TY - JOUR

T1 - A new view on the mechanism of UV photodegradation of the tricyclic antidepressant carbamazepine in aqueous solutions

AU - Novikov, Mikhail V

AU - Snytnikova, Olga A

AU - Fedunov, Roman G

AU - Yanshole, Vadim V

AU - Grivin, Vyacheslav P

AU - Plyusnin, Victor F

AU - Xu, Jing

AU - Pozdnyakov, Ivan P

N1 - Funding: Russian Science Foundation (Grant RSF-NSFC N 21-43-00004) and the National Natural Science Foundation of China (Grant NSFC-RSF 22061132001). Copyright © 2023. Published by Elsevier Ltd.

PY - 2023/7

Y1 - 2023/7

N2 - Mechanism of direct UV photolysis of the tricyclic antidepressant carbamazepine (CBZ) at neutral pH was revealed by a combination of nanosecond laser flash photolysis, steady-state photolysis combined with high resolution LC-MS and DFT quantum-chemical calculations. The detection of short-lived intermediates and the detailed identification of final products were performed for the first time. The quantum yield of CBZ photodegradation (282 nm) is about 0.1% and 0.18% in air-equilibrated and argon-saturated solutions. The primary stage is photoionization with the formation of CBZ cation radical followed by a rapid nucleophilic attack by a solvent molecule. The primary photoproducts are 10-oxo-9-hydro-carbamazepine, 9-formylacridine-10(9H)-carboxamide (a result of ring contraction) and various isomers of hydroxylated CBZ. Prolonged irradiation results to accumulation of acridine derivatives, which should lead to an increase of the toxicity of photolyzed CBZ solutions. The obtained results may be important for understanding the fate of tricyclic antidepressants in processes of UVC disinfection and in natural waters under action of sunlight.

AB - Mechanism of direct UV photolysis of the tricyclic antidepressant carbamazepine (CBZ) at neutral pH was revealed by a combination of nanosecond laser flash photolysis, steady-state photolysis combined with high resolution LC-MS and DFT quantum-chemical calculations. The detection of short-lived intermediates and the detailed identification of final products were performed for the first time. The quantum yield of CBZ photodegradation (282 nm) is about 0.1% and 0.18% in air-equilibrated and argon-saturated solutions. The primary stage is photoionization with the formation of CBZ cation radical followed by a rapid nucleophilic attack by a solvent molecule. The primary photoproducts are 10-oxo-9-hydro-carbamazepine, 9-formylacridine-10(9H)-carboxamide (a result of ring contraction) and various isomers of hydroxylated CBZ. Prolonged irradiation results to accumulation of acridine derivatives, which should lead to an increase of the toxicity of photolyzed CBZ solutions. The obtained results may be important for understanding the fate of tricyclic antidepressants in processes of UVC disinfection and in natural waters under action of sunlight.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85152707450&origin=inward&txGid=c977eb18f3ca6e68550db2ab7be175a2

U2 - 10.1016/j.chemosphere.2023.138652

DO - 10.1016/j.chemosphere.2023.138652

M3 - Article

C2 - 37040836

VL - 329

JO - Chemosphere

JF - Chemosphere

SN - 0045-6535

M1 - 138652

ER -