Lipidomic profiling of dried seahorses by hydrophilic interaction chromatography coupled to mass spectrometry

• Phospholipid classes are separated using a diol column in HILIC mode.
• Molecular species of each phospholipid class are separated in the ion source.
• Phospholipids in dried seahorse contain many polyunsaturated acyl chains.
• The method is validated and shown to be reliable and efficient.
• Phospholipid can be used as potential marker for species differentiation.

Dried seahorse is a precious raw food material for cooking soups. In this study, a lipidomics strategy using the techniques of solid-phase extraction (SPE) and hydrophilic interaction chromatography–tandem mass spectrometry (HILIC–QTOF/MS) was developed for extraction, visualization, and quantification of phospholipids in dried seahorses. The parameters of SPE were optimized, and 1 mL of sample and chloroform/methanol (1:2, v/v) were found to be the best loading volume and eluting solvent, respectively. Afterwards, each phospholipid class was successfully separated on a HILIC column and analyzed by mass spectrometry. A total of 50 phospholipid molecular species were identified and determined, including 15 phosphatidylcholines (PCs), 14 phosphatidylethanolamines (PEs), 12 phosphatidylinositols (PIs) and 9 phosphatidylserines (PSs). In comparison to previously methods, this strategy was robust and efficient in extraction, characterization, and determination of phospholipids. The dried seahorse was found to contain large amounts of polyunsaturated fatty acyl phospholipids which are beneficial to human health.