Deep Eutectic Solvents and Layered Double Hydroxides in Solid‐Phase Extraction of Antidepressant Drugs.

For the first time, an acidic deep eutectic solvent (DES) comprised of malonic acid and ChCl was used to complete dissolution of Co‐Al, Ni‐Al, and Cu‐Al layered double hydroxides (LDHs) as sorbents in the vortex‐assisted in‐situ solid‐phase extraction of doxepin and amitriptyline followed by high‐performance liquid chromatography‐ultraviolet (HPLC‐UV). Moreover, the ability of urea:ChCl and ethylene glycol:ChCl was investigated to dissolve the LDH sorbents. The extraction conditions were optimized in terms of vortex time, molar ratio of Co2+:Al3+, NaOH concentration, and volume of DES based on the Box‐Behnen design. The linearity, limit of detection, and coefficient of determination R2 for both analytes were assessed as well. Recoveries of more than 93.1 % with relative standard deviations of less than 5.3 % were achieved for spiking urine and pharmaceutical formulation samples. [ABSTRACT FROM AUTHOR]