Method for Determination of Enrofloxacin and Ciprofloxacin in Pig Excreta by HPLC

A HPLC-FLD method was developed for determination of enrofloxacin (ENR) and ciprofloxacin (CIP) levels in feces and urine of pig.The pig feces was ultrasonic extracted by acetonitrile-ammonia, then added trichloroacetic acid to make the extraction acidification.The pig urine was acidulated by phosphoric acid and the extraction of feces solution were enriched and purified by solid phase extraction small column, took purification liquid for HPLC analysis.Conditions of HPLC mobile phase was acetonitrile (A):citric acid/ammonium acetate buffer (B), the procedure of gradient elution was 0 to 25 min, A:10% to 40%;25 to 30 min, A:40% to 10%.The detector of fluorescence excitation wavelength was 278 nm, emission wavelength was 465 nm, chromatographic data were measured and recorded.The results showed that the LOD of ENR and CIP were lower than 0.01 mg/L in urine and 0.021 mg/kg in feces, the LOQ of ENR and CIP were lower than 0.03 mg/L in urine and 0.056 mg/kg in feces.ENR and CIP in the concentration of 0.01 to 1.0 mg/mL levels range had good linear relationship, R² were 0.9994 and 0.9992 in pig urine, respectively;ENR and CIP in the concentration of 0.02 to 2.0 mg/mL levels range had good linear relationship, R² were 0.9986 and 0.9981 in pig feces, respectively.The recovery ratio of ENR were 79.4% and 88.5%, and the recovery ratio of CIP were 75.8% and 89.9% in pig feces and urine.After get on validation, the method was easy in sample processing and testing, the results were accurate, reliable and high sensitivity, which was a worth promoting detection method.