ABSTRACT
Since the term “hydrophilic interaction chromatography (HILIC)” was proposed by Alpert in 1990,1 a large number of highly polar (or hydrophilic) substances have been separated ef“ciently using the HILIC approach. HILIC requires an aqueous organic mobile phase and a polar stationary phase, such as bare silica or silica modi“ed with ionic, neutral, or complex functional groups. HILIC is a variant of normal-phase liquid chromatography and is suitable for the separation of water-soluble polar substances that are poorly retained on conventional reversed-phase stationary phases, such as ODS-silica. Most recent HILIC applications have focused on the analyses of
4.1 Introduction ....................................................................................................77 4.2 Polyphenolic Compounds ............................................................................... 78 4.3 Chromatography Challenges for Separation of Various PAs ......................... 79 4.4 HILIC Conditions for Separation of PAs ........................................................80 4.5 HILIC Separation Pro“les of Apple PA Mixtures Eluted
Using a Gradient Method ................................................................................ 81 4.6 Retention Behavior of Oligomeric PA Standards in HILIC ........................... 81 4.7 Retention Mechanism of Oligomeric PAs in HILIC ......................................84 4.8 HILIC Separation of Other Polyphenolic Compounds...................................86 References ................................................................................................................88
