title: Multiple unknown degradants generated from the insect repellent DEET by photoinduced processes on TiO2.
abstract: This paper deals with the photocatalytic transformation of N,N-diethyl-m-toluamide (DEET), one of the most widespread and efficient mosquito repellents, under simulated solar irradiation using titanium dioxide as the photocatalytic source of oxidizing species. The investigation involved monitoring of the DEET decomposition, the identification of intermediate compounds and the assessment of mineralization. High-resolution mass spectrometry was employed to assess the evolution of the photocatalyzed process over time. Fifty-one main species were identified after DEET transformation. Several isomeric species were formed and were characterized by analyzing MS and MS(n) spectra in full, and by comparison with parent molecule fragmentation pathways. In the DEET molecule, the initial transformation involved mono- and polyhydroxylation followed by oxidation of the alcohol groups, cleavage of the alkyl chains or ring opening. All these intermediates are easily degraded and DEET is completely mineralized after 4 h of irradiation. Microtox bioassay (Vibrio fischeri) was employed to evaluate the ecotoxicity of solutions treated by photocatalysis.
authors.affiliation: Department of Analytical Chemistry, University of Turin, via P. Giuria 5, 10125 Torino, Italy. claudio.medana@unito.it
authors.forename: Claudio
authors.initials: C
authors.lastname: Medana
authors.forename: Paola
authors.initials: P
authors.lastname: Calza
authors.forename: Federica
authors.initials: F
authors.lastname: Dal Bello
authors.forename: Elena
authors.initials: E
authors.lastname: Raso
authors.forename: Claudio
authors.initials: C
authors.lastname: Minero
authors.forename: Claudio
authors.initials: C
authors.lastname: Baiocchi
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects; D003671:DEET / Q000737:chemistry* / Q000633:toxicity; D006900:Hydroxylation; D007700:Kinetics; D008163:Luminescent Measurements; D013058:Mass Spectrometry / Q000379:methods; D055668:Photochemical Processes; D014025:Titanium / Q000737:chemistry*; D018675:Toxicity Tests
chemical_list: D003671:DEET; C009495:titanium dioxide; D014025:Titanium