氟环唑在小麦及土壤中的残留及消解动态

为了评价氟环唑在小麦生产上使用的残留安全性,建立了气相色谱-电子捕获检测器检测氟环唑在小麦植株、小麦籽粒及土壤中残留的分析方法,并对氟环唑在小麦植株、小麦籽粒和土壤中的最终残留量及小麦植株和土壤中的消解动态进行了研究。结果表明:在添加水平为0.01、0.1和2 mg/kg（小麦籽粒和土壤）和0.01、0.1和10 mg/kg（小麦植株）下,氟环唑的回收率为82%~93%,相对标准偏差为3.0%~9.7%。氟环唑在小麦植株、小麦籽粒和土壤中的定量限均为0.01 mg/kg。氟环唑在小麦植株和土壤中的消解半衰期分别为3.5~8.4和10~30 d。当以有效成分112.5 g/hm2的剂量施药2次、采收间隔期为21 d时,小麦籽粒中氟环唑的残留量为<0.05 mg/kg,低于中国制定的小麦中氟环唑的最大残留限量值（0.05 mg/kg）。建议氟环唑在小麦上使用时最大剂量为有效成分112.5 g/hm2,施药2次,安全间隔期为21 d。     

A method for the estimation of 1,2-dibromoethane in vegetables

Residues of 1,2-dibromoethane (EDB) were readily estimated in treated vegetables down to levels of 0.2 mg/kg. Clean-up was effected by steam distillation into a toluene trap. This was followed by X-ray fluorescence determination of the collected EDB in the toluene. Good recoveries of added EDB were obtained at 0.5, 2, 5 and 20 mg/kg in cucumbers, pumpkins and zucchinis.     

Tank-mix adjuvants and pesticide residues: some regulatory and quantitative aspects

Although it is well known that judicious use of adjuvants can increase the performance of foliage-applied sprays of many agrochemicals, little information is available in the public domain about their ultimate effects on pesticide residues in treated crops. In the present work, the influence of Agral (polyoxyethylene nonylphenols), Toil (methyl esters of rapeseed fatty acids) and Bond (styrene-butadiene copolymers) on surface and crop residues of diclofop-methyl/diclofop and propiconazole in wheat and field beans was investigated using a model system simulating field practice. Pesticides were applied as commercial formulations, diclofop-methyl 378 g litre(-1) EC (Hoegrass) and propiconazole 250 g litre(-1) EC (Tilt), at their maximum approved rates, 1135 g AI ha(-1) and 125 g AI ha(-1), respectively, both in the presence or absence of the maximum rate recommended for each candidate adjuvant. No detectable residues of diclofop-methyl or propiconazole were found in wheat 35 days after any of the four applications. However, residues of diclofop were present in this crop, and those from applications containing Agral (0.07 mg kg(-1) fresh weight (FW)) or Bond (0.08 mg kg(-1) FW) were significantly lower than those with no adjuvant (0.14 mg kg(-1) FW) or Toil (0.16 mg kg(-1) FW). Unlike wheat, residues of both diclofop and propiconazole were detected in field beans after harvest. Significantly higher residues of the former were recorded from the applications with Agral or Bond (ca 0.32 mg kg(-1) FW) than with those with no adjuvant or Toil (ca 0.15mg kg(-1) FW). All the propiconazole applications containing adjuvants showed a similar significant increase in residues (0.10-0.16 mg AI kg(-1) FW) over the no-adjuvant treatment (0.05 mg kg(-1) FW) in this crop. There appeared to be little agreement between the apparent amounts of uptake, as indicated by the rates of decline of surface residues up to 5 days after application, and final residues in either target species. On wheat, surface residues of diclofop-methyl decreased from initially ca 20 to as little as 0.02 mg kg(-1) FW using adjuvants; the corresponding values for propiconazole were ca 2 to ca 0.03 mg kg(-1) FW. Recoveries of diclofop-methyl from the surfaces of field beans were much higher than those from wheat, declining from ca 30 to only ca 6 mg kg(-1) FW during the course of 5 days; the corresponding residues for propiconazole were ca 2 mg to 0.15 mg kg(-1) FW. These findings are discussed in relation to uptake results obtained with radiolabelled pesticides and adjuvants in the laboratory, and to the mandatory requirements for pesticide residue data for the authorised use of adjuvants in the UK.     

The fate of the herbicide benzoylprop-ethyl in crops grown in treated soils

The herbicide benzoylprop-ethyl (SUFFIX,^a ethyl (±)-2-(N-benzoyl-3,4-dichloro-anilino) propionate) is applied post-emergence for the control of wild oats (Avena spp.) in wheat. During application some falls onto the soil and in the present work the possible uptake of residues from the soil, particularly by rotation crops has been studied using radioisotope techniques under indoor and outdoor conditions. Soil application at 1 kg/ha gave lower residues in wheat in the year of application than were found in previous studies using overall foliar-soil application. In the radiochemical experiments soil residues did persist into the following year, but residues in potatoes and wheat grown in these soils, although generally below the limit of determination (0.005 mg/kg), were occasionally just above this level (0.006 mg/kg). On the results of the present work, residues in rotational crops from soils treated in the previous year are unlikely to reach the limits of normal analytical determination.     

三唑醇在京皖两地小麦和土壤中残留动态研究

本文采用田间试验的方法,研究了15%三唑醇可湿性粉剂在小麦及土壤中的消解动态和最终残留量。试验结果表明,三唑醇在麦苗中消解较快,半衰期为3.82～4.94d,土壤中消解相对缓慢,其半衰期为17.17～20.91d;15%三唑醇可湿性粉剂按最高推荐剂量(商品)60g/mu和最高推荐剂量的2倍120g/mu施药2、3次,采收距末次施药间隔7、14、21d,三唑醇在小麦籽粒中残留量为0.029 1～0.153 0mg/kg,麦杆中残留量为0.029 1～0.153 0mg/kg,土壤中为0.005 9～0.046 0mg/kg。该药属于低毒农药,按推荐剂量使用是安全的。     

QuEChERS-超高效液相色谱-串联质谱法测定双氟磺草胺和氯氟吡氧乙酸在小麦和土壤中的残留及消解动态

建立了同时测定小麦及其土壤中双氟磺草胺和氯氟吡氧乙酸残留的QuEChERS-超高效液相色谱-串联质谱方法,并采用该方法研究了低温冷藏条件下双氟磺草胺和氯氟吡氧乙酸在小麦上的储藏稳定性以及15%双氟磺草胺?氯氟吡氧乙酸悬乳剂在小麦和土壤中的最终残留及消解动态。结果表明:在添加水平为0.005~1 mg/kg范围内,双氟磺草胺和氯氟吡氧乙酸在小麦及土壤中的平均回收率在82%~108%之间,相对标准偏差在0.41%~11%之间 (n=5) ,均能满足农药残留分析的要求。在 –20℃下储藏365 d后,麦粒中双氟磺草胺和氯氟吡氧乙酸的残留量变化小于30%,符合植源性农产品中农药残留储藏稳定性试验准则要求,储藏稳定。双氟磺草胺在小麦植株和土壤中的消解半衰期分别为4.4~8.1 d和2.4~9.3 d;氯氟吡氧乙酸在小麦植株和土壤中的消解半衰期分别为7.9~10.6 d和11.8~24.8 d,即在相同的试验条件下双氟磺草胺在植株和土壤中消解速率快于氯氟吡氧乙酸的。采用推荐剂量有效成分180 g/hm2和推荐高剂量有效成分270 g/hm2的15%双氟磺草胺?氯氟吡氧乙酸悬乳剂于小麦田施药1次,在小麦收获期的麦粒中均未检出双氟磺草胺和氯氟吡氧乙酸残留。     

顶空气相色谱法测定小麦中熏蒸剂氰及其代谢物氰化氢的残留量

采用溶剂顶空毛细管气相色谱-氮磷检测器(NPD)建立了熏蒸剂氰(C2N2)及其代谢物氰化氢(HCN)在小麦中残留的分析方法。在气相与液相体积比(β)为4时,采用GS-Q大孔毛细管色谱柱和进样60 μL顶空气体,可提高C2N2和HCN的分离效果和灵敏度。以质量分数为50%的磷酸作溶剂,在25 ℃下平衡4 h,C2N2和HCN在液相与气相间的分配系数(k)分别为0.44和48.82。平衡温度和基质对C2N2和HCN挥发的影响存在差异,而盐化效应的影响较小。用50% 的磷酸提取熏蒸过的小麦72 h,释放至顶空的C2N2和HCN的量最大,用添加标准品的小麦作标准可评价熏蒸小麦中C2N2和HCN的残留量。C2N2和HCN标准曲线的线性范围分别在质量浓度为1.0~500 μg/L和1.2~500 μg/L之间,相关系数(R2)分别为0.999 7和0.999 8,相对标准偏差分别为4.6%和7.4%,检出限(LOD)分别为0.032和0.145 mg/kg,定量限(LOQ)分别为0.107和0.483 mg/kg。方法操作简单、灵敏度高、干扰少,适用于小麦中C2N2和HCN残留量的检测。     

叶菌唑在小麦中的残留消解及膳食风险评价

为评价叶菌唑在小麦中的残留行为及其产生的膳食摄入风险,于北京、安徽及黑龙江进行了1年3地田间试验,建立了叶菌唑在小麦中的残留分析方法,并对我国不同人群的膳食暴露风险进行了评价。样品用乙腈提取,经Florisil固相萃取柱净化,气相色谱-氮磷检测器(GC-NPD)检测,外标法定量。结果表明:在0.02~10 mg/kg的添加水平下,叶菌唑在小麦籽粒和植株中的平均回收率在81%~101%之间,相对标准偏差(RSD)在2.1%~9.1%之间;其在小麦籽粒和植株中的定量限(LOQ)分别为0.02和0.04 mg/kg。叶菌唑在小麦植株中的消解符合一级动力学方程,半衰期为4.9~7.3 d。收获时小麦籽粒中叶菌唑的最大残留量为0.037 mg/kg,低于美国和欧盟设定的最大残留限量(MRL)0.15 mg/kg。针对我国不同人群的膳食摄入及风险评估暴露,风险商值(RQ)在0.001~0.002之间,表明叶菌唑在小麦中的膳食摄入风险较低。     

水稻秸秆还田结合炔草酯对禾本科杂草和小麦生长发育的影响

为改进水稻秸秆还田条件下小麦田杂草治理技术,通过田间小区试验研究了不同还田量单独或结合炔草酯施用对后茬小麦田禾本科杂草的控制效果和小麦生长发育及产量的影响。结果表明,随着水稻秸秆单独还田量从1 125 kg/hm2增至4 500 kg/hm2,小麦田杂草发生密度显著下降,4 500 kg/hm2秸秆还田量下小麦分蘖期前杂草发生密度下降60%左右;结合炔草酯施用时,杂草发生密度随秸秆还田量的增加而下降,但不同还田量之间无显著差异,且炔草酯除草活性未受到影响。秸秆还田或炔草酯单独或结合施用均对小麦生长发育无明显的胁迫影响,4500 kg/hm2秸秆单独还田量下,小麦苗期功能叶SPAD值较对照增加7.0%,净光合速率和蒸腾速率分别增加14.9%和12.2%;抽穗期净光合速率、气孔导度、蒸腾速率分别增加28.3%、85.2%和100.0%;千粒重、有效穗数和产量分别增加3.9%、6.7%和16.1%。4 500 kg/hm2秸秆单独还田量对杂草控制效果、小麦生长及产量的影响均与炔草酯推荐剂量单独施用无显著差异,表明该秸秆还田量具有良好的农田生态效应。     

高效液相色谱-串联质谱法测定小麦和土壤中氨氯吡啶酸的残留量

建立了小麦植株、麦粒、面粉、麦麸和土壤样品中氨氯吡啶酸的高效液相色谱-串联质谱(HPLC-MS/MS)检测方法。样品用丙酮提取,经N-丙基乙二胺(primary secondary amine,PSA)串联石墨化炭黑柱净化,以Agilent ZORBAX SB-C18 色谱柱分离,以电喷雾电离串联质谱正离子多反应监测(multiple reaction monitoring,MRM)模式进行测定。结果表明: 在0.01、0.1、0.5、1 mg/kg 4个添加水平下,氨氯吡啶酸在小麦植株、麦粒、面粉、麦麸和土壤中的平均回收率在78.9%~97.9%之间,相对标准偏差在3.6%~9.6%之间。该方法样品前处理简单、快速、分析时间短,灵敏度、准确度和精密度均符合农药残留检测要求,适用于小麦和土壤中氨氯吡啶酸残留的检测。     

Pesticide residues in foodstuffs in Great Britain: Organochlorine residues in imported cereals,nuts, pulses and animal foodstuffs

Results are presented for the determination of organochlorine insecticide residues in imported cereals, nuts, pulses and animal foodstuffs for the 2 year period July 1969 to June 1971. BHC was found in all but four of the 248 samples examined but only in 25 (10%) did the level exceed 0.5 mg/kg. DDT was found in 39% of the samples of which three samples of wheat contained more than 1 mg/kg and two samples of cottonseed cake more than 0.5 mg/kg. The other commodities sampled had less than 0.2 mg/kg. DDE was detected in trace amounts in 26 % of the samples examined.     

联苯菊酯、噻虫嗪及其代谢物噻虫胺在小麦上的残留及膳食风险评估

建立了小麦及其秸秆中联苯菊酯、噻虫嗪和代谢物噻虫胺残留量的分析方法。样品经乙酸-乙腈提取,无水硫酸镁、N-丙基乙二胺 (PSA) 及GCB净化,超高效液相色谱-三重四极杆串联质谱仪 (UPLC-MS/MS) 检测。结果表明:在0.0025~0.1 mg/L范围内,联苯菊酯、噻虫嗪和噻虫胺的峰面积与其质量浓度间呈良好线性关系,R2均大于0.99。麦粒样品在0.01、0.1和0.5 mg/kg,秸秆样品在0.05、0.5和3 mg/kg添加水平下,联苯菊酯、噻虫嗪和噻虫胺在小麦及其秸秆中的添加回收率分别在93%~98%、87%~98%和87%~98%之间,相对标准偏差 (RSD) 分别在0.8%~4.8%、0.6%~4.1%和1.0%~3.3%之间。按照《农作物中农药残留试验准则》在全国12个小麦主产区开展规范残留试验,采用35%联苯菊酯 ? 噻虫嗪悬浮剂,以制剂用量150 g/hm2 (有效成分52.5 g/hm2) 的剂量,于小麦蚜虫始盛时期施药1次,施药后间隔14 d和21 d采集的麦粒中联苯菊酯、噻虫嗪和噻虫胺的残留量结果验证了相关残留限量 (MRL) 值的适用性,且多点试验的结果具有更高的可靠性。长期及短期膳食暴露风险评估结果表明,小麦中联苯菊酯、噻虫嗪和噻虫胺残留量对1~6岁儿童和普通人群产生的膳食暴露风险在可接受范围内。     

气相色谱串联质谱方法测定小麦中唑草酮的残留及消解动态

采用田间试验方法研究唑草酮在小麦中的残留动态,建立了气相色谱-串联质谱(GC-MS/MS)测定唑草酮在小麦植株与麦粒上的残留分析方法.唑草酮在小麦植株中的平均回收率为99.4％～102.2％,变异系数为3.0％～6.5％;在麦粒中平均回收率为88.3％～90.6％,变异系数为2.8％～8.9％.动态结果表明:在小麦上使用唑草酮后,利用该方法检测唑草酮在山东和河南两地小麦植株中的残留消解半衰期分别为3.50 d和3.67 d;收获期唑草酮在麦粒中最终残留量均小于0.01 mg/kg.     

Fumigation of citrus fruit with ethylene dibromide: Desorption of residues and ethylene evolution

The desorption of ethylene dibromide (EDB) residues from fumigated Shamouti citrus fruits is fitted by a single exponential equation at 17 and 22°C, and by an equation with a double exponential term at 5°C. Establishing the rate constant enables calculation of the initial concentration of EDB residues in the peel, thereby obtaining information on conditions during fumigation and on the possibility of peel injury development in the fumigated fruit. Healthy, harvested Shamouti citrus fruit evolve ethylene at a low rate, which is increased by EDB fumigation. Fumigated fruit in which EDB caused peel injury evolved ethylene at a higher rate than fumigated fruit in which peel injuries did not develop. This information could be used for predicting peel injuries and in studies aimed at a better understanding of the processes leading to the development of peel injuries in fumigated citrus fruit.     

QuEChERS-高效液相色谱-串联质谱法测定主要谷物和油料作物中氯虫苯甲酰胺的残留

采用QuEChERS样品前处理方法,建立了主要谷物和油料作物产品 (糙米、小麦、玉米和大豆) 中氯虫苯甲酰胺残留量的高效液相色谱-串联质谱 (HPLC-MS/MS) 检测方法。样品经乙腈-水提取及盐析处理后,用N-丙基乙二胺 (PSA) 和石墨化碳黑 (GCB) 固相萃取填料净化,高效液相色谱-串联质谱(HPLC-MS/MS)、多反应监测模式 (MRM) 下测定。基质标准曲线外标法定量。结果表明:在0.005~0.5 mg/L范围内,不同样品基质中氯虫苯甲酰胺的峰面积与其相应的质量浓度间均有良好的线性关系(R2>0.99),检出限 (LOD) 为0.001 mg/L。在0.02、0.05、0.1和0.5 mg/kg添加水平下,氯虫苯甲酰胺在4种基质中的平均回收率在89%~114%之间,相对标准偏差 (RSD) 在1.3%~11% (n = 5) 之间,4种基质中的最低检测浓度 (LOQ) 均为0.02 mg/kg。该方法适用于主要谷物和油料作物产品中氯虫苯甲酰胺残留量的检测。     

噻虫嗪及其代谢物噻虫胺在麦叶和麦穗中的痕量检测方法及其应用

建立了超高效液相色谱-串联质谱(UPLC-MS/MS)测定麦叶和麦穗中噻虫嗪及其代谢物噻虫胺残留的痕量、快速检测方法.麦叶或麦穗中噻虫嗪及其代谢物噻虫胺用乙腈提取,NH2/Carb固相萃取柱净化,内标法定量.结果表明:噻虫嗪和噻虫胺在0.001～～0.5 mg/L范围内线性关系良好,相关系数r大于0.99;噻虫嗪和噻虫...     

Bromine residues in potato and wheat crops grown in soil fumigated with methyl bromide

The bromine content of potato tubers grown in soil fumigated with methyl bromide at 487 and 975 kg/ha (1 lb and 2 lb/100 ft2) averaged 170 and 280 mg/kg of dry weight. Most of the bromine was in the outer layers of the tubers; peeled tubers has less than 100 mg/kg, which remained after boiling. Potato haulm contained 4000 or 6700 mg/kg bromine respectively for the two rates of application. The bromine content of wheat grain grown after potatoes depended on the rate of application of methyl bromide and the time interval between treatment and wheat crop. Wheat grain harvested 31/2 21/2 and 11/2 years after fumigation with methyl bromide at 975 kg/ha had mean bromine contents of 4.5, 15 and 44 mg/kg. but the amounts in grain from plots having the same treatments varied more than two-fold; wheat grain harvested 11/2 years after fumigation at 487 kg/ha contained 23 mg bromine/kg. Wheat yields were unaffected by fumigation.     

QuEChERS-超高效液相色谱-串联质谱方法快速测定小麦中的咪鲜胺残留

建立了简便、快速测定咪鲜胺在小麦籽粒中残留量的方法。前处理采用以乙腈作提取剂、PSA(primary secondary amine,N-丙基乙二胺)为分散净化剂的QuEChERS方法,并利用超高效液相色谱-串联质谱(UPLC-MS/MS)在多反应离子监测模式下进行检测,外标法定量。在0.001 ~0.1 mg/kg 范围内线性关系良好,相关系数为0.999 4。结果表明,在3个添加水平(0.001、0.01和0.1 mg/kg)范围内的平均回收率为91.8% ~98.3%,相对标准偏差为3.7% ~7.0%,咪鲜胺在麦粒中的定量限为0.000 1 mg/kg。     

氟唑磺隆、甲基二磺隆、炔草酯和炔草酸在小麦中的残留分析

以QuEChERS前处理方法为基础，采用高效液相色谱-串联质谱(HPLC-MS/MS)检测技术，建立了除草剂氟唑磺隆、甲基二磺隆、炔草酯及其代谢物炔草酸4种化合物在小麦中残留的分析方法。麦粒样品中加入5 mL体积分数为0.1%的甲酸水溶液后，以10 mL乙腈提取，用50 mg C₁₈与100 mg 无水硫酸镁净化；麦秆样品中加入10 mL体积分数为2%的甲酸水溶液后，以10 mL乙腈提取，用100 mg C₁₈与200 mg无水硫酸镁净化。结果表明:氟唑磺隆在0.005、0.01和0.1 mg/kg，甲基二磺隆在0.01、0.02和0.1 mg/kg，炔草酯和炔草酸在0.05、0.1和0.5 mg/kg添加水平下，4种化合物在麦粒中的回收率在76%~97%之间，在麦秆中的回收率在83%~102%之间，相对标准偏差均小于10%，r > 0.99。4种化合物在麦粒和麦秆中的定量限分别为:氟唑磺隆0.005 mg/kg，甲基二磺隆0.01 mg/kg，炔草酯和炔草酸均为0.05 mg/kg。该方法可满足小麦样品中4种化合物的残留分析要求。     

黄土区旱地长期施用微肥对冬小麦农艺性状及产量的影响

以长达20年的微量元素肥料定位实验数据为基础,分析长期施用微肥对冬小麦农艺性状及产量的影响。结果表明:长期施用微肥对冬小麦有明显的增产效果,小麦施B增产481.8 kg/hm2,增产率30.3%;施Zn增产610.8 kg/hm2,增产率38.4%;施Mn肥籽粒增产368 kg/hm2,增产率23.1%;施Cu籽粒产量无明显变化。施用微肥小麦,籽粒、秸秆中微量元素含量增加,籽粒中含锌量增加10.47 mg/kg,增加率为49.79%;秸秆中含锌量增加3.84 mg/kg,增加率为47.5%;与施KH2PO4肥相比,籽粒中含锌量增加8.03 mg/kg,增加率为33.0%;秸秆中含锌量增加4.78 mg/kg,增加率为66.8%。