Determination of polyhydroxy antibiotics by capillary electrophoresis with amperometric detection at a copper electrode

Capillary electrophoresis(CE) was employed to separate polyhydroxy antibiotics in alkaline solution, combined with electrochemical detection at copper electrode. The electrode used was a 350 mu m diameter Cu disk operated in a wall-jet configuration, A sample mixture containing 7 different polyhydroxy antibiotics was separated within 30 min. The linearity varied over a 2-3 order of magnitude and the detection limits were 0.5 mu mol/L, The reproducibility for the peak current and the migration time of 50 mu mol/L doublemycin injected every hour in a period of 8 h, was 7.6% and 2.2% RSD, respectively, and the recovery of the determination of the real sample was 99.6%.