2.1. Materials
The extraction solvents ethanol (99.5%, ACS reagent), dichloromethane
(99.5%, ACS reagent), and ionic liquids (ILs) (IL1:
1-n-Hexyl-3-methylimidazolium chloride, 98% and IL2:
1-Ethyl-3-methylimidazolium chloride, 97%) were purchased from Fisher
Scientific (Fisher Scientific, Waltham, MA, USA). The selection of ionic
liquids was based on previous literature for higher affinity for polar
lipids and phenolic molecules. The solutions of ILs (40 mL) were
prepared by mixing two ionic liquids with ethanol (99%) as co-solvent
at 1:2 (w/v) ratio. The waxy burgundy whole grain sorghum was kindly
donated by Nu Life Market LLC (Nu Life Market LLC, Scott City, KS, USA).