Detection technique of sulfonylurea herbicides

• Main Authors: Yun-Zein Lai, 賴郁仁
• Other Authors: Ching-Yuh Wang
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/50697696393611800075

碩士 === 國立中興大學 === 農藝學系 === 92 === 　　A less toxic, simple and highly reproducible technique for the detection of acetolactate synthase (ALS)-inhibiting herbicides was conducted. Under the action of ALS-inhibiting herbicides, e.g. sulfonylureas and imidazolinones, 2-oxobutyric acid, the substrate of ALS reaction, accumulates immediately in plant and rapidly transaminates into 2-aminobutyric acid (2-aba), which is a candidate of chemical marker in ALS-inhibiting herbicide detection. 　　Bioassay using four winter vegetables showed that both field mustard (Brassica campestris L.) and Chinese mustard (Brassica rapa L.) were more sensitive to three sulfonylureas (SUs), i.e., bensulfuron, imazosulfuron and pyrazosulfuron, than other two vegetables. Screening of sensitive summer vegetables based on injury index revealed that field mustard was again the most sensitive species. After foliar application of bensulfuron at 0.487 µM on sensitive field mustard, 2-aba accumulation reached the maximum within 6 to 12 h and maintained to 72 h later. Furthermore, under the application of three SUs ranging from 10-2 to 102 µM, 2-aba in field mustard accumulated with a linear regression to the logarithm-transformed concentration of applied SUs. 　　Evaluation study showed that 2-aba accumulated rapidly in sensitive field mustard 6 h after bensulfuron treatment, whereas no accumulation was found in rice seedlings. Among six vegetables with differential sensitivities to SUs, maximal accumulation of 2-aba, coincide with the onset of injury, occurred in field mustard. In addition, 6 h after application of either water or sodium bicarbonate extracts from paddy soil containing three SUs, a significant accumulation of 2-aba in field mustard reflected the toxicity of SUs. 　　Three SUs, were purified and preconcentrated with soild-phase extraction (SPE) technique followed by analysis of three HPLC systems. With three unique systems specific to each SU, the linear regressions could be obtained with concentrations ranging from 0.014 to 10.96 nmole for bensulfuron, 0.002 to 2018 nmole for imazosulfuron, and 0.001 to 12.65 nmole for pyrazosulfuron, respectively. Among these three systems, only the one with mobile phase of acetonitrile and water, coupled with Nucleosil 100 C18 column, was able to detect three SUs simultaneously. In addition, both water and sodium bicarbonate were suitable for the simultaneous extraction of three SUs from paddy soil, with a recovery rate of 85 to 100%.