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Abstract
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Simultaneous spectrophotometric determination of a mixture of overlapped complexes of Fe3+, Mn2+,
Cu2+, and Zn2+ ions with 2-(3-hydroxy-1-phenyl-but-2-enylideneamino) pyridine-3-ol(HPEP) by orthogonal
projection approach-feed forward neural network (OPA-FFNN) and continuous wavelet
transform-feed forward neural network (CWT-FFNN) is discussed. Ionic complexes HPEP were formulated
with varying reagent concentration, pH and time of color formation for completion of complexation
reactions. It was found that, at 5.0 104 mol L1 of HPEP, pH 9.5 and 10 min after mixing the complexation
reactions were completed. The spectral data were analyzed using partial response plots, and identified
non-linearity modeled using FFNN. Reducing the number of OPA-FFNN and CWT-FFNN inputs were
simplified using dissimilarity pure spectra of OPA and selected wavelet coefficients. Once the pure dissimilarity
plots ad optimal wavelet coefficients are selected, different ANN models were employed for
the calculation of the final calibration models. The performance of these two approaches were tested with
regard to root mean square errors of prediction (RMSE %) values, using synthetic solutions. Under the
working conditions, the proposed methods were successfully applied to the simultaneous determination
of metal ions in different vegetable and foodstuff samples. The results show that, OPA-FFNN and
CWT-FFNN were effective in simultaneously determining Fe3+, Mn2+, Cu2+, and Zn2+ concentration.
Also, concentrations of metal ions in the samples were determined by flame atomic absorption spectrometry
(FAAS). The amounts of metal ions obtained by the proposed methods were in good agreement with
those obtained by FAAS.
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