DMTAQ光度法测定微量镍的研究及应用

早在1888年Traumarn就提出了4-(2-噻唑偶氮)-间苯二酚(TAR)和1-(2-噻唑偶氮)-2-萘酚(TAN)等噻唑偶氮化合物,但并未研究它与金属离子的生色性和在分析上的应用.噻唑偶氮类试剂是继吡啶偶氮类试剂之后发展起来的另一类重要的有前途的显色剂.此类试剂中的基本分析功能团是:由于其中电负性大的氮、氧等原子共同存在并同时参与金属螯合物的形成,从而增强了邻羟基偶氮酚与金属离子的生色作用,提高了显色反应的灵敏度.此类试剂在分析化学中的应用已见诸报道.自Savvin S B于1970年首次合成2-(2-4,     

新显色剂2-(2-噻唑偶氮)-5-二乙氨基苯甲酸分光光度法测定微量钴

近年来,杂环偶氮苯甲酸类显色剂取得了较快的发展。由于氨基取代结构对试剂性能有较大的影响^[1],因此本文合成了新显色剂2-(2-噻唑偶氮)-5-二乙氨基苯甲酸,(TAEB)并研究了它与钴的显色反应。     

噻唑偶氮染料在分析化学中的应用

一、前言早在1888年Traumann就提出4-(2-噻唑偶氮)-间苯二酚(简称TAR)和1-(2-噻唑偶氮)-2-萘酚(简称TAN)等噻唑偶氮染料,但并未研究它与金属离子的生色性和在分析化学中的应用。直到1955年程广禄等提出1-(2-吡啶偶氮)-2-萘酚(简称PAN)作为分析试剂之后,才相继由金庭、柳原等、Jensen和Svoboda等应用噻唑偶氮衍生物作为螯合滴定法的金属指示剂和比色法的显色剂。新近更合成了许多类似于PAN的噻唑偶氮染料。由于此类化合物较     

钴(Ⅱ)的新显色反应的研究

苯并噻唑偶氮类染料由于其灵敏度高和选择性好,自1962年Дpапкина等人合成6-溴苯并噻唑偶氮萘酚以来,越来越引起人们的注意。我们合成了2-(6＇-溴苯并噻唑-2＇-偶氮)-5-羧基苯酚(2-(6＇-Bromo-2＇-Benzothiazolylazo)-5-Carboxyl Phenol,Br-BTACP),该试剂的合成及应用尚未见报道。本文报告Co~(2+)与Br-BTACP的新显色反应的研究。在乳化荆OP存在下,于pH6.8硼酸-氯化钠-硼砂缓冲溶液中,Co~(2+)与Br-BTACP形成     

吡啶酮结构分散染料的合成及其偶氮-腙式异色机理

研究了(N-乙基-3-氰基-4-甲基-5-(4-硝基偶氮苯)-6-羟基-2-吡啶酮)(D1)和(N-乙基-3-氰基-4-甲基-5-(2-氯4-硝基偶氮苯)-6-羟基-2-吡啶酮)(D2)这2种吡啶酮分散染料在溶剂(DMF和CH₂Cl₂)和织物(涤纶和锦纶)上的偶氮-腙式异构行为,分析染料在极性和非极性溶剂中的吸收光谱差异,染料在涤纶和锦纶织物上的异色行为。运用高斯计算模拟染料的优化构型以及在溶剂和无溶剂状态下的染料吸收光谱,研究吡啶酮染料在不同环境下的偶氮-腙式存在形式。核磁共振氢谱(¹H NMR)表明,吡啶酮结构分散染料在极性溶剂中以偶氮结构存在,在非极性溶剂中以腙式结构存在。染色结果结合量子计算表明,染料在涤纶织物以腙式结构存在,在锦纶织物以偶氮结构存在。此外,吡啶酮分散染料在涤纶织物表现出超高的耐光色牢度,而在锦纶织物上的耐光色牢度较差,染料在异种织物上耐光色牢度的巨大差异归因于染料在不同织物上呈现出不同的分子结构。     

新荧光试剂5-(4′-氯-2′-羧基苯基偶氮)-4-氧代-2-硫代四氢噻唑的合成及分析应用研究

本文报道了新荧光试剂5-(4’-氯-2’-羧基苯基偶氮)-4-氧代-2-硫代四氢噻唑(CC-POST)的合成及其荧光分析应用。确证了其结构。在pH=5.0～5.4时。它与铜(Ⅱ)形成荧光螯合物。λ_(ex)/λ_(em)=310mn/408nm,检测限为0.5ng/g。用此法测定了茶叶中的痕量铜,结果满意。     

新显色剂咪唑偶氮对甲苯的合成及其与钴的显色反应

合成了一种新的杂环偶氮类显色试剂 2 - ( 2′-咪唑偶氮 ) - 4-甲基苯 ( IAP-4M) ,进行了结构鉴定和光度性质测试。研究了该试剂与钴的显色反应的适宜条件 ,并应用于维生素 B12 、水样中微量钴的测定 ,络合物的摩尔吸光系数为 1 .1 6× 1 0 5L·mol-1· cm-1。     

2-(6-甲基-2-苯并噻唑偶氮)-5-二乙胺基酚吸光光度法测定微量Co(Ⅱ)

噻唑偶氮类试剂吸光光度法测定钴报道灵敏度均小于 1 .0 5× 1 0 5L· mol- 1 ·cm- 1 [1～ 4] 。本文报道用 2 - ( 6-甲基 - 2 -苯并噻唑偶氮 ) - 5-二乙胺基酚( MBTAE)测定微量钴 ,摩尔吸光系数为 1 .1 5×1 0 5L· mol- 1 · cm- 1 ,是目前同类试剂二元体系测钴灵敏度最高的一种方法。试剂与 Co2 反应迅速 ,配合物可稳定 1 6h。试剂最大吸收波长 λmax为51 5nm,配合物的最大吸收波长λmax为 61 0 nm,对比度 95nm,在 p H5.0的 HOAc- Na OAc介质中 Co∶MBTAE=1∶ 2 ,Co2 浓度在 0～ 2 5μg/ 2 5ml范围内服从比耳定律。方法应用…     

新型含咔唑环和芳环/芳稠杂环的N-酰腙衍生物的合成及蛋白酪氨酸磷酸酶1B(PTP1B)抑制活性评价

为寻找高效、低毒的新型蛋白酪氨酸磷酸酶1B(PTP1B)抑制剂,设计并合成出了一系列新型含咔唑环和芳环/芳稠杂环的N-酰腙衍生物6～8和11.利用IR、1H NMR、13C NMR和2D NMR(包括1H-1H COSY和NOESY)谱及元素分析确定了其结构和构型.评价了目标化合物对PTP1B的抑制活性.实验结果表明,目标化合物对PTP1B均有较强的抑制活性,除了化合物N'-[9-(2-氯噻唑-5-甲基)咔唑-3-亚甲基]-2-苯氨基乙酰肼(6a)、N'-[9-(2-氯噻唑-5-甲基)咔唑-3-亚甲基]-2-(4-甲基苯氨基)乙酰肼(6b)、N'-[9-(2-氯噻唑-5-甲基)咔唑-3-亚甲基]-2-(3-硝基苯氨基)乙酰肼(6g)和N'-[9-(2-氯噻唑-5-甲基)咔唑-3-亚甲基]-2-(4-硝基苯氨基)乙酰肼(6h)外,其它化合物的活性均高于阳性对照药物齐墩果酸,其中N,N'-[(9-丁基咔唑基)-3,6-二亚甲基]-2,2'-[二(4-硝基苯氨基)]双乙酰肼(11b)的活性最高,IC50=(0.89±0.06)μmol/L.利用分子对接分别研究了代表目标化合物N'-[9-(2-氯噻唑-5-甲基)咔唑-3-亚甲基]-2-(4-溴苯氨基)乙酰肼(6d)、N'-[9-(2-氯噻唑-5-甲基)咔唑-3-亚甲基]-2-((2-(1-萘氧基)甲基)苯并咪唑-1-基)乙酰肼(7f)和11b与PTP1B酶的结合模式.     

2-(4,5-二甲基-2-噻唑偶氮)-5-二甲氨基苯甲酸分光光度法测定微量铜

本文研究了新显色剂2-(4,5-二甲基-2-噻唑偶氮)-5-二甲氨基苯甲酸(简称DMT-AMB)与铜(Ⅱ)的显色反应。实验表明,在pH4.5～6.0的溴代十六烷基三甲胺(CTMAB)介质中,铜(Ⅱ)可与试剂DMTAMB形成1:1稳定的蓝色络合物,其表观摩尔吸光系数ε_(650)=5.5×10~4L·mol~(-1)·cm~(-1),铜浓度在0～24μg/25ml范围内符合比尔定律。此方法具有较好的选择性,可不经预分离而直接应用于纯铝和铝合金中微量铜的测定,结果满意。     

Mechanism of Separate Interaction of Oxygen and Methane with the Perovskite Catalyst SrCoO3−x Modified by Alkali Metals

We have studied the initial steps of activation of O₂ and CH₄ on strontium cobaltite, with the perovskite structure and modified by alkali metals, under nonsteady-state conditions using a TAP reactor (TAP = Temporal Analysis of Products). We have established that adsorption of oxygen can be described by a three-step mechanism including intermediate formation of molecularly adsorbed oxygen followed by its dissociation and insertion of atomically adsorbed oxygen into the interior of the catalyst. The kinetics of reaction of methane with the oxidized catalyst is described satisfactorily by a first-order equation.     

Photocrosslinking between peptide-peptide or peptide-oligonucleotide by Ru(II)-TAP complexes

Ru(II)-TAP complexes have been shown to be very attractive compounds in the frame of developments of new anticancer drugs targeting the genetic material. This increasing interest originates from observations of covalent bond formations, triggered by photo-induced electron transfer (PET) between Ru(II)-TAP complexes and guanine bases of DNA. This photoreaction has recently been extended to the tryptophan (Trp) amino acid for future applications involving peptides. Thus, a double photo-addition of Trp residues of peptides on Ru(II) complexes is demonstrated by mass spectrometry with some structural issues. Such bi-adduct formations offer the possibility of photocrosslinking two Trp-containing biomolecules, which is investigated in this study. Thus, photocrosslinking between two complementary oligonucleotides (ODNs) derivatized by Trp-containing tripeptides is demonstrated by polyacrylamide gel electrophoresis (PAGE) in the presence of Ru(II)-TAP complexes. Both PAGE and MS indicate that such photocrosslinkings arise from two reaction pathways: either via the double addition of Trp residues on the Ru complex or from dimerization of Trp radicals. The competition between these two pathways depends on the experimental conditions. Heterobridgings between guanine bases and tryptophan residues mediated by Ru(II)-TAP complexes is also examined, opening the way to ODN-peptide photocrosslinkings.     

Development and Optimization of an Indirect Enzyme‐Linked Immunosorbent Assay for Thiamphenicol

Abstract

The specificity of an enzyme‐linked immunosorbent assay (ELISA) was modified by changing the chemical structure of the haptenated coating antigen. A competitive indirect immunoassay was developed, evaluated, and validated to measure thiamphenicol (TAP) in eels. The working range of the assay was placed between 0.45 and 8.35 µg/L. Moreover, the influence of several physicochemical parameters, such as incubation time, ionic strength, detergent concentration, and pH, were studied. The specificity of this immunoassay was evaluated using 23 structurally related compounds. Finally, a good correlation was observed between the chromatographic and immunoassay techniques while analyzing five certified eel samples.     

Steady-state and unsteady-state kinetic approaches for studying reactions over three-way natural gas vehicle catalysts

Kinetics has been proven to be a powerful method to probe catalytic surfaces under reaction conditions in order to elucidate, at molecular level, complex chemical processes. Numerous techniques and methodologies have been already implemented (surface science approaches, TAP, SSITKA…) running in very different pressure ranges (pressure gap) which led to controversial statements regarding suggested mechanism schemes, especially for DeNO_x reactions. Two typical reactions taking place over NGV catalysts have been selected to illustrate which information can be tackled from kinetic measurements. Both reactions occur in different temperature ranges and are sensitive to the structure of the catalyst, to the surface composition of bimetallic particles, with possible surface enrichments, and to the participation of the support. Hence, it will be tentatively demonstrated that kinetic combined with spectroscopic or theoretical methods can be appropriate to establish relevant correlations between kinetic parameters and the topology of the catalyst surface.     

Fundamental Aspects of Ceria Supported Au Catalysts Probed by In Situ/Operando Spectroscopy and TAP Reactor Studies

The discovery of the activity of dispersed gold nanoparticles three decades ago paved the way for a new era in catalysis. The unusual behavior of these catalysts sparked many questions about their working mechanism. In particular, Au/CeO₂ proved to be an efficient catalyst in several reactions such as CO oxidation, water gas shift, and CO₂ reduction. Here, by employing findings from operando X-ray absorption spectroscopy at the near and extended Au and Ce L_III energy edges, we focus on the fundamental aspects of highly active Au/CeO₂ catalysts, mainly in the CO oxidation for understanding their complex structure-reactivity relationship. These results were combined with findings from in situ diffuse reflectance FTIR and Raman spectroscopy, highlighting the changes of adlayer and ceria defects. For a comprehensive understanding, the spectroscopic findings will be supplemented by results of the dynamics of O₂ activation obtained from Temporal Analysis of Products (TAP). Merging these results illuminates the complex relationship among the oxidation state, size of the Au nanoparticles, the redox properties of CeO₂ support, and the dynamics of O₂ activation.     

Advances in Structure-function Relationships and Mechanism of Transporter Associated with Antigen Processing

The transporter associated with antigen processing (TAP) belongs to the ATP-binding cassette (ABC) transporter superfamily. Driven by ATP hydrolysis, TAP translocates antigenic peptides from the cytosol into the ER (endoplasmic reticulum) lumen where the antigenic peptides are loaded onto the HLA class Ⅰ molecules. Recently, numerous studies show that TAP is closely related with various diseases such as viral infections, autoimmune diseases, and different malignancies. In consideration of important roles of TAP in human adaptive immunity, this review summarizes the recent advances in structure-function relationships of crucial domains and transport mechanism systematically. The challenging problems and potential methods are also pointed out for in-depth researches.     

酞菁（H_2TAP）的X－射线光电子能谱（XPS）

酞菁（Ｈ_２ＴＡＰ）的Ｘ－射线光电子能谱（ＸＰＳ）朱志昂，卜显和，刘月霞（南开大学化学系天津３０００７１）ＰａｕｌＧ．Ｇａｓｓｍａｎ（美国明尼苏达大学化学系）关键词酞青，ＸＰＳ，Ｃ１ｓ电子结合能，Ｎ１ｓ电子结合能酞菁及其金属配合物作为叶绿素，血红素的?..     

Effect of Cationic Valence State on Formation of Defects inCrystal of Thallium Hydrogen Phthalate（TAP）

ＥｆｆｅｃｔｏｆＣａｔｉｏｎｉｃＶａｌｅｎｃｅＳｔａｔｅｏｎＦｏｒｍａｔｉｏｎｏｆＤｅｆｅｃｔｓｉｎＣｒｙｓｔａｌｏｆＴｈａｌｌｉｕｍＨｙｄｒｏｇｅｎＰｈｔｈａｌａｔｅ（ＴＡＰ）￥ＧｕａｎＴｉｅ－Ｔａｎｇ；ＬｉｎＳｈｕ－Ｋｕｎ；ＣｈｅｎＹｉ－Ｐｉｎ；...     

图尔敏论证模式在应用型院校理科教学中的应用*

通过在美国应用型院校中设计实施的教学实验实例,从一个全新的视角深入探讨了图尔敏论证模式在帮助学生构建科学结论及其推理过程,以及增加学生对知识的理解掌握程度等方面的作用,从而为我国应用型本科院校教学模式改革提供了一种有益的借鉴。     

Synthesis of N-Pyridylmethylidene-2-aminopyridines and their Methyl-substituted Derivatives in the Presence of Molecular Sieves

We have studied condensation of 2-, 3-, 4-pyridinealdehydes and 6-methylpyridine-2-aldehyde with 2-aminopyridine and its 3-, 4-, and 6-methyl derivatives in benzene in the presence of molecular sieves. The reactions occur even at room temperature to form the corresponding pyridyl-pyridyl azomethines, and also aminals. We have determined the optimal conditions for carrying out the processes with the aim of obtaining both types of products. We consider the characteristics of the mass spectra for the synthesized aldimines. We present the X-ray diffraction results for the two aminals.