Determining Tolfenpyrad in Water Samples Using Liquid-Liquid Extraction with Low Temperature Purification (LLE-LTP)

Tolfenpyrad is an insecticide and acaricide of the pyrazole class, which has been used to control pests in cereal, legume and vegetable crops. Despite its high efficiency, this insecticide is considered highly toxic to humans by Brazilian legislation. Therefore, this study aims to optimize and validate liquid-liquid extraction with low temperature purification followed by analysis by high-performance liquid chromatography with diode array detection to determine tolfenpyrad in water. The results showed that the optimal extraction conditions were achieved using only acetonitrile as extracting phase and 60 min as freezing time. Under these conditions, the extraction method was selective, accurate, and precise, with a recovery of 102.41% and a relative standard deviation of 11.29%. The method was linear from 2.0 to 150.0 μg L^-1, with a limit of quantification of 2.0 μg L^-1, and the matrix effect was –7.67%. The half-life was 23 days (with sunlight) and 30 days (no sunlight).

Keywords:
insecticidal pyrazoles; heterocyclic pyrazole insecticide; extraction method; LLE-LTP