【作者】 杨玉柱；

【导师】 焦必宁； 郭东梅；

【作者基本信息】 西南大学 ， 食品科学， 2007， 硕士

【摘要】 本文开展了柑橘中嘧菌酯、咯菌腈和抑霉唑农药残留检测方法、三种农药对柑橘贮藏病害防治效果及其残留降解动态的研究，以期为制定嘧菌酯、咯菌腈农药残留检测标准和柑橘贮藏期病害防治提供一定的理论依据和技术支撑。主要研究结果如下：1．建立了气相色谱—电子捕获检测器(GC-ECD)测定柑橘中嘧菌酯残留的检测方法。样品采用乙酸乙酯+正己烷(1:1，v／v)振荡提取，不需净化，提取液经浓缩定容后直接测定，毛细管柱为DB5MS。样品前处理方法简单，嘧菌酯在0.10、0.50、1.00mg／kg添加浓度下，果皮和果肉中的平均回收率分别为81.6％～90.2％、78.4％～86.4％，变异系数(RSD)分别为4.3％～13.9％、1.7％～4.5％，果皮、果肉样品嘧菌酯的最低检出浓度均为0.001mg／kg，符合农药残留检测要求。2．建立了柑橘中抑霉唑残留的气相色谱—电子捕获检测器(GC-ECD)检测方法。样品采用乙酸乙酯／正己烷(1:1，v／v)振荡提取，不需净化，提取液经浓缩定容后直接测定，毛细管柱为DB1701。样品前处理方法简单，抑霉唑在0.10、0.50、1.00mg／kg添加浓度下，果皮和果肉中的平均回收率分别为83.5％～96.2％、87.6％～102.2％，RSD分别为2.3％～14.5％、4.3％～7.6％，果皮、果肉样品抑霉唑的最低检出浓度均为0.01mg／kg，符合农药残留检测要求。3．建立了高效液相色谱—紫外检测器(HPLC-UV)测定柑橘中咯菌腈残留的检测方法。采用280nm的扫描波长，甲醇：水(75:25，v／v)为流动相洗脱，咯菌腈保留时间为5.10min。样品采用丙酮振荡提取两次，正己烷液—液分配萃取，Florisil—SPE注净化。咯菌腈加标浓度为1.0、5.0mg／kg时，在果皮中的平均回收率为81.7％～89.0％，RSD为2.2％～6.3％，果肉中的平均回收率为85.7％～93.0％，RSD为3.2％～5.8％。在果肉、果皮中咯菌腈的最低检出浓度均为0.02mg／kg，符合农药残留检测要求。4．抑菌试验结果表明，供试的三种药剂，对柑橘青、绿霉病菌均有不同程度的抑制作用，并且随着浓度的增加抑菌活性相应增强。咯菌腈与咯菌腈／嘧菌酯混剂对两种病原菌的抑制效果明显优于抑霉唑和嘧菌酯。100mg／L咯菌腈、250mg／L咯菌腈、100mg／L咯菌腈／嘧菌酯(1：1，v／v)混合溶液、250mg／L咯菌腈／嘧菌酯(1：1，v／v)混合溶液可以完全抑制绿霉菌的的菌落生长，抑制率达到100％。在250mg／L的浓度下，咯菌腈、嘧菌酯／咯菌腈混剂对青霉菌的抑菌圈直径最大，均为45.6mm，其次是抑霉唑，嘧菌酯再次之。5．分别用不同浓度咯菌腈、嘧菌酯和抑霉唑三种杀菌剂浸泡处理447锦橙，于改良通风库贮藏100d，试验结果表明，嘧菌酯、咯菌腈在供试浓度下对447锦橙都有较好的防腐效果，嘧菌酯的适宜浓度为250mg／L，咯菌腈的适宜浓度为500或800mg／L。研究也表明，贮藏100d时，500mg／L和800mg／L咯菌腈处理，褐腐、蒂腐等一类病害的发病率分别占总发病率的39.28％和59.89％，均低于其它药剂处理的发病率，可见，咯菌腈对蒂腐、褐腐病等一类病害具有较好的防治效果。6．残留动态研究结果表明，嘧菌酯和抑霉唑这两种农药均能通过果皮渗入到果肉中，且果皮中的农药残留量均高于果肉，而果肉中未检出咯菌腈残留，这可能是与咯菌腈的非内吸性有关；贮藏100天后检测，可食部分的最终残留水平均很低，均分别未超过国外橙中规定的最大残留限量(MRLs)，可以安全食用。果皮中的嘧菌酯、咯菌腈最终残留水平也未超标，适宜用作皮渣综合加工利用的原料。7．嘧菌酯、抑霉唑农药在果皮和果肉中以及咯菌腈在果皮表面的农药残留量均随着时间的延长呈不同程度的缓慢降解趋势。三种农药在果皮中的降解半衰期，抑霉唑降解半衰期最长，其次为咯菌腈，嘧菌酯，分别为55d、50.6d、33.6d。而嘧菌酯、抑霉唑在果肉中的降解半衰期分别为36.9d，26.8d。更多还原

【Abstract】 The determination of azoxystrobin, fludioxonil and imazalil residues in citrus fruit, decay control and residue levels during 447 Jinchen orange fruit with the treatment of three fungicides were conducted in this paper in order to provide a theoretical basis for the standard-setting of azoxystrobin and fludioxonil and pesticide storage citrus disease prevention, the main findings are as follows:1. A gas chromatography-electron capture detection (GC-ECD) method for determiniong azoxystrobin residue in Citrus is here presented, azoxystrobin residue was extracted by oscillation from citrus samples added n-hexane/ethyl acetate(1:1,v/v), without purification, extract solution being concentrated was injected in the GC column, quartz capillary column DB-5MS was used as separation column. Sample pre-treatment method is simple, The average recovery in orange pulp at fortification levels of 0.1-1.0mg/kg Azoxystrobin were in the range 78.4%-86.4% with relative standard deviations(RSD) between 1.7% and 4.5%. In Orange peel, the average recovery were 81.6%-90.2%, RSD 4.3%-13.9%, The minimum detectable concentration of azoxystrobin was 0.001mg/kg in orange samples, The method accords with the standards of determination of pesticide residues.2. A gas chromatography-electron capture detection (GC-ECD) method for determiniong imazalil residue in Citrus is here presented, imazalil residue was extracted by oscillation from citrus samples added n-hexane/ethyl acetate(1:1,v/v), without purification, extract solution being concentrated was injected in the GC column, quartz capillary column DB1701 was used as separation column. Sample pre-treatment method is simple, The average recovery in orange pulp at fortification levels of 0.1, 0.5, 1.0mg/kg imazalil were in the range 87.6%-102.2% with relative standard deviations(RSD) between 4.3%-7.6%. In Orange peel, the average recovery were 83.5%-96.2%, RSD 2.3%-14.5%, The minimum detectable concentration of imazalil was 0.01mg/kg in orange samples, The method accords with the standards of determination of pesticide residues.3. A liquid chromatographic method with ultraviolet detector(HPLC-UV) method has been established for the determination of fludioxonil residue in citrus. The determination of fludioxonil retention time was 5.10min using high-performance liquid chromatography with UV detection at 280nm, The mobile phase was methanol/water (75:25,v/v) with gradient elution. Samples added extracted acetone were shaked twice, after hexane liquid-liquid extraction, the extract was purified through Florisil-SPE column. The recoveries in orange peel, at spiked concentrations between1.0 and 5.0mg/kg, were between 69.7% and 78.0% with relative standard deviations ranging from 2.2 to 6.3%. The average recovery in orange pulp was 65.7%-73.0%, RSD 3.2%-5.8%. The minimum detectable concentration of fludioxonil in orange flesh and orange peel was 0.02mg/kg. The accuracy of the method is higher, the minimum detection limit of the requirements in line with demands for the determination of pesticide residues.4. The Fungistatic Test results indicate that the concentration 25-500mg/L pilot, the strongest fungicides against citrus Blue and Green Mold was fludioxonil and azoxystrobin/fludioxonil mixture the inhibitory rate of 100mg/L, 250 mg/L fludioxonil and 100mg/L, 250mg/L azoxystrobin/fludioxonil mixture to citrus Green Mold all amounted to 100%, azoxystrobin, Imazalil, Second. Under the same concentration 250 mg/L, the inhibiting effect of fludioxonil and azoxystrobin/fludioxonil mixture to citrus Blue Mold are the best, Imazalil, Second, Azoxystrobin, again.5. 447 Orange separately soaked with different concentrations fludioxonil, azoxystrobin, imazalil fungicides were stored in Ventilated Storage House more than three months, test results indicated that 250mg/L azoxystrobin, 500mg/L or 800mg/L fludioxonil immersion treatment can preferably control the occurrence of 447 Orange rot disease; The disease incidence of stem end rot and Brown rot, etc. for 500mg/L or 800mg/L fludioxonil immersion treatment are respectively 39.28%, 59.89%, They all lower than that of other treatment. It is visibile that fludioxonil on have better control effect on stem-rot, brown rot, etc.6. The residue-dynamics results of this fungicides indicated that azoxystrobin and imazalil can intake into the pulp through the peel, and the residual levels on peel is higher than the flesh; fludioxonil residue was not determined in pulp, it is probably related with non-system of Fludioxonil. The ultimate residual levels of the edible part are all very low after storage for 100 days, it is safety to eat. azoxystrobin and fludioxonil residue levels in 447 Orange peel also do not exceed the MRLs of foreign oranges, and the peel materials are suitable for peel integrated processing for raw materials.7. Fungicide residue degradation dynamics results in orange storage show that azoxystrobin and imazalil residue in citrus peel and flesh, fludioxonil residue in peel overall slow decreased at different degrees with the progress of the time. The half-life for Imazalil in pulp, the longest, was 55d, fludioxonil and azoxystrobin, the second, is respectly 50.6d 33.6d. The half-life for imazalil and fludioxonil in pulp was respectly 36.9d ,26.8d.更多还原