Degradation studies of quizalofop-p and related compounds in soils using liquid chromatography coupled to low and high resolution mass analyzers.

摘要: A comprehensive degradation study of quizalofop-p, quizalofop-p-ethyl, quizalofop-p-tefuryl and propaquizafop in soil samples have been firstly performed using ultra high performance liquid chromatography coupled to Orbitrap mass spectrometry (UHPLC-Orbitrap-MS). Thus, metabolites or products, such as CHHQ (dihydroxychloroquinoxalin), CHQ (6-chloroquinoxalin-2-ol), PPA ((R)-2-(4-hydroxyphenoxy)propionic acid) 2,3-dihydroxyquinoxaline were also monitored. An extraction procedure based on QuEChERS was used. Acidified water (0.1M hydrochloric acidified acetonitrile (1% acetic acid, (v/v)) used solvents, magnesium sulfate sodium chloride salts. Dispersive solid phase with C18 sorbent, needed a clean-up step. Several commercial products (Panarex®, Master-D® Dixon®) evaluate the target compounds into their metabolites. The concentration main active substances (quizalofop-p-tefuryl, quizalofop-p-ethyl propaquizafop) decreased during studies, whereas quizalofop-p increased. Dissipation rates half-live evaluated, it observed that this compound is easily degraded, obtaining values lower than 1day. Taking account R enantiomer quizalofop, chiral separation by tandem spectrometry, concluding containing quizalofop-p-tefuryl, there 15% contribution from S 85% enantiomer. Metabolites PPA, detected after 15days application product at concentrations between limits detection (LOD) quantification (LOQ). higher LOQ 50 80days application, increasing time up 500%.