113g/L抗倒酯微乳剂在小麦上的残留分析及消解动态研究

【作者】 钟蕾；

【导师】 胡德禹；

【作者基本信息】 贵州大学 ， 有机化学， 2016， 硕士

【摘要】 本文采用超高效液相色谱仪(UPLC-PDA)及液相色谱-串联质谱仪(LC-MS/MS)建立了一种分析方法同时检测小麦中抗倒酯及抗倒酸残留量。于2014-2015年分别在安徽、山东及黑龙江进行了113 g/L抗倒酯微乳剂在小麦植株、麦粒及土壤上的残留降解动态及最终残留试验,研究并总结了抗倒酯及抗倒酸在小麦上的消解动态和最终残留数据,为抗倒酯在小麦上残留检测和安全使用提供了理论依据。抗倒酯属环己烷羧酸类植物生长调节剂,光照下极易代谢成抗倒酸。其明显特征通过植物绿色部分的吸收,作用于植物生长部位上,作用机理是阻止作物体内赤霉素后期生物合成,然后达到抗倒伏效果。目前,国内外抗倒酯在农药残留方面的研究报道较少,对于抗倒酯及抗倒酸在超高效液相色谱仪和液相色谱-串联质谱仪上的残留检测方法及其在小麦上的消解和最终残留动态均尚未见报道。小麦土壤、麦粒及植株均采用乙腈提取后分别经UPLC-PDA和LC-MS/MS检测。抗倒酯在土壤、麦粒和植株中最低检测浓度分别为0.05、0.05及0.01 mg/kg,添加浓度为0.02-1.0 mg/kg范围内,平均回收率在71.09%-105.24%,变异系数均<10%;同时抗倒酸分别为0.05、0.05及0.2 mg/kg;浓度在0.05-5.0 mg/kg范围内,平均回收率分别在76.66%-101.00%,变异系数仍是均<10%。说明该方法具有可行性。进行了113 g/L抗倒酯微乳剂在小麦植株、麦粒及土壤中两年三地残留降解动态及最终残留试验,对小麦土壤、麦粒及植株中抗倒酯及抗倒酸的残留量进行了研究。结果表明,施用剂量为110.63 mL/mu时,抗倒酯及抗倒酸总残留量在植株和土壤中消解较快,小麦植株中消解动态符合化学反应一级动力学方程,并计算出其半衰期为3.83-7.15 d,表明抗倒酯属于易降解农药。施用剂量为73.75mL/mu,两年三地收获期内三种基质中抗倒酯及抗倒酸总残留量均低于0.5mg/kg,因此,只要合理使用,抗倒酯在小麦上使用生产是安全的。此外本文首次研究了在室内不同条件下抗倒酯及抗倒酸在土壤中的降解行为,结果表明:在本实验条件下,微生物越多、含水率越少、土壤碱性越强抗倒酯及抗倒酸的降解速率越快。更多还原

【Abstract】 In current work, a rapid analysis method for the simultaneous determination of trineaxapac-ethyll and trinexapac by ultra-performance liquid chromatography(UPLC-PDA) and liquid chromatography coupled with tandem mass spectrometry(LC-MS/MS) were established. In order to evaluate the residual dynamics and environmental safety of trinexapac-ethyl in wheat, studies on the terminal residue and dynamic degradation of 113 g/L trinexapac-ethyl microemulsion in soils, kernels and wheat plants were carried out respectively in Anhui, Shandong and Heilongjiang provices in 2014 and 2015. The data could help the government establish appropriate application frequency and harvest intervals in the use of trinexapac-ethyl on wheat plants.Trinexapac-ethyl belongs to cyclohexane carboxylic acid PGR, which was easily metabolized to corresponding free acid metabolite. It could supress the anaphase biosynthesis of gibberellic acid in plant, mainly through the green part of the plant absorption, the effect occured during the growth site, inhibition of cell elongation, reach the effect of lodging. Currently, few studies reported on the analysis method and residual dynamics of trinexapac-ethyl and trinexapac in wheat by UPLC-PDA and LC-MS/MS.The soil, kernel and wheat plant samples were extracted with ethyl acetate without further clean up. The residues of trinexapac-ethyl and trinexapac were determined by UPLC-PDA and LC-MS/MS.The limit of quantitation(LOQ) of trinexapac-ethyl in soil, kernel and wheat plant were 0.05, 0.05 and 0.01 mg/kg, respectively. Average recovery rates were around 77.83%-105.24% at spiked levels of 0.02-1.0 mg/kg. The LOQ of trinexapac in soil, kernel and wheat plant were 0.05, 0.05, 0.2 mg/kg, respectively. Average recovery rates ranged from 76.66% to 101.00% at spiked levels of 0.05-5.0 mg/kg. The relative standard deviations(RSDs) were <10%. The established method was sensitivity, the accuracy and precision could meet the requirements for detection of pesticide residues.The terminal residue and dynamic degradation of trinexapac-ethyl in soil, kernel and wheat plant were carried out at three fields in two years. The results demonstrated that when the applied dosage was at 110.63 mL/mu, trinexapac-ethyl and trinexapac degraded fast. Furthermore, the degradation of trinexapac-ethyl in wheat plants followed the first-order kinetics. The half-livers of trinexapac-ethyl was 3.83-7.15 days, which indicated trinexapac-ethyl belonged to the easily degraded of pesticides(t1/2<30). When the applied dosage was at 73.75 mL/mu, the terminal residue levels of trinexapac-ethyl were lower than 0.5 mg/kg in these three matrices.Moreover, the thermodynamics of degradation behavior of trinexapac-ethyl and trinexapac were also investigated. The result showed that the higher microorganism, less moisture content and stronger alkalinity of soil was the faster speed of trinexapac-ethy and trinexapac degrade.更多还原