氰戊菊酯和甲氰菊酯对棉铃虫的亚致死效应

本文通过饲喂法测定了氰戊菊酯、甲氰菊酯两种拟除虫菊酯杀虫剂亚致死剂量(LC1与LC50)对棉铃虫3龄幼虫拒食、体重、生长发育以及驱避作用的影响。结果表明,各处理棉铃虫3龄幼虫,取食量均低于对照。处理后48h,LC50剂量以氰戊菊酯拒食活性较高,拒食率为38.65%,且LC50剂量的各处理与对照差异显著。所有处理对棉铃虫幼虫—蛹、蛹—成虫的存活率都有影响。药剂处理后,幼虫的历期延长,幼虫的化蛹也受到影响,出现畸蛹,但各处理畸蛹率均低于15%。亚致死剂量杀虫剂对棉铃虫的生长发育、幼虫体重及蛹重都有抑制作用。在LC1与LC50剂量下,两种药剂对棉铃虫也表现出驱避作用。处理48h,氰戊菊酯LC1与LC50剂量的驱避率分别为76.25%与98.75%。这些研究结果显示,低剂量的拟除虫菊酯对棉铃虫生物学方面存在不良影响。     

Determination of pyrethroids in chicken egg samples: development and validation of a confirmatory analytical method by gas chromatography/mass spectrometry

The aim of this study was to develop and validate an efficient analytical method based on gas chromatography/tandem mass spectrometry (GC/MS/MS) for detection and quantification of six pyrethroids residues (Phenothrin, Permethrin, Cyfluthrin, Cypermethrin, Deltamethrin and Fenvalerate) in chicken eggs. The method was based on a preliminary liquid–liquid extraction of albumen‐free yolk samples, followed by a clean‐up by solid‐phase extraction. GC/MS/MS analyses were carried out in the selected reaction monitoring mode. Validation parameters such as specificity, detection capability, decision limit, precision, recovery, stability and ruggedness were determined, resulting in compliance with Decision 2002/657/EC. No complicated apparatus are required; moreover, low volumes of organic solvents and a nonintensive manual labour are required. These low costs and simple procedure, based on rapid and safe operations, may represent a useful tool in the routine analysis of pyrethroids pesticides, in the place of the currently used conventional techniques.     

基质固相分散-气质联用法测定荞头中多种拟除虫菊酯类农药残留量

试样中加入石墨化碳黑-XAD-2担体（质量比1：1），分散混匀，再用丙酮-正己烷（体积比1：2）提取，提取液浓缩后用GC-MS测定，外标法定量。当添加水平为0．025mg／kg-1.0mg／kg时，方法回收率在72．1％-127．8％之间。RSD为1．5％-16．6％，检出限是0．025mg／kg-0．060mg／kg。采用保留时间和选择监视离子丰度比对阳性样品进行确证。该法简便、快速、灵敏，各项技术指标均满足残留检测的要求。     

新型肟醚拟除虫菊酯化合物杀粘虫活性3D-QSAR研究

用比较分子力场分析（CoMFA）方法对50个自主设计并合成的新型芳基烷基肟醚化合物杀粘虫活性的定量构效关系进行了研究。所得模型交叉验证参数q^2为0．598，非交叉验证相关系数r^2为0．949，标准偏差SE=0．136，F=92．419，影响药效的立体场与静电场的贡献分别50．6％和49．4％。CoMFA等值线图表明化合物肟苯环对位取代基是影响其杀粘虫活性的主要因素，体积和电性增加有利于提高化合物的杀粘虫活性。该模型三维等值线图为该类化合物的结构改造提供了理论依据。     

偏氯代含氟氰菊酯的生物活性研究

偏氯菊酸α-氰基-4-氟-3-苯氧基苄酯是一类新型拟除虫菊酯。它对淡色库蚊幼虫的相对杀死毒力是溴氰菊酯的2.3～10.5倍;对农业中的三大类典型害虫(粘虫、蚜虫、螨虫)的平均杀死率分别为66.7%(1mg/L),84.3%(1mg/L)和91%(50mg/L),表现出高杀死活性;对大鼠急性经口毒性分别为LD50=116.5mg/kg(雄性)和158mg/kg(雌性)。     

拟除虫菊酯异构体差异降解与转化

拟除虫菊酯为手性化合物,有多个立体异构体.从顺反异构体、光学异构体两方面对拟除虫菊酯异构体的降解差异及稳定性差异进行了综述.     

Residue analysis of 500 high priority pesticides: Better by GC–MS or LC–MS/MS?

This overview evaluates the capabilities of mass spectrometry (MS) in combination with gas chromatography (GC) and liquid chromatography (LC) for the determination of a multitude of pesticides. The selection of pesticides for this assessment is based on the status of production, the existence of regulations on maximum residue levels in food, and the frequency of residue detection. GC-MS with electron impact (EI) ionization and the combination of LC with tandem mass spectrometers (LC-MS/MS) using electrospray ionization (ESI) are identified as techniques most often applied in multi-residue methods for pesticides at present. Therefore, applicability and sensitivity obtained with GC-EI-MS and LC-ESI-MS/MS is individually compared for each of the selected pesticides. Only for one substance class only, the organochlorine pesticides, GC-MS achieves better performance. For all other classes of pesticides, the assessment shows a wider scope and better sensitivity if detection is based on LC-MS.     

Genotoxic and mutagenic effects of permethrin in mice: Micronuclei analysis in peripheral blood erythrocytes

Pyrethroids such as permethrin are synthetic compounds widely used in the agriculture of many countries to combat plagues and in domestic products, such as acaricides. Not so long ago these chemicals were characterized as non‐toxic for non‐target organisms; however, recent studies have showed that these compounds could present toxic potential for many organisms. In this sense, this study presents genotoxic and mutagenic potential of permethrin administered intraperitoneally in mice under artificial conditions by the use of micronucleus assay in the peripheral blood of these animals. The mice were divided into five groups: group I = negative control (distilled water), group II = positive control (cyclophosphamide), group III = 30% of permethrin LD₅₀ (96 mg/kg), group IV = 50% of permethrin LD₅₀ (160 mg/kg), and group V = 80% of permethrin LD₅₀ (256 mg/kg). The peripheral blood was collected 24, 48, and 72 h after treatment. Results showed that all the tested permethrin dosages presented genotoxic and mutagenic effects 24 h after treatment, which would contradict the classification of this chemical product as moderately toxic, i.e., unable to cause damages to the cell DNA. Microsc. Res. Tech. © 2012 Wiley Periodicals, Inc.     

平菇及其培养料中5种拟除虫菊酯类农药的残留消解动态

在确证平菇培养料中联苯菊酯、甲氰菊酯、高效氟氯氰菊酯、高效氯氰菊酯和溴氰菊酯5种拟除虫菊酯类农药多残留分析方法的基础上,研究供试拟除虫菊酯类农药在平菇和培养料中的消解动态规律。结果表明:5种供试拟除虫菊酯类农药在平菇和培养料中的消解半衰期分别为3.01～5.06、25.48～54.59d。平菇培养料的灭菌会显著减少其中拟除虫菊酯类农药的残留量,降解率达18.80%～61.16%。平菇在含有联苯菊酯等5种拟除虫菊酯类农药的培养料中栽培42、62、83、103d后,培养料中供试农药残留量仍较高,分别为1.29～7.40、1.55～6.81、0.32～1.78、0.14～1.76mg/kg,同步采集的平菇子实体中均未检测到供试农药的残留量。因此,平菇培养料中供试拟除虫菊酯类农药残留不会向平菇子实体转移,对食用菌产品质量安全的影响较小。     

Dietary exposure of Hong Kong adults to pesticide residues: results of the first Hong Kong total diet study

The use of pesticides and other chemicals has become a common practice in modern agriculture to enhance and stabilise crop yield, protect the nutritional integrity of food, facilitate food storage to assure year-round supplies, and provide attractive and appealing food products. With the adoption of strict good agricultural practice (GAP), only minimal amounts of pesticide residues should remain on the crops or in connected foods of animal origin up the food chain. To assess their associated health risk to local people, the dietary exposure of Hong Kong adults to residues of four groups of pesticides or their metabolites – organophosphorus pesticides (OPPs), carbamates, pyrethrins and pyrethroids, and dithiocarbamate (DTC) metabolites – is estimated in the first Hong Kong Total Diet Study (TDS). A total of 150 commonly consumed food items were collected and prepared “as consumed”. A total of 600 composite food samples were analysed for 85 pesticides or their metabolites by liquid chromatography-tandem mass spectrometry (LC-MS/MS). These pesticides were primarily found at low levels (highest mean = 350 μg kg^?1) in food samples of plant origin such as vegetables and fruits. Dietary exposures to pesticide residues were estimated based on the analytical results and the food consumption data of the local residents. The estimated dietary exposures of Hong Kong adults to all individual pesticides were well below their respective acceptable daily intakes (ADIs). The percentage contributions of the estimated mean and 95th percentile dietary exposures to the ADIs of individual pesticides were <6% and <24% for the OPPs, <1% for the carbamates and pyrethrins and pyrethroids, and <1% and <4% for the DTC metabolites, respectively. The findings indicate that dietary exposures to all the pesticide residues analysed in this study were unlikely to pose unacceptable health risks to the Hong Kong population.