Use of two-dimensional gas chromatography with electron-capture detection for the measurement of lipopolysaccharides in peritoneal fluid and plasma from rats with induced peritonitis.

The content of 3-hydroxymyristic acid from Escherichia coli lipopolysaccharide in peritoneal fluid and plasma from rats was determined by two-dimensional gas chromatography with electron-capture detection of the 3-O-pentafluorobenzoyl methyl ester derivative. The detection limit of lipopolysaccharide in peritoneal fluid was 3 ng/ml. An experimental model of E. coli peritonitis in the rat was used, with and without coinjection of bile. The concentrations of lipopolysaccharide were highest in both peritoneal fluid and plasma samples from rats injected with E. coli and bile, reaching a maximum 1 h after injection by the gas chromatographic method. Corresponding Limulus assay results for peritoneal samples showed a small increase of lipopolysaccharide concentrations during the first 4 h after injection, followed by a substantial increase. The results indicate that bile salts cause an increased release of lipopolysaccharide from gram-negative bacterial cells in vivo and that this may be responsible for the high mortality caused by peritonitis. In contrast to the Limulus assay, gas chromatography enables the total amount of lipopolysaccharide in a clinical sample to be determined.