This thesis concerns experiments with natural compounds and vitamins. In the first part I described these substances, which I proved by chromatography or I made other experiments with them in the second part. I created four worksheets with instruction for laboratory practise. There are thein solutions in the supplement. I verified these four experiments at Grammar School in Prague 9.

Orientador: Lauro Tatsuo Kubota / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-25T06:42:10Z (GMT). No. of bitstreams: 1 Bassetto_VictorCosta_M.pdf: 5997549 bytes, checksum: c28ca3fa1e15c81712b8aab83f1a7f0e (MD5) Previous issue date: 2014 / Resumo: Esta dissertação apresenta os desenvolvimentos realizados para a aplicação de ligas de cobre como detector de aminoácidos em cromatografia de íons. O trabalho apresenta o desenvolvimento desde estudos eletroquímicos fundamentais, onde a propriedade de metais como ouro, atual padrão para a técnica, e cobre são investigados frente aos aminoácidos. Neste passo a técnica de voltametria cíclica foi escolhida, pois permitiu explorar os vários fenômenos que ocorrem nos processos de óxido redução das moléculas sobre os eletrodos. Uma particularidade do trabalho é o eletrólito, que deve ser também a fase móvel da cromatografia, no caso hidróxido de sódio 0,15 mol L-1. Após o entendimento dos mecanismos básicos de óxido redução dos diferentes aminoácidos sobre os eletrodos de ouro e cobre em meio alcalino, este foi transferido para a aplicação em células de fluxo. Nessa fase observou-se que o cobre puro não apresentava suficiente resistência a corrosão que viabilizasse sua aplicação no sistema de cromatografia de íons. Sendo assim, optou-se pela aplicação do bronze como material sensor. O bronze escolhido possui 86% de cobre em sua composição e após comprovação através de estudos viu-se que o comportamento de óxido redução dos aminoácidos é similar ao cobre puro, porém com vantagens na resistência à corrosão. Também foram desenvolvidos, em conjunto com a University of Southampton, substratos de cobre que apresentam o efeito SERS. Este trabalho foi realizado para permitir a investigação das espécies intermediarias que se formam entre o aminoácido e o cobre (II) formado na superfície do eletrodo. Para a aplicação em fluxo foi necessário o desenvolvimento de pulsos de potencial para viabilizar a detecção dos aminoácidos e aumentar o tempo de vida útil do eletrodo. Após o desenvolvimento os pulsos foram otimizados e o sistema foi utilizado para detecção de valina em amostras de suplemento alimentar / Abstract: This dissertation presents the developments made for the application of copper alloys as detector for amino acids in ion chromatography. The work presents the development from fundamental electrochemistry studies, where properties of metals such as gold, current standard for the technique, and copper where tested against amino acids were performed through cyclic voltammetry technique. This method was chosen for the investigation because it allowed exploring the various phenomena that occur in the oxide reduction processes of the molecules on the electrodes. As a feature of the working electrolyte must also be the mobile phase of the chromatography, where 0.15 mol L-1 sodium hydroxide was used. After understanding the basic mechanisms of reduction and oxidation of the different amino acids over gold and copper electrodes in an alkaline medium, the knowledge obtained was transferred to the flow cells. At this time it was observed that the pure copper did not present sufficient resistance to corrosion, limiting its application in ion chromatography system. Thus, we chose the application of brass as sensor material. The chosen brass had 86% copper in its composition and demonstration through the studies, which its redox behavior of the amino acids is similar to those observed on pure copper, but with advantages in corrosion resistance. In addition, copper substrates showing the SERS effect was also developed in conjunction with the University of Southampton. This study was conducted to allow the investigation of intermediary species that are formed between the amino acid and copper (II) on the electrode surface. For application in flow was necessary to develop potential pulses to enable the detection of amino acids and increase the lifetime of the electrode. After the development of the pulses, it was optimized and the system was used for detection of valine in samples of food supplement / Mestrado / Quimica Analitica / Mestre em Química

Made available in DSpace on 2014-07-29T15:12:42Z (GMT). No. of bitstreams: 1 Dissertacao Fernanda Dias Silva.pdf: 112667 bytes, checksum: 9ef746769100aea66ac5ebc1d67874c6 (MD5) Previous issue date: 2006-03-17 / The production of industrial foods derived from tomato generates high levels of rejects that are composed basically of seeds and tomato peels. This reject it is rich in carotenoids, especially lycopene and β-carotene, which are pigments whose ingestion is directly linked to the decrease of the risk of chronic-degenerative diseases. The present study has as objective develops simplified and efficient extraction and analysis methods of lycopene and β-carotene starting from this reject using palm oil as coadjutant, seeking the subsequent use of this extract for enrichment of products of easy access to classes economically inferior of the population and as a vehicle of medicines. Initially it was developed the chromatographic analysis method for three columns of RP-HPLC: C18 Chromolith SpeedROD (50 mm x 4,6 mm), C18 Nova-Pack (300 mm x 3,9 mm x 4 µm) and C30 YMC Carotenoid (250 mm x 4,6 mm x 5 µm). All the columns present a considerable reduction in the time of analysis and efficient separation between lycopene and β-carotene, when compared to the analysis reported on scientific literature. Later it was done a study of the thermal stability of the pigments by means of TG, DSC and RP-HPLC seeking to evaluate the maximum temperature which the reject can be heated without the occurrence of considerable losses of the pigments. The thermogravimetric curves demonstrated that the loss of mass happens to temperatures higher than those observed by the degradations of the pigments by RP-HPLC. It means that occurs the transformation of lycopene and β-carotene in intermediary compounds which are volatilized in higher temperatures. For the development of the extraction method several variables were tested being obtained the following optimized condition: 25 g of sample was dissolved in 50 mL of hexane and 0.1 mL of palm oil, shaking by 90 minutes under 50ºC. The proposed method demonstrated to be viable once it happens in only one stage, with the use of only an solvent which can be used again after the process. The time of extraction is completely acceptable, as well as the amount of solvent used, being all the parameters compatible with industrial implementation. The oily extract was still characterized with regard to the tocopherols and tocotrienols levels in the palm oil as well as the fatty acid and triacylglicerol compositions. It was obtained the prevalence of y-tocotrienol, oleic and palmitic acids and POO and POP triacylglicerides. / A produção de alimentos industriais derivados do tomate gera elevados níveis de rejeitos que são compostos basicamente de sementes e cascas de tomate. Este rejeito é extramente rico em carotenóides, especialmente licopeno e β-caroteno, pigmentos cuja ingestão está diretamente ligada à diminuição do risco de doenças crônico-degenerativas. O presente estudo tem como objetivo desenvolver métodos de extração e análise simplificados e eficientes de licopeno e β-caroteno a partir deste rejeito utilizando azeite de dendê como coadjuvante, visando a posterior utilização deste extrato para enriquecimento de produtos de fácil acesso ás camadas economicamente inferiores da população e como veículo de medicamentos. Inicialmente, foi desenvolvido o método cromatográfico de análise para três colunas de RP-HPLC: C18 Chromolith SpeedROD (50 mm x 4,6 mm), C18 Nova-Pack (300 mm x 3,9 mm x 4 µm) e C30 YMC Carotenoid (250 mm x 4,6 mm x 5 µm). Todas as colunas apresentaram uma redução considerável no tempo de análise e eficiente separação entre licopeno e β-caroteno, quando comparadas as análises publicadas na literatura científica. Posteriormente, foi realizado um estudo da estabilidade térmica dos pigmentos através de TG, DSC e RP-HPLC visando avaliar a máxima temperatura na qual o rejeito pode ser aquecido sem que ocorram perdas consideráveis de pigmentos. As curvas termogravimétricas demonstraram que o inicio da perda de massa ocorre à temperaturas muito superiores aquelas observadas para a degradação dos pigmentos via RP-HPLC. Isso significa que ocorre a transformação do licopeno e β-caroteno em compostos intermediários que serão volatilizados somente em temperaturas superiores. Para o desenvolvimento do método de extração foram testadas diversas variáveis sendo obtida a seguinte condição otimizada: 12,5 g de amostra solubilizada em 25 mL de hexano e 0,1 mL de azeite de dendê, com agitação de 90 minutos à 50ºC. O método proposto demonstrou ser viável uma vez que ocorre em uma única etapa, e com a utilização de um único solvente passível de reutilização após o processo. O tempo de extração é completamente aceitável, assim como a quantidade de solvente utilizada, sendo todos os parâmetros compatíveis com a implementação industrial. O extrato oleoso foi ainda caracterizado com respeito aos teores de tocoferóis e tocotrienóis no azeite de dendê, bem como sua composição em ácidos graxos e triacilglicerídeos. Obteve-se o predomínio de y-tocotrienol, ácidos oléico (O) e palmítico (P) e triacilglicerídeos POO e POP.

Current commercially available mimics contain varying amounts of either the actual explosive/drug or the chemical compound of suspected interest by biological detectors. As a result, there is significant interest in determining the dominant chemical odor signatures of the mimics, often referred to as pseudos, particularly when compared to the genuine contraband material. This dissertation discusses results obtained from the analysis of drug and explosive headspace related to the odor profiles as recognized by trained detection canines. Analysis was performed through the use of headspace solid phase microextraction in conjunction with gas chromatography mass spectrometry (HS-SPME-GC-MS). Upon determination of specific odors, field trials were held using a combination of the target odors with COMPS. Piperonal was shown to be a dominant odor compound in the headspace of some ecstasy samples and a recognizable odor mimic by trained detection canines. It was also shown that detection canines could be imprinted on piperonal COMPS and correctly identify ecstasy samples at a threshold level of approximately 100ng/s. Isosafrole and/or MDP-2-POH show potential as training aid mimics for non-piperonal based MDMA. Acetic acid was shown to be dominant in the headspace of heroin samples and verified as a dominant odor in commercial vinegar samples; however, no common, secondary compound was detected in the headspace of either. Because of the similarities detected within respective explosive classes, several compounds were chosen for explosive mimics. A single based smokeless powder with a detectable level of 2,4-dinitrotoluene, a double based smokeless powder with a detectable level of nitroglycerine, 2-ethyl-1-hexanol, DMNB, ethyl centralite and diphenylamine were shown to be accurate mimics for TNT-based explosives, NG-based explosives, plastic explosives, tagged explosives, and smokeless powders, respectively. The combination of these six odors represents a comprehensive explosive odor kit with positive results for imprint on detection canines. As a proof of concept, the chemical compound PFTBA showed promise as a possible universal, non-target odor compound for comparison and calibration of detection canines and instrumentation. In a comparison study of shape versus vibration odor theory, the detection of d-methyl benzoate and methyl benzoate was explored using canine detectors. While results did not overwhelmingly substantiate either theory, shape odor theory provides a better explanation of the canine and human subject responses.

This master's thesis deals with a present problem of alternative dental fillings, which should replace amalgam fillings. Although there are health concerns about these alternative materials, especially resin composite fillings raise concerns, because they release potentionally harmful substances into the oral cavity. Accordingly even this medical device subjects various tests before releasing to the commercial market and one of these tests was carried out according to ČSN EN ISO 10993 and available scientific literature in the experimental part of this thesis. The amalgam controversy, substances used for manufacturing of resin dental fillings and analytical methods are described in the theoretical part of the thesis. In the experimental part of the thesis, 30 days long cumulative extraction experiments were carried out into various extraction mediums in order to assess suitability of new dental resin filling from ADM, a.s. by comparison with commercially available dental material from company GC EUROPE N.V. These samples were analysed by LC-MS and the amount of eluted substances from dental composites to extraction medium was quantified.