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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Diferentes estratégias espectroanalíticas para a determinação de metais em cosméticos / Different spectroanalytical strategies for the determination of metals in cosmetics

Batista, Érica Ferreira 22 October 2015 (has links)
Submitted by Izabel Franco (izabel-franco@ufscar.br) on 2016-10-07T13:17:49Z No. of bitstreams: 1 TeseEFB.pdf: 1317890 bytes, checksum: 82fae1c425af918f9fd0775d660bec52 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-20T19:36:02Z (GMT) No. of bitstreams: 1 TeseEFB.pdf: 1317890 bytes, checksum: 82fae1c425af918f9fd0775d660bec52 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-20T19:36:09Z (GMT) No. of bitstreams: 1 TeseEFB.pdf: 1317890 bytes, checksum: 82fae1c425af918f9fd0775d660bec52 (MD5) / Made available in DSpace on 2016-10-20T19:36:15Z (GMT). No. of bitstreams: 1 TeseEFB.pdf: 1317890 bytes, checksum: 82fae1c425af918f9fd0775d660bec52 (MD5) Previous issue date: 2015-10-22 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / In this work, it was developed a procedure for the determination of metals in cosmetics, employing the techniques ICP OES, GF AAS, LIBS and LA-ICP OES; in addition, it was explored the potential of chemometric tools. For the determination of Cd, Co, Cr, Cu and Ni by ICP OES and Pb by GF AAS in eyeshadow and lipstick samples, it was developed a sample preparation method using diluted nitric acid and a hot block. For the optimization of chemical parameters of sample preparation and operating parameters of ICP OES, it was used factorial design and for data analysis and selection of the best working conditions, the desirability functions were employed. In total, it was analyzed 30 samples of cosmetics (21 eyeshadow and 9 lipstick), of different colors, brands and from different countries (Brazil, USA and China). These samples were analyzed in triplicate and with standard addition to perform the recovery calculations. The analyzed samples showed concentration of Cd and Pb within the limits set by the laws, however, 7 eyeshadow samples had concentration of Cr and Ni above than 5 g g-1. In the case of lipstick samples, all values were below this safe limit. All samples analyzed by ICP OES and GF AAS were also analyzed without sample pretreatment by LIBS. The values obtained in the quantitative analysis were employed in the development of supervised classification models such as the KNN and SIMCA. For the obtainment of these models, data of children´s cosmetics samples were included. The classes considered in the models were: below and above the legislation, with a limit set at 5 mg kg-1, according to the recommendations in the literature. In addition to analysis of eyeshadow and lipstick samples, it was explored the potential of the techniques LIBS and LA-ICP OES along with chemometric tools for exploratory analysis of sunscreen samples. The results were obtained for three different equipment (two LIBS and one LA-ICP OES), and several models employing principal component analysis (PCA) were generated. The signals profile of Al, Ni, Ti, and Zn were analyzed and the results obtained between the three equipment were similar. / Nesta tese foram desenvolvidos procedimentos para a determinação de metais em cosméticos, empregando as técnicas ICP OES, GF AAS, LIBS e LA-ICP OES, além de explorar as potencialidades das ferramentas quimiométricas. Para a determinação de Cd, Co, Cr, Cu e Ni por ICP OES e Pb por GF AAS em amostras de sombra e batom, foi desenvolvido um método de preparo de amostra empregando ácido nítrico diluído e um bloco digestor. Para a otimização dos parâmetros químicos do preparo de amostra e dos parâmetros operacionais do ICP OES, utilizou-se planejamentos fatoriais e para o tratamento dos dados e seleção das melhores condições de trabalho, foram empregadas as funções de desejabilidades. No total, foram analisadas 30 amostras de cosméticos (21 amostras de sombra e 9 amostras de batom), de diferentes cores, marcas e provenientes de diferentes países (Brasil, EUA e China). Essas amostras foram analisadas em triplicata e com a adição de padrão para realização dos cálculos de recuperação. As amostras analisadas apresentaram concentrações de Cd e Pb dentro dos limites estabelecidos pelas legislações, entretanto, 7 amostras de sombra apresentaram concentrações de Cr e Ni superiores a 5 μg g-1. No caso das amostras de batom, todos os valores estavam abaixo desse limite seguro. As amostras analisadas por ICP OES e GF AAS também foram analisadas, sem o tratamento prévio das amostras, por LIBS. Os valores adquiridos nas análises quantitativas foram empregados no desenvolvimento de modelos de classificação supervisionados, como o KNN e o SIMCA. Para a construção desses modelos, foram incluídos os dados de amostras de cosméticos infantis. As classes consideradas nos modelos foram: acima e abaixo da legislação, com um limite estipulado em 5 mg kg-1, segundo as recomendações de trabalhos disponíveis na literatura. Além das análises das amostras de sombra e batom, foram exploradas as potencialidades das técnicas LIBS e LA-ICP OES em conjunto com as ferramentas quimiométricas, para análises exploratórias das amostras de protetor solar. Os resultados foram obtidos por três equipamentos diferentes (dois LIBS e um LA-ICP OES) e vários modelos empregando a análise de componentes principais (PCA) foram gerados. Os perfis dos sinais de Al, Ni, Ti e Zn foram analisados e os resultados obtidos para os três equipamentos foram semelhantes.

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