Green vortex-assisted emulsification microextraction using a ternary deep eutectic solvent for extraction of tetracyclines in infant formulas.

A novel green alternative vortex-assisted emulsification liquid-liquid microextraction based on a new hydrophobic deep eutectic solvent (DES) was developed to extract tetracyclines in infant formulas. Five new ternary DESs were synthesized and tested in this regard. Among them [thymol]:[ethylene glycol]:[benzyl alcohol] (2:2:1) DES demonstrated the highest extraction efficiency. The analyzes were performed by HPLC. The DES was characterized by attenuated total reflectance-FTIR, nuclear magnetic resonance spectroscopy, and octanol-water partition coefficient. The effect of type, mole ratio, and volume of DES, dispersing agent, pH, and ionic strength was studied. The limits of quantification and linear range were 3-9.32 and 3-500 μg kg, respectively. The method was applied to detect tetracyclines in infant formulas, and the recoveries were obtained as 68.9-102.0 % with relative standard deviations < 9 %. The procedure greenness was assessed using the Analytical Eco-Scale. This paper represents the first application of a novel ternary DES to analyze tetracyclines in infant formulas.