稻田施用氯氟吡氧乙酸后其在水稻植株、糙米、稻壳、土壤和田水中的残留消解动态

Study on residue decline dynamics of fluroxypyr in rice plant,rice and rice hull,paddy soil and water

研究了稻田施用氯氟吡氧乙酸后,其在水稻植株、糙米、稻壳、稻田土壤和田水中的残留动态。样品采用氢氧化钠-甲醇溶液振荡提取,二氯甲烷液液分配,甲酯化后经气相色谱-电子捕获检测器(GC-ECD)测定。结果表明:氯氟吡氧乙酸在水稻植株、稻田土壤、田水、糙米和稻壳中的平均回收率在85.5%～103.2%之间,相对标准偏差在1.9%～9.9%之间;其最小检出量为2.0×10-12g,在植株、糙米、稻壳、土壤和田水中的最低检测浓度分别为0.005,0.02,0.005,0.002mg/kg和0.001mg/L。2007和2008年在安徽潜山、广东广州两地的田间残留试验结果表明:氯氟吡氧乙酸在水稻植株中的降解半衰期为4.9～6.0d,土壤中为5.5～8.6d,田水中为11.0～13.8d;收获的糙米中氯氟吡氧乙酸的最终残留量在未检出～0.13mg/kg之间,均低于其在糙米上的最大残留限量(MRL)值0.2mg/kg(中国)。建议5%氯氟吡氧乙酸可湿性粉剂用于防治水稻田杂草时,施药剂量按有效成分计不得超过168.8g/hm2,于返青期施药1次。

Residue decline dynamics of fluroxypyr in rice plant,rice and rice hull,paddy soil and water was reported.Fluroxypyr in the samples was extracted with NaOH-methanol,purified with liquid-liquid extraction and detected by capillary gas chromatography with electron capture detector after methyl esterification.The results showed that the average recoveries in paddy plant,soil,water,rice and rice hull ranged from 85.5% to 103.2%,the RSD was from 1.9% to 9.9%,the limit of detection of fluroxypyr standard was 2.0×...