Purification of human milk gangliosides by silica gel chromatography and analysis of trifluoroacetate derivatives by gas chromatography.

Two of the main gangliosides in human milk were purified by silica gel (230-400 mesh) column chromatography. The gangliosides were identified as GD3 and GM3 by methanolysis (2 M hydrochloric acid; 60 or 85 degrees C) and gas chromatography of trifluoroacetate derivatives on a fused-silica capillary column. The molar ratios of galactose, glucose and sialic acid were 1:1:2 and 1:1:1, respectively, and the sequence in both gangliosides comprised sialic acid--galactose--glucose--ceramide, as indicated by the time course of cleavage of individual components during methanolysis at 60 degrees C.