噻虫胺、噻虫嗪、毒死蜱、杀虫单在土壤和甘蔗中的残留消解动态

Residues and Dissipation of Clothianidin,Thiamethoxam,Chlorpyrifos and Thiosultap-monosodium in Soil and Sugarcane

[目的]建立了噻虫胺、噻虫嗪、毒死蜱及杀虫单在甘蔗和土壤中的残留分析方法,开展田间试验研究了4种杀虫剂颗粒剂在甘蔗种植时以撒施方式施用后在甘蔗植株和土壤中的消解动态。[方法]甘蔗样品用乙腈提取,经固相萃取小柱净化,分别采用气相色谱-火焰光度检测器(GC-FPD)、高效液相色谱仪(HPLC-UVD)、气相色谱-ECD检测器(GC-ECD)检测。[结果]甘蔗种植时以撒施方式施用后,噻虫胺在广西和湖南甘蔗地土壤中的原始沉积量为0.121~0.709 mg/kg,半衰期为11.2~99.0 d;毒死蜱在2地甘蔗地土壤中的原始沉积量为21.04~40.39 mg/kg,半衰期为7.0~60.3 d;噻虫嗪在2地甘蔗地土壤中的原始沉积量为0.765~1.625 g/kg,半衰期为8.7~27.3 d;杀虫单在2地甘蔗地土壤中的原始沉积量为30.29~63.39 mg/kg,半衰期为1.9~3.1 d。种植时撒施待甘蔗植株生长至约50 cm高时开始检测甘蔗植株体内残留量,噻虫胺在广西和湖南2地甘蔗植株中的原始沉积量为0.229~0.397 mg/kg,半衰期为2.7~7.5 d;毒死蜱在甘蔗植株中的原始沉积量均<0.01 mg/kg;噻虫嗪在植株中的初始沉积量为0.005~0.069 mg/kg,最高值可达0.25 mg/kg;杀虫单(以沙蚕毒素计)在甘蔗植株中的原始沉积量均<0.01 mg/kg。[结论]甘蔗种植时土壤撒施后,烟碱类农药噻虫胺和噻虫嗪颗粒剂在土壤中表现出良好的缓释效果,在60 d的处理时间内保持了较为稳定的浓度,而毒死蜱和杀虫单则在土壤中较快的降解。新烟碱类杀虫剂在甘蔗植株中具有良好的内吸传导性,这对于甘蔗苗期的虫害防治是有利的,而毒死蜱、杀虫单未发现明显植株传导性。

[Aims]This study aims to establish an analytical method to determine residues of clothianidin,thiamethoxam,chlorpyrifos and thiosultap-monosodium in soil and sugarcane.A field experiment was conducted to study residues and dissipation in sugarcane of the four insecticide granules.[Methods]Sugarcane samples were extracted with acetonitrile and purified by a solid-phase extraction cartridge,followed by detection with gas chromatography-flame photometric detector(GC-FPD),high-performance liquid chromatography(HPLC-UVD),and gas chromatography-ECD detector(GC-ECD)respectively.[Results]The results showed that after application by spraying during sugarcane planting,the original deposition of clothianidin in the soil of Guangxi and Hunan soil was 0.12-0.71 mg/kg,and the half-life was 11.2-99.0 d;for chlorpyrifos was 21.04-40.39 mg/kg,and the half-life was 7.0-60.3 d;for thiamethoxam was 0.765-1.625 mg/kg,and the half-life was 8.7-27.3 d;for thiosultap-monosodium was 30.29-63.39 mg/kg,and the half-life was 1.9-3.1 d.When the sugarcane plant grows to about 50 cm height,the residual amount in the sugarcane plant will be detected.The original deposition of clothianidin in sugarcane in Guangxi and Hunan was 0.229-0.397 mg/kg,and the half-life was 2.7-7.5 d;for chlorpyrifos was<0.01 mg/kg;for thiamethoxam in the plants was 0.005-0.069 mg/kg,and the highest value reached 0.25 mg/kg;thiosultap-monosodium in sugarcane plants were all less than 0.01 mg/kg.[Conclusions]After soil application,clothianidin and thiamethoxam showed good slow-release effect in the soil,kept a relatively stable concentration within 60 days after application,while chlorpyrifos and thiosultap-monosodium degraded rapidly in the soil.The new nicotine insecticides have good absorption and conduction in sugarcane plants,which is beneficial to control of insects in sugarcane.Chlorpyrifos and thiosultap-monosodium show no obvious plant conduction.