Photocatalytic Degradation of Trifluralin, Clodinafop-Propargyl, and 1,2-Dichloro-4-Nitrobenzene As Determined by Gas Chromatography Coupled with Mass Spectrometry

Abstract

Phototransformation is considered one of the most key factors affecting the fate of pesticides. Therefore, our study focused on photocatalytic degradation of three selected pesticide derivatives: trifluralin (1), clodinafop-propargyl (2), and 1,2-dichloro-4-nitrobenzene (3). The degradation was carried out in acetonitrile/water medium in the presence of titanium dioxide (TiO2) under continuous purging of atmospheric air. The course of degradation was followed by thin-layer chromatography and gas chromatography-mass spectrometry techniques. Electron ionization mass spectrometry was used to identify the degradation species. GC-MS analysis indicates the formation of several intermediate products which have been characterized on the basis of molecular ion, mass fragmentation pattern, and comparison with NIST library. The photocatalytic degradation of pesticides of different chemical structures manifested distinctly different degradation mechanism. The major routes for the degradation of pesticides were found to be (a) dealkylation, dehalogenation, and decarboxylation, (b) hydroxylation, (c) oxidation of side chain, if present, (d) isomerization and cyclization, (e) cleavage of alkoxy bond, and (f) reduction of triple bond to double bond and nitro group to amino.

Simultaneous determination of pinoxaden, cloquintocet‐mexyl, clodinafop‐propargyl ester and its major metabolite in barley products and soil using QuEChERS modified with multi‐walled carbon nanotubes coupled with LC–MS/MS

“…So far, several methods have been explored for the determination of PXD, CPE, and CLM using GC (Guo & Liu, 2014; Singh et al, 2012), GC–MS (Mir et al, 2014), HPLC (Duan et al, 2013; Sugata & Shashi Bala, 2019; Vishwakarma et al, 2017), and LC–MS/MS (Jing et al, 2019; Shen et al, 2012). Our groups previously developed a method to simultaneously determine PDX, CLM, and CPE in barley using LC–MS/MS (Han et al, 2020).…”

“…Therefore, it is crucial to develop multi-residue methods to simultaneously monitor the levels of these analytes in barley and soil samples that would facilitate their risk assessment and appropriate application. So far, several methods have been explored for the determination of PXD, CPE, and CLM using GC (Guo & Liu, 2014;Singh et al, 2012), GC-MS (Mir et al, 2014), HPLC (Duan et al, 2013;Sugata & Shashi Bala, 2019;Vishwakarma et al, 2017), and LC-MS/MS (Jing et al, 2019;Shen et al, 2012). Our groups previously developed a method to simultaneously determine PDX, CLM, and CPE in barley using LC-MS/MS (Han et al, 2020).…”