[Methods of lipopolysaccharide component derivation in evaluating their structures by chromatographic techniques]

The pathogenicity of Gram-negative bacteria is mediated mainly by the outer membrane-associated lipid-polysaccharide structure, called endotoxin or lipopolysaccharide (LPS). This structure consists of three parts, O-antigen, core oligosaccharide, and lipid A, which differ in chemical composition and biological properties. Gas-liquid chromatography coupled with mass spectrometry (GLC/MS) is commonly used to determine LPS structure. The carbohydrate profiles of endotoxins are analyzed after derivation to alditol acetates or partially methylated alditol acetates, which enables one to establish the site of glycosidic linkages. The chromatographic analysis of LPS lipid components requires their modification to ester derivatives, most frequently to methyl esters.