Hydrolysis and photolysis of bentazone in aqueous abiotic solutions and identification of its degradation products using quadrupole time-of-flight mass spectrometry
Hydrolysis and photolysis of bentazone in abiotic aqueous solutions were examined under laboratory conditions. Hydrolysis was studied in different buffer solutions (pH 4.0 ± 0.1, 7.0 ± 0.1, and 9.0 ± 0.1), at different temperatures (15 °C ± 2 °C, 25 °C ± 2 °C, 35 °C ± 2 °C, and 45 °C ± 2 °C), and at different Fe3+ concentrations (1, 5, and 10 mg/L). Photolysis was assessed in different buffer solutions and at different solvent (methanol and ethyl acetate) concentrations (10%, 20%, and 30%) or Fe3+ (1, 5, and 10 mg/L) concentrations and under mercury or xenon light irradiation. Hydrolysis half-lives ranged 46–99 days at three different conditions. Photolysis half-lives ranged 2.3–7.5 h in three different conditions under mercury and xenon irradiation. Hydrolysis and photolysis of bentazone were accelerated by both alkaline conditions and elevated temperatures, and solvents and Fe3+ strongly enhanced bentazone degradation. Photodecomposition was much faster under a mercury lamp than under a xenon lamp. N-methyl bentazone and 6-OH bentazone/8-OH bentazone were identified as degradation products using UPLC-Q-TOF-MS. The data generated from this study could be useful for risk assessment of pesticides in the environment.
KeywordsBentazone Hydrolysis Photolysis Degradation products UPLC-Q-TOF-MS
This work was financially supported by National Key R&D projects of comprehensive evaluation and optimization of environmental effects of chemical fertilizers and pesticides in tea garden [grant number 2016YFD0201208-4] and Guangxi Science and Technology Major Projects [grant number AA17204043].
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Conflict of interest
The authors declare that they have no conflict of interest.
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