Determination of linezolid and its achiral impurities using sweeping preconcentration by micellar capillary electrophoresis

Linezolid is the first compound of a truly new class of antibiotics—the oxazolidinones. The elaborated method of capillary electrophoresis (CE) of linezolid separation from its achiral impurities was successfully performed using sweeping preconcentration, followed by UV absorption detection at 254 nm. The best results were obtained with 125 mM Tris buffer, pH 2.0, with addition of 20% (v/v) methanol as background electrolyte. Sodium dodecyl sulfate (150 mM) was added to the electrolyte in the inlet vial as the sweeping agent. The separation was carried out at negative polarity. Then, the optimized method was validated in terms of linearity, accuracy and precision. Sweeping preconcentration of linezolid provides detection limit at 0.05 μg/ml level.The evaluated CE method was applied in the analysis of medicinal product containing linezolid–linezolid solution for infusion.