Chemometrics-enhanced simultaneous spectrophotometric determination of aluminum and bismuth with hematoxylin in vegetables and water using multivariate calibration

A simple, novel and sensitive spectrophotometric method was described for simultaneous determination of aluminum and bismuth mixtures. All factors affecting the sensitivity were optimized, and the linear dynamic range for determination of aluminum and bismuth found. The simultaneous determination of aluminum and bismuth and use of spectrophotometric methods is a difficult problem due to the spectral interference. The multivariate chemometrics methods were used for this study. Chemometrics methods such as continuous wavelet transform (CWT), wavelet orthogonal signal correction-partial least squares (WOSC-PLS) and least squares-support vector machine (LS-SVM) methods were used without prior separation steps. The method is based on the colored complexes formed by aluminum and bismuth with hematoxylin in the presence of cetyltrimethylammonium bromide as a surfactant at pH 5.8. In this study, absorption spectra were recorded in the wavelength range 400–650 nm. The results showed that aluminum and bismuth could be determined simultaneously in the range of 0.1–11.0 and 0.1–7.0 μg mL–1, respectively. The validation of the developed methods was tested by analyzing various synthetic mixtures of the aluminum and bismuth. The proposed methods have been applied to the simultaneous determination of aluminum and bismuth in vegetables and different water samples.