A comparative study of capillary zone electrophoresis and pH-potentiometry for determination of dissociation constants.
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.
Andrasi
Melinda
M
Department of Inorganic and Analytical Chemistry, University of Debrecen, PO Box 21, 4010 Debrecen, Hungary.
Buglyo
Peter
P
Zekany
Laszlo
L
Gaspar
Attila
A
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
D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D002434:Cefadroxil; D002433:Cefaclor; D002440:Cefoxitin; D002438:Cefoperazone; D002439:Cefotaxime; D002506:Cephalexin