DETERMINATION OF TETRACYCLINE AND OXYTETRACYCLINE BY FLOW-INJECTION CHEMILUMINESCENCE METHOD

Objective To establish a rapid and precise continuous flow-injection chemiluminescence method for the determination of tetracycline and oxytetracycline. Methods In NaOH solution, tetracycline and oxytetracycline can sensitize obviously the chemiluminesence （CL） intensity of the reaction of luminol with KIO4, the sensitized CL intensity is proportional to the concentration of tetracycline and oxytetracycline. So, a new flow-injection CL method has been developed. The optimum chemical conditions for the CL reaction were investigated. Results Under the optimized conditions （KIO 4 concentration: 1.0×10 -5 mol/L; NaOH concentration: 0.1 mol/L; luminol concentration: 1.0×10 -4mol/L）, tetracycline and oxytetracycline were determined. The linear range of the working curves was 1.0×10 -7 - 1.0×10 -4g/mL, the detection limits was 1.0×10 -8g/mL and 1.1×10 -8g/mL, and the relative standard deviation was 2.6% （CS=1.0×10 -6g/mL; n=11） and 2.0% （CS=1.0×10 -6g/mL; n=11） respectively. Conclusion The method is simple, rapid, and sensitive, and it has been successfully applied to the the determination of tetracycline and oxytetracycline tablets, the mean recoveries being 99.7% and 98.8% respectively.