Desenvolvimento de um sensor quimico de fibras opticas para a determinação simultanea de metais pesados empregando metodos de calibração multivariada

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

This work describes the development of an optical fibre chemical sensor ( optode ) for determination of heavy metals, by employing the 4-(2-piridylazo(resorcinol) reagent, PAR, immobilised on Amberlite XAD-4 resin, which was fixed at the common end of a bifurcated optical fibre bundle. The optode was employed for simultaneous determination of two (Ni(II)/Cd(II)) and three (Ni(II)/Cd(II)/Mn(II)) metal ions, in the concentration range from 0.5 to 3.5 mgL, which was chosen based on the saturation capability of the sensing phase. Multivariate calibration methods, such as Principal Component Regression ( PCR ) and Partial Least Square ( PLS ), including PLS1 (that employs a model for each component) and PLS2 (that employs a single model for all components), were employed to perform the simultaneous determinations. Different procedures for pre-processing of spectral data, such as mean centring, smoothing by sliding average and first derivative were employed. The best result for the simultaneous determination of Ni(II) and Cd(II) were obtained when the PLS1 method, with the data centred on the mean, was employed, providing RMSEP ( root mean square error of prediction ) values of 0.27 and 0.21 mgL for Ni(II) and Cd(II), respectively. In the simultaneous determination of Ni(II)/Cd(II)/Mn(II), the model based on PLS1, after centring the data on the mean, showed the best prediction capability, providing RMSEP values of 0.19, 0.29 and 0.43 mgL for Ni(II), Cd(II) and Mn(II), respectively.

ASSUNTO(S)

calibração detectores quimicos metais pesados

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