二氯喹啉草酮在水稻植株上的消解动态及其在稻秆、稻谷和土壤中的最终残留

Dissipation dynamic of quintrione in rice plants and terminal residue in rice straw,grain and soil

二氯喹啉草酮是经中国农业农村部批准登记的茎叶处理除草剂,迄今为止对其潜在的环境污染尚未见报道。本研究建立了一种采用QuEChERS前处理方法结合高效液相色谱-串联三重四极杆质谱(HPLC-MS/MS)联用技术检测二氯喹啉草酮在水稻植株、稻谷和土壤中残留的方法,并采用该方法测定了二氯喹啉草酮在水稻植株中的消解动态和最终残留。结果表明:二氯喹啉草酮的进样质量浓度与其峰面积间呈良好的线性相关,R2>0.99;其在植株、土壤、田水、稻壳和糙米中的平均回收率在78%~99%之间,相对标准偏差(RSD)在3.9%~11%之间,在植株、土壤、田水、稻壳和糙米中的最低检测浓度(LOQ)均为0.002 mg/kg。二氯喹啉草酮在水稻植株中的消解半衰期为6.7~12.8 d。以有效成分900~1350 g/hm2的剂量于水稻苗期施用1次,在施药96 d后采集的土壤、稻壳和糙米中均未检测出二氯喹啉草酮。本研究结果可为水稻中二氯喹啉草酮最大残留限量值和田间使用规范的制定提供参考。

Quintrione(2-(3,7-dichloroquinoline-8-carbonyl)cyclohexane-1,3-dione)is a new postemergence herbicide just approved by Ministry of Agriculture and Rural Affairs in China.However,the potential environmental pollution caused by quintrione has not been investigated to date.A combined high-performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)and modified quick,easy,cheap,effective,rugged,and safe(Qu ECh ERS)method was developped for the analysis of quintrione residue in rice plant,grain and soil.The dissipation and terminal residues of quintrione in rice plant were determined by using this method.Results showed that there was a good linear correlation between the concentrations and peak areas with R^2 higher than 0.99.The average recoveries of quintrione in rice plant,soil,paddy water,paddy hull and brown rice varied from 78%to 99%with the relative standard deviation(RSD)ranged from 3.9%to 11%.The limits of quantification(LOQ)of quintrione in rice plant,soil,paddy water,paddy hull and brown rice were all 0.002 mg/kg.The investigation of dissipation dynamic data revealed that quintrione degraded quickly in rice plants with half-lifevalues betwwen 6.7 to 12.8 days.96 days after quintrione application at 900 and 1350g a.i./ha on rice seedling,no terminal residual was detected in paddy soil,paddy hull,or brown rice samples.The study will contribute to the setting of the maximum residue limits(MRL)of quintrione in rice and the field application strategy.