Tricyclazole is a fungicide which has been used for various crops including proso millet to control of Pyricularia grisea, Cochliobolus miyabeanus and Acidovorax avenae subsp. avenae. LC-MS/MS (Shimadzu LC-MS 8040) on electrospray mode was used for the analysis of tricyclazole. In multiple reaction monitoring, m/z=136 and m/z=163.15 were engaged as the quantification ion and qualification ion, respectively. Method limit of quantitation (MLOQ) was 0.01 mg/kg. The compound was separated on Raptor ARC-18 column (100 x 2.1 mm, 2.7 um) with mobile phases of A (water containing 5mM ammonium formate and 0.1% formic acid) and B (methanol containing 5 mM ammonium formate and 0.1% formic acid) with optimized gradient elution. The linearity of matrix-matched calibration curve (r2) was ≥0.99 at the calibration range of 0.0025-0.25 mg/kg. For the recovery test, 10 g of macerated grain or straw of proso millet was treated with standard solutions at 10MLOQ and 50MLOQ levels. The sample was soaked with 10 mL of distilled water for 30 min and extracted with 10 mL of acetonitrile by shaking (30 min). Then 4 g of MgSO4 and 1 g of NaCl were added, shaken for 1 min and centrifuged at 3,500 rpm for 5 min. The supernatant (1 mL) was transferred to dispersive SPE tube containing 7.5 mg of GCB, 25 mg of PSA and 150 mg of MgSO4. The tube was shaken for 1 min and centrifuged at 13,000 rpm for 5 min before analysis (5 uL). Recovery rates were in the range of 70-120% (RSD≤20%) at two spiked levels (10MLOQ and 50MLOQ) for grain and straw. In field study, tricyclazole 20% suspension concentrate formulation was treated on each 4 plots (50/40/30 days, 40/30/21 days, 30/21/14 days and 21/14/7 days before harvest) with three replicates. After harvest, grain and straw were analyzed to show that the residue levels of trycyclazole decreased according to treatment time. Maximum levels of residue were 5.68 mg/kg and 1.13 mg/kg for grain and straw in treatment plot of 21/14/7 days before harvest.

Analytical method development and analysis of tricyclazole residue Proso Millet using LC-MS/MS

2019 Spring National Meeting

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