Behavior of quizalofop-p and its commercial products in water by liquid chromatography coupled to high resolution mass spectrometry.

A degradation study of quizalofop-p and its commercial products (quizalofop-p-ethyl, quizalofop-p-tefuryl and propaquizafop) in water samples has been performed using ultra high-performance liquid chromatography coupled to Orbitrap mass spectrometry (UHPLC-Orbitrap-MS). CHHQ (dihydroxychloroquinoxalin), CHQ (6-chloroquinoxalin-2-ol) and PPA ((R)-2-(4-hydroxyphenoxy)propionicacid) were the main metabolites of this active substance (quizalofop-p) in water. The degradation of the parent compound has been monitored in distilled water. Several commercial products (Panarex®, Master-D® and Dixon®) were used to evaluate the degradation of the target compounds into their metabolites. The concentration of the main active substances (quizalofop-p-tefuryl, quizalofop-p-ethyl and propaquizafop) decreased during the degradation studies, whereas the concentration of quizalofop-p increased. DT50 of the main active substances ranged from 10 days to 70 days for most of the analytes, so it can be concluded that compounds are medium-high persistent in this matrix. Metabolites, such as PPA, CHHQ and CHQ, were detected in water samples after 7 days of the application of the commercial products at concentrations higher than their limits of quantification (> 0.1 µg/L). CHQ was detected at 1400 µg/L after 75 days of the application of quizalofop-p-ethyl commercial product. CHHQ and CHQ were found at the highest concentrations at 7-45 days after the application of quizalofop-p-tefuryl, whereas PPA was detected at higher concentrations (up to 5.37 µg/L) in propaquizafop samples.