Application of Deep Eutectic Solvents as Additives in Ultrasonic Extraction of Two Phenolic Acids fromHerba Artemisiae Scopariae

This paper reports the extraction of two phenolic acids from Herba Artemisiae Scopariae using deep eutectic solvents that were synthesized with various salt and hydrogen bond donors. The optimal conditions were found to be 50% of a synthesized deep eutectic solvent from tetramethyl ammonium chloride and urea (1:4) mixed with methanol/water (60:40, v/v). Phenolic acid extraction was optimized using an ultrasonic power of 89 W for 30 min with a solid/liquid ratio of 1:10. Under the optimized conditions, good calibration curves were observed at phenolic acid concentrations ranging from 10.0 to 500.0 µg/mL. The method recovery ranged from 97.3% to 100.4%, and the inter-day and intra-day relative standard deviations were less than 5%. Under the optimal extraction conditions, the amounts of chlorogenic acid and caffeic acid extracted from Herba Artemisiae Scopariae were 9.35 mg/g and 0.31 mg/g, respectively.