Development of a Separation Method of Four Penicillin Derivatives by Capillary Electrophoresis

Introduction: The objective of this paper is the development and optimization of a capillary electrophoresis method, which allows the separation of four frequently used penicillin derivatives (amoxicillin, ampicillin, benzilpenicillin and oxacillin), with possible application in the analysis of environmental samples.
Material and method: In our experiments we worked on water solutions of the studied penicillins. The analysis was performed on an Agilent Capillary Electrophoresis System with a diode array detector. The data were recorded and processed by Chemstation software.
Results: Different buffer solutions were tried out in order to reach the most efficient separation of the studied compounds. The influence of different analytical parameters was evaluated by varying the buffer concentration, buffer pH, voltage, temperature, injection time and pressure. The analytical performance of the method was verified, in order to estimate reproducibility and sensitivity.
Conclusions: A micellar electrokinetic capillary chromatography method has been developed for the separation of the four penicillins. We obtained the best results with a buffer solution containing 25 mM sodium tetraborate and 100 mM sodium dodecyl sulfate (pH = 9.3), the separation being achieved in approximately 5 minutes.