Residue analysis of ciprofloxacin in milk of dairy animals by LC-FD method

Abstract

Increasing use of antimicrobials to combat bacterial diseases among dairy animals has imposed the threat of antimicrobial drug residues in the milk of dairy animals. Monitoring of drug residues in foods of livestock animals is essential to establish benchmarks for the quality of livestock food, including milk. The MRL (maximum residue limit) of ciprofloxacin in bovine milk is 0.1 ppm, as recommended by European Commission regulations. The present study was conducted to establish the residual concentration of ciprofloxacin, an antimicrobial drug of the fluoroquinolone group, in milk samples collected from different areas of North Gujarat. Milk samples were collected from 49 dairy animals from unorganized dairy farms and farmers' doorsteps located in two districts of North Gujarat, namely, Banaskantha and Aravalli. The concentration of ciprofloxacin in milk was analysed using validated high-performance liquid chromatography (HPLC) with a fluorescent detector (LC-FD). The mobile phase contained a mixture of acetonitrile and buffer (50:50) and was maintained at a flow rate of 2.0 mL/min. The excitation and emission wavelengths were 295 and 500 nm, respectively. The limit of quantification (LOQ) and limit of detection (LOD) were 0.01 μg/mL and 0.003 μg/mL, respectively. Out of 49 milk samples, none was found to contain detectable concentrations of ciprofloxacin.