Separation by Capillary Electrophoresis of Six Extensively Used Antibacterial Compounds

Background: Penicillins and fluoroquinolones are two of the most extensively utilized class of antibacterial substances. Taking into account the importance of these compounds in the human and veterinary antibacterial therapy, identification and separation of these compounds in different complex matrices represent a necessity and also a challenge.
Objective: The aim of our study was to elaborate an alternative separation technique, suitable for the identification and separation of four penicillin derivatives – amoxicillin, ampicillin, benzylpenicillin and oxacillin – and two fluoroquinolones: ciprofloxacin and norfloxacin, and to optimize the analytical conditions.
Material and methods: MEKC proved to be the appropriate method of analysis for the separation of the studied compounds. The CE experiments were conducted on the Agilent 6100 CE System; the data were recorded and processed with Agilent Chemstation software.
Results: An optimum separation was achieved using a buffer solution containing 25 mM sodium tetraborate, 100 mM sodium dodecyl sulfate and 100 mM boric acid. The migration order of the six compounds was: amoxicillin, ampicillin, benzylpenicillin, oxacillin, ciprofloxacin and norfloxacin. The analytical performance of the method was evaluated by calculating the standard deviation for the peak area and also by checking the linearity of the determination.
Conclusions: The proposed method proved to be an efficient and useful tool in the separation of the studied substances and can find useful applications in the analysis of the studied substances from environmental samples.