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苯丙共聚物-聚硅氧烷复合固相微萃取涂层的制备及性能研究 总被引:4,自引:0,他引:4
合成了苯乙烯-丙烯酸乙酯共聚物,以此聚合物与甲基聚硅氧烷色谱固定液混合作为固相微萃取头涂层。通过热分析手段考察了该涂层的热稳定性,涂层使用温度可达280℃。使用微量进样器和不锈钢毛细管,自制了SPME装置。使用该涂层萃取分析了水中氯苯系化合物,各标准样品质量浓度在0—20μg/L内与色谱峰面积呈良好线性关系(r=0.9674—0.9934),检出限为0.28—0.64ng/L,相对标准偏差为5.4%-7.7%,加标回收率为91%-99%。将自制涂层与商品涂层(PDMS、PA)进行了比较,结果表明苯丙聚合物-甲基聚硅氧烷复合涂层对氯苯系化合物具有优良的吸附特性。在固相微萃取研究和应用中,提供了新的吸附物质和色谱固定液与石英纤维结合的新途径。 相似文献
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固相微萃取—毛细管气相色谱法快速分析水中氯苯类化合物 总被引:17,自引:0,他引:17
杨红斌 《理化检验(化学分册)》1999,35(3):103-105
固相微萃取是一种快速,简便,集萃取浓缩进样于一体的样品前处理技术,具有分析时间短,灵敏度高,无需有机溶剂的优点。方法用固相微萃取富集水中氯苯类化合物,毛细管气相色谱分离分析,整个分析过程只需20min,检出限可达0.1-2μg.l^-1,已用于地面水水源中氯苯类化合物含量的测定。 相似文献
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《理化检验(化学分册)》2010,(12)
合成了硅氧烷-聚氨酯共聚物,并采用红外光谱、扫描电子显微镜和能谱仪对该共聚物进行了表征。将其用于固相微萃取用石英纤维的表面涂层并制备了萃取头。将此固相微萃取装置的萃取头萃取和分离顶空样瓶水样中的芳香化合物并引入仪器进行色谱分析。结果表明:用共聚物涂层的石英纤维制成的萃取头的最高使用温度为260℃,涂层表面硅元素分布均匀。苯、氯苯、硝基苯的质量浓度均在50.0μg·L~(-1)范围以内与其色谱峰峰高呈线性关系,方法的检出限(3S/N)依次为0.432,0.756,0.511μg·L~(-1)。 相似文献
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聚丙烯酸树脂涂层HS-SPME-GC-MS监测城市污水中的芳香烃化合物 总被引:2,自引:0,他引:2
采用聚丙烯酸树脂涂层-固相微萃取-气相色谱-质谱(PA—SPME—GC—MS)联用技术,在优化的萃取条件下检测了城市污水中的苯系物和多环芳烃等芳香烃化合物.该方法的最低检出限达12ng/L水平,相对标准偏差为1.7%~9.8%. 相似文献
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本文报道了利用固相氧化剂1,3,4,6,—四氯—3a,6a,-二苯基甘脲(Iodogen)对人血清低密度脂蛋(LDL)进行125Ⅰ标记的方法,结果表明:125I-LDL的比放射性为185~518cpm/ngLDL,游离125Ⅰ含量在0.27~1.75%之间,脂质标记率<1%,125I-LDL浓度250~750μg/ml,125I-LDL的生物活性经受体实验证实与天然脂蛋白一致.符合脂蛋白代谢研究的要求.本法具有反应条件温和,不易损伤脂蛋白,脂质标记率低.固相标记,不需要复杂设备等优点,为进行脂蛋白受体的研究提供了可靠的方法. 相似文献
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顶空固相微萃取谱-气相色谱-质谱联用测定饮用水中6种致嗅化合物 总被引:1,自引:0,他引:1
采用顶空固相微萃取谱-气相色谱-质谱联用法对饮用水中2-甲基异茨醇、土味素、2-甲氧基-3-异丙基吡嗪、2-甲氧基-3-异丁基吡嗪、2,4,6-三氯苯甲醚和2,3,6-三氯苯甲醚共6种致嗅化合物进行了分析。通过对固相微萃取纤维的类型、解吸附时间、NaCl溶液浓度、溶液pH、顶空温度、转速、顶空时间等顶空条件及GC-MS条件的优化,建立了一次性顶空固相微萃取快速测定饮用水中6种致嗅化合物的方法。采用0.10 mol/L的NaOH溶液将水样调至pH 6.0。以DVB/Carboxen/PDMS涂层的固相微萃取纤维头对20 mL添加了NaCl溶液浓度为0.3 g/mL的水样于70℃水浴顶空萃取25 min。被萃取的致嗅化合物于250℃解吸附4 min供GC-MS分析。6种致嗅化合物在0.25~100 ng/L范围内线性关系良好(R>0.986),检出限低于0.1 ng/L。对实际水样进行分析,低、中、高3种不同浓度的加标回收率为93.0%~106.6%,相对标准偏差为3.0%~6.6%(n=6)。该分析方法可对饮用水中6种致嗅化合物进行同时监测。 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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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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《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
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Hao Xu Liyang Pan Xiaomin Fang Baoying Liu Wenkai Zhang Minghua Lu Yuanqing Xu Tao Ding Haibo Chang 《Tetrahedron letters》2017,58(24):2360-2365
A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis. 相似文献
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A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs). 相似文献
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Andrey A. BerezinPanayiotis A. Koutentis 《Tetrahedron》2011,67(22):4069-4078
Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO4 oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised. 相似文献