Structure elucidation of phase II metabolites by tandem mass spectrometry: an overview

On-line electrochemistry/liquid chromatography/mass spectrometry for the simulation of pesticide metabolism

“…This quinoid species was not found in in vivo experiments; however, this does not necessarily mean that it is not formed under cytochrome P450 catalysis. In vivo, quinoid species are often trapped and detoxified by addition of GSH [23], and the fact that hydroxylated GSH adducts were found in vivo might suppose that these can also be formed via a quinoneimine and not necessarily after epoxide formation as reported before [22].…”

“…A species with m/z 614 should be formed if GSH directly substitutes the chlorine atom of ring A, as was described before ( [22], Scheme 1). This was not observed in the EC/LC/MS set-up, presumably because the reaction time of oxidized boscalid and GSH is extremely short in the EC experiments compared to in vivo studies.…”

“…It has a broad spectrum of action against most fungal diseases affecting these crops, and in combination with other fungicides in a wide variety of other crops as well. The metabolic pathway of boscalid includes the formation of different hydroxylated species and glutathione (GSH) adducts [22]. GSH adduct formation is described to proceed either by nucleophilic substitution of the chlorine atom at ring A (Scheme 1a) or after arene oxide formation as phase I metabolism step and subsequent nucleophilic attack of GSH to the arene oxide resulting in different isomeric species (Scheme 1b).…”

Targeted and non-targeted liquid chromatography-mass spectrometric workflows for identification of transformation products of emerging pollutants in the aquatic environment

“…Moreover, for identification of TPs in environmental, food and biological samples, hybrid HR mass analyzers [e.g., linear ion trap Orbitrap MS and quadrupole time-of-flight MS (Q-TOF)] have been used, following specific workflows [12][13][14][15][16]. More specifically, human and microbial metabolites, oxidation and photodegradation TPs of pharmaceuticals have been discussed often [17][18][19][20][21]. Similarly, TPs of pesticides in biological (human metabolism, phase II), food and environmental samples have been reviewed [22,23].…”

Quasi-targeted analysis of hydroxylation-related metabolites of polycyclic aromatic hydrocarbons in human urine by liquid chromatography–mass spectrometry

“…In addition, mass-to-charge (m/z) values of precursor ions of potential metabolites, usually quasi-molecular ions can be obtained in PIS mode. Furthermore, NLS is also a useful approach for confirming metabo- lites, particularly for phase II metabolites such as conjugates of glucuronide, sulfate and glutathione [16]. By means of these scan modes and referring to predicted in vivo metabolic logics of xenobiotics, potential metabolites can be preliminarily screened out.…”