HPLC-MS/MS Determination of Fenpyroximate, Rotenone, Triadimefon, Diflubenzuron and Carboxin in Tea

A method of HPLC-MS/MS for the determination of 5 pesticides, i.e., fenpyroximate, rotenone, triadimefon, diflubenzuron and carboxin in tea was proposed. The sample was extracted with acetonitrile and solid MgSO4 and NaCl. Shiseido C18 MGII column was used as stationary phase, and mixtures of acetonitrile and 0.005 mol·L-1 ammonium acetate solution in different ratios were used as mobile phase in gradient elution. ESI+ and multi-reaction monitoring were adopted in MS/MS. Linear relationships between values of peak area and mass concentration of the 5 pesticides were kept in the same range of 1.00-20.0 μg·L-1, with detection limits (3S/N) of 0.005 mg·kg-1. Tests for recovery were made at the concentration levels of 0.005, 0.010 and 0.020 mg·kg-1, giving values of recovery and RSD′s (n=10) in the ranges of 88.2%-104% and 4.8%-13% respectively.