Liquid-phase microextraction approach using supramolecular solvent formed in aqueous systems based on di(2-ethylhexyl)phosphoric acid salt: Spectrophotometric determination of antipyrine in saliva

Abstract

In this study, di(2-ethylhexyl)phosphoric acid salt was investigated as a double-chain anionic surfactant for supramolecular solvent formation in a liquid-phase microextraction procedure for the first time. Inorganic electrolytes (sodium salts) were shown to be coacervation agents, due to their salting-out property in solution of sodium di(2-ethylhexyl)phosphate, obtained by deprotonation of the acid. The physico-chemical properties of the newly synthesised solvents were studied. Sodium carbonate and sodium phosphate were found to be the most suitable coacervation agents, due to their alkaline nature and low viscosity of the supramolecular solvent phases they produce. The extraction ability of the novel solvent was demonstrated in liquid-phase microextraction of a colored derivative of antipyrine from saliva for further spectrophotometric determination. The extraction recovery was found to be 70 %. The proposed green sample preparation technique enabled the exclusion of traditional toxic solvents and reduction of reagent consumption. The satisfactory analytical performance of the procedure was validated with real sample analysis. The calibration graph was linear over the concentration range of 0.03 to 0.5 mmol/L. The limit of detection (3σ) and limit of quantification (10σ), calculated from blank tests, were 0.01 and 0.03 mmol/L, respectively.