Simultaneous detection of four nitrofuran metabolites in honey using a multiplexing biochip screening assay

A chemiluminescence-based biochip array sensing technique has been developed and applied to the screening of honey samples for residues of banned nitrofuran antibiotics. Using a multiplex approach, metabolites of the four main nitrofuran antibiotics could be simultaneously detected. Individual antibodies specific towards the metabolites were spotted onto biochips. A competitive assay format, with chemiluminescent response, was employed. The method was validated in accordance with EU legislation (2002/657/EC, 2002), and assessed by comparison with UHPLC-MS/MS testing of 134 honey samples of worldwide origin. A similar extraction method, based on extraction of the analytes on Oasis™ SPE cartridges, followed by derivatisation with nitrobenzaldehyde and partition into ethyl acetate, was used for both screening and LC-MS/MS methods. The biochip array method was capable of detecting all four metabolites below the reference point for action of 1 μg kg(-1). The detection capability was below 0.5 μg kg(-1) for the metabolites AHD, AOZ and AMOZ; it was below 0.9 μg kg(-1) for SEM. IC(50) values ranged from 0.14 μg kg(-1) (AMOZ) to 2.19 μg kg(-1) (SEM). This biosensor method possesses the potential to be a fit-for-purpose screening technique in the arena of food safety technology.