Experimental design for the optimization of micelle mediated extraction of malachite green using anionic surfactant, sodium dodecyl sulfate

A new and simple cloud point extraction (CPE) methodology has been developed for the preconcentration and spectrophotometric determination of trace amounts of malachite green from water samples. In this method, an anionic surfactant, sodium dodecyl sulfate (SDS), was used as the extracting agent at room temperature. Central composite design (CCD) based response surface methodology (RSM) was applied for the optimization of the main experimental parameters such as pH of solutions, concentration of surfactant and concentration of salt. Under the optimum conditions the calibration graph was linear in the range of 8 x 10(-9)-9 x 10(-7) mol L-1 with a detection limit of 3 x 10(-9) mol L-1. The relative standard deviation for six replicates of 6 x 10(-8) mol L-1 malachite green was 1.21%. The method was applied successfully to the determination of malachite green in different spiked samples including fish farming water and tap water samples.