【作者】 邓立刚；

【导师】 耿越；

【作者基本信息】 山东师范大学 ， 细胞生物学， 2009， 硕士

【摘要】 阿维菌素属大环内酯类抗生素,是从土壤放线菌的发酵产物中分离出来的,B1a是其主要的生物活性组分,其含量不低于80%,B1b不高于20%,以B1a来标定其含量。阿维菌素具有高效的杀虫、杀螨和抗寄生虫活性,被广泛用于农作物害虫、害螨和家畜抗寄生虫的防治。由于阿维菌素的用药量少,残留低,液相色谱-紫外检测技术根本达不到检测的要求,而液相色谱-荧光检测技术由于受到衍生条件的限制,重现性和再现性较差。本文建立了超高效液相色谱-串联质谱对阿维菌素在甘蓝和土壤中的残留分析方法并对其在环境中的残留动态进行研究,为掌握阿维菌素在甘蓝上使用后的残留情况,及评价阿维菌素对环境的安全性和制定其在甘蓝中的安全、合理使用准则提供科学依据。建立了阿维菌素在甘蓝和土壤中的超高效液相色谱-质谱联用(UPLC-MS-MS)残留检测方法。样品经乙腈提取后,浓缩,经NH2固相萃取柱净化,超高效液相色谱梯度分离,质谱采用电喷雾离子源,以正离子检测方式进行质谱分析。实验结果表明,在1～200μg?L-1的质量浓度范围内,阿维菌素农药的工作曲线呈线性,其相关系数r=0.9998,甘蓝添加回收率为75.4%～90.0%,相对标准偏差为3.8%～5.2%,土壤添加回收率为77.4%～109.7%,相对标准偏差为4.3%～5.7%。定量限可达到1μg?kg-1,该方法灵敏、准确,选择性好,抗干扰能力强,可作为蔬菜中阿维菌素残留检测的确证方法。研究阿维菌素在甘蓝和土壤中的残留及降解动力学规律。用已建立的UPLC-MS-MS方法对田间试验采集的甘蓝和土壤样品进行测定。消解动态试验结果显示,阿维菌素的消解规律符合一级动力学方程模型,阿维菌素在甘蓝中的半衰期为1.52～1.89天,在土壤中的半衰期为2.01～2.23天,在甘蓝中的消解速率快于在土壤中消解速率,说明阿维菌素属于易降解农药。最终残留试验结果表明,在施药量分别为10.8g·hm-2(推荐剂量,有效成分)和16.2 g·hm-2(有效成分)两个剂量,施药分别1～2次,采样距最后一次施药7、14、21天的条件下,间隔7天后甘蓝中阿维菌素的残留量在<1.00～2.25μg?kg-1,14、21天均未检出,间隔7天后土壤中的阿维菌素的残留量在1.72～5.94μg?kg-1,14、21天均未检出。根据两地的农药残留试验结果以及现行的国内制定MRL值,同时参照国际上其他地区或组织制定的MRL值,建议按照推荐剂量10.8g·hm-2(有效成分),施药1次,安全间隔期为7天以上,食用甘蓝是安全的。更多还原

【Abstract】 Abamectin is macrolides antibiotics isolated from a fermentation broth of the soil actinomycete,Streptomyces avermitilis.Avermectin B1a is its main active component. Abamectin comprises at least 80% avermectin B1a and not more than 20% avermectin B1b,and for this reason the avermectin B1a component is considered as the target analyte in this study. Abamectin is potent insecticide,acaricide and antiparasitics used on a variety of agricultural crops as well as livestocks. Because its dosage is small and low-residual. Ultraviolet detector coupled with HPLC couldn’t fit for the low-level residue measurement,and yet Liquid chromatography-fluorescence detector requires derivatization during sample preparation and is restricted by stringent derivatization conditions.As a result,its repeatability and reproducibility are not good enough.So a new method for the determination of abamectin in cabbage and soil by ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS-MS),and degradation dynamics and final residue of abamectin in cabbage and soil was studied, which could provide scientific basis for evaluating the safety of abamectin in environment and establishing secure,reasonable using guideline of abamectin in cabbage.The analytical method was developed. The samples were extracted with acetonitrile, then concentrated and cleaned up by solid phase extraction (SPE) with a NH2 cartridge, separated by LC with gradient elution,and detected by tandem mass spectrometry with electrospray ionization in positive mode(ESI+).Experimental results indicated that the calibration curve of abamectin was well linear and its correlation coefficient was 0.9998 from 1μg?L-1 to 200μg?L-1.Cabbages and soils were spiked with abamectin at 1,10 and 100μg?kg-1 levels.The recoveries of abamectin in cabbage ranged from 75.4% to 90.0%, and the relative standard deviation(RSD) was 3.8%~ 5.2%.The recoveries in soil ranged from 77.4% to 109.7% ,and the RSD was 4.3%~5.7%.The quantification limit was found to be 1μg?kg-1. The method was sensitive,accurate and selective without interference and suitable for the determination and confirmation of abamectin residue in vegetables as well as fruits.Using UPLC-MS-MS method determined the abamectin residues in cabbage and its soil samples which came from field trial.The results showed that the degradation rate of abamectin in cabbage and soil samples followed the first-order kinetics equation C=C0?e-kt .The degradation rate of abamectin in cabbage is quicker than that in soil.The half-lives of abamectin were 1.52~1.89 days in cabbage,and 2.01~2.23 days in soil.Abametin is easily degradable pesticide.The results of final residual trial revealed that when the cabbage was sprayed at 1~2 times successively at the recommended dosages(10.8g ai·hm-2) and the higher dosages(16.2g ai·hm-2), The residues in cabbage were lower than 0.01mg?kg-1 after 7 days treatments and hadn’t been detected after 14 and 21days respectively, and the residues in soil were between 1.72μg?kg-1 and 5.94μg?kg-1 after 7 days, and hadn’t been detected after 14 and 21days.Based on the results of the field results and maximum residue limit(MRL) which is according to China current standard or refers to other international countries or organizations, the conclusion was that the cabbage was edible safely after 7 interval days if the cabbage was sprayed 1 time at the recommended dosage(10.8g ai·hm-2) during the growth season of cabbage.更多还原