A test house study of pesticides and pesticide degradation products following an indoor application

Preexisting pesticide degradates are a concern for pesticide biomonitoring studies as exposure to them may result in overestimation of pesticide exposure. The purpose of this research was to determine whether there was significant formation and movement, of pesticide degradates over a 5‐week period in a controlled indoor setting after insecticide application. Movement of the pesticides during the study was also evaluated. In a simulated crack and crevice application, commercially available formulations of fipronil, propoxur, cis/trans‐permethrin, and cypermethrin were applied to a series of wooden slats affixed to the wall in one room of an unoccupied test house. Floor surface samples were collected through 35 days post‐application. Concentrations of the pesticides and the following degradates were determined: 2‐iso‐propoxyphenol, cis/trans 3‐(2,2‐dichlorovinyl)‐3‐3‐dimethyl‐(1‐cyclopropane) carboxylic acid, 3‐phenoxybenzoic acid, fipronil sulfone, fipronil sulfide, and fipronil desulfinyl. Deltamethrin, which had never been applied, and chlorpyrifos, which had been applied several years earlier, and their degradation products, cis‐3‐(2,2‐dibromovinyl)‐2,2‐dimethylcyclopropane‐1‐carboxylic acid, and, 3,5,6‐trichloro‐2‐pyridinol, respectively, were also measured. Propoxur was the only insecticide with mass movement away from the application site. There was no measurable formation or movement of the degradates. However, all degradates were present at low levels in the formulated product. These results indicate longitudinal repetitive sampling of indoor degradate levels during short‐term studies, is unnecessary.     

氟虫腈为配基的亲和介质制备及鱼类GABA受体纯化

以琼脂糖凝胶(Sepharose)CL-6B为载体,衍生化的氟虫腈为亲和配基,制备亲和层析介质,对其进行FT-IR和XPS表征。用制备的亲和层析介质分离鱼类脑组织中的GABA(γ-氨基丁酸)受体,研究分离蛋白质的效率。结果表明,成功将氟虫腈作为配体偶联到亲和介质上,偶联量为36.68μmol/g胶;SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)显示两条蛋白质条带,其相对分子质量约为44 kD和55 kD。     

固相萃取和气相色谱法测定大米中氟虫腈(锐劲特)残留

建立运用固相萃取技术检测大米中的氟虫腈残留的气相色谱分析方法。样品经过乙腈/丙酮(70/30)抽提,通过硅酸镁(Florisil)固相萃取(SPE)小柱净化,旋转蒸干后用乙腈定容,应用微池电子捕获检测器(μ ECD)检测。样品在10 μ g/kg、15 μ g/kg和30 μ g/kg三个浓度水平添加,回收率为83.18%、 84.49%和88.85%,方法变异系数为1.60%、 1.89%和1.54%。本方法在大米样品中的最低检测定量限为10 μ g/kg     

Effective Degradation of Fipronil Using Combined Catalytic Ozonation Processes

Effective removal of Fipronil, an agricultural pollutant, was studied here by coupling heterogeneous catalyst (Degussa P-25 TiO₂ nanopowder) with molecular ozone. Compared to molecular ozone alone (74%), enhanced activity (89%) was noted with a coupled TiO₂/O₃ system at 40 min, which is due to the generation of active superoxide ion species by surface adsorption and reaction of TiO₂ with the molecular ozone. The catalytic activity quantification was followed by liquid chromatography with electrospray ionization-tandem mass spectrometry.     

2，6—二氯—4—三氟甲基苯胺的合成

锐劲特是新型吡唑类广谱杀虫剂,2,6-二氯-4-三氟甲基苯胺是其关键中间体。对以4-三氟甲基苯胺、硫酰氯、氯仿等为原料合成2,6-二氯-4-三氟甲基苯胺进行了研究。确定了最佳工艺条件：4-三氟甲基苯胺：硫酰氯=1:3.0(mol比）;反应时间为4h。产品收率为88.0%。     

Household processing factors of acrinathrin,fipronil, kresoxim-methyl and pyridaben residues in green beans

The influence of household washing and boiling processes on the residue levels of acrinathrin, fipronil, kresoxim-methyl and pyridaben in green beans was studied. The study was conducted on green beans samples collected from an experimental greenhouse during a two weeks period after treatment. Analyses were carried out by QuEChERS extraction method and gas chromatography with electron-capture detection (GC/ECD). Pesticide levels in the unprocessed green beans samples where within the range of 0.1 and 4 mg/kg. The washing processing factors were 0.51 for fipronil, 0.32 for pyridaben, 0.59 for acrinathrin and 0.38 for kresoxim-methyl whereas the boiling factor ranged between 0.50 and 0.72.     

氟虫腈的催化氧化合成研究

氟虫腈是一高效、广谱的吡唑类杀虫剂,以5-氨基-3-氰基-1-（2,6-二氯-4-三氟甲基苯基）-吡唑为原料,经硫氰化、缩合、催化氧化合成了氟虫腈。     

杀虫剂氟虫腈的合成研究进展

氟虫腈是一种专利保护即将过期,低毒、高效的杀虫剂,在国内有较好的市场前景,概要地叙述了其性状、毒性、合成路线和展望。     

0.3%锐劲特颗粒剂防治稻水象甲及兼治螟虫试验

试验结果表明：０．３％锐劲特颗粒剂防治稻水象甲成虫、幼虫速效性好，并且有持效，对一代二化螟也有兼治效果。田间药量１５００～２０００ｇ／６６７ｍ＾２，防治稻水象甲成虫效果达８１．７％～１００％，同时对照药剂２０％三唑磷１００ｍｌ／６６７ｍ＾２和３％呋喃丹颗粒剂１５００ｇ／６６７ｍ＾２药剂相当，防治劲虫效果达７７．３％～１００％，对螟虫兼治效果均在６０％～８０％之间，好于上述两种对照药。     

Enantioselective degradation of fipronil in Chinese cabbage (Brassica pekinensis)

Chiral pesticide enantiomers often show different bioactivity and residual toxicity, but this property is usually ignored when evaluating the environmental risk and public safety. In this study, a convenient and precise chiral method was developed and validated for measuring fipronil enantiomers in Chinese cabbage (Brassica pekinensis) based on a high-performance liquid chromatography (HPLC) using (R,R) Whelk-O 1 column. Then the proposed method was successfully applied to the study of enantioselective degradation of fipronil in Chinese cabbage under field conditions. The results showed that the degradation of the two enantiomers in Chinese cabbage was proved to be enantioselective and followed pseudo first-order kinetics (R² ? 0.98). The (R)-enantiomer degraded faster than the (S)-enantiomer, resulting in the relative enrichment of (S)-enantiomer in residue. The detected metabolites MB46513 (desthio), MB45950 (sulfide) and MB46136 (sulfone) by GC–MS suggested that degradation was mainly contributed by oxidization, reduction and photodegradation. Due to the more insecticide activity and lower mammalian toxicity of S-form, the higher concentration of S-fipronil may result in higher activity in crop protection and lower risk to environment and human beings compared to the recemate. This result should be considered in future environmental risk and food safety evaluation.