噻吩磺隆的水解、光解行為分析

李新安+李廣領+李松偉+谷珊山+陳錫嶺

摘要：采用室內模擬試驗研究了噻吩磺隆水解及光解行為，以期為環境和生態安全性評價提供科學依據。土壤樣品經乙腈提取，水樣經二氯甲烷提取，高效液相色譜儀（DAD檢測器）檢測。結果表明，噻吩磺隆在不同pH緩沖溶液中水解速率大小依次為pH 4.0、 pH 9.0、pH 7.0，在25 ℃、pH 7.0時，其半衰期最長，達2 310.49 h（96.27 d）;噻吩磺隆在純水中的光解半衰期為2.30 h，土表光解試驗在7 d內，光照下光解速率與黑暗狀態下無顯著差異。溫度和pH對噻吩磺隆的水解有顯著影響。根據《化學農藥環境安全評價試驗準則》劃分標準，噻吩磺隆水解特性屬易水解和較難水解，水中和土表光解特性屬易光解和難光解。

關鍵詞：噻吩磺隆;水解;光解

中圖分類號：TQ450.2 ? ? ? ?文獻標識碼：A ? ? ? ?文章編號：0439-8114（2015）23-5862-04

DOI：10.14088/j.cnki.issn0439-8114.2015.23.017

Environmental Behaviors Including Hydrolysis，Photolysis of Thifensulfuron-methy

LI Xin-an，LI Guang-ling，LI Song-wei，GU Shan-shan，CHEN Xi-ling

（College of Resources and Environment，Henan Institute of Science and Technology，Xinxiang Henan 453003，china）

Abstract： To supple the scientific evidence of the environment and ecological safety， environmental behaviors including hydrolysis， photolysis of thifensulfuron-methy were studied by laboratory simulation. Soil samples were extracted with acetonitrile， and water samples were extracted by dichloromethane， both of them were detected by reversed-phase HPLC with an ultraviolet detector. The results showed that hydrolysis rate of thifensulfuron-methy in different buffers was pH 4>pH 9>pH 7，and the half-life of thifensulfuron-methy was the longest when the tempreature was 25 ℃， pH was 7， up to 2 310.49 h（96.27 d）. The photolytic half-life of thifensulfuron-methy in pure water was 2.30 h. The result of soil surface photolysis test in 7 days showed that its photolysis rate in illumination had no significant differences with that in dark. Temperature and pH had significantly influence on the hydrolysis of thifensulfuron-methy. Based on the dividing standard of guidelines on environmental safety assessment for chemical pesticides， thifensulfuron-methy was easily and difficult to hydrolyze， very easy in pour water and difficult in soil surface to photolyze.

Key words：thifensulfuron-methy;hydrolysis; photolysis

噻吩磺隆（Thifensulfuron-methy）是由杜邦公司開發的一種磺酰脲類除草劑，其化學名稱為3-（4-甲氧基-6-甲基-1，3，5-三嗪-2-基）-1-（2-甲氧基甲酰基噻吩-3-基）-磺酰脲，為弱酸性農藥，具有高效、低毒、低殘留的特點，目前在中國已廣泛用于防除小麥、玉米、大豆田間的闊葉雜草[1，2]。國內外關于噻吩磺隆的研究多集中于藥效[3，4]、殘留[5-7]和土壤吸附[8]方面。Cambon等[9]的研究結果表明，噻吩磺隆的水解符合一級反應動力學方程，其水解速率與pH相關，在pH 5緩沖溶液中的水解半衰期最長，達277.3 h。歐盟研究結果表明，光照下噻吩磺隆光解速率遠快于黑暗下[10]。目前國內關于噻吩磺隆水解、光解的研究尚未見報道，因此研究噻吩磺隆的水解、光解行為對在我國指導科學合理使用該農藥及其環境和生態安全性評價具有重大的現實意義。