Determination of Fe,Nb and Si in titanium (IV) oxide white pigments by AAS using multivariate linear calibration methods

Models for the quantitative determination of Fe, Nb and Si in titanium (IV) oxide white pigments by flame atomic absorption spectrometry (AAS) are described. For the models two multivariate linear calibration techniques have been used: principal component regression (PCR) and partial least squares (PLS1). Absorbances measured at wavelengths for elements present in solution have been considered as independent (x) variables, while the concentrations of elements (or their oxide) to be determined have been taken as dependent (y) variables. The results obtained by the models do not differ significantly (alpha=0.05) from those achieved by the XRF method checked in advance by another independent method, the neutron activation analysis (NAA).