SALLE-HPLC-FLD variant protocols for the analysis of enrofloxacin/ciprofloxacin in chicken

To minimize the risk of developing antibiotic resistance, the EU has established an MRL (Maximum Residue Limit) for poultry treated with enrofloxacin. Residual fluoroquinolones (i.e., enrofloxacin and ciprofloxacin) can be determined using high pressure liquid chromatography coupled to a fluorescence detector (HPLC-FLD). However, a quick and efficient sample clean-up procedure has to be performed first. Sample clean-up can be done by solid phase extraction (SPE) or salt assisted liquid liquid extraction (SALLE), with the latter being the newer but cheaper option. The SALLE-HPLC-FLD protocol presented in this study is much simpler and quicker than the other methods but has lower extraction efficiency (EF). Three protocol variants were tested using internal standards, matrix matching, and standard addition techniques to correct this. The three SALLE-HPLC-FLD variants tested in this study achieved sufficient accuracy and precision. Except for a few trials when doing standard addition, all trials for all variants resulted in accuracies and precision within the Codex Alimentarius' specifications. In the future, the techniques applied in this study will be used for other analytes in different matrixes if the EF in doing SALLE is low, thus eliminating the need for optimization and additional sample preparation steps.