Fast C18 solid-phase desalting/delipidation of the human serum apolipoproteins for matrix-assisted laser desorption ionization and electrospray ionization mass spectrometric analysis

A new method for the delipidation of human serum lipoproteins involving the use of a reversed-phase C18 solid-phase extraction (SPE) cartridge is introduced for use with matrix-assisted laser desorption ionization and electrospray ionization mass spectrometry. This method is compared with two other methods of lipoprotein delipidation. The SPE method of delipidation produces a higher and more reproducible protein yield than the conventional liquid-liquid methanol-diethyl ether delipidation technique. Furthermore, the SPE method implements a fast, sequential, desalting and delipidation of the lipoproteins for subsequent mass spectrometric analysis providing high quality spectra.