C18:1 3’-sulfo Galactosylceramide is a member of the sulfatide class of glycolipids. It has been found in mouse brain.1 It has been used as a standard for the quantification of C18:1 3’-sulfo galactosylceramide in dried blood spots from patients with metachromatic leukodystrophy (MLD) by UPLC-MS.2As this product is derived from a natural source, there may be variations in the sphingoid backbone.