Determination of Oxytetracycline,Doxycycline,Tetracycline and Chlortetracycline in Tetracycline Antibiotics by HPLC

A rapid and sensitive high-performance liquid chromatographic method for the simultaneous determination of oxytetracycline,doxycycline,tetracycline and chlortetracycline was developed.The separation was performed on a reverse-phase C18 column with gradient elution using a mixed solution composed of methanol and sodium acetate buffer(containing disodium salt of EDTA and calcium chloride,pH 8.10).UV detection at 386 nm was used,linearity of the calibration curve was obtained in the range of 8-4 000 μg·L-1.The detection limits for oxytetracycline,doxycycline,tetracycline and chlortetracycline were 6,13,6 and 7 μg·L-1 respectively.The method has been applied to the analysis of commercial tetracycline antibiotics,giving RSD′s in the range from 1.2% to 3.6%,and recoveries from 95% to 102%.