Monitoring of oxolinic acid residues in tilapia flesh ( Oreochromis niloticus ) using a microbiological screening technique and an LC-UV confirmatory method

A relevant analytical strategy was developed by combining a microbiological screening and an LC-UV chromatographic method for the identification and the quantification of oxolinic acid (OXO) in tilapia ( Oreochromis niloticus ) flesh. The sensitivity, accuracy and specificity of the test were 100% for OXO. The detection capacity (CCß) of the screening test was 0.75 times the maximum residue limits for OXO (100 µg kg −1 ). The performance parameters of the LC-UV method were satisfactory in terms of linearity within the range of 2.5 to 1000 µg kg −1 (R 2 = 0.99), precision (< 23%), accuracy (− 20% to + 10%), selectivity and specificity. The limit of quantification (LOQ) and detection (LOD) was 5 and 2.5 µg kg −1 respectively. The withdrawal of OXO in tilapia is estimated for 8 days after treatment of six successive days with a dose of 12 mg kg −1 body weight per day. The strategy used in this study is simple, inexpensive and practical for the control of oxolinic acid residues in fishery products and foodstuffs.