Use of liquid chromatography/electrospray ionization tandem mass spectrometry to study the degradation pathways of terbuthylazine (TER) by Typha latifolia in constructed wetlands: identification of a new TER metabolite

• Published in: Rapid communications in mass spectrometry 2012-01, Vol.26 (2), p.181-188
• Main Authors: Gikas, Evagelos, Papadopoulos, Nikolaos G., Bazoti, Fotini N., Zalidis, Georgios, Tsarbopoulos, Anthony
• Format: Article
• Language: English
• Subjects: Chromatography, High Pressure Liquid - methods; Environmental Pollutants - chemistry; Environmental Pollutants - metabolism; Herbicides - chemistry; Herbicides - metabolism; Metabolic Networks and Pathways; Spectrometry, Mass, Electrospray Ionization - methods; Tandem Mass Spectrometry - methods; Triazines - chemistry; Triazines - metabolism; Typhaceae - metabolism; Wetlands
• ISSN: 0951-4198; 1097-0231
• DOI: 10.1002/rcm.5310

S‐Triazines are used worldwide as herbicides for agricultural and non‐agricultural purposes. Although terbuthylazine (TER) is the second most frequently used S‐triazine, there is limited information on its metabolism. For this reason, an analytical method based on liquid chromatography/electrospray ionization tandem mass spectrometry (LC‐ESI MS/MS) has been developed aiming at the identification of TER and its five major metabolites (desisopropyl‐hydroxy‐atrazine, desethyl‐hydroxy‐terbuthylazine, desisopropyl‐atrazine, hydroxy‐terbuthylazine and desethyl‐terbuthylazine) in constructed wetland water samples. The separation of TER and its major metabolites was performed by reversed‐phase high‐performance liquid chromatography (HPLC) on a C8 column using a gradient elution of aqueous acetic acid 1% (solvent A) and acetonitrile (solvent B), followed by MS/MS analysis on a triple quadrupole mass spectrometer. The data‐depended analysis (DDA) scan approach has been employed and the main degradation pathways of both hydroxyl and chloro (dealkylated and alkylated) metabolites are elucidated through the tandem mass spectral (MS/MS) interpretation of triazine fragments under CID conditions. In addition, another major metabolite of TER, namely N2‐tert‐butyl‐N4‐ethyl‐6‐methoxy‐1,3,5‐triazine‐2,4‐diamine, has been identified. This methodology can be further employed in biodegradation studies of TER, thus assisting the assessment of its environmental impact. Copyright © 2011 John Wiley & Sons, Ltd.