Synthesis, Characterization, and Application of Hydrophobic Deep Eutectic Solvents Based on Dicarboxylic Acids for Amlodipine Microextraction

In this study, a new hydrophobic deep eutectic solvent was synthesized using dicarboxylic acid (adipic acid, tartaric acid, and itaconic acid) as a hydrogen bond donor and glycerol as a hydrogen bond acceptor in a molar ratio 1:2. The DESs were then employed for Liquid-Liquid MicroExtraction (LLME). The performance of this method was compared to organic solvents for the determination of Amlodipine in pure and pharmaceutical preparations, followed by spectrophotometric analysis. The effects of various influencing conditions were investigated, including pH value, reaction time and temperature, type and volume of the DES, type and volume of the disperser solvent, and centrifugation speed and duration. Under the perfect conditions, a linear range of 1.0-14.0 mg/L with a determination coefficient (R2) of 0.9975 for microextraction with organic solvents, while a linear range of 1.0-16.0 mg/L with a determination coefficient (R2) of 0.9985 for microextraction with DESs solvents. The limit of detection and limit quantification were 0.81 and 2.4 mg/L for microextraction using organic solvents and 0.71 and 2.19 mg/L for microextraction using DESs solvents. The suggested method is green, simple, and efficient, and can be used for the evaluation of Amlodipine in pharmaceutical formulations.