Photocatalytic degradation of the herbicide isoproturon: characterisation of by-products by liquid chromatography with electrospray ionisation tandem mass spectrometry.
By-products arising from immobilised TiO2-catalysed photodegradation of the herbicide isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea] in aqueous solution under solar radiation were analysed by reversed-phase liquid chromatography combined with electrospray ionisation ion trap mass spectrometry. Structural information on by-products, formed at different degradation times, was then obtained from interpretation of the relevant MS/MS spectra. Several species were identified through this approach, and in many cases several isomers were found. As expected, most by-products resulted from single or multiple hydroxylation (by photo-generated OH* radicals) of the isoproturon molecule at different positions. However, substitution of some functional groups of the herbicide (isopropyl or methyl) by OH* was also observed. A possible degradation scheme is hypothesised.
Amorisco
A
A
Università di Bari, Dipartimento di Chimica, Via E. Orabona 4, 70126 Bari, Italy.
Losito
I
I
Palmisano
F
F
Zambonin
P G
PG
D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D006540:Herbicides / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects*; D008027:Light; D015394:Molecular Structure; D010671:Phenylurea Compounds / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects*; D010777:Photochemistry; D021241:Spectrometry, Mass, Electrospray Ionization
D006540:Herbicides; D010671:Phenylurea Compounds; C028904:isoproturon