Feasibility of liquid phase microextraction based on a new supramolecular solvent for spectrophotometric determination of orthophosphate using response surface methodology optimization

A new supramolecular solvent made up of non-ionic nonylphenol ethoxylate surfactant was introduced, and its potential was evaluated for microextraction of orthophosphate before molybdenum blue spectrophotometric determination. This method is based on the formation of the heteropoly blue complex of orthophosphate followed by vortex assisted-supramolecular solvent based microextraction of the formed complex for final spectrophotometric measurement. Experimental design using fractional factorial design and response surface methodology based on the central composite design was applied for optimization of different variables influencing the extraction efficiency. Under the optimized conditions, orthophosphate can be determined in the linear range of 0.5-28.0 mu g L-1 (R-2 = 0.9933) with a detection limit (3S(b)) of 0.1 mu g L-1 and preconcentration factor of 50. Relative standard deviations were less than 3.5% for repeatability and 4.5% for reproducibility. The presented method has been successfully applied for the determination of orthophosphate in real water samples, and acceptable recoveries were obtained between 97.2 and 102.8% with relative standard deviations of <5%. (C) 2019 Elsevier B.V. All rights reserved.