1-Palmitoyl-2-oleoyl-sn-glycero-3-PC- 13 C 16 (POPC- 13 C16)is 13 C labeled 1-Palmitoyl-2-oleoyl-sn-glycero-3-PC. 1-Palmitoyl-2-oleoyl-sn-glycero-3-PC (POPC), a phospholipid, is a major component of biological membranes. 1-Palmitoyl-2-oleoyl-sn-glycero-3-PC is used for the preparation of liposomes and studying the properties of lipid bilayers.