Química

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Programa de Pós-Graduação em Química

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Agora exibindo 1 - 20 de 321

Ácidos graxos e compostos fenólicos como substâncias fitotóxicas nos resíduos agroindustriais: vinhaça, torta de filtro e bagaço
(Universidade Federal do Espírito Santo, 2018-02-16) Luz, Dandara Alves; Gomes, Anne Caroline Candido; Kuster, Ricardo Machado; Cunha Neto, Álvaro; Santos, Roberto Pereira
The residues of agroindustry from sugar cane vinasse, filter cake and bagasse are abundant in Brazil, a leading country in the production of sugar and alcohol. The use of this waste solves problems related to waste and environmental pollution. Extracts were produced by solvent maceration, some of them were submitted to liquid / liquid partitions and others were saponified, resulting in numerous samples that were tested for phytotoxic activity and analyzed by GC-MS, by ESI (-) FT-ICR-MS and ESI (-) MS / MS leading to the identification of 22 substances, among them ten fatty acids and twelve phenolic compounds. The DIC experiments of the pseudomolecular ions [MH] –327,21796 (C18H32O5) and 329,23355 (C18H34O5) led to the proposition of the polyhydroxylated unsaturated fatty acids, 9,12,13-trihydroxy-10,15-octadecadienoic, for the first and the isomers 9 , 12,13-trihydroxy-10-octadecenoic acid / 9,10,13-trihydroxy-12-octadecenoic acid for the second, which have not been described so far in Saccharumssp. GC-MS analyzes corroborated the chemical profile already observed by the FT-ICR-MS technique. In the phytotoxicity bioassay in Lactuca sativa, the most active fractions were the dichloromethane partition of vinasse (IC50 = 168.4 ppm) and ethyl acetate of vinasse (IC50 = 262.3 ppm). The FT-ICR-MS and CG-EM analyzes demonstrated that the VDiCl sample consists of a proportionally similar mixture of fatty acids and phenolic acids, whereas VAcOEt is formed in a higher proportion by a mixture of phenolic compounds. In the bioassays with Ipomoea purpurea(weed), the dichloromethane partition of vinasse was also more active, inhibiting root growth by 52% (IC 50 = 344 ppm). At the same concentration, the ethyl acetate partition inhibited only 25.74% root growth. It has been suggested that the interaction between fatty acids and phenolic compounds is important for a higher rate of inhibition and that the presence of oxilipins (polyhydroxylated unsaturated fatty acids)is essential for the more marked phytotoxicity of this sample. This work demonstrated the potentiality of fatty acids and phenolic compounds present in the agroindustrial residues regarding phytotoxicity, indicating that these can be used as raw materials in the elaboration of innovative products for the control of weeds, minimizing the risks that the incorrect disposal to the environment.
Adequação e verificação de procedimentos para determinação de mercúrio em amostras de fígado e rim de rato utilizando a técnica CV-GF AAS
(Universidade Federal do Espírito Santo, 2014-08-24) Santos, André Eliziário dos; Jesus, Honério Coutinho de; Athayde, Geisamanda Pedrini Brandão; Barthus, Rosangela Cristina; Ribeiro, Araceli Veronica Flores Nardy
Mercury is an element that still needs constant monitoring because it is highly toxic at trace-level concentrations, with possibility exposure and contamination by a variety of forms present in the environment. Thus, the aim of this work was adapt and verify a simple and efficient procedure for mercury determination in Wistar rat tissues using cold vapor generation, pre-concentration in graphite furnace and analysis by atomic absorption spectrometry (CV-GF AAS). They were made comparison of amalgamation methods, procedure optimization, verification of merit figures and analysis of liver and kidneys of chronically treated rat. The best results were obtained using the hot block digestion method as sample pre-treatment and gold coated tube combined with and net of gold for amalgamation. It was necessary to use dichromate, isopropanol and simeticone pre-analysis. Procedure accuracy was verified through recovery tests at five concentration (between 92 and 114 %), enabling the use of the proposed procedure.
Adulteração de óleo diesel e determinação do tamanho de gota de emulsões
(Universidade Federal do Espírito Santo, 2016-03-09) Cunha, Danyelle Alves da; Barbosa, Lúcio Leonel; Lacerda Júnior, Valdemar; Pasa, Vanya Marcia Duarte
Crude oil canbe defined as a complex mixture of hydrocarbons and compounds containing S, O, N, and metals in its composition. During the production process occurs the formation of water in oil emulsions (W / O) or oil in water (O / W). These types of emulsions are harmful since they increase viscosity, reduce drainage rate and can promote the precipitation of paraffin crystals and asphaltene aggregates. Precipitation of these compounds interferes the production lines, since they are deposited in the tubing, decreasing its inner diameter and increasing production costs. The industry requires oil free of water to reduce the risks of corrosion and, consequently, reduced manufacturing costs. Therefore, the monitoring of such systems by determining the droplet size distribution (DTG) is indispensable. From the refining of crude oil, are obtained derived petroleum products such as LPG (cooking gas), kerosene, gasoline, diesel oil, among others. The diesel oil is a middle distillate, since the boiling point varies between 125ºC and 328ºC. This distillate has utmost importance as a fuel in the Brazilian road transport, leading the ranking of fuel consumption in the road sector in Brazil. Thus, the adulteration of this fuel is crescent and areadded, to this oil, products such as kerosene, biodiesel and residual oils, since they have good miscibility. Among the most widely used techniques for the study of this oil there is the infrared spectroscopy, mass spectrometry and nuclear magnetic resonance (NMR) High resolution. However, studies involving diesel adulteration by Low field -NMR hadnot been publishedyet. This study aims to verify by low field-NMR adulteration of diesel and also to determine the droplet size of emulsions water / diesel and water / biodiesel
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.
Alcaloides isoquinolínicos e atividade citotóxica in vitro de Hippeastrum canastrense J. Dutilh & R. S. Oliveira (Amaryllidaceae)
(Universidade Federal do Espírito Santo, 2016-10-24) Vicente, Andressa Reis; Borges, Warley de Souza; Fronza, Márcio; Lima, Murilo Marinho de Castro; Kuster, Ricardo Machado
The Amaryllidaceae family lies between the 20most applied plant families as therapeutic agents against various diseases.An important characteristic of this family is the presence of a unique group of alkaloids, exhibitingseverals biological activities such as antitumor, antibacterial, antifungal, antimalarial,antiviral, analgesic, and antiparasiticand acetylcholinesteraseinhibition. This work presents a chemical study of the alkaloidscontent found in the bulbs and flowerlystems of Hippeastrum canastrense, an endemic species from Brazilthat notably has no studies concerning it’s chemicals components so far. In addition,the investigation of the cytotoxicityeffects of the extracts and alkaloidsisolatedwere carried out with tumor cells assays. Therefore, a classical acid-base extraction of methanol extracts of both parts of H. canastrensewas performed, followed by chromatographic separation techniques in order to isolate the alkaloids present in the species.The GC-MS analysis was ableto identify 40 alkaloids, and 16 well-known alkaloidswere isolated: sanguinine(1), hippeastrine(4), candimine(5), 7-methoxy-O-methyllycorenine(7), albomaculine(8), homolycorine(9), lycorine(10), 8-O-demethylhomolycorine(13), norpluviine(14), 2a,7-dimethoxyhomolycorine(15), 2a-hydroxihomolycorine(16), 2a-hydroxialbomaculine(17), masonine(18), normasonine(19), nerinine(20), e trisphaeridine(21), and yet five novel alkaloids here reported as 8-O-demethyl-2a-hydroxihomolycorine(2), 7-methoxymasonine(3), 2-O-metthylcandimine(6), 7-methoxynormasonine(11) e 2a-methoxyhomolycorine(12).Thecrudeextracts and enriched extracts, as well as the compounds 1, 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, 15, 18, 19e 20 were evaluated for their cytotoxicity in normal fibroblast-cells and also for breast, liver and panceas tumor-cells.The alkaloids hippeastrine, candimine and lycorine showedsignificantcytotoxic effect in all assays. The lowest IC50values for hippeastrine and candimine were obtained for human pancreatic carcinoma cells, while for lycorine was in hepatocelluar carcinoma cells assays.The crude extracts of Hippeastrum canastrenseshowed remarkable cytotoxicity in tumor cells especially in hepatocellular carcinoma cells. The ethyl acetate alkaloids-enriched extracts from the flowerly stems and bulbs, along with the hexane extract from bulbs expressed a relevant cytotoxic potencial in tumor cells. However, bulbs extracts appears to be most selective then the extracts of flowerly stems
Alcaloides isoquinolínicos isolados das partes aéreas de Worsleya procera (Lem.) Traub (Amaryllidaceae)
(Universidade Federal do Espírito Santo, 2016-10-24) Moraes, Carolina Torres; Borges, Warley de Souza; Cunha Neto, Álvaro
Many natural compounds have shown interesting biological and pharmacological activities and are considered important targets and one of the largest sources of new drugs, used directly or indirectly as a starting point for developing new drugs. Of plant compounds with biological potency, the alkaloids present in the Amaryllidaceae family are especially effective, for example, the alkaloid galanthamine, a selective, reversible and competitive inhibitor of the enzyme acetylcholinesterase and is marketed for the treatment of Alzheimer's disease. No study of chemical and biological characterization of the plant Worsleya procera(Lem.)Traub (Amaryllidaceae) was found in the literature and thus, for the purpose of phytochemical characterization of this plant, various chromatographic techniques were used in their extracts for the isolation and identification of alkaloids. As a result, 19 alkaloids and a mixture of two epimers alkaloids (18and 19)were isolatedfrom the aerial parts of W. procera: 3-epimacronine (1),albomaculine (2), lycorine (3), galanthine (4), tazettine (5), hippeastrine (6), O-methyllycorenine (7), 7-methoxy-O-methyllycorenina (8), homolycorine (9), 8-O-demethylhomolycorine (10), trisphaeridine (11), haemanthamine (12), 8-O-demethyl-O-methyllycorenine (13), ismine (14), 6-O-methylpretazettine (15), pretazettine (16), alkaloidwith skeleton type haemanthamine(17), haemanthidine (18), 6-epihaemanthidine (19), 8-O-demethyl-2a-hydroxyhomolycorine (20) e N-fomylismine (21), where their structures could be elucidated by the 1H NMR technique one-and two-dimensional, in compared with literature data. The alkaloid 8-O-demethyl-2a-hydroxyhomolycorineis reported for the first time from natural source.Nineisolated alkaloids(Tazettine, 3-epimacronine, albomaculine, lycorine, galanthine,hippeastrine, O-methyllycorenine, 7-methoxy-O-methyllycorenina and 8-O-demethylhomolycorine) were evaluated for antimicrobial activity, with all weak activity when compared to posivito control.The GC-MS technique proved to be a rapid and efficient technical alkaloids identification, since the analysis results of W.proceraplantextractsfound that the majority were alkaloids 22with skeleton homolicorina type, skeleton lycorinetype and skeletontazetina type, which was confirmed by the total mass of alkaloid obtained
Alternativas para o processamento do gás natural do Espírito Santo
(Universidade Federal do Espírito Santo, 2023-10-27) Altenerath, Kelen Carolina; Lacerda Júnior, Valdemar; https://orcid.org/0000000282575443; http://lattes.cnpq.br/9819471276433138; https://orcid.org/0009-0003-8034-7716; http://lattes.cnpq.br/3299877921334667; Madureira, Claudio Penedo; http://lattes.cnpq.br/4199732799442853; Silva, Andre Romero da; https://orcid.org/0000000214976093; http://lattes.cnpq.br/3079774974302460; Cunha Neto, Alvaro; http://lattes.cnpq.br/7448379486432052
Natural gas has been presenting an increase in demand on the recent years, largely due to its competitive advantages over other fossil fuels. However, in Brazil, its production and supply chain remains under one dominant agent, which makes it difficult for new ones to enter the market and often causes other producers to dispose of their production with little or no financial return. Therefore, the objective of this work is to identify alternative natural gas processing technologies, to allow other natural gas producing companies to process and commercialize their natural gas production without depending on the infrastructure belonging to the dominant agent, considering the technical and regulatory limitations applicable to the activity, to minimize the effects of monopoly influence on the production chain and, finally, to guide the design of new production arrangements that enable the expansion of the supply of salable gas in the country. As a result, three technologies were identified that are already being applied in other countries, which are: compressed natural gas, liquefied natural gas and gas to liquids.
Análise da distribuição espacial de designer drugs em selos por MALDI FT-ICR Imaging MS
(Universidade Federal do Espírito Santo, 2020-02-18) Almeida, Camila Medeiros de; Romão, Wanderson; https://orcid.org/0000000222546683; http://lattes.cnpq.br/9121022613112821; https://orcid.org/0000-0003-3318-8583; http://lattes.cnpq.br/4627760102080131; Lopes, Norberto Peporine; https://orcid.org/0000-0002-8159-3658; http://lattes.cnpq.br/1357061371579771; Borges, Warley de Souza; https://orcid.org/0000000344751028; http://lattes.cnpq.br/9742402285970429
The phenethylamines derivatives, the NBOMes, N-bomb or Smiles, are potent hallucinogens, which are often sold as blotter paper. Changes in their molecular structures are constantly carried out, such as the exchange of halogen in the carbon 4 (C4) or the substitution of the methyl to a hydroxyl, observed in the modification of NBOMe to NBOH. This happens so that the new substances are not classified as illicit and preserved the psychoactive effects of molecules. In order to follow the dynamics of designer drugs market, the use of different analytical methods for the identification of these substances has been a solution. In this study, the matrix assisted laser desorption/ionization mass spectrometry (MALDI MS) and MALDI mass spectrometry imaging (MALDI MSI) were coupled to a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) and used to analyze seven blotter papers of NBOMes containing 25I-NBOH (2-({[2-(4-iodo-2,5- dimethoxyphenyl) ethyl]amino}methyl) phenol, m/z 414,05) and 25I-NBOMe ((2-(4-iodo-2,5-dimethoxyphenyl)-N-[(2 methoxyphenyl) methyl]ethanamine), m/z 428,07). An optimization study was performed to evaluate the matrix application (pipette versus sprayer assisted by an ESI probe); the matrices (α-cyano-4-hydroxycinnamic acid (CHCA), 2,5 dihydroxybenzoic acid (DHB), 7,7,8,8-tetracyanoquinodimethane (TCNQ) and sinapinic acid (SA)) effect in the process of desorption and ionization and their concentration (from 5 to 25 mg.mL−1). After, a study of the spatial distribution of the NBOMes derivatives detected in the front and back of the blotter paper surface was performed. MALDI MS and MALDI MSI results showed that the matrix sprayer was the best method for matrix application, which allowed a homegeneous detection of the compound when compared to the pipette application. The CHCA matrix, in a concentration ≥ 15 mg.mL−1, displayed a higher ionization efficiency of the 25I-NBOMe compound, commonly detected in blotter paper, where an intense distribution was observed in relation to others matrices. The distribution of the active ingredient studied in the front and back between the six blotter papers analyzed showed that the three of them had a higher concentration of the active ingredient in only one of the sides (two in the back and one in the front), while the others presented a similar distribution in both sides.
Análise de cocaína e seus metabólitos em fios de cabelo por MALDI-TOF MS
(Universidade Federal do Espírito Santo, 2023-12-12) Donateli, Patrícia Oliveira; Romão, Wanderson; https://orcid.org/0000000222546683; http://lattes.cnpq.br/9121022613112821; https://orcid.org/0009-0003-1736-7810; http://lattes.cnpq.br/0034594722146131; Kitagawa, Rodrigo Rezende; https://orcid.org/0000000222086699; http://lattes.cnpq.br/4424075292014459; Franca, Hildegardo Seibert; http://lattes.cnpq.br/1284874997224988
Hair can provide chemical information about drug use, which generates great interest in forensic sciences. A technique that has shown promising results for the detection of drugs in this study matrix is the matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), in which it is possible to achieve, in a single shot, the detection of drugs of abuse, even if a long time has elapsed since the use of the illicit compound. In this study, the MALDI ionization source was used to detect drugs and metabolites in the hair strands of drug users and non-drug users. For this, a method was developed with an initial evaluation of the most efficient MALDI matrix for the ionization of the monitored analytes. Among the evaluated matrices (2,5-dihydroxybenzoic acid (DHB) and α-cyano-4-hydroxycinnamic acid (CHCA)), CHCA was chosen, and among its tested concentrations (from 1.5 to 10 mg mL-1). Subsequently, the results were compared with gas chromatography-mass spectrometry analyses, where a good relationship was observed between the responses of both methods. In addition, the effect of the pre-analysis (hair washing) and its influence on the detection of the monitored compounds were evaluated, in addition to the evaluation of the effect of hair lightening on hair fortified with a drug and analyzed with the proposed method. The results show little influence on the preanalysis stage and confirm the reduction in drug detection in hair submitted to bleaching. In this sense, the results add information that asserts the applicability of the method for rapid detection of drugs and metabolites in hair.
Análise de Parafinas por APCI-FT-ICR MS : Uma Análise Rápida e Simples na Identificação de Hidrocarbonetos Saturados, Cíclicos e Poliaromáticos
(Universidade Federal do Espírito Santo, 2014-12-01) Tose, Lilian Valadares; Romão, Wanderson; Vaz, Boniek Gontijo
The analysis of hydrocarbon using atmospheric or ambient ionization techniques still remains a challenge in mass spectrometry. Traditionally, the ionization occurs via protonation or deprotonation. The molecules of interest must have a basic or acidic group to generated [M + H]+ or [M - H]- ions. To overcome such limitation, it is proposed a simple, easy, fast and powerful analytical methodology to ionize saturated (linear and branched), unsaturated, and cyclic hydrocarbons as well as polyaromatic and heteroaromatic hydrocarbonsby atmospheric pressure chemical ionization (APCI) using small hydrocarbons as reagents in a FT-ICR mass spectrometer. These molecules may be present in hydrocarbon fraction samples and paraffin/crude oil blends. Among the APCI hydrocarbon reagents studied, isooctane provided the best results when compared to pentane, hexane, cyclohexane and heptane. The method renders the ionization of hydrocarbons to yield [M – H]+ ions with no associated fragmentation using nitrogen as sheath gas.
Análise de petróleo por espectroscopia de impedância eletroquímica e da corrosão do aço AISI 1005 em soluções contendo íons sulfeto
(Universidade Federal do Espírito Santo, 2011-02-11) Perini, Nickson; Freitas, Marcos Benedito José Geraldo de; Souza, Ernesto Chaves Pereira de; Castro, Eustaquio Vinicius Ribeiro de
The electrochemical impedance spectroscopy is technique that allowtomonitoring ofcrude oil, blends,emulsions, and the interaction between these multiphase fluids and steel, allowing the evaluation of corrosion resistance. Crude oils are dielectric and has low conductivity. Therefore it is difficult to conduct measurements in conventional electrochemical cells with three electrodes, which under these conditionsrequired the use of only two parallel electrodes and validation of the impedance measurements. The behavior of the blends and crudeoil is framed for the characterization in the Nyquist diagram for a homogeneous distribution in constant relaxationtime, represented by undistorted semicircle in high frequency. At low frequencies, presents a distorted semicircle assigned to the interface metal/oil. The Nyquist diagram for water in oil emulsions showstwo semicircles in high and medium frequency attributed, respectively, to oil phase and emulsion. The thirddistorted semicircle at low frequency indicates the value of the corrosion resistance of carbon steel in contact with the emulsion. Multivariate analysis (PCA) is used to correlate oil properties with the values obtained by equivalent circuit of the impedance spectra. The corrosion of carbon steel, followed by film formation in aqueous solutions containing H2S in low concentration, is measured by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), SEM, XRD and Mossbauer. The films of iron sulfide formed under these conditions are corrosive and it increases the rate of corrosion. In CV are detected two peaks of anodic current density, attributed to film formation of iron sulfide and its subsequent oxidation. The irregular and compact morphology was observed by SEM and the composition of the film by EDX, with the majority consisting of Fe, S and O. The crystalline phases were detected by XRD, containing Mackenawite, Marcasite, Pyrite,Troilite, iron hydroxide and hydrate iron sulfate. The effect Mossbauer characterization indicatedthat the film is 85,3% as FeS2, mainly Pyrite. The impedance of the films in solution0.1 mol.L-1Na2SO4reveals that the films of iron sulfide formed under these conditions are corrosive and it increases the rate of corrosion
Análise de pimenta-do-reino por espectrometria atômica: diferentes abordagens
(Universidade Federal do Espírito Santo, 2018-02-19) Krause, Maiara; Lima, Maria Tereza Weitzel Dias Carneiro; Lima, Inobert de Melo; Athayde, Geisamanda Pedrini Brandão
The present study was divided into two chapters. First, it was determined the concentrations of the elements Cd, Co, Cu, Fe, Mn, Mo, Ni, Pb, Se, Ti, V and Zn black pepper samples marketed in the State of Espírito Santo. The samples underwent an acidic decomposition procedure assisted by microwave radiation. The Fe and Zn elements were determined by flame atomic absorption spectrometry (F AAS), while the others were determined using the inductively coupled plasma mass spectrometry (ICP-MS) technique. The accuracy of the procedures was evaluated through the analysis of the certified reference material Agro C1003a of tomato leaf. The values measured using the methodology adopted in this study and the certified values did not present significant difference, when Student's t-test with 95% confidence level was applied. After verification of accuracy, the analysis methodology wasapplied to 50 commercial pepper samples. For each manufacturer, denominated as A, B, C, D and E, 5 grain samples and 5 ground samples were obtained to verify a possible supply of trace elements during the processing of the black pepper. Each of the samples was chosen from a different lot, in order to obtain a greater variability of the set of samples that are commercialized in the region. The results show that two of the five analyzed brands showed a great increase in the concentrations of Fe, Pb and V after grinding, suggesting that the increase in the concentration of these elements can be influenced by the milling process. Moreover, for samples where there was a significant increase in Pb, it exceeded safe limits for human consumption according to Brazilian legislation, which is 200 µg kg-1. In the second part of the work a simple and fast methodology for the determination of Pb in pepper samples was developed. The developed method consisted in the use of suspension sampling together with the technique of atomic absorption spectrometry with atomization in graphite furnace. The preparation stage of the suspensions was optimized applying experiment planning. Parameters such as pyrolysis and atomization temperatures, calibration and the necessity of use chemical modifiers were evaluated. The analysis methodology presented simplicity and speed in it experimental stages, and provided low limits of detection and quantification. The method also showed good accuracy and allowed the calibration by aqueous standards. The methodology adopted is presented as an alternative to the traditional procedures of analysis and can be considered adequate for routine analyzes, it also can be extended to other trace elements present in black pepper
Análise de resíduo de disparo de armas de fogo utilizando ICP-MS: caracterização de munições limpas
(Universidade Federal do Espírito Santo, 2016-09-29) Costa, Rayana Alvarenga; Romão, Wanderson; Lima, Maria Tereza Weitzel Dias Carneiro; Athayde, GeisamandaPedrini Brandão; Aquije, Glória Maria de Farias Viegas
Given the strong relationship between the crimes of murder and the use of firearms in Brazil, Forensic Ballistics is an important tool to detect waste generated by shooting firearms (GSR -gunshot residues) in the hands of a suspect , helping to determine the authorship of a shot. Among the types of ammunition, clean ammunition was developed in the last decade to minimize exposure of the shooters to lead (Pb), as in conventional ammunition, this element and the Ba and Sb present significativas1 concentrations. Studies show difficulties in GSR detection clean ammunition by energy dispersive spectroscopy coupled with scanning electron microscopy (SEM / EDS) and residuográfico test, thus modern analytical techniques such as mass spectrometry with inductively coupled plasma (ICP-MS) has being used as a quick analysis for the detection of chemical elements present in GSR, since a high sensitivity, selectivity and multielement character. Thus, the objective of this study was to evaluate the applicability of ICP-MS technique to quantify the GSR coming from clean ammunition (from the English "clean range ammunition") using caliber .40 pistol and .38 depending on the number of shots (n = 1-7 and n = 1-5). The GSR were collected in the regions of the clamp-palmar and dorsal clamp and evaluated on both hands (right and left). The results were compared with classic techniques in forensic ballistics: colorimetric assay using sodium rhodizonate (residuográfico) and SEM / EDS. Negative results were observed for Pb and Ba using residuográfico test for GSR analysis clean ammunition shots to 7. The analysis by SEM / EDS was performed on the GSR produced from n = 7 (.40 caliber pistol) and n = 5 (.38 revolver) of clean ammunition. Photomicrographs showed that the GSR produced from clean ammunition presents no defined as the morphology of conventional ammunition GSR. In addition, EDS results of the particularly identified elements as C, O, K, Al, S, Si, Cu, Zn, Ti, Cr, Cl, Mo, Sr and Fe. Unlike convencionas methods, ICP-MS technique showed positive results for Pb, Ba and Sb with maximum concentration of 2.64 µg·L-1(± 0.60) 10.9 µg·L-1(± 5.44) and 0.119 µg·L-1(± 0.02) to40 pistoland 4.59 µg·L-1(± 1.8), 1.95 µg·L-1(± 1.1) 0.099 µg·L-1(± 0.07 ) to .38 revolver. Besides them, elements such as Al, Ti, Cr, Mo, Cu, Zn and Sr were also detected in the clean ammunition GSR. It was observed that with increasing number of shots was in the concentration of all investigated elements and suggested that Al, Sr, Zn and Cu may be used as markers for new GSR clean ammunition. Therefore, the ICP-MS technique showed promising results and proved adequate for GSR analysis of clean ammunition.
Análise de resíduos de disparos de armas de fogo (GSR) usando ICP OES : desenvolvimento de uma nova metodologia analítica
(Universidade Federal do Espírito Santo, 2014-01-01) Vanini, Gabriela; Romão, Wanderson; Lima, Maria Tereza Weitzel Dias Carneiro; França, Hildegardo Seibert; Bruns, Roy Edward
Violence involving firearms is a big issue in the state of Espírito Santo and the development of new methods and techniques that can help the police to elucidate homicides is extremely important to the reduction of crime. Optical emission spectrometry with inductively coupled plasma (ICP OES) stands out as a highly sensitive, versatile and cheap technique when compared to current techniques used by the police. Therefore, the objective of this work was to develop a fast, sensitive and reliable method for collection and quantification of gunshot residues (GSR) using ICP OES to determine the concentrations of lead (Pb), barium (Ba) and antimony (Sb) released by .38 caliber handgun and .380 and .40 caliber pistols. The work was divided into three chapters. In the first, it was discussed the optimization step of the ICP OES technique for GSR, which evaluated the operating parameters of radio frequency power, nebulizer gas flow rate and aspiration rate, using multivariate central composite design. In the second chapter, a study was conducted using Taurus® .38 handgun, which investigated the best residue collection region of the hand in men and women, the feasibility of different collectors for GSR , the comparison of the colorimetric analysis and ICP OES technique for varying distances and the influence of hand washing before and after shots. The results showed that the regions of the thumb and forefinger palm, and the back of the thumb and forefinger are the best collection areas. The pure swab showed better results in terms of cost / benefit and it is possible to obtain concentrations of the metals of interest even with hand washing of shooter. In the third chapter a comparative study between .38 handgun and .380 and .40 pistols it was done. It was quantified Pb, Ba and Sb on the right and left hands of the shooters for the three weapons and held a prediction of the number of shots through the construction of a calibration curve. It was noted the amount of GRS found on the weapons, follows the order .38 handgun>.380 pistol> .40 pistol. Overall results showed important information in GSR analysis, representing a breakthrough in forensic investigations.
Análise do teor e da qualidade dos lipídeos presentes em sementes de oleaginosas por RMN de baixo campo
(Universidade Federal do Espírito Santo, 2013-02-27) Constantino, André Fazolo; Santos, Reginaldo Bezerra dos; Lacerda Júnior, Valdemar; Liao, Luciano Morais; Freitas, Jair Carlos Checon de
In order to choose from the variety of oleaginous plants for biodiesel production, the oil content of several matrices was determined through different experiments of low-field 1H Nuclear Magnetic Ressonance (NMR) with varied pulse sequences, namely single pulse, spin-echo, CPMG and CWFP (Continuous Wave Free Precession). The experiments applying the first three sequences showed high correlation with each other and with the solvent extraction method. The best results were achieved through CPMG experiments. When the CWFP sequence was used, the correlation with the solvent extraction method was very low and the results were not compatible with those employing the other sequences. Quality of the vegetable oils was also evaluated. The study was based on the existing correlation between the T2 values of the oils obtained through 1H NMR signals achieved through CPMG and their properties, such as viscosity, iodine index and cetane index. These analyses were carried out using HCA and PCA chemometric tools. The results were significant enough to separate the oleaginous matrices according to their quality. The signals achieved using the CWFP and CP-CWFP (Carr-Purcell - Continuous Wave Free Precession) sequences were also used in the chemometric analyses. However, the study identified that the signals generated from these sequences depend both on T1 and T2. Therefore except for the most viscous oleaginous matrices, in HCA and PCA analyses, the matrices were not grouped according to their qualities. The experiments carried out through CP-CWFP were even more advantageous than those through CWFP because the former had higher signal amplitude variation in the quasi steady state (QSS). Thus, using the most adequate pulse sequence, the low-field 1H NMR technique was confirmed as an important tool to help selecting oleaginous matrices for biodiesel production.
Análise Multivariada de Dados em Petroleômica por Técnicas de Alta Resolução: Espectrometria de Massas de Ressonância Ciclotrônica de Íons por Transformada de Fourier e Ressonância Magnética Nuclear
(Universidade Federal do Espírito Santo, 2024-02-24) Folli, Gabriely Silveira; Romão, Wanderson; https://orcid.org/0000-0002-2254-6683; http://lattes.cnpq.br/9121022613112821; Filgueiras, Paulo Roberto; https://orcid.org/0000-0003-2617-1601; http://lattes.cnpq.br/1907915547207861; https://orcid.org/0000-0003-0665-7540; http://lattes.cnpq.br/1256230443856795; Neto, Álvaro Cunha; https://orcid.org/0000-0002-1814-6214; http://lattes.cnpq.br/7448379486432052; Rosa, Thalles Ramon; https://orcid.org/0000-0001-9913-5885; http://lattes.cnpq.br/2629035369494897; Terra, Luciana Assis; https://orcid.org/0000-0003-2687-9669; http://lattes.cnpq.br/4918273242518895; Chinelatto Júnior, Luiz Silvino; https://orcid.org/0000-0002-0974-0465; http://lattes.cnpq.br/8008284454162318
Crude oil is a complex matrix, and the more in-depth study of its chemical structure (Petroleomics) has begun to be adopted by high-resolution techniques such as Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and high-field nuclear magnetic resonance (NMR) spectroscopy. However, high-resolution data presents challenges in spectral processing due to spectral variations. Consequently, the objective of this thesis was to develop multivariate data analysis applications (classification, regression, and design of experiments) to help overcome some of the limitations posed by high-resolution data. The first objective was to investigate the spectral profiles of analytical instruments (NMR, FT-ICR MS, nearinfrared – NIR, mid-infrared – MIR, and high-efficiency gas chromatography – HTGC). It was observed that high-resolution spectra predominantly exhibited a discrete profile (less correlated variables), while lower-resolution spectra showed a more continuous profile (more correlated variables), making them better suited for information clustering methodologies. The second objective involved estimating the intermediate precision of high-resolution mass spectrometers (FT-ICR MS and Orbitrap MS). It was noticed that both equipment presented oil with similar classes, but FT-ICR MS attributed a higher number of statistically assigned signals and had a lower detection limit compared to Orbitrap MS, due to its higher sensitivity. Furthermore, repeatability and intermediate precision of both spectrometers, although similar, demonstrated better values for FT-ICR MS in comparison to Orbitrap MS. The third objective focused on optimizing experimental parameters for ESI(±)FT-ICR MS in crude oil analysis. Plackett-Burman filtering planning was used to identify significant parameters, and the optimal analysis conditions were determined through a full factorial design. Global desirability determined by spectral quality metrics served as the response parameter for all experimental designs. The fourth objective aimed to develop a variable selection method that identifies variable correlations (Angular Search Algorithm with Variance Inflation Factor – ASA-VIF) and applies it to high-field 1H NMR, comparing it with MIR and NIR in linear (Partial Least Squares, PLS) and non-linear (Support Vector Regression, SVR) regression. An outlier identification methodology for non-linear models was also created. The results demonstrated that 1H NMR performed better using ASA-VIF-SVR. Furthermore, this selection drastically reduced the amount of information in MIR and NIR compared to 1H NMR, as these instruments contained a greater amount of correlated information (see the first application chapter). The final objective involved constructing a methodology for generating virtual samples (synthetic samples and artificial outliers) in complex data group classification models. This was essential as sample balance is crucial for more reliable metrics. The models showed good performance using virtual samples in both linear (PLS-DA) and non-linear (SVR) methodologies and with highresolution (Orbitrap MS) and low-resolution (MIR) spectra. In conclusion, all objectives resulted in improvements in the treatment of complex data using highresolution techniques.
Análises de padrões isoméricos de canabinóides e produtos de Cannabis por GC-MS, GCxGC-qMS e UPLC acoplado a espectrometria de massas de mobilidade iônica (TWIM-MS)
(Universidade Federal do Espírito Santo, 2018-02-15) Santos, Nayara Araújo dos; Vaz, Boniek Gontijo; Romão, Wanderson; Ortiz, Rafael Scorsatto; Kuster, Ricardo Machado
CannabissativaL. plant, popularly known as marijuana, is considered a complex matrix due to its many constituents, among them more than 100 are classified as cannabinoids. These compounds are distributed in the plant in different isomeric forms, which hinders the unambiguous characterization of the psychoactive compounds. Therefore, the present study reported the analysis of seven cannabinoid standards (five neutral: ?9-THC, CBD, CBC, CBN and CBG,and two cannabinoid acid standards: ?9-THCA A and CBDA), as well asCannabisproducts (hashish and marijuana) and parts of theCannabisplant (flower andleaf) using four different analytical techniques, mono and two-dimensional gas chromatography (GC-MS and GCxGC-qMS), Ultra performance liquid chromatography coupled to mass spectrometry (UPLC-ESI(±)TOF-MS) and ion mobility spectrometry (UPLC-ESI(±)-TWIM MS). The results obtained by GC-MS demonstrated extremely close retention times (?t=1.303 min) in the five cannabinoids analyzed from the use of a non-polar stationary phase, DB5. However, GCxGC-qMS resulted in a better distinction in the identification of cannabinoids constitutional isomers, where four of eleven cannabinoids were detected in the three samples; hashish, flower andCannabisleaf. The analysis, by UPLC-ESI(±)TOF-MS, of marijuana and hashish samples, allowed the identification of eight isomers in the XIC mode at m/z315.2354. In the analyzes by UPLC-ESI(-)TWIM MS, a largenumberof compounds was mainly detected for hashish and flower samples. Asfor cannabinoidsofm/z357, ten peaks could be detected,equally distributed, in flower and hashish chromatograms. Although GC is one of the most used techniques in the study of cannabinoids inCannabisand its products, it does not allow the identification of acid cannabinoids, which are widely available in the plant, without previous laborious preparatory stages. Differently, liquid chromatography combined with ion mobility mass spectrometry, allowed the identification of both types of cannabinoids (acids and neutrals), in addition to providing a greater detection of constitutional isomers compounds compared to classical GC technique
Aplicabilidade da eletrocoagulação, eletrocoagulação seguida de reativo de fenton e eletrofenton no tratamento de lixiviado de aterro sanitário
(Universidade Federal do Espírito Santo, 2010-04-14) Lima, Claudia Maria Russo de; Borges, Raquel Machado; Jesus, Honerio Coutinho de; Schneider, Edgar; Freitas, Marcos Benedito José Geraldo de; Dias, Mauro Cesar
This work aimed to study processes of electrochemical treatment applied in a sanitary landfill leachate, with the investigation of physical and chemical parameters of interest and its better operation conditions. The following systems were studied: electrocoagulation, electrocoagulation followed by the Fenton ´s reagent and eletroFenton. Leachates from the landfill in the municipality of Aracruz (Espírito Santo) were used in the research, collected in 2008 and 2009. The samples were sent to the Laboratory of Analytical Chemistry, Federal University of Espirito Santo, and preserved in refrigerator. An electrochemical reactor was constructed using a 3L beaker, mechanical agitation, and electrodes of carbon steel 1020 plates, coupled to a 9 A source of constant direct current. Several experiments were performed for studies of electrocoagulation in order to determine the best operation, with changes in the structural parameters (electrode geometry) and operational (temperature, electrolyte volume and polarity reversal). For the tests of electrocoagulation followed by Fenton ´s reagent, it has changed the relationship between the quantities of ferrous sulfate heptahydrate and hydrogen peroxide, using the ratio of 1:17 and 1:25 of the salt with hydrogen peroxide. For eletroFenton tests were also conducted tests on the change in relationship, but in amounts of 1:20 and 1:25. As result of this research, it was observed that the electrolytic process and this in combination with advanced oxidation process are indicated for the treatment of landfill leachate generated from municipal solid waste. The initial characterization of leachate (pH, organic matter, ammonia nitrogen, chloride and metals) indicated that it comes from landfill over the age of 2 years with a degree of stabilization of the landfill in the acidogenic phase. The electrocoagulation, electrocoagulation followed by Fenton's reagent and eletroFenton shown to be adequate for the process of removing color, turbidity, organic compounds and metals, but not suitable for removal of ammonia and particulate matter. Better results were obtained by combining the electrolytic process with the oxidative, and the treatment eletroFenton showed better results in general, combined with a treatment period shorter (30 minutes). We obtained a removal efficiency of COD between 40 and 50% in electrocoagulation, 60 to 70% in electrocoagulation followed by Fenton, and up to 78% in eletroFenton system. The results of this study are of great importance as support for project development of physical-chemical treatments on an industrial scale for the treatment of leachate from landfill
Aplicação da calibração multi-isotópica para determinações multielementares em sangue total por ICP-MS
(Universidade Federal do Espírito Santo, 2022-12-14) Oliveira, Poliana Borges de; Lima, Maria Tereza Weitzel Dias Carneiro; https://orcid.org/0000-0002-8731-5093; http://lattes.cnpq.br/9989703911201351; https://orcid.org/0009-0005-5417-2099; http://lattes.cnpq.br/2240723064209959; Athayde, Geisamanda Pedrini Brandão; https://orcid.org/0000-0002-4315-0653; http://lattes.cnpq.br/8037324704189596; Virgilio, Alex; https://orcid.org/0000-0002-7263-5094; http://lattes.cnpq.br/5249134846307879
The multielement determination in samples of biological fluids is essential in several areas of research. Therefore, it is essential to develop ever more efficient techniques, strategies and methods to simplify, accelerate and make the process of analyzing these samples less expensive. One technique that stands out for this purpose is inductively coupled plasma mass spectrometry (ICP-MS), which has the main characteristics of being highly sensitive and capable of multielement and isotope analysis. However, ICP-MS has some limitations caused by matrix, transport and spectral interferences that are very present when analyzing biological samples, since they are complex matrices. Thus, it is necessary to use strategies aimed at correcting these interferences, such as the use of reaction/collision cells and appropriate calibration methods. This study proposes the use of multi-isotopic calibration (MICal) in the determination of Cd, Cr, Hg, Mo, Ni, Pb, Se, Sn and Zn in whole blood and compares the performance of MICal with the already traditional, external calibration ( EC), internal standardization (IS), matrix matching calibration (MMC) and standard addition calibration (SA). MICal consists of the simultaneous monitoring of several isotopes of the elements of interest in only two solutions, both containing the same amount of sample. The calibration solutions used in MICal were prepared in the proportion of 5% vv¹ of sample and 95% vv-¹ of standard or blank, in order to provide greater dilution for the matrix. The concentration of the standard to be added for each analyte was optimized for MICal, from these concentrations the constructed calibration curves were evaluated, identifying possible discrepant points. In the evaluation of the graphic representations, the isotopes of each element that presented outliers were verified due to the presence of polyatomic and isobaric interferences, being possible to remove these signals, which improved the linearity of the curves and the coefficient of determination. Accuracy, precision and limits of detection and quantification were also determined for MICal and compared with the other calibrations. For most of the analytes, the concentrations found in MICal showed significant differences compared to those obtained by EC and IS, however, they were equivalent to the concentrations determined by MMC and SA, at a confidence level of 95%. In calibrations using matrix, the results obtained were better in terms of recovery, calculated from the concentration of the control material in whole blood. MICal presented recoveries in a range of 67.97-108.86% for the analytes studied, standing out as a good alternative for the determination of trace elements in whole blood. The LOD's and LOQ's for MICal were compared with those for MMC and SA also showed similar concentrations. These results confirm that MICal is a viable strategy for determining the studied elements present in whole blood, providing advantages over other techniques due to its time and material savings, less waste generation and identification of interferences.
Aplicação da cromatografia gasosa bidimensional abrangente na caracterização de classes de compostos do petróleo
(Universidade Federal do Espírito Santo, 2019-09-19) Silva, Samantha Ribeiro Campos da; Castro, Eustaquio Vinicius Ribeiro de; https://orcid.org/0000-0002-7888-8076; http://lattes.cnpq.br/1055263403980509; https://orcid.org/; http://lattes.cnpq.br/8592661743827044; Cunha Neto, Alvaro; https://orcid.org/0000-0002-1814-6214; http://lattes.cnpq.br/7448379486432052; Franca, Hildegardo Seibert; https://orcid.org/0000-0001-6129-8793; http://lattes.cnpq.br/1284874997224988; Lacerda Junior, Valdemar ; https://orcid.org/0000000282575443; http://lattes.cnpq.br/9819471276433138; Santos, Roberto Pereira
Crude oil is the term used for a wide variety of oils extracted from sedimentary rocks. Due to the variety and complexity of oil matrices an important oil assay is to quantify the content of saturated, aromatic, resin and asphaltene compounds (SARA). However, proper separation of saturated and aromatic components depends on the internal phase of the chromatographic column and on the method used for its quantification. Here works were described: aiming at the relative quantification of nonpolar components present in the saturated petroleum fraction and the use silica gel modified with boric acid to obtain aromatic fractions enriched with nitrogen aromatic compounds. The results showed that GCxGC-qMS technique was efficient in the relative quantification of n-paraffins from C11 to C35 and of branched paraffins in the saturated petroleum fraction. In addition, it allowed the determination of bicyclic, tricyclic, tetracyclic and pentacyclic compounds. In general, the classes of monocyclic and iso-paraffin compounds were the most abundant in the undegraded petroleum saturated fraction. Relative quantification of normal and branched paraffins allowed an understanding of the pour point values of light oils (API gravity greater than 30). The modification of the silica gel (column) with boric acid in the separation of the aromatic components of petroleum was selective to obtain fractions enriched with nitrogen aromatic compounds. However, the nitrogenous components identified in the aromatics fraction are characteristic of resins. Combining the FT-ICR MS (ESI (±) and APPI (±) sources using the Intensity vs DBE graphs) and GCxGC-qMS techniques allowed to ratify the good selectivity of the modified silica gel for the elution of aromatic nitrogen compounds. In the FT-ICR MS analyzes it was possible to visualize intense signals in all ionization sources for the nitrogen classes. The other visualized classes, such as hydrocarbons and oxygenated, were shown as low intensity peaks, corroborating the efficiency of separation of the modified column for nitrogen compounds. The concentration of nitrogenous compounds in crude oils is generally less than 2 wt%, however, they are detrimental to the refining processes and knowledge of the nitrogenous species present in crude oil is desirable. Thus, the methodology using the silica gel modified with boric acid column aimed to supply this important refining demand.

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