In this work analytical methods were optimized for the determination of inorganic constituents in cassava flours, corn flour and wheat flour using atomic spectrometry techniques. Factorial design techniques were applied to the optimization of the procedure of microwave assisted digestion of the samples and operating conditions of the inductively coupled plasma optical emission spectrometer (ICP OES). The operating conditions of the inductively coupled plasma mass spectrometer (ICP-MS) were optimized using univariate experimental designs. The proposed analytical methods showed acceptable sensitivity for the determinations, with limits of quantification (LOQ) for Al, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Ni, P, S, Sb, Sr and Zn, ranging from 0.02 to 23 Ýg g-1. The accuracy of the analytical methods were confirmed by analysis of certified reference materials of rice flour (NIST 1568a), wheat flour (NIST 1567a) and tea leaves (NCS DC 73351), with concordances between 81 ¡Ó 1 and 118 ¡Ó 12% (n = 3). Precision was expressed as the relative standard deviation (RSD) and all values are better than 14% (n = 3). The proposed methods were applied to determine the mineral composition of 38 samples of flour. The macroconstituents in the samples were Ca, K, P, Mg and S at concentrations ranging from 2.72 ¡Ó 1.09 (Ca) and 4253 ¡Ó 103 Ýg g-1 (K). For microconstituents and trace elements such as Ba, Cd, Co, Cu, Fe, Mn, Sr and Zn concentrations varied between 0.02 ¡Ó 0.01 (Sr) and 65.5 ¡Ó 9.7 Ýg g-1 (Fe). Exploratory analysis techniques were applied in order to characterize the cassava flours, corn flour and wheat flour. The formation of three distinct groups type of flour was observed according to the each elementary composition. As food, wheat flour showed the highest concentrations for Cu, Fe, Mn, P, S and Zn, and represent 35% of the recommended daily intake (IDR) established for Fe and Mn. / Neste trabalho foram otimizados metodos analiticos para a determinacao de constituintes inorganicos em farinhas de mandioca, milho e trigo, empregando a espectrometria atomica. Tecnicas de planejamento experimental simultaneo foram aplicadas para as otimizacoes do procedimento de digestao das amostras assistida por micro-ondas e das condicoes operacionais do espectrometro de emissao optica com plasma acoplado indutivamente (ICP OES). Foi otimizada de forma univariada as condicoes operacionais do espectrometro de massas com plasma acoplado indutivamente (ICP-MS). Os metodos analiticos propostos mostraram-se sensiveis para as determinacoes de Al, Ba, Ca, Cd, Co, Cu, Fe, K, Mg, Mn, Ni, P, S, Sb, Sr e Zn, com limites de quantificacao (LQ) que variaram entre 0,02 e 23 Ýg g-1. A exatidao dos metodos analiticos foi confirmada atraves da analise dos materiais de referencia certificados de farinha de arroz (NIST 1568a), farinha de trigo (NIST 1567a) e folhas de cha (NCS DC 73351), apresentando valores de concordancia entre 81 ¡Ó 1% e 118 ¡Ó 12% (n=3). A precisao foi expressa como desvio padrao relativo (RSD), sendo melhor do que 14% (n=3). Os metodos propostos foram aplicados na determinacao da composicao mineral de 38 amostras de farinhas. Os macroconstituintes nas amostras foram Ca, K, P, Mg e S, com concentracoes variando entre 2,72 ¡Ó 1,09 Ýg g-1 (Ca) e 4253 ¡Ó 103 Ýg g-1 (K). Para os microconstituintes e elementos traco como Ba, Cd, Co, Cu, Fe, Mn, Sr e Zn, as concentracoes variaram entre 0,02 ¡Ó 0,01 Ýg g-1 (Sr) e 65,5 ¡Ó 9,7 (Fe). Foram aplicadas tecnicas exploratoria de dados com o objetivo de caracterizar as farinhas de mandioca, milho e trigo, quanto a sua composicao mineral, onde foi observada a formacao distinta de tres grupos dos tipos farinhas estudadas conforme a presenca dos elementos quantificados. Como alimento, a farinha de trigo apresentou as maiores concentracoes para Cu, Fe, Mn, P, S e Zn, chegando a representar ate 35% do indice de digestao recomendada (IDR), estabelecido para ferro e manganes.
| Identifer | oai:union.ndltd.org:IBICT/oai:ri.ufs.br:riufs/6085 |
| Date | 10 March 2014 |
| Creators | Correia, Felipo Obed |
| Contributors | Araújo, Rennan Geovanny Oliveira |
| Publisher | Pós-Graduação em Química |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Format | application/pdf |
| Source | reponame:Repositório Institucional da UFS, instname:Universidade Federal de Sergipe, instacron:UFS |
| Rights | info:eu-repo/semantics/openAccess |
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