title: Critical points in the analysis of ciprofloxacin by high-performance liquid chromatography.
abstract: Chromatographic analysis of the antibiotic compound ciprofloxacin on a C18 column proved to show some critical points. On a C18 column, ciprofloxacin analysis resulted in two peaks in the chromatogram. Effects of stock solution composition, mobile phase composition and type of stationary phase were investigated to understand the occurrence of both peaks. Esterification of the carboxylic group of ciprofloxacin was shown when methanol was used as stock solution solvent in acidic conditions. Secondly, a ciprofloxacin pK(a) value of 3.64 in water at position N-1 was found which could not fully explain the observation of the two peaks: mobile phase composition and type of stationary phase were also found to be important parameters with respect to the peak area ratio of both peaks.
authors.affiliation: Research Group EnVOC, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium. jo.dewulf@UGent.be
authors.forename: Bavo
authors.initials: B
authors.lastname: De Witte
authors.forename: Jo
authors.initials: J
authors.lastname: Dewulf
authors.forename: Kristof
authors.initials: K
authors.lastname: Demeestere
authors.forename: Michael
authors.initials: M
authors.lastname: De Ruyck
authors.forename: Herman
authors.initials: H
authors.lastname: Van Langenhove
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D002939:Ciprofloxacin / Q000032:analysis* / Q000737:chemistry; D004952:Esters / Q000138:chemical synthesis; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry
chemical_list: D004952:Esters; D002939:Ciprofloxacin