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321.
An amino-functionalized magnetic covalent organic framework composite TpBD-(NH2)2@Fe3O4 (Tp=Tp1,3,5-triformylphloroglucinol, BD-(NH2)2 is 3,3',4,4'-biphenyltetramine) was prepared by post-synthesis modification. Due to its abundant benzene rings and amino groups, large specific surface area and porous structure, the prepared TpBD-(NH2)2@Fe3O4 exhibits high extraction efficiency toward sulfonylurea herbicides. Based on this, a new method of magnetic solid-phase extraction with TpBD-(NH2)2@Fe3O4 as the sorbent combined with high-performance liquid chromatography and ultraviolet detection was developed for trace analysis of sulfonylurea herbicides in environmental water, soil and tobacco leaves samples from tobacco land. Under the optimized conditions, the limits of detection within 0.05–0.14 μg/L were achieved with a high enrichment factor of 217-260-fold, and the relative standard deviations were 4.9–7.5% (n = 7, c = 0.5 μg/L). The linear range was around three orders of magnitude with the square of correlation coefficient higher than 0.9936. The method was applied to analyze five sulfonylurea herbicides in the environmental water, soil, and tobacco leave samples collected from tobacco land. No sulfonylurea herbicides were detected in these samples. The recoveries of target sulfonylurea herbicides in spiked environmental water, soil, and tobacco leaf samples were found in the range of 90.7–104, 70.7–99.0, and 59.3–97.8%, respectively. The results illustrate that the established TpBD-(NH2)2@Fe3O4-magnetic solid-phase extraction- high-performance liquid chromatography–ultraviolet detection method is efficient for the analysis of trace sulfonylurea herbicides in environmental samples. 相似文献
322.
Novel solid‐phase membrane tip extraction and gas chromatography with mass spectrometry methods for the rapid analysis of triazine herbicides in real waters
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Mohd. Marsin Sanagi Sarmad S. Muhammad Iqbal Hussain Wan Aini Wan Ibrahim Imran Ali 《Journal of separation science》2015,38(3):433-438
Novel, fast, selective, eco‐friendly and reproducible solid‐phase membrane tip extraction and gas chromatography with mass spectrometry methods were developed and validated for the analysis of triazine herbicides (atrazine and secbumeton) in stream and lake waters. The retention times of atrazine and secbumeton were 7.48 and 8.51 min. The solid‐phase membrane tip extraction was carried out in semiautomated dynamic mode on multiwall carbon nanotubes enclosed in a cone‐shaped polypropylene membrane cartridge. Acetone and methanol were found as the best preconditioning and desorption solvents, respectively. The extraction and desorption times for these herbicides were 15.0 and 10.0 min, respectively. The percentage recoveries of atrazine and secbumeton were 88.0 and 99.0%. The linearity range was 0.50–80.0 μg/L (r2 > 0.994), with detection limits (<0.47 μg/L, S/N = 3) and good reproducibility (<8.0%). The ease of operation, eco‐friendly nature, and low cost of solid‐phase membrane tip extraction made these methods novel. The Solid‐phase membrane tip extraction method was optimized by considering the effect of extraction time, desorbing solvents and time. 相似文献
323.
Yanfang Zhao 《International journal of environmental analytical chemistry》2013,93(14):1331-1341
ABSTRACTIn this work, a low-cost melamine-formaldehyde polymer with large-surface-area mesoporous structure was prepared and applied as an efficient solid sorbent for pre-concentration of five kinds of chlorinated herbicides including fomesafen, atrazine, pyrithiobac-sodium, benazolin and acifluorfene from water samples. Extraction parameters such as pH of the sample solution, amount of mesoporous melamine-formaldehyde polymer (mMFP), extraction time, type of desorption solv-ent and volume of the sample were systematically investigated. Combining dispersive solid-phase extraction with high-performance liquid chromatography (HPLC), the detection limits (S/N = 3) of the five herbicides were ranged from 0.04 to 0.18 μg L?1 with good linearity (R2 ≥ 0.9908). Then the tap water and river water samples were analysed by the developed method, and the obtained results indicated that this method provides acceptable recoveries and precisions. mMFP can be prepared through one-pot catalyst-free polymerisation from low-cost starting materials, so that they could be easily scaled up for the sample pre-treatment and have the powerful potentiality in purification of contaminated water. 相似文献
324.
325.
气相色谱-质谱法同时测定粮谷及油籽中多种酰胺类除草剂残留量 总被引:3,自引:1,他引:2
粮谷及油籽样品经丙酮-水提取,经去脂和弗罗里硅土固相萃取小柱净化,气相色谱-质谱(GC-MS)选择离子监测模式(SIM)对净化液进行检测;一次进样,便可对粮谷及油籽样品中的9种酰胺类除草剂及常混用的莠去津和嗪草酮等除草剂残留进行准确定量和确证。除草剂回收率为63%~96%;相对标准偏差为2.1%~11.2%;定量下限为0.02~0.05 mg/kg。该法快速、灵敏、准确,各项技术指标均满足农药残留检测的要求。 相似文献
326.
327.
The quantitative relationship between the structures of 20 sulfonylureas and their herbicidal activities against rape was analyzed using physicochemical parameters and regression analysis. The results showed that the electronic properties of the molecules are the dominant factor to the activity and there is apparently an optimum electronic property (∑σ or pKa) for the molecules to fit the receptor. Combined with the previous QSAR results for herbicidal triazolopyrimidine-2-sulfonamides, we can conclude that the structure-activity relationships of these two sets of compounds are identical, which suggested that these two sets of compounds acted on the same target site. 相似文献
328.
Quantitative structure-activity relationships for herbicidal activity against rape of sulfonylurea and triazolopyrimidine-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.
Project supported by the National Natural Science Foundation of China (Grant No. 29832050), the Special Key Fund of Natural
Science of Tianjin (Grant No. 983801011) and the Doctoral Fund of the Education Ministry of China. 相似文献
329.
Summary A rapid and simple method has been developed for determination of imidazolinone (IMI) residues in soil.
Extraction of the analytes from the soil matrix was performed with a pressurized-liquid-extraction apparatus built in this
laboratory. Four different types of soil sample (clay, clay loam, sandy clay loam, and silty loam) were fortified with target
compounds at levels of 10 and 50 ng g−1 by a procedure which can mimic weathered soils. The samples were then dried and packed in a 25 cm×4.6 mm i. d. stainless
steel column; this was placed inside a GC oven and extracted by passing an aqueous solution of KCl (0.1m, 20 mL) through the column at 90°C.
Quantification of the analytes in the final extract (50-μL injection) was performed by reversed-phase liquid chromatography-mass
spectrometry with a TurbolonSpray interface. Recoveries of the analytes were greater than 83% andRSD less than 7%. The method detection limit was in the 1–2.5ng g−1 range in analysis by time-scheduled selected-ion monitoring (SIM). 相似文献
330.
气相色谱—负化学源质谱法测定蔬菜中11种醚类除草剂残留 总被引:2,自引:1,他引:2
建立了一种测定蔬菜中11种醚类除草剂残留量的分析方法。样品由乙腈提取后经石墨化碳黑和中性氧化铝柱双柱串联固相萃取净化,运用气相色谱-负化学离子源质谱联用-分时段选择离子监测技术测定,外标法定量。11种除草剂在10~200μg/L范围内线性均良好;方法灵敏度高,定量限(LOQ)均低于或等于1μg/kg;方法准确度和精密度高,在4、10、20和40μg/kg 4个添加水平下所有农药的回收率均在70%~120%之间,RSD≤10.3%;方法选择性好,抗干扰能力强,可作为测定各种蔬菜基质中醚类除草剂残留量的确证方法。 相似文献