The method has a LOD of 0.03–1.00 ng/mL, a recovery of 90.4–103%
for made tea and 90.3–102% for tea-infused liquid, respectively. By using the proposed method, the leaching
characteristics of above 7 pesticides during infusing process were investigated. The experimental
results revealed that: (1) diflubenzuron can be most easily extracted out during infusing process, followed
by triflumuron, teflubenzuron, hexaflumuron, chlorfluazuron, flufenoxuron and fluazuron. (2)
The leaching of flufenoxuron and chlorfluazuron during infusing process seems to be controlled by only
their solubility, whereas, the leaching of other 5 benzoylurea insecticides was primarily controlled by
their partitioning coefficient between made tea and hot water. The results of this study are helpful for
the accurate evaluation of the safety of Oolong tea.