Determination of Metronidazolem, Dimetridazole and Ronidazole in Honey by On-line Solid-phase Extraction Coupled to Isotope Dilution-Ultra-high Performance Liquid Chromatography-Tandem Mass Spectrometry

In this study, we established a method for the determination of metronidazolem, dimetridazole and ronidazole in honey by ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The analytes were extracted from samples, purified using a cation exchange cartridge, separated on a C18 (3.0 mm × 100 mm, 1.7 μm) chromatographic column, detected in the multiple reaction monitoring (MRM) mode, and quantitated by an internal standard method. Metronidazolem, dimetridazole and ronidazole were separated well and their calibration curves were linear in the concentration range of 1.0–100.0 ng/mL. The relative standard deviation for replicate determinations was 1.6%–3.7% (n = 6), and the average recoveries for spiked samples ranged from 95.0% to 101.4%. This method has the advantages of low matrix interference, simple operation and high accuracy, an is suitable for the determination of the residues of metronidazolem, dimetridazole and ronidazole in honey.