Avaliação voltamétrica de metais pesados através de calibração multivariada
Desenvolveu-se um programa em linguagem QuickBasic 4.5 para aquisição e gerenciamento de dados do polarógrafo PAR, modelo 384B. Esses dados foram adquiridos do polarógrafo através de uma interface serial padrão RS232C para um microcomputador PC 586,133 MHz. Dentre as técnicas disponíveis no polarógr...
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Universidade Federal de Viçosa
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|Citação:||MAYRINK, Maria Isabel Cristina Batista. Avaliação voltamétrica de metais pesados através de calibração multivariada. 1999. 133f. Dissertação (Mestrado em Agroquímica) - Universidade Federal de Viçosa, Viçosa. 1999.|
|Resumo inglês:||A program was developed in QuickBasic 4.5 language for the acquisition and management of data from a PAR polarograph, model 384B. These data were gathered from the polarograph through a standard serial interface RS232C to a PC-586, 133 MHz microcomputer. Among the available techniques of the polarograph, the voltametric differential pulse anodic dissolution was automated, stressing, however, that its characteristics allows, with few changes in the current program, implementation of the other thecniques as well. The choice of this particular thecnique was due to the fact that it exhibits high selectivity and sensitivity, being, also, frequently used in routine analysis of samples such as water, soils and sediments. Statistical methods of multivariate calibration, base on partial least squares (PLS), was employed for data reduction and determinations of individual concentrations of Cd(II), TI(I) and Pb(II) in mixtures. The reason for the choice of this particular set of ions is due to the fact that they exhibit superposition of their voltametric waves, even using the voltametric differential pulse anodic redissolution technique. In view of the results obtained for the analysis of Pb(II), Cd(II), Zn(II) and Cu(II) and for the analysis of Cd(II), Pb(II) and TI(I), good performance of the software was verified. The accuracy of the method was checked by analysis of a certified standard sediment, compared with the results obtained by atomic absorption spectrophotometry, higher versatility, speed and simplicity was observed during the analytical process. The results obtained for Cd(II), Pb(II) and TI(I) in the multivariate analysis exhibited correlation coefficients of 0.995; 0.988; and 0.989, respectively.|