A MICRO-QUANTITATIVE METHOD FOR DIRECT-DETECTION OF BACTERIAL-ENDOTOXIN BY FLUORESCENCE LABELING OF L-GLYCERO-D-MANNO-HEPTOSE

A new method for analysis of bacterial endotoxin was developed using L-glycero-D-manno-heptose (LD-Hep) as a chemical marker. AuthentiC LD-Hep was coupled with a fluorescence probe, 2-aminopyridine. by pyridylamination. The product, pyridylaminated LD-Hep, was separated by high performance liquid chromatography and the fluorescence intensity was measured by a highly sensitive detector system by excitation at 300 nm and emission at 368 nm in 0.7 M H3BO3-KOH buffer (pH 9.0)/CH3CN (9:1, v/v). The fluorescence intensity of LD-Hep increased in a dose-dependent manner over the range of 30 pg to 100 mug tested. As little as 400 pg of Salmonella abortus equi endotoxin could be quantitatively measured by this method.