Monodisperse microsphere-based immobilized metal affinity chromatography approach for preparing Antarctic krill phospholipids followed by HILIC-MS analysis.

Phospholipids enriched krill is a functional food beneficial in cardiovascular diseases. Herein, monodisperse microsphere-based immobilized metal affinity chromatographic material (MM-IMAC) was synthesized with Ti4+ incorporated to enrich phospholipids from krill by coordination with phosphate group. The extract was profiled by hydrophilic interaction chromatography-mass spectrometry (HILIC-MS) with 154 phospholipid molecular species detected. The parameters were loading solvent n-hexane/isopropanol (2:8, v/v), flow rate 0.8 mL·min-1, and eluting volume 1 mL. Besides, eicosapentaenoic and docosahexaenoic acids structured phospholipids were located, such as phosphatidylcholine (PC) 20:5/22:6, phosphatidylinositol (PI) 18:0/20:5, etc. Finally, this method was validated in linearity (R2 ≥ 0.9953), sensitivity (LOD ≤ 0.53 μg·mL-1 and LOQ ≤ 1.66 μg·mL-1), precision (RSDintraday ≤ 4.86% and RSDinterday ≤ 6.25%), and recovery (58-83%). It indicated that the MM-Ti4+-IMAC-HILIC-MS was reliable and efficient in specific study of phospholipids in food matrix.