Photodegradation of flumorph in aqueous solutions and natural water under abiotic conditions.
Flumorph is an oomycete fungicide that is now used extensively in China (Hu, J. Y.; Liu, C.; Yan, H. Degradation of flumorph in soils, aqueous buffer solutions, and natural waters. J. Agric. Food Chem. 2008, 56, 8574-8579). The photodegradation of flumorph in aqueous solutions and natural water have been assessed under natural and controlled conditions in this work. The kinetics of photodecomposition of flumorph was determined using the high-performance liquid chromatography (HPLC)-diode array detector (DAD), and the identification of photoproducts was carried out with HPLC-mass spectrometry (MS) [electrospray ionization (ESI) positive mode]. The rate of photodecomposition of flumorph in aqueous solutions and natural water followed first-order kinetics in both UV radiation and natural sunlight, and the Z isomer of flumorph could convert to the E isomer. The degradation rates were faster under UV light than sunlight, with the half-lives (t(1/2) = ln 2/k) of 36.5-64.2 min and 36.3-73.1 days, respectively. One major photoproduct was detected in UV light and tentatively identified according to HPLC-MS spectral information as (E or Z)-3-(3, 4-dimethoxyphenyl)-3-(4-fluorophenyl)-2-acrylamide. Photosensitizers, such as H(2)O(2) and riboflavin, could enhance photolysis of flumorph in natural sunlight. The results obtained indicated that photoreaction was an important dissipation pathway of flumorph in natural water systems.
Hu
Ji Ye
JY
School of Applied Science, University of Science and Technology Beijing, Beijing 100083, China. jiyehu@sas.ustb.edu.cn
Liu
Chang
C
Zhang
Xue
X
Qin
Dong Mei
DM
Liu
Chang-Ling
CL
D005659:Fungicides, Industrial / Q000737:chemistry*; D007700:Kinetics; D009025:Morpholines / Q000737:chemistry*; D010782:Photolysis / Q000528:radiation effects*; D013472:Sunlight; D014874:Water Pollutants, Chemical / Q000737:chemistry*
D005659:Fungicides, Industrial; D009025:Morpholines; D014874:Water Pollutants, Chemical; C528737:flumorph