Solid-liquid extraction into hydrophilic deep eutectic solvent followed by preconcentration into primary amine-based supramolecular solvent: liquid chromatography-mass spectrometry determination of tetracyclines in chicken meat.

The phenomenon of supramolecular solvent formation in an aqueous phase containing a primary amine, in the presence of a hydrophilic three-component deep eutectic solvent based on choline chloride, a polar carboxylic acid and water was described for the first time. The established phenomenon was implemented for the preconcentration of polar analytes after their separation from solid samples into the three-component deep eutectic solvent. The mixed supramolecular aggregates were formed by mixing the extract phase containing analytes and deep eutectic solvent precursors with the primary amine. The developed approach was applied to the determination of tetracyclines (minocycline, oxytetracycline, tetracycline, chlortetracycline, and doxycycline) in chicken meat samples by liquid chromatography-mass spectrometry. Various three-component deep eutectic solvents were investigated for the separation of tetracyclines from meat matrices. The most appropriate composition contained choline chloride and glycolic acid at a molar ratio of 1:1 with water (20 %). Effective protein precipitation during solid-liquid extraction from meat samples into the deep eutectic solvent was established. For supramolecular solvent-based liquid-phase microextraction 1-nonylamine was chosen as an amphiphile. Limits of detection of tetracyclines in chicken meat samples were from 1 to 4 μg kg-1.