RO, J.*; MUNOZ-GARCIA, A.; BROWN, J.C.; WILLIAMS, J.B.; Ohio State Univ.; Ohio State Univ.; Applied Biosystem, MA.; Ohio State Univ.: Identification of Complex Mixtures of Sphingolipids in the Stratum Corneum by Reverse Phase High Performance Liquid Chromatography and Atmospheric Pressure Photospray Ionization Mass Spectrometry

Characterized by a fatty acid moiety bound to a sphingosine base, sphingolipids, such as ceramides and cerebrosides, are an integral component of the outer layer of skin, the stratum corneum (SC), important in the formation of the epidermal barrier to water vapor diffusion and in retarding the penetration of potentially harmful substances from the environment. We develop a protocol to identify and quantify the ceramides and cerebrosides in a complex mixture of lipids extracted from the SC of the skin of House Sparrows using reverse phase HPLC coupled with atmospheric pressure photoionization mass spectrometry. We identified 80 molecular species of cerebrosides and 79 of ceramides in the SC of House sparrows, from 11 to 31 molecular types in each ceramide family. Carbon chain lengths of the fatty acids in the sphingolipids were longer than those occurring in the mammalian SC; chain lengths of over 40 carbons were common. Comparisons of quantities of lipid classes as determined by TLC and MS yielded close concordance.