Determination of robenidine in animal feeds by liquid chromatography coupled with diode-array detection and mass spectrometry after accelerated solvent extraction

A rapid and effective analytical procedure for the determination of robenidine in animal feeds was developed. Robenidine was extracted from samples with acidified methanol using accelerated solvent extraction (ASE). Extracts were dried and subjected to clean-up with aluminium oxide. Robenidine was eluted with methanol and determined by HPLC using UV diode-array (DAD) and MS detectors. Separation was carried out on a Purosphere ODS column in isocratic mode, with methanol-water mixture (70 + 30%) acidified with 0.1% trifluoroacetic acid as an eluent. DAD UV detection was done at 317 nm. MS analysis was performed with electrospray ionisation (ES) in positive mode. The procedure has been successfully applied for a variety of animal food products. The recovery of robenidine ranged from 85 to 95%, with R.S.D. of 2%. Limit of quantitation was estimated at 0.1 and 0.02 mg kg−1 for DAD UV and MS detection, respectively.