Determination of nitrofuran metabolites in honey using a new derivatization reagent, magnetic solid-phase extraction and LC-MS/MS.

In this study, 5-nitro-2-furaldehyde (5-NFA) was proposed as a new derivatizing agent for nitrofuran metabolites. It reacts with nitrofuran metabolites producing the parent nitrofurans (furazolidone, furaltadone, nitrofurantoin, and nitrofurazone). Magnetic hypercrosslinked polystyrene (HCP/FeO) was first used for magnetic solid phase extraction (MSPE) clean-up before the determination of nitrofuran metabolite derivatives in honey via LC-MS/MS. Main parameters affecting the derivatization and MSPE efficiency were investigated in detail and the optimal conditions were found. The method was validated using honey spiked with the four metabolites at 1, 2 and 200 μg kg. Recoveries of >85% were achieved for the all analytes. The matrix calibration curve was fitted with the correlation coefficient (R) > 0.99 in the range of 1-200 μg kg. Precision values expressed as relative standard deviation (RSD) were <12% and <15% for intra-day and inter-day precision, respectively. The limits of detection (LODs) for the nitrofuran metabolites were of 0.1-0.3 μg kg and the limits of quantitation (LOQs) were of 0.3-1.0 μg kg. The proposed LC-MS/MS method was applied to the analysis of real honey samples.