Silicic acid HPLC of cardiolipin, mono- and dilysocardiolipin, and several of their chemical derivatives.

A silicic acid HPLC system in hexane-2-propanol-1 mM H3PO4 50:50:3.5 (v/v/v) is described for the analysis and/or purification of cardiolipin (CL), monolysocardiolipin (MLCL), dilysocardiolipin (DLCL), and several of their chemical derivatives. Derivatives that have been successfully analyzed include CL that is acetylated, succinylated, or tetrahydropyranylated at the 2-hydroxyl; MLCL acetylated at the 2 and 2'-hydroxyls; DLCL acetylated at the 2-hydroxyl and both 2'-hydroxyls; and MLCL tetrahydropyranylated at only the 2-hydroxyl. Water can replace 1 mM H3PO4 in the eluting solvent, but prior conditioning of the silicic acid column with the phosphoric acid solvent is necessary for acceptable chromatography. The most significant factor affecting the elution times of these compounds is the percentage of aqueous component, i.e., water or 1 mM H3PO4.