25%西草净WP在水稻、田水和土壤中的残留动态分析

Residual Decline of Simetryn 25% WP in Rice Plant, Field Water and Soil

[目的]建立测定水稻、田水和土壤中西草净上的残留量气相色谱质谱联用分析方法。[方法]通过田间试验和气相色谱质谱联用分析技术研究25%西草净可湿性粉剂在水稻、田水和土壤中的消解动态及其最终残留量。[结果]吉林长春市、黑龙江海伦市和湖南长沙市2年3地的田间试验结果表明:2011年,西草净在水稻植株、田水和土壤中的原始沉积量分别为5.048 mg/kg、22.299 mg/L和7.730 mg/kg,半衰期(t1/2)分别为2.5、1.4、3.9 d;2012年,西草净在水稻植株、田水和土壤中的原始沉积量分别为5.854 mg/kg、5.854 mg/L和0.090 mg/kg,半衰期(t1/2)分别为1.6、1.7、2.9 d。最终残留试验表明西草净在糙米、稻壳、稻株和土壤中的最终残留量均小于0.02 mg/kg。[结论]25%西草净可湿性粉剂可以在水稻上使用,但施药剂量最高为3 750 g/hm2,施药1次。

[Aims] A new method was developed for residual analysis of simetryn in rice by gas chromatographymass spectrum （GC-MS）. [Methods] Field trial and gas chromatography-mass spectrum are carried out to study residual decline and final residues of simetryn rice plants, the field water and the soil. [Results] The detection results showed that, in 2011, the residue simetryn in the rice plants, field water and soil were 5.048 mg/kg, 22.299 mg/L and 7.730 mg/kg, with the half life （t1/2） of 2.5, 1.4 and 3.9 d, respectively; in 2012, the residue of simetryn in the rice plants, field water and soil were 5.854 mg/kg, 5.854 mg/L and 0.090 mg/kg, with the half life （t1/2） of 1.6, 1.7 and 2.9 d, respectively. The results of the final residue experiments showed that the final residues of simetryn in brown rice, rice hulls, rice plants and soil were all below 0.02 mg/kg. [Conclusions] The simetryn 25% WP could be applied on rice once with the maximum dosage of 3750 g/ha.