DETERMINATION OF BENZODIAZEPINES BY MICELLAR ELECTROKINETIC CHROMATOGRAPHY

A method for the separation and determination of benzodiazepines by mi cellar electrokinetic chromatography (MEKC) has been developed. Separa tion buffers consisted of aqueous solutions of glycine and triethanola mine (pH 9.0), containing sodium dodecyl sulfate (SDS) as surfactant a nd methanol as organic modifier. The effect of the concentration of SD S, methanol, glycine and triethanolamine on migration times and resolu tion was studied. Ten benzodiazepines were baseline separated at a 25 mM SDS concentration and 20% v/v methanol in a 75mM glycine-250 mM tri ethanolamine buffer. Under these conditions, the within-day reproducib ilities were 0.3-0.5% for migration times and 1.7-1.9% for peak areas at a concentration of 10 mu g/mL. The limits of detection and quantifi cation for oxazepam were 0.2 and 0.7 mu g/mL, respectively, using an i njection time of 5 s.