Method for the determination and evaluation of oxytetracycline depletion in marine shrimp

Abstract

This work aimed at validating a method for the determination of oxytetracycline (OTC) residues in shrimp by means of high performance liquid chromatography (HPLC), and at evaluating the OTC residue depletion in shrimps in vivo using the validated method. The shrimp used for validation were either not submitted or submitted to in vitro OTC addition. Selectivity, retention time, linearity (correlation coefficient), work range, relative recovery, detection and method quantification limits and repeatability were determined. For the in vivo experiment, shrimp were fed with feed medicated with OTC at 200, 400 and 500 mg g-1 for 14 days. Oxytetracycline residue concentration in the animals' muscle and carapace was assessed for up to 22 days after stopping medication. The results obtained were: 0.9997 linear correlation coefficient for the fortified matrix extract within a work range of 0.02–0.4 mg g-1, 106±17.1% recovery and 0.006 and 0.019 mg g-1 detection and quantification limits, respectively. A greater OTC residence time was observed in the carapace (10 to 13 days) when compared to the muscle (5 days).