Optimal Extraction of Gallic Acid from Suaeda glauca Bge. Leaves and Enhanced Efficiency by Ionic Liquids

Table 3

Results of extraction of gallic acid by different solvents.

Solvents	Extraction technique	Conditions	EE of gallic acid (mg·g^−1)
Emim]Cl	UAE	51°C, 20 mL·g^−1, 42 min	8.40
Bmim]Cl	UAE	51°C, 20 mL·g^−1, 42 min	8.51
Hmim]Cl	UAE	51°C, 20 mL·g^−1, 42 min	8.90
Omim]Cl	UAE	51°C, 20 mL·g^−1, 42 min	7.90
0% ethanol	UAE	51°C, 20 mL·g^−1, 42 min	3.47
40% ethanol	UAE	51°C, 20 mL·g^−1, 42 min	4.98
70% ethanol	UAE	51°C, 20 mL·g^−1, 42 min	6.21
100% ethanol	UAE	51°C, 20 mL·g^−1, 42 min	4.21
Methanol	UAE	51°C, 20 mL·g^−1, 42 min	5.65
70% ethanol	MAE	51°C, 20 mL·g^−1, 10 min	6.02
70% ethanol	HRE	20 mL·g^−1, 240 min	6.11

[Emim]Cl is 1-ethyl-3-methylimidazolium chloride; [Bmim]Cl is 1-butyl-3-methylimidazolium chloride; [Hmim]Cl is 1-hexyl-3-methylimidazolium chloride; [Omim]Cl is 1-octyl-3-methylimidazolium chloride; their concentrations were all 0.5 mol·L⁻¹ in extraction process.
UAE represents ultrasound-assisted extraction; MAE represents microwave-assisted extraction; HRE is hot reflux extraction.
Extraction conditions involved extraction temperature, liquid-solid ratio, and extraction time.