Veterinary drugs are used for therapeutic and growth promotion purposes for animals or fishes. To provide assurance that food from animals is safe in regard to veterinary medicine residues, regulatory authorities have established Maximum Residue Limits (MRL) for certain drugs in target tissues and animal species. Veterinary drugs analysis commonly uses liquid chromatography coupled to mass spectrometer which is fast, highly sensitive and highly selective. This work describes the application of high-throughput LC-MS/MS system utilizing fast polarity switching. Faster, easier and high precision total workflow was investigated with QuEChERS method combined with solid-phase extraction cartridge to enhance purification efficiency.