Abstract
Hydrophilic interaction liquid chromatography (HILIC), coupled to tandem mass spectrometry, can be used to separate and determine various polar lipid classes. The development of an HILIC chromatographic separation of several molecular species among five phospholipid classes (PC, PE, PG, PI and PS) is reported here. In this method, a gradient with acetonitrile and 40 mM ammonium acetate buffer was employed. The initial composition was 95% of acetonitrile, then this proportion was decreased to 70% in order to elute all the compounds of interest for a total running time of 11 mins. Furthermore, mobile phase pH can affect the ionizable character of the compounds, according to their pKa values, and also the stationary phase charge state. The influence of such a parameter on both retention times and resolution was evaluated. Besides, the response of different kinds of internal standards (post-extraction standard addition) was evaluated in four different biological matrices, two microalgae extracts and two marine fish extracts. This study found that the recovery rates were between 70 and 140% of the expected value, with relative standard deviations between 10 and 35%, and then limited matrix effects.•HILIC approach can be used to separate phospholipid according to their polar head-group, and electrospray ionization in negative mode as well as MS/MS allows further identification of the molecular species within each phospholipid class.•Matrix effects are low and compensated with appropriate internal standards.•The limits of quantifications were ranging from 0.05 to 0.14 µg.mL(-1), depending on the analyte.