Enantioselective analysis of ofloxacin enantiomers by partial‐filling capillary electrophoresis with bacteria as chiral selectors

The enantiomeric separation of ofloxacin enantiomers ( OFLX ) was achieved by using capillary electrophoresis partial‐filled with E scherichia coli , P seudomonas aeruginosa ( G ram‐negative), and S taphylococcus aureus ( G ram‐positive) as chiral selectors. Experimental parameters, including the concentration of background electrolyte, applied voltage, length of the filled bacteria plug, and p H of the buffer, were intensively investigated. Baseline separation of OFLX could be achieved within 7 min by using E . coli and P . aeruginosa as chiral selectors under the following conditions: electrophoretic buffer composed of 10 mM phosphate buffer at p H 7.4, applied voltage at 15 kV, and the bacteria (6.0 × 10 8 cells/mL) were injected into the capillary by gravity with injection height of 17.5 cm for 180 s ( E . coli ), 300 s ( P . aeruginosa ), and 300 s ( S . aureus ), respectively. E . coli and P . aeruginosa had better chiral selectivity for OFLX than S . aureus , which was in good agreement with OFLX having better antimicrobial activity on G ram‐negative rather than G ram‐positive bacteria. A novel method was developed for the enantioselective separation of enantiomers using bacteria as chiral selectors, which provides a new approach for antimicrobials enantioselective analysis, chiral pharmacodynamics, and chiral pharmacokinetics studies.