Validação de metodologias para determinação de antimicrobianos em pescado por cromatografia líquida de alta eficiência

Abstract

Antimicrobials are widely used in veterinary medicine and these residues may remain in food of animal origin, above values considered safe, creating risks to human health and the environment. This work was validate methodologies for determination of sulfonamides in shrimp and florfenicol in shrimp and tilapia using High Performance Liquid Chromatography as analytical technique. The determination of sulphonamides in shrimp was accomplished using a C18 column and mobile phase composed of ACN:water (25:75) in gradient method. The sample was extracted using acetonitrile and filtrade on anhydrous sodium sulphate. After evaporation, was a clean up in ion exchange cartridges (500 mg/6mL) followed by evaporation of the solvent to dryness and subsequent ressuspension in acetic acid 0.5% for filtration and analysis by HPLC. The determination of florfenicol in shrimp and tilapia was also used a C18 column and isocratic method. The extraction was performed with ethyl acetate, followed by centrifugation and extraction of fat phase with hexane. After a second centrifugation, the upper phase was discarded and the aqueous phase filtered and taken for analysis by HPLC. The methodology for determination of sulfonamides was shown to be selective and linear for a range of work from 100 to 1000μg L-1. The LOD and LOQ (μg L-1) was 6.35 and 20.19 to sulfathiazole, 2.44 and 7.76 for sulfamethazine, 0.58 and 1.83 for sulfamethoxazole, 1.49 and 4.75 for sulfadimethoxine and 3.41 and 10.85 for sulfaquinoxaline. The methodology for determining florfenicol shown to be selective and linear for a range of work from 0.1 to 3.0 mg L-1 and the LOD and LOQ (mg L-1) to matrix shrimp were 2.97 and 15.01 mg kg-1 respectively. For tilapia matrix the lowest concentrations detected and quantified by method, were 3.64 and 18.54 mg kg-1 respectively. All results are in accordance with applicable law for the determination of antimicrobial by HPLC.