The structurally related glycopeptide antibiotics vancomycin, ristocetin A, and teicoplanin can all be used as chiral selectors in capillary electrophoresis (CE). Both experimental modeling studies were done to elucidate their similarities differences. There are identifiable morphological differences the aglycon macrocyclic portions of these three compounds. In addition, there other structural distinctions that affect CE enantioselectivity, migration times, efficiency. Teicoplanin is most...

Abstract Macrocyclic antibiotics are the newest class of chiral selector used in capillary electrophoresis (CE) enantioseparations. Two basic types compounds have proven to produce useful They ansa and glycopeptides. The best resolve or cationic racemates while glycopeptides acidic anionic analytes. structure use these selectors discussed. factors affecting separation mechanism considered as well.

Vancomycin forms a stable complex with Cu2− in neutral aqueous solutions. The enantioselectivity of native vancomycin was compared to that the copper-vancomycin using capillary electrophoresis (CE). There were significant differences their enantioselectivities. This can be attributed fact copper ion coordinates some same functional groups are essential for chiral recognition and enantioresolution. An amine moiety provides one more important enantioselective interactions identified....

A new macrocyclic of the bis(benzylisoquinoline) alkaloid family, d-(+)-tubocurarine chloride (DTC), has been evaluated as a chiral selector for separation optical isomers organic carboxylates using capillary electrophoresis (CE). The pertinent physicochemical properties, such absorption spectrum, isoionic point, and solution conformation, DTC were determined. effects varying experimental parameters concentration, pH, methanol content in running buffer assessed. CE enantiomers 18 different...

Abstract The estimation of association constants chiral analytes to selectors is often useful in determining the nature and extent interactions that exist between them. These determinations also provide insight into mechanisms are involved enantiorecognition these analytes. Simple models have been developed previously estimate binding through a 1:1 stoichiometry with ligand. extrapolated explain behavior systems containing two ligands. In present study, some was studied micellar capillary...

The macrocyclic antibiotic rifamycin B was found to be highly surface-active and aggregate in aqueous solution. aggregational behavior studied using small-angle neutron scattering (SANS). Aqueous solutions of showed pronounced at both small-length scales (Q ≥ 0.1 Å-1) large-length ≤ Å-1). larger association colloids appear rather open low-density aggregates. addition 10% 2-propanol greatly reduces the number size Somewhat higher amounts alcohol completely suppress or eliminate aggregation....

SUMMARYThe porosity of phosphate coatings obtained using a calcium-zinc cold phosphating bath containing some flotation surfactants as additives has been studied. Empirical chemical methods and the more reliable electrochemical indicate that these contribute significantly to reducing in their presence. The pore-sealing efficiencies have compared conventional chrome post-rinse.

SummaryA calcium-zinc cold phosphating bath has been formulated and suitably modified with some thio non-thio surface-active agents. The suitability of the phosphate coatings obtained in these baths was evaluated under simulated aggressive conditions commonly encountered during service life coatings. stability characteristics indicate that addition agents provides a substitute for use conventional chromium(VI) post-treatments. processes, thus provide dual advantage eliminating process stage...