Residue Determination Method and Photolysis Process of Picoxystrobin in Three Soils by QuEchers and HPLC/MS.

The dissipation and residue of picoxystrobin in three different soils (Xerosols, Yermosols and Chernozem) was investigated. An easy-to-implement and sensitive method was established to determine picoxystrobin in the three different soils via modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) combined with HPLC (high-performance liquid chromatography). The photodegradation process of picoxystrobin in three different soils was detected by HPLC-mass spectrometry. The linearity of picoxystrobin detection was studied in the range of 0.3–10 mg/L (0.3, 0.5, 1, 2 and 10 mg/L), good linearity was obtained and the correlation coefficients (R2) was 0.9999. The recoveries of picoxystrobin ranged from 78.4% to 106.4% and relative standard deviation of 0.67%-4.46% in three kinds of soil spiked at 0.5, 1, and 2 mg/kg. The results of the recovery study indicated that the method meets the precision and accuracy requirements for picoxystrobin in the three different soils. The photodegradation experiments revealed that the compound had a degradation half-life ranging from 3.80–4.29 days. The rule of photodegradation of picoxystrobin on the surface of three soils was consistent with first-order reaction kinetic model. Finally, two possible routes of picoxystrobin fragmentation were indicated by mass spectrometry. This work will provide a theoretical reference for the analysis of picoxystrobin residues in soil and practical applications. [ABSTRACT FROM AUTHOR]