氯虫苯甲酰胺在甘蔗及土壤中的残留消解动态

建立了氯虫苯甲酰胺在甘蔗和土壤中残留的高效液相色谱检测方法,应用该方法对氯虫苯甲酰胺在甘蔗和土壤中的残留消解规律进行了研究。样品用乙腈提取,经Florisil固相萃取柱及N-丙基乙二胺(PSA)净化,紫外检测器检测,外标法定量。结果表明:当添加水平为0.05~2 mg/kg时,氯虫苯甲酰胺在甘蔗植株地上部分(包括茎秆和叶片)、茎秆(去除叶片后的地上至肥厚带部位)和土壤中的平均回收率为77%~97%,相对标准偏差(RSD)为3.4%~11.6%。氯虫苯甲酰胺在3种基质中的最小检出量(LOD)均为0.2 ng,最低检测浓度(LOQ)均为0.05mg/kg。两年两地的田间残留试验结果表明:0.4%氯虫苯甲酰胺颗粒剂在甘蔗下种时一次沟施后覆土,以有效成分用量120和180 g/hm2施药时,在土壤中的原始沉积量在1.18~3.57 mg/kg之间,半衰期为12.4~18.2 d;成熟时采收,甘蔗茎秆中氯虫苯甲酰胺的残留量低于0.05 mg/kg。参照我国制定的甘蔗上氯虫苯甲酰胺的临时最大残留限量(TMRL)值0.05 mg/kg,按照推荐剂量及推荐剂量的1.5倍分别施药1次,成熟时采收甘蔗是安全的。

Residues and dissipation of chlorantraniliprole in sugarcane and soil

An analytical method with high performance liquid chromatography detection was established to determine chlorantraniliprole residues in soil, plant(aerial parts of sugarcane which stem and leaves are included) and stem(aerial parts of sugarcane without leaves) of sugarcane. Residues and dissipation of chlorantraniliprole in sugarcane and soil were investigated. Chlorantraniliprole residues were extracted with acetonitrile, then cleaned up on florisil based solid phase extraction column and by primary secondary amine(PSA), followed by determining with liquid chromatography equipped with a UV detector. The results showed that the recoveries of chlorantraniliprole in soil and sugarcane were 77%-97% at three fortification levels ranging from 0.05 to 2 mg/kg, with the relative standard deviations of 3.4%-11.6%. Limit of detection (LOD) of the method was 0.2 ng and the limit of quantification (LOQ) was 0.05 mg/kg for all these matrices. Field experiments showed that the initial residues were 1.18-3.57 mg/kg and the half lives of chlorantraniliprole were 12.4-18.2 d, when 0.4% chlorantraniliprole granules(120, 180 g a.i./hm²) was applied into the ditch when planting the sugarcane. The residues in stems of sugarcane were lower than 0.05 mg/kg at harvest time. According to the temporay maximum residue limit (TMRL) for sugarcane (0.05 mg/kg) in China, chlorantraniliprole applied once at recommended dosage and 1.5 times formed acceptable residues in sugarcane.