Two-dimensional gas chromatography with electron-capture detection used in the determination of specific peptidoglycan and lipopolysaccharide constituents of gram-negative bacteria in infected human urine

Comparison of the limulus amebocyte lysate test and gas chromatography-mass spectrometry for measuring lipopolysaccharides (endotoxins) in airborne dust from poultry-processing industries

“…f Gram-negative cells calculated from the concentration of DAP assuming that 1 ng of DAP corresponds to 2.9 x 106 cells (33). g LPS calculated from the amount of DAP, assuming that 1 ng of DAP corresponds to 8.7 ng of LPS (28).…”

“…In addition, we measured diaminopimelic acid (DAP), which has been shown to be a useful marker of peptidoglycan in gram-negative bacteria (33). The DAP analyses were performed with two-dimensional GC with electron-capture detection (ECD) (28). It was found that it is predominantly cell-envelope-dissociated LPS that are measured with the LAL assay, whereas the GC methods measure the total amounts of gram-negative cells, debris, and free LPS in the sample.…”

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

“…not that of chenodeoxycholic acid, increases the With two-dimensional GC, only preselected fractions of tions of cell wall-dissociated LPS. The induction the total sample are introduced into the analytical column plus bile peritonitis by means of deoxycholic acid attached to the ECD (9,28). This improved selectivity, found to give a higher mortality in rats, compared although not comparable with that of GC-MS ( Fig.…”

“…The sample was heated at 110°C for 4 h and allowed to cool, and then 1 ml of saturated sodium chloride solution, 2 ml of chloroform, and 35 ng of 3-OH-C16:0 (internal standard, dissolved in chloroform) were added. The tube was shaken and centrifuged (1,000 x g), and then the organic phase was transferred to a new tube and evaporated in a desiccator under reduced pressure (28). The sample was heated in 1 ml of 4 M methanolic hydrochloric acid at 100°C for 18 h (29).…”

“…. LPS determined in peritoneal washout fluid in E. coli peritonitis and E. coli plus bile peritonitis by the LAL assay (A) and GC-ECD (B).VOL 28,. 1990 on September 22, 2020 by guest http://jcm.asm.org/ Representative chromatograms (GC-ECD) of peritoneal washout fluid samples from E. coli plus bile peritonitis (A) and control (B).Peritoneal fluid was sampled 1 h after injection.…”