新型葡萄糖氮苷化合物的合成与表征

通过自由基溴代反应得到活性中间体溴代二甲戊乐灵, 再以2,3,4,6-四-O-乙酰化-β-葡萄糖胺亲核取代得到一种新型糖苷化合物, 产物经MS和NMR进行表征.     

单滴液相微萃取-高效液相色谱法测定水中二甲戊乐灵农药残留

应用单滴液相微萃取(SD-LPME)技术建立了水体中二甲戊乐灵农药的高效液相色谱(HPLC)分析方法.研究了不同的萃取条件(萃取剂、体积、萃取时间、搅拌速度、温度等)及测定条件对检测二甲戊乐灵的影响,确定了最佳萃取条件:环己烷作萃取剂,萃取剂体积5 μL,液滴体积2 μL,搅拌速度350 r/min,35 ℃条件下萃取35 min.应用此方法测定了自来水和太湖水样中的二甲戊乐灵农药残留,相对标准偏差(RSD)在2 5%～3.4%(n=6)之间;回收率为88.0%～99.8%.     

Pendimethalin in surface waters of rivers in the proximity of irrigated paddy fields by solid phase microextraction and gas chromatography

The aim of this study was to develop an analytical methodology for the determination of the herbicide pendimethalin in river waters in the towns of Turvo and Meleiro in the southern region of Santa Catarina State, Brazil. The method, based on solid phase microextraction (SPME) followed by separation and detection by gas chromatography (GC) and electron capture detection (ECD), respectively, was optimised and validated. The limits of detection (LOD) and quantification (LOQ) of 0.02 and 0.06?µg?L^?1, respectively, and recovery values in the range of 86.2 (±11.5)% to 103.4 (±9.5)% were obtained. It was verified that 53 river water samples showed contamination by pendimethalin at levels that ranged from 0.06 to 0.38?µg?L^?1.     

Comparison of extraction techniques for quantitative analysis of pendimethalin from soil and rice grain

The paper exploits the development, optimization, and comparison of fast, efficient, quantitative analytical extraction techniques such as ultrasonic-assisted extraction (UAE) and matrix solid-phase dispersion (MSPD) for proficient extraction of pendimethalin from soil and rice samples. Residues of pendimethalin were quantified using high-performance liquid chromatography. Impact of several experimental parameters of UAE and MSPD techniques on extraction of pendimethalin from soil and rice samples was also evaluated. Under the optimized conditions, the mean percent recoveries obtained from both methods were in the range of 80.3–101.3 and 81.7–103.1, respectively, with relative standard deviation <10. Linearity was in the range of 0.003–5.0?µg?mL^?1 with limit of detection and limit of quantification as 0.001 and 0.003?µg?g^?1, respectively. MSPD method was found superior in terms of low solvent consumption, small sample size, and reduced matrix coextracts due to simultaneous extraction and cleanup steps. Both extraction methodologies were successfully applied in monitoring routine soil and rice samples, in which pendimethalin residues (0.003–0.007?µg?g^?1) were detected in few rice samples while residues in soil samples were below the quantification limit.     

Development and Validation of a Simple and Efficient Method for the Determination of Pendimethalin and Its Metabolite M455H001 in Soil by Liquid Chromatography–Tandem Mass Spectrometry (LC-MS/MS)

A new analytical method has been developed and described for the rapid determination of pendimethalin and its major metabolite M455H001 in soil by liquid chromatography coupled with ion-spray tandem mass spectrometry (LC-MS/MS) after a single acidic solvent extraction. The chromatographic separation of the analytes was achieved using a Zorbax C18 reversed phase column and water/0.1% formic acid and methanol as the mobile phase at a flow rate of 0.2?mL?min^?1. The recoveries of the method ranged from 78.8% to 119.8% for pendimethalin and from 73.7% to 108.8% for M455H001, and the relative standard deviation was lower than 16% for both analytes. The validated limit of quantification was 0.01?µg?g^?1 soil dry weight for both compounds. The matrix effects were evaluated and were less than 20% for both substances in the examined soil samples. It is concluded that the method is easy, with reasonable consumption of reagents, characterized by reliability and sensitivity, and therefore, it is suitable for monitoring the levels of pendimethalin and its major metabolite M455H001 in soils.     

Gas chromatography with surface ionization detection of nitro pesticides

A surface ionization gas chromatographic detector, based upon positive surface ionization, was used in capillary gas chromatography to sensitively and selectively detect nitro pesticides: pendimethalin, trifluralin, flumetralin. Higher sensitivity (better detection limit), substance specificity, and advantageous applicability are reported. Sensitivity to pendimethalin, trifluralin, and flumetralin was 1.4 C g⁻¹, 1.1 C g⁻¹, and 1.0 C g⁻¹, respectively, with the linear range of operation greater than 1 × 10⁵ for these compounds. The minimum detectable level was in the range of 10⁻¹³ g s⁻¹. Compared with an atomic emission detector, SID provided a 110 times better detection limit for trifluralin.     

Mass Spectrometry-Based Peptide Profiling of Haemolymph from Pterostichus melas Exposed to Pendimethalin Herbicide

Pendimethalin-based herbicides are used worldwide for pre-emergence selective control of annual grasses and weeds in croplands. The endurance of herbicides residues in the environment has an impact on the soil biodiversity and fertility, also affecting non-target species, including terrestrial invertebrates. Carabid beetles are known as natural pest control agents in the soil food web of agroecosystems, and feed on invertebrates and weed seeds. Here, a mass spectrometry untargeted profiling of haemolymph is used to investigate Pterostichus melas metabolic response after to pendimethalin-based herbicide exposure. Mass spectrometric data are examined with statistical approaches, such as principal component analysis, for possible correlation with biological effects. Those signals with high correlation are submitted to tandem mass spectrometry to identify the associated biomarker. The time course exposure showed many interesting findings, including a significant downregulation of related to immune and defense peptides (M-lycotoxin-Ls4a, Peptide hormone 1, Paralytic peptide 2, and Serine protease inhibitor 2). Overall, the observed peptide deregulations concur with the general mechanism of uptake and elimination of toxicants reported for Arthropods.     

Residue measurement of pendimethalin in tobacco by using heart‐cutting two dimensional liquid chromatography coupled with tandem mass spectrometry

A novel heart‐cutting two‐dimensional liquid chromatography coupled with tandem mass spectrometry method was developed for quantitative analysis of pendimethalin residue in tobacco. The strategy of reversed phase liquid chromatography coupled with another reversed‐phase liquid chromatography was employed for high column efficiency and excellent compatibility of mobile phase. In the first dimensional chromatography, a cyano column with methanol/water as the eluent was applied to separate pendimethalin from thousands of interference components in tobacco. By heart‐cutting technique, which effectively removed interference components, the target compound was cut to the second dimensional C18 column for further separation. The pendimethalin residue was finally determined by the tandem mass spectrometry under multiple reaction monitoring reversed‐phase liquid chromatography mode. Sample pretreatment of the new method was simplified, involving only extraction and filtration. Compared with traditional methodologies, the new method showed fairly high selectivity and sensitivity with almost no matrix interference. The limit of quantitation for pendimethalin was 1.21 ng/mL, whereas the overall recoveries ranged from 95.7 to 103.3%. The new method has been successfully applied to non‐stop measure of 200 real samples, without contamination of ion source. Detection results of the samples agreed well with standard method.     

高效液相色谱-三重四极杆质谱法测定克氏原螯虾中二甲戊灵残留

建立了高效液相色谱-三重四极杆质谱（HPLC-MS/MS）测定克氏原螯虾中二甲戊灵残留的分析方法。用含0.1%（v/v）乙酸的乙酸乙酯溶液提取克氏原螯虾中的二甲戊灵,于35℃旋蒸至干,经含0.1%（v/v）乙酸的甲醇-水（8∶2,v/v）溶解残渣后,用酸性氧化铝柱、石墨化炭黑（GCB）进行净化。采用Symmetry C18色谱柱（100 mm×2.1 mm,3.5 μm）进行分离,用加热大气压电喷雾电离（HESI）源、正离子模式进行扫描,在多反应监测模式（MRM）下检测。结果表明,二甲戊灵在1.0~20.0 μg/L范围内线性良好,相关系数为0.9960,检出限为0.2 μg/kg;二甲戊灵的加标回收率为63.3%~104.7%,精密度为6.9%~14.5%（n=7）。该方法简单、快速、灵敏度高,能够满足克氏原螯虾中二甲戊灵药物残留检测的需求。     

微分脉冲溶出伏安法结合化学计量学测定3种农药

代森锌、代森锰和除草通在汞电极上采用微分脉冲溶出伏安扫描时均具有良好的还原峰,但各个组分的伏安峰之间呈现严重的重叠,在不分离的情况下很难进行测定。讨论3种农药在汞电极上的还原反应机理,并采用化学计量学方法对重叠伏安波进行解析和定量分析,结果表明,偏最小二乘法能得到最好的结果。选择萃取率较大的三氯甲烷作为萃取剂,对几种蔬菜水果样品中的农药进行萃取分离,并用提出的方法进行分析,回收率在99%~104%之间。