新型绿色农药——光活化农药

光活化农药包括光活化杀虫剂和光活化除草剂, 与传统农药相比具有廉价、高效、无污染等优越性。光活化农药的关键是光敏剂, 在有光和氧存在条件下光敏剂催化产生单重态氧, 杀灭害虫。光敏剂效果取决于其单重态氧的量子产率, 其分子本身只起催化作用并不介入毒性反应, 并且易被降解, 因此对环境无污染。由于单重态氧在细胞上的生物化学作用点多, 使害虫不易对其产生抗药性。这类绿色农药正在逐步走向实用化, 它的发展将会大大改善因长期使用传统农药而造成的危害, 对农业发展将会产生巨大的促进作用。     

光活化农药

一、引言近年来,在农药领域出现了一类被称为光活化农药(Photoacitivated Pesticides)的新产品,这种农药在存放时并无毒性,但进入生物体后可被光激活而对摄入者起毒杀作用。     

焦脱镁叶绿酸-a作为光活化农药的光活化机理研究

介绍了焦脱镁叶绿酸-a作为光活化农药的可能性, 利用激光光解时间分辨吸收技术和自旋捕获EPR技术对其光活化机制进行了研究. 研究发现, 焦脱镁叶绿酸-a的光活化反应主要沿II型即单线态氧机制进行. 另外, 还就单线态氧对选定的光敏氧化靶分子(DNA, 亚油酸和L-色氨酸)的作用情况进行了探索.     

《有机农药及中间体质谱手册》

该书是一部有机农药及中间体与代谢物的质谱工具书。全书共收集整理了1412种有机农药及中间体与代谢物,包括有机氯杀虫剂、有机磷杀虫剂、氨基甲酸酯类杀虫剂、沙蚕毒素类杀虫剂、卫生及建筑害虫防治剂、拟除虫菊酯类杀虫剂、其他杀虫剂、杀螨剂、增效剂、杀鼠剂、杀菌剂、除草剂、植物生长调节剂及农药中间体十四部分,几乎每个品种均列出     

光动力氧活化的球堆集模型探讨

对已搜集的 30多种化合物的光动力活化作了球堆集模型的计算处理。这些事例的各种效应可用化合物有关组成组合的∑e=n× 13± 8及∑A =m× 13.6 6或∑A± 16 =m× 13.6 6双重满堆模式概括地说明。对1O2 的产生、抑制、消除或转化为3O2 作了球堆集式的分析。对硒的光电效应、光纤传导、光活化农药及光动力医疗等现象予以统一的理论说明。     

有机磷杀虫剂

世界农药生产与研究工作的巨大增长,是由于有机合成杀虫剂的发展而引起的;这是第二次大战前后的事。在这以前农药生产的主要对象是无机产品与植物浸剂。有机合成杀虫剂中首先发展的是氯化烃类杀虫剂,有机磷杀虫剂的发展是比较晚些。由于有机磷杀虫剂有很多的特点,经过二十年来的发展,大大巩固了它在杀虫剂中的地位。目前其锋芒已分别超过其他类型的药剂,甚至氯化烃类。有机磷杀虫剂的优点可大致概括为五方面:     

《有机农药及中间体质谱手册》

该书是一部有机农药及中间体与代谢物的质谱工具书。全书共收集整理了1412种有机农药及中间体与代谢物,包括有机氯杀虫剂、有机磷杀虫剂、氨基甲酸酯类杀虫剂、沙蚕毒素类杀虫剂、卫生及建筑害虫防治剂、拟除虫菊酯类杀虫     

《有机农药及中间体质谱手册》

该书是一部有机农药及中间体与代谢物的质谱工具书。全书共收集整理了1412种有机农药及中间体与代谢物,包括有机氯杀虫剂、有机磷杀虫剂、氨基甲酸酯类杀虫剂、沙蚕毒素类杀虫剂、卫生及建筑害虫防治剂、拟除虫菊酯类杀虫     

《有机农药及中间体质谱手册》

该书是一部有机农药及中间体与代谢物的质谱工具书。全书共收集整理了1412种有机农药及中间体与代谢物,包括有机氯杀虫剂、有机磷杀虫剂、氨基甲酸酯类杀虫剂、沙蚕毒素类杀虫剂、卫生及建筑害虫防治剂、拟除虫菊酯类杀虫     

化学学报第六十四卷2006年总目次

第一期CXN天然沸石的研究VII.骨架高硅超稳化改性.........................................................................................................................................................程晓维汪靖张枚钟鹰黄强龙英才*(1)4,6-二甲氧基-2-[甲氧脲基硫代脲基]嘧啶的合成、晶体结构和理论计算..............................................................................................................黄洁宋纪蓉*任莹辉马海霞王花丽胡怀明文振翼(9)焦脱镁叶绿酸-a作为光活化农药的光活化机理研究......…     

An Efficient Synthesis of Pyrethroid Insecticides Containing Spiro-fused Cyclopropane Carboxylate

Among the active pyrethroid insecticides containing various substituted cyclpropanecarboxylates, esters derived from 2,2-dimethyl-5,6-benzospiro [2,4] heptene-1-carboxylic acid (1) have been 1 found to have particularly high activity, Our continuing interest in the synthesis of novel pyrethroid insecticides2 led us to a study of synthetic methodology for constructing spiro-fused systems such as (1).     

Separation of pesticides by capillary gas chromatography. Part 2: Organophosphorus insecticides

This article considers the separation of 23 organophosphorus insecticides to which two metabolites have been added. The high resolution of the column permits detection of the Z and E isomers of three of these insecticides.     

Determination of trace arsenic(III) by differential-pulse anodic stripping voltammetry with in-situ plated bismuth-film electrode

Abstract

A systematic survey of the quality status of the main aquifers in rural areas of Catalonia (Spain) regarding pesticide pollution has been carried out. A total number of 139 wells, distributed among 13 different hydrogeological units have been sampled and analyzed by GC-MS and GC-ECD, during the period 1997—98. Pesticides monitored were selected among triazine herbicides, organochlorine and organophosphorus insecticides. A positive presence of pesticides has been detected in 84.2% of the samples analyzed, 23.7% of them exceeding the requirements of the EU drinking water Directive (98/83/CE). Organochlorine insecticides were present in 62.6% of the samples, triazines in 49% and organophosphorus insecticides in 28.8%. The results obtained have been interpreted by Principal Component Analysis.     

Multiresidue determination of thermolabile insecticides in cereal products by gas chromatography-mass spectrometry: evaluation with on-column injection and conventional hot splitless injection

This communication presents a study on the simultaneous determination of thermolabile N-methylcarbamate and organophosphorus insecticides in cereal products by gas chromatography-mass spectrometry. The thermal stability of the multiple insecticides was evaluated with conventional hot splitless injection and on-column injection. The results obtained by GC-MS with these two injection techniques were compared in terms of the recovery, the limit of detection, the limit of qualification, and the reproducibility. With on-column injection, the pesticide recoveries in cereal samples were better than 82%, with relative standard deviations lower than 5.4%. The limits of qualification for most insecticides were in the range of 0.009-0.08 mg/kg, i. e. lower than the maximum residue limits established for insecticides in cereal products by the European Union. The long-term stability using on-column injection for analysis of insecticides in real samples was evaluated and normal chromatographic performance could be obtained within 50 analyses. The results revealed that it was possible for application of on-column injection in the analysis of thermolabile multiple insecticides in food sample after comprehensive sample clean-up, despite the highly contaminated nature of the column system.     

The impact of insecticides containing deltamethrin and cyfluthrin on the composition of surface compounds in the larvae,females and males of Tenebrio molitor

This paper presents the effect of insecticides on the composition of the surface compounds of one of the most harmful insects, Tenebrio molitor, by analysis using GC–MS. As a result of the use of insecticides, the composition of the chemical compounds on the surface of insects changes, depending on the insecticides used. The most numerous groups of the marked compounds were fatty acids, alkanes, esters and sterols. The content of the identified compounds in the larvae increased at both 24 and 48 h after the application of insecticides, in comparison with the control samples. The content of identified compounds in the samples taken from the females increased 24, 48 and 72 h after the application of insecticides in comparison with the control samples. By contrast, in samples prepared from males, the content of identified compounds decreased 24 h after the application of insecticides, compared with the control samples. The highest content of chemical compounds was for fatty acids and alkanes after the use of insecticides. The content of fatty acids after the application of the insecticide with deltamethrin was 62.1 ± 3.3–466.9 ± 5.9 μg/g, and after the application of the insecticide with cyfluthrin was 49.9 ± 1.9–458.3 ± 4.2 μg/g. However, the content of alkanes after the use of deltamethrin was 115.6 ± 4.2–4672.0 ± 32.1 μg/g, and after the use of cyfluthrin was 189.4 ± 3.8–3975.0 ± 10.2 μg/g.     

Die Neonicotinoide. Nicotin und die Neonicotinoide – Teil 2

The cholinergic synapse is an important target for many highly selective insecticides. Nicotine and the neonicotinoids bind to the postsynaptical nicotinic acetylcholine receptor. The neonicotinoids did not derive of lead‐optimisation of natural products, e.g. nicotine or epibatidine, but from artificial nitro‐substituted ketene aminales. Today, the neonicotinoids are attributed as the most important group of insecticides on the crop protection market. Many smart syntheses have been published.     

Thin-layer chromatographic detection of pyrethroid insecticides containing a nitrile group.

A spray reagent for the detection of pyrethroid insecticides containing a nitrile group by thin-layer chromatography is described. These insecticides on alkaline hydrolysis yield cyanide ion, which in turn reacts with copper(II) acetate and o-tolidine in an acetic acid medium to give a blue colour. Organochlorine, organophosphorus and carbamate insecticides do not interfere. The limit of detection is about 1 microgram.     

Syntheses of Pyrethroid Acids

In the course of the last decade the chemistry of insecticides was expanded with the discovery of new cyclopropanecarboxylic acid esters of specific structure, far superior in action to the hitherto known insecticides of other substance classes or the natural prototypes from the group of pyrethrum constituents. The discovery quickly precipitated a host of wide-ranging studies on the synthesis of these compounds. The development of selective methods of synthesizing complicated small rings called for a comprehensive repertoire: thus, synthesis of the compounds on an industrial scale makes use of sigmatropic rearrangement, radical addition, and nucleophilic ring closure with carbanions. These new industrial syntheses have acquired particular topicality because of their use of stereospecific and enantioselective methods.     

Electronic structure and biological activity of chosen DDT-type insecticides studied by 35Cl-NQR

A correlation between the electronic structure and biological activity of chosen dichlorodiphenyltrichloroethane (DDT)-type insecticides: 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane, 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane, 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene, 2,2-bis(4-chlorophenyl)ethanoic acid and 4,4'-dichlorobenzophenone (used in agriculture) has been analysed on the basis of the (35)Cl-nuclear quadrupole resonance (NQR) spectroscopy. The (35)Cl-NQR resonance frequencies measured at 77 K have been correlated with the lethal dose (LD(50)) parameter that characterises the biological activity of these insecticides.     

Dispersive liquid‐phase microextraction in combination with HPLC for the enrichment and rapid determination of benzoylurea pesticides in environmental water samples

Benzoylurea (BU) insecticides have contributed greatly to the output of crops. Their residue in the environment put serious threats on human health and environmental safety. In this study, we have established a new, rapid, and reliable method for the monitoring of typical BU insecticides such as diflubenzuron, flufenoxuron, triflumuron, and chlorfluazuron with dispersive liquid–liquid microextraction prior to HPLC. Chlorobenzene and ethanol were employed as the extraction solvent and disperser solvent, respectively. The possible parameters which would influence the extraction efficiency such as the kinds and volumes of extraction and disperser solvents, extraction time, sample pH, centrifuging time, and salting‐out effect were optimized in detail. Under the optimal conditions, the linear range of proposed method was in the range of 1.0–70 μg/L. The detection limits varied from 0.24 to 0.82 μg/L and the precision of the method was <6.5% (RSD, n = 6). The proposed method was validated with real water samples and satisfactory spiked recoveries were achieved. All these results indicate that the proposed method is a low cost, easy to operate, efficient, and sensitive method for the analysis of BU insecticides in water samples.