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The lipopolysaccharide (LPS) of enterobacteria frequently contains various numbers of charged non-stoichiometric substituents such as phosphate (P) and ethanolamine (EtN) groups and a third residue of 3-deoxy-D-manno-2-octulosonic acid (KDO) on the R-core polysaccharide backbone. These substituents can modify the biological activities of LPS including varying the stability of the outer membrane, tolerance to cationic antibiotics, pathogenicity, and sensitivity to enterobacteria bacteriophages. These diverse substituents can be clearly detected in degraded samples of LPS from E. coli C using electrospray ionization single quadrupole mass spectrometry (ESI-Q-MS) from a 0.1 mg/mL solution in a 50:50 mixture of methanol and 10 mM ammonium acetate (pH 6.8). The O-deacylated derivative showed multiple peaks of [M-3H](3-) ions which corresponded to species having up to eight phosphates, two ethanolamines, and an additional KDO on the backbone of Hex(5) Hep(3) KDO(2) GlcN(2) C14:0(3-OH)(2). The major components of the O,N-deacylated derivative were the species associated with four and five phosphates on Hex(5) Hep(3) KDO(2) GlcN(2). The polysaccharide portion of LPS also revealed species which corresponded to Hex(5) Hep(3) KDO associated with two to four phosphates and an ethanolamine. The present method was proved to be useful to investigate the structural diversity of enterobacterial LPS.

The O,N-deacylated derivative (deON) and polysaccharide part (PS) from the lipopolysaccharide (LPS) of Escherichia coli C strain were separated by strongly basic anion-exchange chromatography (SAX) based on the differences in the number of charged phosphate and ethanolamine substituents. They were also successfully separated and characterized by capillary zone electrophoresis and subsequent ESI-ion trap-MS (CZE/ESI-IT-MS). The O-deacylated LPS (deO) presented as a broad peak in CZE/ESI-IT-MS. However, more than twelve species could be discriminated by an extracted ion electropherogram (EIE) and monitoring the species which have different numbers of phosphate and ethanolamine substituents on polysaccharide backbone.

The lipopolysaccharide (LPS) of enterobacteria frequently contains various numbers of charged non-stoichiometric substituents such as phosphate (P) and ethanolamine (EtN) groups and a third residue of 3-deoxy-D-manno-2-octulosonic acid (KDO) on the R-core polysaccharide backbone. These substituents can modify the biological activities of LPS including varying the stability of the outer membrane, tolerance to cationic antibiotics, pathogenicity, and sensitivity to enterobacteria bacteriophages. These diverse substituents can be clearly detected in degraded samples of LPS from E. coli C using electrospray ionization single quadrupole mass spectrometry (ESI-Q-MS) from a 0.1 mg/mL solution in a 50:50 mixture of methanol and 10 mM ammonium acetate (pH 6.8). The O-deacylated derivative showed multiple peaks of [M-3H](3-) ions which corresponded to species having up to eight phosphates, two ethanolamines, and an additional KDO on the backbone of Hex(5) Hep(3) KDO(2) GlcN(2) C14:0(3-OH)(2). The major components of the O,N-deacylated derivative were the species associated with four and five phosphates on Hex(5) Hep(3) KDO(2) GlcN(2). The polysaccharide portion of LPS also revealed species which corresponded to Hex(5) Hep(3) KDO associated with two to four phosphates and an ethanolamine. The present method was proved to be useful to investigate the structural diversity of enterobacterial LPS.

A new approach for the separation and inline characterization of lipopolysaccharide (LPS) related compounds has been developed. The separation was based on the difference in the number of charged phosphate and ethanolamine groups, as non-stoichiometric substituents, on the polysaccharide backbone, and was achieved with reverse phase ion-pairing chromatography (RPIP-HPLC). Tributylamine was used as an ion-pair reagent. In the conditions used in this study, tributylammonium then binds to the LPS related compounds through the negatively charged phosphate groups. This changes the hydrophobicity of the analytes at different positions and allows for separation based on both the number and position of the substituents on the analyte. The RPIP-HPLC was found to be effective for the separation of the O,N-deacylated derivative (deON) and polysaccharide portion (PS) from the LPS of Escherichia coli C strain. Post-column fluorescence derivatization (FLD), using sodium periodate and taurine, was used to detect the separated LPS related species. On the other hand, the separated species were also detected by direct infusion into the ESI-Q-MS using a volatile ammonium acetate buffer rather than the more traditional potassium phosphate buffer. The signal to noise ratio (S/N ratio) was low for the total ion chromatogram, however, high S/N ratios as well as good resolution were attained by selected ion monitoring (SIM) using m/z numbers corresponding to species with different numbers of non-stoichiometric substituents. Five species for deON and ten species for PS were clearly identified on the SIM chromatogram on the RPIP-HPLC/ESI-Q-MS. Accordingly, the present method allows for the effective separation and inline identification of the species corresponding to the diverse non-stoichiometric substitutions in LPS related compounds.

A marked decrease in parts per billion levels of mercury from distilled and natural waters during storage is discussed. Radioactive mercury ( 203 Hg) was added to distilled water, pond water, and seawater, and the loss of activity from the solutions was measured and compared to that of 65 Zn added to the same media. Behavior of inorganic and organic mercury is also examined using 203 HgCl 2 , and CH 3 203 HgCl. The specific behavior of Hg is mainly ascribed to three factors: vaporization, adsorption to the surface of containers and/or penetration through the walls, and susceptibility to biological activities in natural waters. Highly sensitive Hg analysis was therefore required for determining the low levels of Hg in natural waters. It was achieved by adopting the long quartz absorption cell to the cold-vapor flameless atomic absorption method. The sensitivity increases linearly with increasing cell length and the highest detection limit, 0.02 ng of Hg, was obtained when a 150-cm cell was used. Some precautions to eliminate a loss or change in the concentration of Hg in natural waters are stated.