Assessment of enrofloxacin and ciprofloxacin accumulation in pig and calf hair by HPLC and fluorimetric detection.

Enrofloxacin is a synthetic bacteriostatic administered in veterinary therapy. It can also be used illegally as a growth promoter to enhance feed efficiency and weight gain. This practice is banned in several countries due to its potential negative effects on the environment and human health. A suitable method for extracting and quantifying enrofloxacin (ENR) and its main metabolite ciprofloxacin (CPR) in cattle and pig hair by high-performance liquid chromatography-fluorimetric detection (HPLC-FLD) had been proposed. ENR and CPR were extracted from hair samples with methanol acidified with trifluoroacetic acid for 24 h at 70 degrees C. The extracts were evaporated and redissolved in the mobile phase before injection. This simplified procedure enabled the detection of both CPR and ENR at ng g-1 levels (limit of detection 4-5 ng g-1) without further purification. Detectable residues of ENR were found in calf and pig hairs after the pharmacological treatment was started. Mean concentrations of quinolone (ENR, CPR) in contaminated hairs ranged from 20 to 2,518 ng g-1 in calves and from 152 to 1,140 ng g-1 in pigs. Hair pigmentation enhanced quinolone accumulation significantly. Hair analysis seems to increase the time window available for the retrospective detection of illegal ENR administration compared to edible tissue analysis.