Multiresidue determination of fluoroquinolone antimicrobials in baby foods by liquid chromatography

According to the current EU legislation, the presence of antimicrobial residues in baby foods is forbidden. Nevertheless, there is a lack of analytical methods to determine veterinary antimicrobials in baby foods and support the zero tolerance policy for this type of foods. This paper describes a simple method based on molecularly imprinted solid phase extraction (MISPE) and liquid chromatography with fluorescence detection (LC-FLD) for the determination of residues of fluoroquinolones (FQs) in baby foods. The method involves sample extraction with a solution of o-phosphoric acid (50 mM, pH 3.0)/ACN (20:80, v/v) and further clean-up by loading the extracts onto MIP cartridges. Optimum MISPE conditions led to recoveries of the target FQs in the range of 92–106%, with RSDs <8%. Method validation has been performed according to Commission Decision 2002/657/EC, in terms of linearity, accuracy, precision, selectivity, decision limit (CCα) and detection capability (CCβ). The proposed method has been successfully applied to the analysis of baby foods of different compositions bought in local supermarkets and pharmacies. The results did not show the presence of residual amounts of FQs in the analysed samples above the method’s decision limits (CCα between 5 and 151 μg kg−1).