Determination of Marbofloxacin Residues In Beef and Pork with an Enzyme-Linked Immunosorbent Assay

摘要

Marbofloxacln Is a fluoroquinolone veterinary antibiotic. An Indirect competitive enzyme-linked. Immunosorbent assay (ELISA) was developed for the detection of marbofloxacln using polyclonal antibody. The half-maximum Inhibition concentrations (IC_(60)) and limit of detection (LOD, calculated as IC_(20)) of the ELISA for marbofloxacln In phosphate buffer were 4.6 and 0.6 ng/mL, respectively. The assay showed little cross-reactlvlty with marbofloxacln structural analogues, except for ofloxacin (148%). Matrixes from the extracts of beef and pork muscle have shown a significant Influence on the ELISA. Standard curves of ELISA for marbofloxacln In the extracts of the appropriate marbofloxacln-free control muscles were used In the analysis of marbofloxacln In the animal muscles without any cleanup. The average recoveries of Intra- and Interassay for marbofloxacln from fortified muscle samples, at five concentrations of 10, 50, 100, 500, and 1000 ng/g, were 87-93 and 84-95%, respectively. The LOD. of this assay for marbofloxacln In real muscle extracts was 0.8 ng/mL, A survey of 55 animal muscle samples purchased from local markets by the ELISA was conducted, and marbofloxacln was detected In one of them at a concentration of 22 ng/g. This positive sample was validated by liquid chromatographγ-electrospray lonlzatlon-tandem mass spectrometry (LC-ESI-MS/MS) to be 28 ng/g of marbofloxacln.