Development of detection methods of residual oxolinic acid and tetracyclines in aquaculture products

Abstract

High performance liquid chromatographic (HPLC) methods were developed for the determination of residual oxolinic acid (OXA) and tetracyclines such as oxytetracycline (OTC), tetracycline (TC) and chlortetracycline (CTC) in aquaculture products. The methods were linear between 0.2 and 2.0 ppm of oxolinic acid, and 0.5 and 10.0 ppm of the three individual tetracyclines, with regression coefficient of 0.999 for all the calibration plots. Recovery studies of the oxolinic acid and tetracyclines were performed at 0.4 μg/g and 1 μg/g spiked level, respectively. Average recoveries of oxolinic acid were 88.60% and an average of 78.62%, 79.89% and 68.26% for OTC, TC and CTC, respectively, with coefficients of variation less than 7.04%. The limit of detection and quantification of oxolinic acid were 0.02 μg/g and 0.06 μg/g, respectively. System suitability tests were performed for both methods to verify that the resolution and reproducibility of the system was adequate for the analysis. All criteria for both methods, such as resolution, plate count (efficiency) and tailing factor and precision were met. The methods proved to be accurate and selective for the antibiotic residues tested.