Desenvolvimento de um espectrofotometro multicanal para analise multivariada em sistema de fluxo

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

In this work was searched the application of chemometric methods for analysis of multiway data, obtained in flow systems that use a concentration gradient generated by dispersion, and multichannel spectrophotometric detection by photodiode array. These techniques can turn analysis even in presence of interference and with a reduced number of standards. It was developed a multichannel spectrophotometer with photodiode array detection to be adapted as a detection unit in a flow system. This spectrophotometer make possible spectra acquisition in reduced times, being able to follow a generated pH gradient. It was generated a pH gradient by sodium phosphate dispersion in a boric acid and citric acid mixture into a homogenization cell. The pH at each time was monitored by multivariate calibration, from the spectra of a set of acid-base indicators. It was obtained in a flow system, spectra of solutions of phenolphthalein, thymolphthalein, methyl red and bromotymol blue, individually, and in mixtures of two, three and four indicators. By using the generalized rank annihilation method (GRAM) with similarity transformation, it was possible to determine the concentrations, the time concentration profile and the spectra of respective indicators in several mixtures.

ASSUNTO(S)

quimiometria espectrofotometria

ACESSO AO ARTIGO

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