title: Effect of the silica support of bonded reversed-phase columns on chromatography of some antibiotic compounds.
abstract: Chromatographic behavior of three types of antibiotics was investigated on bonded C18 and polymeric reversed-phase columns. With penicillins with carboxylic acid functions only, retention and separations on the two types of columns were similar. beta-Lactam antibiotics with basic functions did not give as sharp peaks on the C18 column unless a silanol blocking agent, tetramethyl ammonium chloride (TMA) was added. In 0.01 M orthophosphoric acid-acetonitrile, tetracyclines were separated on the polymeric reversed-phase columns, but not on the C18 columns. With addition of TMA, results on C18 and polymeric reversed-phase columns were nearly identical. Addition of an ion pair also improved separations on the C18 columns, but not as much as TMA. Interaction with the silica support of C18 columns was used to separate tylosin from interferences in extracts of biological materials. The results demonstrate the importance of interactions with the silica support in chromatography of basic antibiotics on C18 packings. These interactions can be either beneficial or detrimental to separations, depending on the conditions used.
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid; D006863:Hydrogen-Ion Concentration; D007933:Leucomycins / Q000032:analysis; D012822:Silicon Dioxide; D015645:Tylosin
chemical_list: D000900:Anti-Bacterial Agents; D007933:Leucomycins; D012822:Silicon Dioxide; D015645:Tylosin