cancer chemopreventive potential associated with quinone reductase induction,inhibition of the nitric oxideproduction, NF-kB and aromatase were also analyzed.Pacovan cultivar, maturation stage 2, showed high inhibition of NF-kB whereas Japira cultivar, at maturation stages 2, 4 and 7 and Ambrosia, stage 4, showed aromatase inhibition higher than 50%. All samples except Pacovan at maturity stage 7, Tropical at maturation stage 7, showed inhibition of iNOS greater than 80%.The polyphenolic profile of seven genotypes ofjuçara was also investigated in this work. Polyphenols were classified into three phytochemical classes: flavonoids, phenolic acids and anthocyanins, with the most abundant flavonoid class.Among the identified compounds are dihydrokaempferol, protocatecuic hexoside acid, syringe hexoside acid, orientin and malvidin-glycoside.

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