碳纳米管修饰电极分子印迹传感器快速测定沙丁胺醇

以单壁碳纳米管(SWNTs)为电极材料,应用分子印迹技术,以邻苯二胺为功能单体、沙丁胺醇为模板,采用电化学聚合法制备了一种新型的快速检测沙丁胺醇分子印迹传感器,并运用电化学方法去除模板.在磷酸盐缓冲溶液(PBS)中,利用线性溶出伏安法对印迹和非印迹膜的性能进行了比较,对分子印迹膜的影响因素进行了优化.实验表明,本传感器...     

界面聚合法合成聚邻苯二胺及其表征

邻苯二胺电聚合膜己广泛用于生物活性物质固定、电催化、腐蚀防护和电色材料研究,近期也用于制备分子印迹型化学/生物传感器[1,2]。人们已经研究了聚邻苯二胺的结构特性、性能及应用前景[3,4,5]。目前聚合物基纳米复合材料的制备方法主要有:分子自组装法、微乳液聚合法、电化学     

碳纳米管修饰电极分子印迹传感器的制备及其对氧乐果的测定

以氧乐果为模板分子,邻苯二胺为功能单体,在碳纳米管修饰的玻碳电极表面通过电聚合方法制成氧乐果分子印迹聚合物膜,用无水乙醇洗脱后制备出对氧乐果有特异响应的电化学传感器。通过循环伏安法和电化学阻抗法对分子印迹传感器的电化学性能进行表征。以K_3Fe(CN)_6为探针,采用差分脉冲伏安法研究了该分子印迹传感器的分析性能,建立了氧乐果的间接测定方法。结果表明,K_3Fe(CN)_6的相对峰电流与氧乐果浓度在1.0×10~(-7)~2.0×10~(-6)mol/L范围内呈良好的线性关系,检出限为3.6×10~(-8)mol/L。     

基于磁性分子印迹聚合物的电化学传感器的研究进展

分子印迹聚合物与磁性纳米材料结合,制备成磁性分子印迹纳米敏感膜,这样做不仅可以发挥分子印迹聚合材料的优势,而且磁性纳米粒子可有效提高电化学传感器的灵敏度、稳定性以及生物相容性等.近年来将磁性分子印迹纳米敏感膜应用于电化学传感器制备成的磁性分子印迹电化学传感器得到了较快的发展.本文就近5年来磁性分子印迹电化学传感器敏感膜...     

基于分子印迹膜修饰丝网印刷电极的地西泮电化学传感器

以地西泮为模板分子,采用循环伏安法在一次性丝网印刷电极表面原位电聚合形成聚邻苯二胺膜,洗脱除去模板分子后得到地西泮分子印迹膜修饰丝网印刷电极。利用差示脉冲法对印迹膜和非印迹膜进行评价,表征了电极表面膜的电化学性质。以KI为印迹电极和底液间的探针,建立了一种间接检测地西泮的传感方法。该传感器的敏感元件为修饰有分子印迹膜的丝网印刷电极,其制备和更换非常方便。用于电化学检测时,样品的富集时间为3min,地西泮的浓度在2.0×10-7～1.0×10-5mol/L范围内与峰电流呈良好的线性关系,检出限为2.5×10-8mol/L,基于猪肉样品的加标回收率为92%～95%。将该传感器初步用于实际样品分析,结果满意。     

分子印迹电化学传感器

分子印迹电化学传感器能够选择性识别并检测特定目标化合物,因其设计简单、灵敏度高、价格低廉、携带方便、易于微型化和自动化等优点,在临床诊断、环境监测、食品分析等方面越来越受到人们的关注.本文作者主要论述分子印迹技术与电化学技术相结合构建分子印迹电化学传感器,包括分子印迹电化学传感器的种类,以及电化学方法制备分子印迹聚合物膜的常用单体等.对分子印迹电化学传感器领域新出现的分子印迹聚合物-纳米材料复合物以及纳米结构分子印迹聚合物也一并做了评述.     

尼泊金乙酯分子印迹膜电化学传感器的制备

以邻苯二胺为功能单体,尼泊金乙酯为模板分子,通过电化学聚合在玻碳电极表面制备了尼泊金乙酯分子印迹膜,采用循环伏安法及方波伏安法,以K3[Fe(CN)6]为电活性探针,建立了间接测定尼泊金乙酯的分析方法。实验结果表明,制备的分子印迹膜电化学传感器对尼泊金乙酯具有较高的选择性和灵敏度,测定尼泊金乙脂的线性范围为2.5×10-6~1.0×10-5 mol/L,检出限为8.61×10-8 mol/L。     

基于BiOI纳米片双识别型毒死蜱光电化学传感器的构建及应用研究

以BiOI纳米片为载体,毒死蜱为模板分子,对巯基苯胺为功能单体,戊二醛为交联剂,采用电聚合法合成毒死蜱分子印迹聚合物膜,在印迹膜表面固定乙酰胆碱酯酶(AChE),对氯化乙酰硫代胆碱(ATCl)浓度、pH值进行优化,构建了双识别型光电化学传感器.采用电流－时间法(I－t)对水样中毒死蜱(CPF)进行检测,结果表明在最佳实...     

桑色素分子印迹传感器的制备与应用

以邻氨基酚( o-AP)为功能单体,桑色素为模板分子,基于分子间的相互作用力,在金电极表面电聚合制备具有特异性识别孔穴的桑色素分子印迹传感器膜。采用循环伏安法( CV)、差分脉冲伏安法( DPV)等研究了分子印迹膜的性能和分子印迹效应。探索了聚合膜配比及聚合扫描圈数对传感器性能的影响,优化了洗脱时间和印迹时间。比较了此传感器对其结构相似物的选择性响应,发现其对桑色素检测具有良好的选择性。在最佳实验条件下,此传感器对桑色素浓度定量测定范围为0.05~1.70μmol/L,线性方程为I(μA)=1.0800lgc(mol/L)+9.3599, R=0.9934,检出限为0.01μmol/L。用此传感器测定黑茶样品中桑色素的含量,加标回收率为104.0%~108.0%。     

自组装碳纳米管-氯洁霉素分子印迹溶胶-凝胶电化学传感器研究

结合自组装技术, 采用电聚合方法在碳纳米管修饰金电极表面制备对氯洁霉素具有特异性识别位点的分子印迹溶胶-凝胶薄膜, 成功构建了一种新型印迹溶胶-凝胶电化学传感器. 通过循环伏安法(CV)、示差脉冲法(DPV)、安培计时法(I-t)和扫描电镜(SEM)表征了该印迹溶胶-凝胶膜的电化学性能和表面形貌. 结果表明, 该传感器具有良好的选择性和灵敏度, 氯洁霉素在多壁碳纳米管修饰的印迹溶胶-凝胶传感器上的响应明显提高. 该印迹溶胶-凝胶传感器对氯洁霉素的浓度响应线性范围为5.0×10^-7~8.0×10^-5 mol/L, 检出限为2.44×10^-8 mol/L. 该传感器被成功地用于人体尿液中氯洁霉素的分析测定.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

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%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

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.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

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.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.