Determination of trifloxystrobin and its metabolites in Hawaii soils by ASE-LC-MS/MS

Analytical methods for the determination of trifloxystrobin and four of its metabolites were developed in a leaching study conducted in Hawaii. To duplicate plots at each of five locations representing various agricultural areas in Hawaii, trifloxystrobin was applied at label rates and allowed to leach under normal rain and irrigation conditions. Soil samples were collected at weekly to monthly intervals and the residual concentrations of trifloxystrobin and metabolites measured. A quantitative analytical method for their determination in various soil samples was developed using accelerated solvent extraction (ASE), coupled with liquid chromatography-tandem mass spectrometry. Extraction solvent with various ratios of methanol to water, addition of EDTANa2 to the extract solvent, and ASE cell temperature were adjusted to improve recovery. Deuterated (E, E)-trifloxystrobin was chosen as the internal standard of the analytical method. The limit of quantitation was 2.5 ppb in the soil for trifloxystrobin and its metabolites. Laboratory aerobic degradation studies with the soils from the five sites were also conducted to measure the same compounds.