除草剂丁草胺的分析测定及其微生物降解产物研究

Decomposition Products of Herbicide Butachlor in Water Media

用高效液相色谱对除草剂丁草胺(N-丁氧甲基氯-25-氯-25,65-二乙基乙酰替苯胺)的测定方法及其在水溶液中的微生物降解进行了研究。结果表明,采用BDSC18柱和紫外检测器,以乙腈和水为流动相(体积比为8∶2),在波长215nm下进行检测,丁草胺的变异系数和平均回收率分别为1.24%和99.58%;在1￣20mg·L-1的浓度范围内具有良好的线性关系,可以用来定量检测水介质中丁草胺的浓度水平。未灭菌水中丁草胺的降解速率比灭菌水中快,接种微生物后丁草胺的降解速率明显加快,说明微生物是丁草胺降解的主要因素,接种用的细菌能快速降解水溶液中的丁草胺。GC-MS分析结果表明,降解产物只有一种主要化合物。

Determination and biodegradation of herbicide butachlor （N-butoxymethyl-25-chloro-25,65-diethy lacetanilide） in water media was investigated using high performance liquid chromatography （HPLC）. The sample was separated on BDS Cis column, with methanol-water （80/20, V/V） as mobile phase. The herbicide samples were detected at 215 nm with UV detector. The average recovery is 99.58% with a coefficient of variation 1.24% for butachlor. The linear range of the developed method is 1-20mg·L^-1. The method is proved to be accurate, rapid and reproducible. Biodegradation of herbicide butachlor in water media was investigated using a kind of bacteria, Bacillus amyloliquefaciens. The bacteria were separated from the paddy field in Beijing. The biodegradation experiment was carried out under the conditions of pH7.2 and 30℃ The biodegradation rate of butachlor in bacteria-containing water is faster than that in the media without bacteria, which indicated that bacteria are the main factor for butachlor degradation. The degradation ratio of butachlor in sterilized water and bacteria-containing water in ten days reached 30% and 70% respectively. The degradation ratio of butachlor in water containing inoculated and purified bacteria in ten days can reach 95%. This result indicated that the bacteria separated from the soil samples can degrade butachlor with high efficiency. Samples after reaction were removed and filtered through cellulose-regenerated filter （0.45μm pore size） and subject to HPLC analysis. The HPLC results showed that there were two kinds of degradation products. Liquid-liquid extraction was performed three times with 10 mL of dichloromethane. The organic extracts were concentrated in a rotatory evaporator to 0.5 mL and subjected to gas chromatography-mass spectrometry （GC-MS） analysis and only one compound was identified.