Development and validation of an ultra performance liquid chromatography Q-Exactive Orbitrap mass spectrometry for the determination of fipronil and its metabolites in tea and chrysanthemum

A fast, sensitive and reliable method for the determination of fipronil and its metabolites in tea and chrysanthemum was developed using a modified QuEChERS technique and an ultra performance liquid chromatography Q-Exactive Orbitrap mass spectrometry. The mixture of adsorbents containing primary secondary amine (PSA), octadecylsilane (C-18) and carbon nanotubes (CNTs), was used as QuEChERS adsorbents. The use of mass resolution at 70000 full width at half maximum (FWHM) and narrow mass windows at 5 ppm achieved high selectivity and repeatability. Satisfactory linearity with correlative coefficient (R-2) higher than 0.996 was achieved for all compounds. Recoveries at three levels (2, 10 and 50 mu g kg(-1)) ranged from 86% to 112%, while the intra- and inter-day accuracies were less than 15%. Limits of quantification for fipronil and its metabolites were 2 mu g kg(-1), which fulfils the requirement of maximum residue limits formulated by European Union and Japan.