0.4%氯菊酯·氯氰菊酯水乳剂的液相色谱分析

介绍了用高效液相色谱法,采用Hypersil SiO2色谱柱,以异辛烷+1,4-二氧六环为流动相,在230nm下检测,外标法定量分析氯菊酯和氯氰菊酯的方法.方法的标准偏差分别为0.0084和0.0084,变异系数分别为4.0%和3.8%,回收率分别为99.31%～100.36%和98.32%～100.09%.     

Low temperature cleanup combined with magnetic nanoparticle extraction to determine pyrethroids residue in vegetables oils

To quantify trace pesticide residue in vegetable oil rapidly, low temperature cleanup combined with magnetic nanoparticle based solid phase extraction was developed to determine eight pyrethroids in vegetable oils, including tetramethrin, fenpropathrin, cypermethrin, decamethrin, fenvalerate, acrinathrin, permethrin and bifenthrin. Polystyrene coated magnetic nanoparticles were synthesised by a modified chemical coprecipitation combined with emulsion polymerisation method. The nanoparticles were afterwards characterised by Fourier transform-infrared spectroscopy, X-ray diffraction, transmission electron microscopy as well as vibrating sample magnetometer, and successfully employed as adsorbents for the magnetic solid phase extraction of pyrethroids which were cleaned up using low temperature approach in advance. Critical impact factors on the efficiency of the extraction method such as the mass of adsorbents used, volume and type of eluent solvent, extraction time as well as elution time were optimised subsequently. Regression analysis of the calibration curves of the eight pyrethroids yielded satisfactory correlation coefficients within the range of 0.980–0.998. Limit of detection and limit of quantification were calculated to be between 0.0290-0.0658 and 0.0890–0.1994 ng g⁻¹, respectively. Intra-day and inter-day reproducibility at different concentration levels also produced satisfactory recovery rates of 83.18–112.79% with relative standard deviations not exceeding 10.84% and 12.01%, respectively, suggesting desirable stability of the proposed method.     

双甲脒与氰戊菊酯或氯氰菊酯混用对烟蚜的药效

用浸渍法测定了双甲脒与氰戊菊酯或氯氰菊酯混用对烟蚜Myzuspersicae(Sulzer)的毒力。结果表明 ,当双甲脒与氰戊菊酯以 1∶2、1∶5和 2∶1的比例混用时表现为药效增效作用 ,其中以 1∶2配比共毒系数最大。当双甲脒与氯氰菊酯以 1∶1、1∶2、2∶1和 5∶1的比例混用时表现为药效增效作用 ,其中以 1∶1配比共毒系数最大。并对双甲脒与拟除虫菊酯类杀虫剂混用防治蚜虫的配比进行了讨论     

氯氰·马拉松乳油气相色谱分析方法研究

采用气相色谱法同时测定氯氰·马拉硫磷乳油中两种组分的含量,以癸二酸二丁酯为内标物,HP-5石英毛细管色谱柱分离,FID检测。试验结果表明:该方法在一定质量浓度范围内成良好的线性关系,相关系数r氯氰=0.9999、r马拉硫磷=0.9998,氯氰和马拉硫磷的标准偏差分别为0.018、0.122,变异系数分别为0.756%、0.665%,平均回收率分别为99.5%、99.7%。     

Residues of cypermethrin in field-treated grapes and raisins produced after various treatments

Residues of the synthetic pyrethroid insecticide cypermethrin in fresh grapes of cv. Thomson Seedless and in raisins were studied. The commercial formulation Cymbush® 10% EC was applied according to the label onto the typical seedless variety and on a seed-producing clone. Samples were collected at time zero and at 15 or 21 days post-application. The raisins were produced either by submersion for 3 min in an aqueous solution of 3% potassium carbonate and 1% ethyl oleate, and dried for 15 days under direct sunlight or were dried without chemical processing. A gas chromatographic method was used for the analysis of residues. The residues in the grapes at the recommended preharvest interval (15 days) ranged from 0.23 to 0.41 mg kg -1 , whereas those in raisins ranged from 0.25 to 0.46 mg kg -1 .     

The impacts of cypermethrin pesticide application on the non-target microbial community of the pepper plant phyllosphere

Although pesticides have been extensively used for controlling insects and disease pathogens of plants, little is known regarding the impacts of applying these pesticides on the microbial community in the plant phyllosphere. Here, we report the effects of cypermethrin pesticide application upon the microbial community of the pepper plant phyllosphere. Assessments were made using culture-independent techniques including phospholipid fatty acid analysis (PLFA) and 16S rRNA gene directed Polymerase Chain Reaction with Denaturing Gradient Gel Electrophoresis (PCR-DGGE). During the 21 day greenhouse study, PLFA results indicated that both total and bacterial biomass increased after application of the pesticide. PLFA profiles also indicated that Gram-negative bacteria became predominant. DGGE analysis confirmed a significant change in bacterial community structure within the phyllosphere following the pesticide application where different dendrogram clusters were observed between control and treated samples. Phylogenetic analysis also suggested a change in bacterial phyla following treatment, where bands sequenced within control cultures were predominantly of the Firmicutes phylum, but those bands sequenced in the treated samples were predominantly members of the Bacteroidetes and γ-Proteobacteria phyla. In conclusion, this study revealed an increase in bacterial abundance and a shift in community composition within the pepper plant phyllosphere following the pesticide application, and highlighted the effective use of PLFA and PCR-DGGE for studying the effect of pesticides upon indigenous phyllosphere microbes.     

氯氰菊酯和溴氰菊酯杀虫活性与电子结构关系的理论研究

用AM1法计算了氯氰菊酯和溴氰菊酯的电子结构,用分子中原子的净电荷、能量讨论了两种杀虫剂杀虫活性的差异.     

Residual toxicity of a commercial cypermethrin formulation on grains against four major storage beetles

In the present study, we investigated the residual insecticidal efficacy of a commercial cypermethrin formulation applied on grains (wheat, maize) against adults of Sitophilus oryzae (L.), Oryzaephilus surinamensis (L.), Rhyzopertha dominica (F.) and Prostephanus truncatus (Horn) in laboratory bioassays. The insecticide was applied in its label dose on the grains and a bioassay was initiated at the day of application and every month for four consecutive months (5 bioassays in total). In each bioassay, adult mortality levels were determined after exposure for 7, 14 and 21 d. After the final evaluation, all beetles (dead and alive) were removed and the number of offspring was assessed after an additional interval of 65 d. Based on our results, the application of the tested cypermethrin formulation as a grain protectant provided long-term protection against R. dominica and P. truncatus adults, as in most cases complete control was achieved for these two species, even after four months of storage of the treated commodities. In the case of S. oryzae and O. surinamensis, adult mortality did not reach 100% in any of the cases, moreover, a gradual decline of mortality levels was recorded over the 4-month period of storage. Finally, for S. oryzae and P. truncatus progeny production was notably suppressed by cypermethrin. Results show that the cypermethrin formulation tested could be a valuable tool for stored grain protection, however, factors such as the target species and the storage interval should be taken into consideration.     

HPLC法检测米曲霉降解体系中氯氰菊酯前处理方法的研究

针对霉菌降解体系中氯氰菊酯HPLC检测结果重复性差的问题,系统研究了HPLC法检测米曲霉降解体系中氯氰菊酯的前处理方法。结果表明,采取培养液全量取样方式可以解决降解体系中氯氰菊酯分散或分布不均的问题;超声辅助乙腈提取法可使菌体内蓄积或菌体表面吸附的氯氰菊酯得到有效释放。HPLC法对经前处理后降解体系中氯氰菊酯含量进行检测,具有精密度高、重复性和稳定性好、加标回收率高的特点。该方法的建立为微生物降解体系中拟除虫菊酯类农药的准确检测提供了方法参考。     

20%吡虫啉+15%氯氰菊酯悬浮乳剂的研制

通过对分散剂、乳化剂等助剂的筛选,确定了20%吡虫啉＋15%氯氰菊酯悬浮乳剂的最佳配方,各项指标均达到相关标准。