Determination of amitraz and 2,4-dimethylaniline residues in honey by using LC with UV detection and MS/MS.

A method for the determination and confirmation of amitraz and its degradation product 2,4-dimethylaniline (2,4-DMA) in honey is reported. Determination of the two compounds was based on HPLC with UV detection and MS/MS (LC-MS/MS) after a liquid-liquid extraction with hexane and isopropyl alcohol. Chromatographic separation was achieved by using a C18 column with a gradient mobile phase consisting of 0.02 M ammonium acetate and ACN. Recoveries for fortified honey ranged from 83.4 to 103.4% for amitraz and from 89.2 to 104.7% for 2,4-DMA with RSD values lower than 11.6% for HPLC and LC-MS/MS methods. LOD was 6 microg/kg for amitraz and 8 microg/kg for 2,4-DMA, while LOQ was 20 microg/kg for amitraz and 25 microg/kg for 2,4-DMA in HPLC method. LOD was 1 microg/kg for amitraz and 2 microg/kg for 2,4-DMA, while LOQ was 5 microg/kg for amitraz and 10 microg/kg for 2,4-DMA in LC-MS/MS method.