title: A comparative study of capillary zone electrophoresis and pH-potentiometry for determination of dissociation constants.
abstract: Acidity constants of six cephalosporin antibiotics, cefalexin, cefaclor, cefadroxil, cefotaxim, cefoperazon and cefoxitin are determined using capillary zone electrophoresis (CZE) and pH-potentiometric titrations. Since CZE is a separation method, it is not necessary for the samples to be of high purity and known concentration because only mobilities are measured. The effect on determination of dissociation constants of different matrices (serum, 0.9% NaCl, fermentation matrix) was examined. The advantages of CZE can be utilized in those fields where potentiometry has limitations (sample quantity, solubility, purity, simultaneous determinations), although pK(a) values that are close to each other can be determined by potentiometry with more accuracy.
authors.affiliation: Department of Inorganic and Analytical Chemistry, University of Debrecen, PO Box 21, 4010 Debrecen, Hungary.
authors.forename: Melinda
authors.initials: M
authors.lastname: Andrasi
authors.forename: Peter
authors.initials: P
authors.lastname: Buglyo
authors.forename: Laszlo
authors.initials: L
authors.lastname: Zekany
authors.forename: Attila
authors.initials: A
authors.lastname: Gaspar
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis / Q000737:chemistry*; D002433:Cefaclor / Q000032:analysis / Q000097:blood / Q000737:chemistry; D002434:Cefadroxil / Q000032:analysis / Q000097:blood / Q000737:chemistry; D002438:Cefoperazone / Q000032:analysis / Q000097:blood / Q000737:chemistry; D002439:Cefotaxime / Q000032:analysis / Q000097:blood / Q000737:chemistry; D002440:Cefoxitin / Q000032:analysis / Q000097:blood / Q000737:chemistry; D002506:Cephalexin / Q000032:analysis / Q000097:blood / Q000737:chemistry; D002511:Cephalosporins / Q000032:analysis / Q000097:blood / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D015394:Molecular Structure; D011199:Potentiometry / Q000295:instrumentation / Q000379:methods
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D002434:Cefadroxil; D002433:Cefaclor; D002440:Cefoxitin; D002438:Cefoperazone; D002439:Cefotaxime; D002506:Cephalexin