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阻抑聚丙烯酰胺催化蛋白质-亚甲基蓝褪色光度法测定痕量铋 总被引:3,自引:0,他引:3
在加热条件下,基于Bi(Ⅲ)对聚丙烯酰胺(PAM)催化蛋白-亚甲基蓝(MB)褪色反应有强的抑制作用,建立了动力学光度法测定铋的新方法。△A与CBi(Ⅲ)呈线性关系的范围为0.08-0.48μg/L;检出限为0.004μg/L;对0.04和0.040μgBi(Ⅲ)/L测定的RSD分别为6.4%一2.6%,本阻抑-催化褪色反应对Bi(Ⅲ)、蛋白质-亚甲基蓝和PAM为一级反应,表观活化能为49.22kJ/mol.该方法已用于某些谷物,人发和水样中Bi(Ⅲ)的测定。结果满意。 相似文献
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4-酰基-双(1,3-二苯基-5-吡唑啉酮)铽(Ⅲ)配合物的和成及荧光性质 总被引:2,自引:0,他引:2
合成了3种4-酰基-双(1,3-二苯基-5-吡唑啉酮),1,5-双(1′,3′-二苯基-5′-吡唑啉酮-4′-基)-1,5-戊二酮;1,6-双(1′,3′-二苯基-5′-吡唑啉酮-4′-基)-1,6-己二酮和1,10-双(1′,3′-二苯基-5′-吡唑啉酮-4′-基)-1,10-癸二酮,通过元素分析,红外光谱和核磁共振氢谱对产物组成进行了表征,合成了它们的Tb(Ⅲ)二元和三元[1,10-二氮杂菲(Phen)或2,2′-联吡啶(Dipy)]配合物,测定了配合物的荧光光谱,对其荧光性质进行了研究,结果表明,配合物发射Tb(Ⅲ)的特征荧光,4-酰基0双(1,3-二苯基-5-吡唑啉酮)配体的三重态能级与Tb(Ⅲ)的最低激发态(5D4)能级匹配较好,配合物荧光强度随4-酰基-双(1,3-二苯基-5-吡唑啉酮)配体2个吡唑环间碳链的增长而减弱,第2配体Phen和Dipy具有荧光增强作用,且前者优于后者。′ 相似文献
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流动注射-荧光光纤传感器测定盐酸 总被引:1,自引:0,他引:1
将3-羟基-4‘-N,N-二甲氨基黄酮甲基丙烯酸酯与甲基丙烯酸甲酯和丙烯酸丁酯共聚,制备了含荧光基团的高聚物(PFMB),以PFMB为敏感膜研制了一种荧光猝灭型的盐酸光纤传感器。在Fe(Ⅲ)存在下,猝灭效率大大增加,猝灭机制主要包括Fe(Ⅲ)与Cl^-形成络合物的初级内滤效应和该络合物与PFMB形成非荧光复合物两种作用。该传感器可直接用于0.1-6.0mol/L盐酸的测量。与流动注射联用可测量0.1-12.0mol/L的盐酸。传感器具有良好的重现性和可逆性,响应和恢复时间均小于40s,且有较长的使用寿命。 相似文献
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2-(3,5-二氯-2-吡啶偶氮)-5-二甲氨基苯胺激光热透镜光谱法测定钯 总被引:5,自引:0,他引:5
基于2-(3,5-二氯-2-吡啶偶氮)-5-二甲氨基苯胺(3,5-diCl-PADMA)与钯的显色反应,以激光热透镜头谱法测定了微量钯。实验表明,在强酸性介质中,Pd^2 与3,5-diCL-PADMA室温显色形成稳定的蓝色配合物,最大吸收波长位于623nm处,与所用激光器输出激光波长匹配较好,从而建立了激光热透镜光谱法测定钯的新方法。钯浓度分别在0.005-0.04mg/L和0.03-0.025mg/L范围内呈线性关系,方法灵敏度高,选择性、重现性好,用于样品测定,结果满意。 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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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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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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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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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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Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields. 相似文献