The photometric determination of gangliosides with the sulfo-phospho-vanillin reaction

A simple, quantitative method is described for the photometric determination of gangliosides. The procedure is based on the sulfo-phospho-vanillin reaction, and does not require prior hydrolysis. It has been shown that the reaction is probably due to oxidation by sulfuric acid of the sphingosine moiety which results in the formation of aldehydes or ketones or both which then react with the phosphoric acid-vanillin reagent to produce a rose-colored complex. The reaction permits the determination of the amount of ganglioside present in a sample; and, together with the resorcinol reaction to measure the NANA content, it can be used to determine whether a purified ganglioside is a mono-, di-, or trisialoganglioside.