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动态液相微萃取-气相色谱法测定水样中有机磷农药残留 总被引:23,自引:0,他引:23
建立了水样中敌敌畏、二嗪农、毒死蜱、甲基对硫磷和对硫磷等5种有机磷农药的动态液相微萃取-气相色谱检测方法。实验表明甲苯是良好的萃取溶剂,甲苯体积为2μL时达到最佳萃取效果。液相微萃取是一种非平衡萃取过程,随着萃取次数的增加,萃取效率不断提高,本研究选择萃取次数为25次。在优化的实验条件下,各目标物的萃取富集倍数为21-60;回收率0.85%-2.38%之间;方法的检出限为0.1-0.3μg/L;基体加标检测的相对标准偏差(RSD)为4.9%-8.0%。本方法可用于水体中痕量有机磷农药的富集检测。 相似文献
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超声辅助固相萃取/离子阱气相色谱-质谱联用测定蔬菜中有机磷农药残留 总被引:1,自引:0,他引:1
通过超声辅助固相萃取提取并富集蔬菜中残留的乐果和氧化乐果等9种有机磷农药,采用离子阱二级质谱定性并定量检测其含量,建立了气相色谱-质谱联用测定蔬菜中有机磷农药残留的分析方法.结果表明,所建立的方法简单,快速,灵敏度高.9种有机磷农药的检出限为0.02~0.04 μg/mL,添加回收率为75.07%~99.47%. 相似文献
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高分子多孔微球富集-HPLC法测定水体中的有机磷 总被引:1,自引:0,他引:1
本文提出应用国产高分子多孔微球-GDX系列富集-反相高效液相色谱法测定废水中久效磷、乐果、甲基对硫磷三种有机磷农药分析方法。三种不同型号色谱固定相(GDX-102,GDX-301和GDX-501)对水体中ng/mL级久效磷、乐果和甲基对硫磷的富集效率分别达到85%、82%和93%以上。采用μ-BondapakC18作固定相,以60%甲醇水溶液作流动相,对三种有机磷农药的分离度可达到1.2以上。本法用于分析水体中有机磷农药,结果令人满意。 相似文献
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分散液相微萃取-气相色谱联用分析水样中菊酯类农药残留 总被引:16,自引:6,他引:16
将分散液-液微萃取(DLLME)与气相色谱-电子俘获检测(GC-ECD)技术相结合,建立了高灵敏度测定水样中7种菊酯类农药残留的新方法。对影响萃取富集效率的因素进行优化,萃取条件选定为:在5.0mL样品溶液中加入10.0μL氯苯和1.0mL丙酮,分散混匀后,以5000r/min离心5min,吸出萃取溶剂氯苯直接进样分析。在优化条件下7种菊酯类农药的富集倍数高达708~1087倍。以α-六六六为内标,7种菊酯类农药在0.8~600μg/L范围内具有良好的线性关系,线性相关系数在0.9990~0.9999之间;检出限为0.04~0.10μg/L(S/N=3)。本方法已应用于自来水、井水及河水等实际水样的分析,平均加标回收率在76.0%~116.0%之间;相对标准偏差在3.1%~7.2%之间。方法具有操作简单、富集效率高和灵敏度高等特点,可满足水样中菊酯类农药残留的检测要求。 相似文献
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利用1-乙烯基-3-己基咪唑溴盐与氧化石墨烯之间的静电吸引力,将其附着于氧化石墨烯表面,然后经聚合、还原,制备了聚合离子液体-石墨烯复合材料,用SEM、FT-IR、UV-vis等对复合材料进行了表征.将聚合离子液体-石墨烯复合材料用于固相萃取(Solid-phase extraction,SPE)的吸附剂,结合高效液相色谱,研究了此吸附剂对环境水样中4种有机磷农药的萃取性能.对影响SPE效率的参数(吸附剂量、上样体积、上样流速、洗脱剂和洗脱剂体积)进行了优化.在优化条件下,杀螟松、对硫磷、倍硫磷和辛硫磷在5~200 μg/L有良好的线性关系,相关系数(R2)为0.9908~0.9995.将本方法用于环境水样中有机磷农药的测定,加标回收率在80.0%~ 110.0%之间,RSD<4.5% (n=3).结果表明,与石墨烯相比,聚合离子液体-石墨烯复合材料作为SPE吸附剂,能降低萃取过程中的团聚现象,对目标物的萃取效能更高;本方法可用于环境水样中有机磷农药残留的测定. 相似文献
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高分子多孔微球富集—HPLC法测定水体中的有机磷 总被引:1,自引:0,他引:1
本文提出应用国产高分子多孔微球-GDX系列富集-反相高效液相色谱法测定废水中久效磷、乐果、甲基对硫磷三种有机磷农药分析方法。三种不同型号色谱固定相(GDX-102,GDX-301和GDX-501)对水体中ng/mL级久效磷、乐果和甲基以硫磷的富集效率分别达到85%、82%和93%以上,采用μ-Bondapak C18作固定相,以60%甲醇水溶液作流动相,对三种有机磷农药的分离度可达到1.2以上。本 相似文献
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果汁中有机磷农药残留的动态液相微萃取/气相色谱法检测 总被引:1,自引:0,他引:1
应用动态液相微萃取与气相色谱联用技术建立了果汁中3种有机磷农药(敌敌畏、甲基对硫磷、对硫磷)的快速分析方法.考察了萃取溶剂、溶剂体积、萃取次数、水样pH值以及离子强度对液相微萃取的影响.3种有机磷农药的线性范围均为40 ~400 μg·L-1,富集倍数22.3 ~51.5,回收率80% ~120%,相对标准偏差2.0% ~8.1%,检出限12.2 ~20.6 μg·L-1. 相似文献
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用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%. 相似文献
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The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments. 相似文献
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Regiospecific and direct imidation of the methyl C(sp3)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products. 相似文献
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KMnO4-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
The review contains a concise historical account and information on the most significant researches undertaken by the staff
at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry
of Heterocyclic Compounds.
Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee.
Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008. 相似文献
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《Tetrahedron》2014,70(21):3377-3384
The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative. 相似文献
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Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner. 相似文献