Isomerization of fenbuconazole under UV-visible irradiation - chemical and toxicological approaches.
Rapid Commun Mass Spectrom
; 29(14): 1335-42, 2015 Jul 30.
Article
em En
| MEDLINE
| ID: mdl-26405795
ABSTRACT
RATIONALE Fenbuconazole is a fungicide commonly used for the protection of vineyards, vegetables and grain crops. Under UV-visible irradiation, it undergoes isomerization through various cyclization processes. Isomeric structures were elucidated by liquid chromatography/high-resolution multiple-stage mass spectrometry (LC/HR-MS(n) ) coupling. The potential toxicities of these isomers were estimated by in silico tests. METHODS:
Aqueous solutions of fenbuconazole and grapes treated with this fungicide were irradiated in a self-made reactor equipped with a mercury vapor lamp. Analyses were carried out using high-performance liquid chromatography (HPLC) coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICRMS). High-resolution m/z measurements, multiple-stage mass spectrometry and isotopic labeling experiments allowed structural elucidation of the isomers of fenbuconazole. In silico toxicity estimations were carried out using the T.E.S.T.RESULTS:
Seven isomers of fenbuconazole were detected after irradiation of the fungicide in aqueous solution; the major ones were also detected in the flesh of treated grapes irradiated under laboratory conditions. Elucidation of their chemical structures owing to high resolution measurements and multi-stage collision induced dissociation experiments allowed confirmation of photo-transformation pathways mainly dominated by cyclization processes. Photo-induced isomers exhibited higher potential toxicities than fenbuconazole for Daphnia magna and fathead minnow species.CONCLUSIONS:
UV-visible irradiation of fenbuconazole in aqueous solution and on grapes leads to the formation of isomers, all of which being potentially much more toxic than the parent fungicide.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Triazóis
/
Fungicidas Industriais
/
Nitrilas
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article