THE VALIDATION OF THE METHOD FOR QUINOLONES RESIDUES DETERMINATION IN SAMPLES OF MILK, EGG POWDER, TISSUES, BLOOD PLASMA OF ANIMALS USING THE METHOD OF ENZYME-LINKED IMMUNOSORBENT ASSAY

The article presents the results of validation of screening method for the determination of quinolone antibiotics residues (enrofloxacin, ciprofloxacin, marbofloxacin, danofloxacin) in tissue samples, egg powder, milk and blood plasma using RIDASCREEN®Chinolone/Quinolones test kits from R-Biopharm (Germany). According to the information provided by the manufacturer of the kit, the quantitative determination of quinolones content of can be carried out in the following matrices: shrimp, fish, eggs, meat. In accordance with European Commission Decision 2002/657/EC, the methods proposed by the manufacturer were validated taking into account the maximum permissible levels (MRLs), and the results of the development of sample preparation techniques for the assay of liver, milk and blood plasma for various representatives of antibiotics of quinolone group and the corresponding validation results were presented. 
The suitability of the technique was confirmed on the basis of establishing of main validation parameters for screening methods (technical threshold and cut-off factor) using control (blank) samples (muscle and parenchymal tissues of poultry and animals, cow’s milk, blood plasma of broiler chickens and egg powder) and spiked with quinolones standard solutions at the level of ½ MRL according to the "added-found" criterion. The main advantages of the developed method are the simplicity of performance, rapidity and economic efficiency. 
The reliability of the results obtained by the developed method was verified using confirmatory UPLC-MS/MS method. The results of comparative study of control (blank) samples of chicken muscle tissues, egg powder and cow’s milk and spiked with enrofloxacin standard solution at the level of 2.5 and 5.0 μg/kg are presented. 
The proposed methods for liver, milk and blood plasma sample preparation can be used to study withdrawal periods and bioequivalence of veterinary drugs based on quinolone antibiotics.