吡虫啉分子印迹电化学传感器的制备及电学传感机理分析

以壳聚糖为功能基体、吡虫啉(imidacloprid,IMI)为模板分子、戊二醛为交联剂,应用恒电位沉积法制备了分子印迹电极并构建了吡虫啉印迹传感器(IMI-MIP/F-CNTs/GCE)。利用循环伏安法(cyclic voltammetry,CV)、差分脉冲伏安法(differential pulse voltammetry,DPV)及交流阻抗法(electrochemical impedance spectroscopy,EIS)考察了新型传感器对吡虫啉的检测性能并构建等效电路模型。结果表明:成功制备了新型分子印迹电化学传感器;传感器表观表面积比裸电极显著提高;新型传感器具有良好的印迹效果,相较于其他结构类似的烟碱化合物(如啶虫脒等),IMIMIP/F-CNTs/GCE对吡虫啉表现出高效的选择识别能力,且在cI M I≤1.0×10-6mol/L范围内传感器峰电流与cI M I存在定量关系;数据模拟分析获得传感器电学阻抗谱等效电路模型为R1(C1(R2(CPE2(R3)))),计算等效电路各元件参数证明该模型能有效模拟传感器检测吡虫啉的传感机理。所得结果可为烟碱类农药残留检测提供一种新的分析方法,为农药残留检测传感器分析机理研究提供有益参考。     

Persistence and metabolism of imidacloprid in different soils of West Bengal

A laboratory experiment was performed to study the persistence of imidacloprid from two formulations (Confidor 200 g litre-1 SL and Gaucho 700 g kg-1 WS), and its metabolism in three different soils (Gangetic alluvial soil of Kalyani, lateritic soil of Jhargram and coastal alkaline soil of Canning) of West Bengal following application at 0.5 kg and 1.0 kg AIha-1. Dissipation of imidacloprid in soil followed first-order kinetics and DT50 values ranged from 28.7 to 47.8 days. The shortest half-lives (28.7 and 35.8 days) were observed in the lateritic soil of Jhargram for both liquid and powder formulations. The formation of two metabolites of imidacloprid, imidacloprid-urea and imidacloprid-olefin, was first detected on day 30 of degradation at 28 (+/- 1) degrees C in all three soils.     

吡虫啉两种测定方法的比较

本文采用正相和反相高效液相色谱对吡虫啉含量进行了测定,并对同类产品进行了比较。结果表明,两种方法对吡虫啉原药及制剂的含量测定相结果对误差在允许范围内,在分离效率方面正相色谱分析更具其优越性。     

Kinetics and hydrolysis mechanism of chlorsulfuron and metsulfuron-methyl

In acidic media, hydrolysis of chlorsulfuron and metsulfuron-methyl occurs via two consecutive reactions which were followed by ultraviolet spectrophotometry. For these two reactions, the pseudo-first-order rate constants increase proportionally to the concentration of hydronium ion in the more acidic media and to the square of this concentration at higher pH values. A kinetic study by HPLC shows that the first reaction leads to the formation of 4-methoxy-6-methyl-1,3,5-triazin-2-amine and (o-chlorophenylsulfonyl) carbamic acid for chlorsulfuron or (o-methoxycarbonylphenylsulfonyl) carbamic acid for metsulfuronmethyl. The second reaction is the conversion of these sulfonylcarbamic acids to sulfonamides and carbon dioxide. The complete lack of saccharin and of o-sulfamoyl benzoic acid proves that the ester function of the methoxycarbonyl group is stable. The lack of general acid-base catalysis and a solvent deuterium isotope effect less than unity are consistent with a rate-determining cleavage of the protonated substrate. In the basic pH range (10–14) a single reaction occurs, the nucleophilic substitution of the methoxy group on the triazine by a hydroxide group.     

吡虫啉在金银花及土壤中的残留动态研究

采用HPLC DAD方法对吡虫啉在金银花及土壤中的残留动态进行研究。该方法最小检出量为0.021 2 ng,样品添加回收率为80.9%~ 84.6%,变异系数为7.74%~ 18.15%。研究结果表明：吡虫啉在金银花和土壤中的半衰期分别为1.52~ 4.65、11.07~ 19.09 d。建议金银花中吡虫啉的最大残留限量（MRL）为3.0 mg/kg;10%吡虫啉可湿性粉剂防治金银花蚜虫,用药量为30 g/hm2（有效成分）,采用喷雾的施药方法,在每茬花中最多施药2次,安全施药间隔期为7 d。     

吡虫啉在生菜中的吸收迁移及转化行为

为了探究吡虫啉在植物中的吸收转运规律,本研究选择生菜为研究对象,将其在含有1 mg/kg吡虫啉的水培液中持续暴露120 h,利用超高效液相色谱-三重四极杆质谱检测吡虫啉及其5种代谢物在生菜不同部位动态吸收变化和转运分布规律.结果表明,吡虫啉在叶部富集程度明显高于根部,当达到吸收稳定状态时,吡虫啉在叶部富集程度约为根部的...     

吡虫啉防治香蕉黄胸蓟马的减量使用技术研究

为了降低吡虫啉在香蕉果实中的残留风险,探索减量使用方法,在香蕉蓟马防控窗口期,试验比较了70%吡虫啉水分散粒剂(WG)与9种低毒药剂对黄胸蓟马的防效,并进行了该吡虫啉制剂的不同稀释倍数及与不同药剂组合使用对蓟马的防治试验。结果表明：9种对比药剂中,22.4%螺虫乙酯悬浮剂(SC)3 000倍液,20%氟啶虫酰胺SC 2 000倍液和60 g/L乙基多杀菌素SC 1 500倍液的防效最好,达80%以上,与70%吡虫啉WG 3 000倍液的防效差异不显著。70%吡虫啉WG 5 000倍药液的防效为85.7%,与1 500倍药液和3 000倍药液的防效差异不显著,但显著高于7 000倍药液的防效。70%吡虫啉WG的5 000倍液分别与2.5%高效氯氟氰菊酯水乳剂(EW)的1 500倍液、60 g/L乙基多杀菌素SC的1 500倍液、25%噻虫嗪WG的2 000倍液和70%啶虫脒WG的5 000倍液组合使用,4种不同药剂组合处理的防效均达81.4%以上,与施用2次70%吡虫啉WG 5 000倍液的防效差异不显著。通过科学选择替换吡虫啉的药剂,合理使用70%吡虫啉WG的剂量,在香蕉蓟马防控窗口期...     

Photolysis of imidacloprid (NTN 33893) on the leaf surface of tomato plants

The photolytic behaviour of the insecticide imidacloprid on the surface of tomato leaves as a result of exposure to natural sunlight was investigated. Photodegradation in sunlight was rapid and the degradation products (⩾10%) were similar to those found in plant degradation studies.     

Synthesis and insecticidal evaluation of imidacloprid analogs

Imidacloprid analogues containing a nitroalkylidene instead of a nitroguanidine unit have been prepared and evaluated for investigation as potential insecticides. No nitroalkylidene analogue showed significant activity against the test insects. © 1998 Society of Chemical Industry     

Effects of formulation on the run-off of imidacloprid from turf

Imidacloprid is a pesticide often used to control insect pests on residential lawns and golf courses. To investigate its potential to be transported into non-target aquatic systems by rainfall events, imidacloprid was applied as 5.0 g kg-1 GR and 750 g kg-1 WP to 12 plots planted with bermuda grass set on a 5% slope. The dimethylamine salt of the herbicide 2,4-D was applied simultaneously to the plots in order to normalize the results to prior trials conducted with other pesticides. At a rate of 2.5 cm h-1, 5-cm rainfall events were simulated at 24 and 48 h after application and 2.5-cm events were simulated at 96 and 192 h. After each event water was collected from each plot and analyzed by HPLC for residual insecticide or herbicide. Approximately 1.4% of the insecticide formulated as WP and 1.9% of that formulated as GR was lost from the plots after four run-off events. Of the total mass lost, 64% and 30% respectively occurred in the first and second run-off events for the WP formulation versus 75% and 20% for the GR formulation. These values compare with a total mass export of 2.6% for 2,4-D, of which 95% and 4% of the loss occurred respectively in the first and second run-off events. The maximum concentration of imidacloprid detected in run-off water was 0.49 mg litre-1 and occurred during the first run-off event.     

灭多威和吡虫啉对棉苗缩合单宁含量的影响

为明确常用杀虫剂对棉花抗虫性的影响,研究了灭多威和吡虫啉营养液处理对棉苗中抗虫次生物质缩合单宁含量的影响。结果表明,25mg/L灭多威处理3叶期棉苗后第6、9、12和15天,50mg/L灭多威处理棉苗后第6天和第15天,棉叶中缩合单宁含量均显著增加,其中25mg/L灭多威处理棉苗15天,棉叶中缩合单宁的含量较对照增加74%。50mg/L吡虫啉处理棉苗后第2天,棉叶中缩合单宁含量与对照相比增加了45%,而吡虫啉的其它处理浓度和处理时间未对棉苗缩合单宁含量产生显著影响。杀虫剂对棉苗缩合单宁含量的影响与杀虫剂本身的性质密切相关,其中灭多威对棉苗缩合单宁含量影响较大,而吡虫啉影响则较小。此外,杀虫剂对棉苗缩合单宁含量的影响还具有一定的剂量效应与时间效应。     

Metabolism of imidacloprid in Apis mellifera

Biotransformation of imidacloprid and the appearance of olefin and 5-hydroxyimidacloprid metabolites in the honeybee were studied by HPLC-MS/MS analysis. Honeybees were treated orally with imidacloprid at 20 and 50 microg kg(-1) bee. Imidacloprid was metabolised relatively quickly and thoroughly. Twenty minutes after the beginning of imidacloprid ingestion, the sum of the residues from the three compounds amounted to only 70% of the actual given dose. Imidacloprid, 5-hydroxyimidacloprid and olefin represented, respectively, 50%, 9% and 8% of the actual ingested dose. Six and 24 h, respectively, after ingestion of imidacloprid at 20 and 50 microg kg(-1) bee, imidacloprid could no longer be detected in the honeybee. Imidacloprid had a half-life ranging between 4.5 and 5 h and was rapidly metabolised into 5-hydroxyimidacloprid and olefin. Except 5-hydroxyimidacloprid in the 20 microg kg(-1) treatment, these two metabolites presented a peak value 4 h after ingestion of the 20 and 50 microg kg(-1) doses. This time fully coincided with the appearance of mortality induced by imidacloprid after acute oral intoxication. These results suggested that the immediate neurotoxicity symptoms are due to the action of imidacloprid, whereas 5-hydroxyimidacloprid and/or olefin are involved in honeybee mortality. In addition, it was likely that the 30% of residues undetected 20 min after intoxication were imidacloprid metabolites, although not 5-hydroxyimidacloprid or olefin. Thus, 5-hydroxyimidacloprid and olefin could not be the major metabolites in the worker bees.     

Uptake, translocation and bioavailability of imidacloprid in several hop varieties

The neonicotinoid insecticide imidacloprid is the most important insecticide in hop cultivation in Germany. A laboratory study was undertaken to investigate its systemic properties and translaminar bioavailability in hop leaves. Radiolabelled [methylene-14C]imidacloprid was applied either alone or in combination with different additives onto leaves of several hop varieties. Uptake and translocation were evaluated 1 and 7 days after foliar application under greenhouse conditions. The uptake of imidacloprid into hop leaves was most pronounced in the first 24 h after application and only negligible amounts were taken up after this period. Significant differences in the quantitative uptake occurred when imidacloprid was combined with additives, such as Amulsol, Genapol C-100, Hasten and LI 700. The uptake of imidacloprid applied without additives was less than 10% 7 days after application, whereas the combination with LI 700 provided 70-80% uptake. Genapol C-100 and Amulsol induced considerable phytotoxicity at the application site. Comparing hop varieties revealed differences up to twofold in foliar penetration of imidacloprid. The translaminar and acropetal bioavailability of imidacloprid foliarly applied to hop leaves was determined by a laboratory bioassay using the damson hop aphid, Phorodon humuli (Schrank). Significantly higher mortality was observed with laboratory formulations containing imidacloprid and the additive LI 700. In contrast to these results from systemic tests, contact mortality at the application site was constantly high over the testing period of 7 days, highlighting the importance of this mode of entry for aphid intoxication.     

不同浓度吡虫啉对禾谷缢管蚜酯酶的影响

采用生物化学方法研究不同剂量吡虫啉对禾谷缢管蚜酯酶活性和酶动力学参数的影响.结果表明,不同浓度吡虫啉处理禾谷缢管蚜后,可极显著诱导禾谷缢管蚜蛋白含量增加和酯酶活力增强,且不同处理组间蛋白含量差异显著,但不同剂量吡虫啉处理并未对禾谷缢管蚜酯酶动力学参数产生明显影响.不同浓度吡虫啉处理禾谷缢管蚜后,并未改变其酯酶的性质,但酯酶的表达量显著增加.     

吡虫啉对豌豆蚜的亚致死效应

室内测定了吡虫啉的亚致死剂量（LC20、LC30、LC40）对豌豆蚜的生长发育、繁殖和种群参数的影响。结果表明,随着吡虫啉亚致死剂量的增加,豌豆蚜F0代成蚜的寿命显著缩短,产蚜量显著降低。亚致死剂量也使F1代种群的内禀增长率、净增殖率和周限增长率降低,而发育历期、平均世代周期和种群加倍时间延长。     

Influence of imidacloprid seed treatments on rice germination and early seedling growth

BACKGROUND: Seed treatments with the chloronicotinyl insecticide imidacloprid (Gaucho 600 FS) were evaluated to determine whether differences in concentration and exposure regime influence the germination and early growth of rice. RESULTS: Continuous exposure to imidacloprid (4 days at 2000 mg AI L(-1)) significantly (P < 0.001) reduced normal germination by an average of 18% across the 15 cultivars examined. Nine days after sowing, plants showed no adverse effects from continuous imidacloprid treatment during germination, with shoot lengths and root system dry weights equalling, or occasionally exceeding (P < 0.05), those of untreated plants. Short-term imidacloprid exposure (2 h at 2000 mg L(-1)) at initial seed wetting did not affect germination (P > 0.05), and short-term (1 h) exposure of 48 h pregerminated seed to imidacloprid (2000 mg L(-1)) similarly had no significant effect on early subsequent growth. Plants arising from 48 h pregerminated seed exposed to imidacloprid (1 h) at concentrations up to 4000 mg L(-1) immediately before sowing were not significantly different from control plants at either 9 or 25 days post-sowing. CONCLUSION: Results show that imidacloprid will have no adverse effects on plant growth if applied to pregerminated rice shortly before sowing. Continuous exposure of seed during germination had more pronounced effects, and the initial response of different cultivars was highly variable. Cultivars with high levels of sensitivity (such as IR72) require further testing before continuous exposure to imidacloprid during germination can be recommended.     

The potential removal of imidacloprid from water by heat-treated kerolites

The adsorption of imidacloprid [1-(6-chloro-3-pyridinylmethyl)-N-nitroimidazolidin-2-ylideneamine] on heat-treated kerolite samples at 110 degrees C (K-110), 200 degrees C (K-200), 400 degrees C (K-400) and 600 degrees C (K-600) from pure water solution at 25 degrees C has been studied. The evolution of the surface properties of the kerolite samples, such as specific surface area and porosity, after heat treatment were analysed. The clays were characterised by using FTIR spectroscopy, X-ray diffraction, thermogravimetric and differential thermogravimetric analysis, surface analysis and Hg porosimetry. The experimental adsorption data points were fitted to the Freundlich equation in order to calculate the adsorption capacities (Kf) of the samples; Kf values ranged from 242 mg kg(-1) for the K-110 sample to 1005 mg kg(-1) for the K-600 sample. The values obtained for the removal efficiency (R) ranged from 62.8% for K-110 to 87.2% for K-600. The adsorption experiments showed that the stronger the heat treatment, the more effective was the adsorption of imidacloprid from pure water. This work shows the potential use of heat-activated kerolite for the removal of imidacloprid from environmental waters and drinking water resources.     

吡虫啉和毒死蜱对尿素氮在土壤中转化的影响

为了考察杀虫剂施用对尿素态氮在土壤中转化过程的影响,采用室内培养法,通过测定土壤铵态氮和硝态氮质量分数以及反硝化损失的动态变化,研究了在施用尿素的土壤（有效氮含量为200 mg/kg）中分别添加不同剂量的吡虫啉和毒死蜱2种杀虫剂时,杀虫剂对尿素的水解、土壤氮的硝化及反硝化过程的影响。结果表明:吡虫啉和毒死蜱各剂量处理在第3天时对尿素水解具有显著的促进作用（PPPPP<0.01）,减少反硝化损失量39.69%。     

吡虫啉及其复配剂不同施药方法对油菜蚜虫控制效果

2006-2009年,采用拌种和播种沟施药的方法,于河南郑州研究了新烟碱类杀虫剂吡虫啉及吡虫啉.辛硫磷复配剂对油菜蚜虫的全程控制效果。小区试验结果表明,用吡虫啉有效成分5g/kg种子拌种仅能有效控制苗期油菜蚜虫的危害,防治效果为90.79%～100%,对中后期油菜蚜虫控制效果不明显;用吡虫啉600g/hm2及吡虫啉.辛硫磷复配剂1320g/hm2采用播种沟施药对油菜蚜虫的防治效果分别为91.82%～94.49%和90.68%～95.34%;试验示范验证防治效果在92%以上,持效期长达7个月以上,可以达到一次用药控制油菜整个生长期蚜虫为害的效果,减少了用药次数,此方法简单易行、保护环境、保护天敌,是一种简化高效的具有推广价值的油菜蚜虫可持续控制技术。