Genetic-algorithm-based wavelength selection in multicomponent spectrometric determinations by PLS: application on indomethacin and acemethacin mixture

A genetic algorithm is a suitable method for selecting wavelengths for PLS (partial least squares) calibration of mixtures with almost identical spectra without loss of prediction capacity. In the calibration of acemethacin and indomethacin, the proposed procedure eliminates the matrix effect due to the solvent which causes greater variability of the calibration spectra than that due to the difference in the concentration of the two drugs. For the calibration samples, the concentrations calculated using the wavelengths selected are, significantly, equal to those obtained with the full spectrum (significance level above 0.7 in the Student t-test for differences) and differ from the true ones in their average value — less than 1.8% relative error — for the four pH values used in the analysis.