Shen Guoqing, Hu Xuan, Hu Yinan
Department of Environment and Resource, College of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, PR China.
J Hazard Mater. 2009 May 30;164(2-3):497-501. doi: 10.1016/j.jhazmat.2008.08.020. Epub 2008 Aug 15.
The disappearance kinetics of pymetrozine was studied in a broccoli-field ecosystem, and an efficient method for the determination of pymetrozine in broccoli and soil was also developed. Pymetrozine residues were extracted from samples using acetonitrile. The extracts were cleaned up by liquid-liquid partitioning with dichloromethane, followed by purification with ethyl acetate, and were then determined by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detector. The average recovery was 87-93% from broccoli, and 84-90% from soil. The relative standard deviation (R.S.D.) was less than 4% in broccoli, and in soil less than 11%. These results are all within the accepted range for residue determination. The limit of detection (LOD) of pymetrozine calculated as a sample concentration (S/N ratio of 3) was 0.005 mg kg(-1). The minimum detectable quantity (MDQ) was 1 x 10(-10)g. The results of the kinetics study of pymetrozine residue showed that pymetrozine degradation in broccoli and soil coincided, with C=1.9826 e(-0.1965t) and C=15.352e(-0.4992t), respectively; the half-lives were 3.5 and 1.4 days, respectively. The final residue level was lower than the new maximum residue limit (MRL) for pymetrozine on vegetables with a harvest interval of 23 days. A dosage of 300 g a.i.hm(-2) was suggested, which is considered to be safe for human beings. These results contribute to establishing the scientific basis of the dosage of pymetrozine for use in vegetable-field ecosystems.
研究了吡蚜酮在西兰花田生态系统中的消解动力学，并建立了一种测定西兰花和土壤中吡蚜酮的有效方法。采用乙腈从样品中提取吡蚜酮残留。提取物通过用二氯甲烷进行液液分配进行净化，然后用乙酸乙酯纯化，再用配有紫外（UV）检测器的高效液相色谱（HPLC）进行测定。西兰花中的平均回收率为87 - 93%，土壤中的平均回收率为84 - 90%。西兰花中的相对标准偏差（R.S.D.）小于4%，土壤中的相对标准偏差小于11%。这些结果均在残留量测定的可接受范围内。以样品浓度计算（信噪比为3），吡蚜酮的检测限（LOD）为0.005 mg kg⁻¹。最小检测量（MDQ）为1×10⁻¹⁰ g。吡蚜酮残留动力学研究结果表明，吡蚜酮在西兰花和土壤中的降解情况相符，分别为C = 1.9826e⁻⁰·¹⁹⁶⁵ᵗ和C = 15.352e⁻⁰·⁴⁹⁹²ᵗ；半衰期分别为3.5天和1.4天。在收获间隔为23天的情况下，最终残留水平低于蔬菜上吡蚜酮的新最大残留限量（MRL）。建议使用剂量为300 g a.i.hm⁻²，该剂量被认为对人类是安全的。这些结果有助于为蔬菜田生态系统中吡蚜酮的使用剂量建立科学依据。
