Elimination of LC-MS/MS matrix effect due to phospholipids using specific solid-phase extraction elution conditions

Background: The objective is to find elution conditions using different solid-phase extraction chemistries to reduce the amount of phospholipids in plasma extract, which is associated with matrix effect in LC-MS. Results: Phospholipids' recovery was reduced by decreasing the eluents' methanol content applied to silica-based and polymer-based reversed-phase solid-phase extraction cartridges while 100% acetonitrile applied to the silica-based cartridges drastically minimized the phospholipids' elution. Silanol interactions are involved in the increased retention of phospholipids with silica-based reversed-phase cartridges when using high percentages of ACN in eluents. The bioanalytical usefulness of these findings was confirmed by successful extraction recovery of pharmaceutical compounds. Conclusion: Combinations of specific eluents and reversed-phase solid-phase extraction cartridges were found to prevent matrix effect due to phospholipids.