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71.
W.M.A. Niessen 《Journal of chromatography. A》2010,1217(25):4061-4070
Current strategies in the LC–MS analysis of pesticides and related compounds in environmental samples, fruits and vegetables, and biological samples mostly rely on the selection of appropriate precursor/product-ion combinations (transitions) for selected reaction monitoring (SRM), often based on automated parameter optimization and selection of the transition. Such a procedure does not require any information on the type of fragmentation reaction involved in the generation of the product ion from the selected precursor ion. However, such information does become important in untargeted screening for unknown contaminants in environmental and food samples, which are generally based on a combination of high-resolution mass spectrometry and (multistage) tandem mass spectrometry. With this in mind, the group-specific fragmentation behaviour has been studied for six classes of pesticides and herbicides, i.e., triazines, organophosphorous pesticides, phenylurea herbicides, carbamates, sulfonylurea herbicides, and chlorinated phenoxy acid herbicides. When relevant, some comparison was made between fragmentation of protonated molecules in MS–MS and of molecular ions generated by electron ionization in GC–MS. 相似文献
72.
Shiqian Gao 《Talanta》2010,82(4):1371-99
The determination of phenylurea and triazine herbicides in milk based on microwave assisted ionic liquid microextraction (MAILME) coupled with high-performance liquid chromatographic separation was described. The experimental parameters of the MAILE, including type and amount of ionic liquid, microwave extraction power, extraction time and salt concentration in sample, were evaluated by a univariate method and orthogonal screening. When 60 μL of [C6MIM][PF6] was used as extraction solvent the target compounds can be isolated from the 4 mL of milk. The MAILME is quick (7 min) and simple. The detection limits for isoproturon, monolinuron, linuron, propazine, prometryne, terbutryn and trietazine are 0.46, 0.78, 1.00, 1.21, 1.96, 0.84 and 1.28 μg L−1, respectively. The proposed method was applied to the analysis of milk samples and the recoveries of the analytes ranged from 88.4 to 117.9% and relative standard deviations were lower than7.43%. 相似文献
73.
Quantitative structure-activity relationships for herbicidal activity against rape of sulfonylurea and triazolopyrimidin-2-sulfonamide derivatives were examined three-dimensionally using comparative molecular field analysis (CoMFA). The CoMFA results show that the slopes in steric and electrostatic fields around the molecule were significant for both series in governing the potency variations in herbicidal activity. Based upon the successful superposition between the two series, the herbicidal activity was analyzable with a single equation for the combined set of compounds, which suggested that the two different series of compounds have a common region of the receptor site. 相似文献
74.
QuEChERS-液相色谱-串联质谱法测定甜玉米及毛豆中32种磺酰脲类除草剂残留 总被引:2,自引:0,他引:2
建立了基于QuEChERS方法的液相色谱-串联质谱同时测定甜玉米及毛豆中32种磺酰脲类除草剂残留的方法。以提取液净化前后蒸发残渣质量及回收率为考察指标,评估了C18、氧化锆包覆硅胶(Z-Sep)/C18混合物、C18键合锆胶(Z-Sep+) 3种分散吸附剂对甜玉米的净化效果,结果Z-Sep/C18吸附剂的净化效果最佳。样品采用乙腈提取、无水硫酸镁及氯化钠盐析、Z-Sep/C18分散固相萃取净化;液相色谱以CSH C18色谱柱梯度洗脱分离,质谱分析采用电喷雾负离子电离、按时间表的多反应监测模式(Scheduled MRM),以基质匹配校准曲线外标法进行定量。32种农药在甜玉米及毛豆中3个添加水平(10、20、100 μg/kg)的回收率为80.0%~108.2%,相对标准偏差为1.2%~13.0%, 32种农药的定量限(S/N≥10)为0.2~5.0 μg/kg。方法简便、灵敏、环保,适用于甜玉米及毛豆中32种磺酰类除草剂残留的定性定量分析。 相似文献
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N-硫代磷酰基磺酰脲的合成及除草活性研究金桂玉,赵国锋,郑健禺(南开大学元素有机化学研究所,天津,300071)关键词硫代磷酰胺,N-硫代酰基磺酰脲,除草活性磺酰脲类化合物作为高效除草剂已得到广泛地应用和开发[1~7].为寻找具有除草活性的新化合物,... 相似文献
79.
Solid‐phase extraction with the metal–organic framework MIL‐101(Cr) combined with direct analysis in real time mass spectrometry for the fast analysis of triazine herbicides 下载免费PDF全文
Xianjiang Li Jiawei Xing Cuilan Chang Xin Wang Yu Bai Xiuping Yan Huwei Liu 《Journal of separation science》2014,37(12):1489-1495
MIL‐101(Cr) is an excellent metal–organic framework with high surface area and nanoscale cavities, making it promising in solid‐phase extraction. Herein, we used MIL‐101(Cr) as a solid‐phase extraction packing material combined with fast detection of direct analysis in real time mass spectrometry (DART‐MS) for the analysis of triazine herbicides. After systematic optimization of the operation parameters, including the gas temperature of DART, the moving speed of the 1D platform, solvent for desorption, amount of MIL‐101(Cr) extraction time, eluent volume and salt concentration, this method can realize the simultaneous detection of five kinds of triazine herbicides. The limits of detection were 0.1~0.2 ng/mL and the linear ranges covered more than two orders of magnitude with the quantitation limits of 0.5~1 ng/mL. Moreover, the developed method has been applied for the analysis of lake water samples and the recoveries for spiked analytes were in the range of 85~110%. These results showed that solid‐phase extraction with metal–organic frameworks is an efficient sample preparation approach for DART‐MS analysis and could find more applications in environmental analysis. 相似文献
80.
Cheng Li Anxiang Lu Jihua Wang Jie Li Hua Ping Yunxia Luan Jiayi Chen Xuejiao Ha 《Journal of separation science》2014,37(24):3714-3721
A fast and novel analytical method was developed for the determination of trace levels of sulfonylurea herbicides in water and soil samples. Graphene was used as a sorbent for extraction, and ultra high performance liquid chromatography with tandem mass spectrometry was used for quantification. Five sulfonylurea herbicides were preconcentrated from water samples using a graphene‐loaded packed cartridge, while extraction from soil samples was performed in a single step using graphene‐supported matrix solid‐phase dispersion. Under the optimized conditions, the calibration plots were linear in the range between 5 and 1000 ng/L for water samples, and between 1 and 200 ng/g for soil samples. All correlation coefficients (R) were >0.99. The limits of detection for water and soil samples were 0.28–0.53 ng/L and 0.08–0.26 ng/g, respectively. This method was successfully applied to the analysis of spiked samples of environmental water and soil, with recoveries ranging from 84.2–109.3 and 86.12–103.2%, respectively, all with relative standard deviations of <10%. 相似文献