Direct Electron Capture Gas Chromatography of 2,3-Dihydro-2,2-Dimethyl-3-Oxo-7-Benzofuranyl N-Methylcarbanate: A Metabolite of Carbofuran Insecticide

Abstract

An electron capture gas chromatographic method utilizing a short glass column of 3% OV-210 at 155°C, has been developed for the direct quantitative determination of 3-oxocarbofuran (3, 3-dihydro-2,2-dimethyl-3-oxo-7-benzofurariyl N-methylcarbamate). The method is rapid, convenient, and does not require the formation of a derivative. Sensitivity permits the detection of quantities as low as 1 ppb in water samples. There was little response to 3-hydroxycarbofuran, 10 ng producing only a small peak. There was no response to carbofuran.     

Preparation,Identification, and Preliminary Application of Monoclonal Antibody Against Pyrethroid Insecticide Fenvalerate

Monoclonal antibodies (MAbs) against pyrethroid insecticide fenvalerate were achieved, identified, and applied in environmental water. Mice were immunized with a novel synthesized hapten conjugated with bovine serum albumin (BSA). Three positive clones of MAbs were obtained after cell fusion and hybridoma selection, among them MAb-2 (5B10) showed the highest reactivity toward fenvalerate. The IC₅₀ of MAb-2 was 94.5 ng mL^?1; moreover, it showed lower cross-reactivity with other pyrethroids such as bifenthrin, tetramethrin, deltamethrin and beta-cypermethrin. Optimization of enzyme-linked immunosorbent assay (ELISA) was studied. The limit of detection (LOD) of the assay was 8.8 ng mL^?1 and the detection range was 0.017–27.33 μg mL^?1. For preliminary application, addition recovery experiments in water samples were performed. The mean recoveries of three kinds of samples varied from 90.6% to 108.7% and the coefficients of variation ranged from 0.5% to 5.3%. The results showed that MAb-2 could be used for the detection of fenvalerate contamination in environmental water.     

Determination of Pesticides in the Rhizome of Traditional Chinese Medicines by Gas Chromatography with Electron Capture Detection

A simple and efficient gas chromatography method for the determination of 27 organochlorine and pyrethroid pesticides in traditional Chinese medicine was developed. Pesticide residues were extracted from the samples by oscillation and ultrasound, and purified by gel permeation chromatography and florisil solid phase extraction. The analysis was performed by gas chromatography with micro-electron capture detection. The purification conditions, such as the extraction and elution solvents, extraction methodology, and gel permeation chromatography conditions, were optimized. Traditional Chinese medicines were purified by different methods based on their composition. Under optimized conditions, the calibration graph was linear from 10 to 500 µg/L and the correlation coefficients varied from 0.9958 to 0.9997. The detection limits of these pesticides were between 0.09 and 1.82 µg/kg. The recovery of the pesticides spiked in various samples at four concentrations ranged from 73.2% to 106.4%, with relative standard deviations between 1.0% and 14.0%. This study indicates that the method is useful for determining pesticides in rhizome traditional Chinese medicines.     

Immersed sol‐gel based amino‐functionalized SPME fiber and HPLC combined with post‐column photochemically induced fluorimetry derivatization and fluorescence detection of pyrethroid insecticides from water samples

A method based on direct immersion solid‐phase microextraction (DI‐SPME) coupled with high performance liquid chromatography combined with post‐column photochemically induced fluorimetry derivatization and fluorescence detection (HPLC‐PIF‐FD) was developed to extract three pyrethroid insecticides, i.e. cyfluthrin, cypermethrin, and flumethrin from water samples. A sol‐gel based coating fiber using 3‐(trimethoxysilyl propyl) amine as precursor was prepared and used for the extraction of the pyrethroids from groundwater samples. A post‐column photochemical reactor was designed and constructed for the derivatization of these environmentally important pollutants to increase their fluorescence sensitivity and determination in HPLC. The parameters affecting extraction process (extraction time and temperature, pH, salt addition, and co‐solvent) and desorption step (solvent, desorption time, and temperature) of the analytes from the sol‐gel‐based fiber, along with photochemical reaction conditions were investigated. The developed method proved to be relatively rapid, simple, and easy and offers high sensitivity and reproducibility. Linear dynamic ranges (LDR) for these insecticides were ranged between 0.25 to 50 μg/L. The regression coefficients were satisfactory (R² > 0.984) for these pyrethroids. The limits of detection and limits of quantification varied between 0.09 and 0.35 μg/L and 0.25 and 1.00 μg/L, respectively. Relative standard deviation RSDs values varied between 4.41% and 6.20%. Relative recoveries obtained from analysis of Jajroud river water sample ranged between 94% and 104%.     

果蔬中8种苯甲酰脲类农药残留量的液相色谱-串联质谱法测定

建立了果汁蔬菜中8种苯甲酰脲类(杀虫脲、氟苯脲、氟虫脲、氟啶脲、除虫脲、氟铃脲、灭幼脲、氟丙氧脲)农药残留量的液相色谱-电喷雾串联质谱(LC-ESI MS/MS)测定方法。样品用乙腈提取后无需净化,经盐析过滤并以水稀释(1∶1)后,经Waters Atlantis(d C18色谱柱分离,5 mmol/L乙酸铵水溶液和乙腈梯度洗脱,以电喷雾电离串联质谱在负离子多反应监测(MRM)模式下进行测定并确证,外标法定量。8种苯甲酰脲类农药在1.0~100μg/L范围内线性良好,相关系数为0.990 0~0.999 9。对8种农药在毛豆基质中3个添加水平下的回收率进行测定,平均回收率为92%~110%,相对标准偏差为5.5%~12%。方法的检出限(S/N=3)为0.04~0.42μg/kg,定量下限(S/N=10)为0.2~1.5μg/kg。     

Simultaneous quantitation of seven pyrethroid metabolites in human urine by capillary gas chromatography–mass spectrometry

Pyrethroid insecticides are applied in the residential environment, as well as in agricultural crops, for insect control purpose. We developed and validated an accurate, sensitive, and reproducible analytical method to simultaneously detect seven pyrethroid metabolites, namely, 3‐(2,2‐dichlorovinyl)‐2,2‐dimethyl‐(1‐cyclopropane) carboxylic acid, 3‐(2,2‐dibromovinyl)‐2,2‐dimethyl‐(1‐cyclopropane) carboxylic acid, 3‐phenoxybenzoic acid, 4‐fluoro‐3‐phenoxybenzoic acid, 2‐methyl‐3‐phenylbenzoic acid, 4‐chloro‐α‐isoproply benzeneacetic acid, and 3‐(2‐chloro‐3,3,3‐trifluoroprop‐1‐enyl)‐2,2‐dimethylcyclopropanecarboxylic acid, in human urine. This method employs deconjugation with enzyme, SPE using Agilent C18 cartridges on a RapidTrace SPE workstation, derivatization using hexafluoro isopropanol and N,N′‐diisopropylcarbodiimide, and compounds separation and identification on GC–MS. The detection limits of seven metabolites were 0.02–0.08 ng/mL in urine. The recoveries of seven metabolites were 81–104%, 85–99%, and 83–99% in urine specimens fortified at 0.1, 0.4, and 3.2 ng/mL concentrations, respectively. The overall coefficient of variation was 4.3–10.8% in two quality control specimens which were repeatedly measured during a period of 2 months. This method was applied to urine samples collected from children living in Boston, MA. The median concentrations of six detected pyrethroid metabolites ranged from 0.06 to 0.86 ng/mL in urine.     

Organosilicon(IV) and organotin(IV) complexes as biocides and nematicides: synthetic,spectroscopic and biological studies of N∩N donor sulfonamide imine and its chelates

A brief account is given of the synthesis and stereochemistry and the antibacterial, antifungal, nematicidal and insecticidal behaviour of organosilicon(IV) and organotin(IV) complexes of a biologically potent ligand, 2‐acetylfuransulfaguanidine. The unimolar and bimolar substitution products have been characterized by elemental analyses, conductance measurements, molecular weight determinations, and spectral studies, viz. IR, ¹H NMR, ¹³C NMR, UV, ²⁹Si NMR and ¹¹⁹Sn NMR spectra. The data support the binding of the nitrogen atom to the metal atom in R₃M(N^∩N), [R₂M(N^∩N)₂ and R₂M(N^∩N)Cl [(R = Me/Ph and M = Si(IV) and Sn(IV)] types of complex. Based on these studies, with coordination number five and six a trigonal bipyramidal and an octahedral geometry have been proposed for the resulting derivatives. The free ligand (N^∩NH) and its respective metal complexes were tested in vitro against a number of microorganisms to assess their antimicrobial properties. The results are indeed positive. In addition to these studies, the complexes also show good nematicidal and insecticidal properties. The results of these findings have been discussed in detail. Copyright © 2004 John Wiley & Sons, Ltd.     

气相色谱法测定蔬菜中拟除虫菊酯类农药残留量

从1.0kg蔬菜中选其可食用部分,切碎后用四分法取样,取适量样品经充分捣碎制得分析用样品。称取试样25.00g用50mL乙腈高速匀浆提取,收集滤液40～50mL与5g氯化钠振荡盐析。定量分取上层清液10mL置于80℃水浴上吹氮至干,加正己烷2mL溶解残渣,所得溶液流经Florisil小柱纯化,用丙酮-正己烷(1+9)混合液淋洗2次,每次5mL,洗脱液在50℃水浴上吹氮至干,用正己烷定容至2.0mL,取1μL进样进行气相色谱分析。采用Varian CP-Sil 5CB毛细管色谱柱分离及电子捕获检测器定量检测,5种拟除虫菊酯类农药可很好地分离。其峰面积值与相应质量浓度均在0.01～1.0mg·L~(-1)之间呈线性,检出限(3S/N)在1.6～2.0μg·kg~(-1)之间。在3个浓度水平上(0.02,0.10,0.50mg·kg~(-1))加入各农药标准溶液,按方法作回收率及精密度试验,测得回收率和相对标准偏差(n=6)分别在90.5%～106.4%和0.98%～6.3%之间。     

基质固相分散-气质联用测定3种基质中28种拟除虫菊酯类农药残留

采用基质固相分散法从3种基质(白菜、梨、鸡肉)中提取、净化28种拟除虫菊酯类农药,用气相色谱-质谱(GC-MS)法进行检测.通过对基质固相分散的条件,如吸附剂、洗脱剂、洗脱体积等参数进行优化,建立了3种基质中28种拟除虫菊酯类农药残留分析的前处理方法.利用所建立的方法进行0.01 mg/kg、0.02 mg/kg和0....     

The acid/base profile of agrochemicals

Drug-likeness has long been studied in the pursuit of finding new medicines. Similarly, in the agrochemical field there is value in exploring the properties of the chemicals involved. Patterns that emerge can potentially influence future discovery campaigns to improve the probability of commercial success. In this study we investigate the acid/base properties and physicochemical characteristics of three classes of compounds: fungicides, herbicides and insecticides. In comparison with FDA-approved drugs, it was noted that the pesticides were generally smaller, possessed a neutral charge state and were more lipophilic. The results are discussed in the light of their intended targets.