Simultaneous spectrophotometric determination of Vitamin K3 and 1,4-naphthoquinone after cloud point extraction by using genetic algorithm based wavelength selection-partial least squares regression

Cloud point extraction has been used for the preconcentration of Vitamin K3 and 1,4-naphthoquinone, after their reaction by aniline, and later simultaneous spectrophotometric analysis by genetic algorithm-partial least squares (GA-PLS) calibration using octylphenoxypolyethoxyethanol (Triton X-114) as surfactant. The chemical variables affecting the analytical performance of the methodology were studied and optimized. Under the optimum conditions [i.e., [aniline]=0.033 M, [Triton X-114]=0.22% (w/v), equilibration time 15 min and cloud point 25 °C], preconcentration of 15 ml of sample solution permitted the detection of 0.05 and 0.08 (mu)g ml^-1 for Vitamin K3 and 1,4-naphtaquinone, respectively. The predictive abilities of partial least squares regression (PLS), genetic algorithm-partial least squares regression, iterative target transformation factor analysis (ITTFA) and principal components-artificial neural networks (PC-ANN) were examined for simultaneous determination of two quinines. The GA-PLS shows superiority over other applied multivariate methods due to the wavelength selection in PLS calibration using a genetic algorithm without loss of prediction capacity, provides useful information about the chemical system.