Determination of Quinolone Antibiotics in Bovine Liver Using Agilent SampliQ QuEChERS Kits by LC–MS–MS
The procedure involves a rapid and efficient pretreatment by SampliQ QuEChERS kits. The homogenized liver sample was initially extracted in a buffered aqueous, 5% formic acid acetonitrile system. An extraction and partitioning step was performed after the addition of salts. Clean-up was done using dispersive solid-phase extraction (dispersive-SPE). The final extracts allowed determination of all compounds in a single run using LC–ESI-MS–MS operating in positive ion multiple reaction monitoring (MRM) mode. Norfloxacin was selected as the internal standard. The accuracy of the method, expressed as recovery, was between 62 and 113%. The precision, expressed as RSD, was between 2.2 and 13.4%. The established limit of quantification (LOQ) was 5 ng/g and is significantly lower than the respective maximum residue limit (MRL) for quinolones in food producing animals.