Experimental design for the optimization of coacervative extraction of brilliant green in water samples using anionic surfactant

Abstract A new and simple method for the determination of trace amounts of brilliant green was developed by coacervative extraction and spectrophotometry. The method is based on the extraction of brilliant green with coacervates made up of sodium dodecyl sulfate as an anionic surfactant, in the presence of saturated NaCl solution. The effect of various experimental parameters such as pH of solutions, concentration of surfactant and concentration of salt was investigated using central composite design based on response surface methodology. Under the optimum conditions the calibration graph was linear in the range of 0.03–2.2 µg mL−1 with a detection limit of 0.012 µg mL−1. The relative standard deviation for seven replicates of 1.2 µg mL−1 brilliant green was 1.75%. The proposed method was successfully applied for the determination of brilliant green in different real samples including fish farming water, river water and tap water samples.