碳纳米管气体传感器研究进展

碳纳米管具有一维纳米结构、高表面吸附能力、良好的导电性和电子弹道传输特性等优异的力学、电学、物理和化学性能,成为制作纳米气体传感器的理想材料之一.近年来,各国研究者广泛开展了碳纳米管气体传感器的研究工作,并取得了许多显著成果.研究结果表明,碳纳米管气体传感器具有灵敏度高、响应速度快、尺寸小、能耗低和室温下工作等诸多特点.本文结合本研究小组近年来在碳纳米管气体传感器领域所做的大量研究工作,从环境监测、医学检测和国防军事等方面,对碳纳米管气体传感器取得的研究进展进行了综述,同时也阐述和分析了碳纳米管气体传感器的工作原理和制作过程.尽管面临诸多挑战,随着研究的不断深入,碳纳米管气体传感器仍有可能凭借其独特的性能优势成为当前商业应用气体传感器的有力竞争者.     

多壁碳纳米管对沙林的敏感性研究

自碳纳米管被发现以来,由于其具有许多独特的电学、磁学、力学和气敏特性而引起了人们广泛的关注,在结构增强、纳米电子器件、场发射、储氢、传感器等众多领域具有非常广阔的应用前景,成为当前研究的热点之一[1,2].近年来,随着碳纳米管在传感器特别是气体检测领域研究的不断深入,碳纳米管为敏感材料的传感器已成功应用于对O2、NO2、NH3、H2等气体的检测研究[3],其中对NO2的检测可达到10×10-9(φ),但尚未见碳纳米管用于毒剂检测的报道.本文以碳纳米管作为石英晶体微天平膜材料,研究了碳纳米管的化学修饰方法及其对检测沙林的影响,结果表明经强酸加热氧化的碳纳米管对沙林响应大、解吸快、重复性好,可以作为传感器检测沙林的膜材料.该研究为碳纳米管在化学毒剂中的应用奠定了基础.     

碳纳米管基气体传感器研究进展

碳纳米管具有灵敏度高、响应快和工作温度低等优异的气敏特性,近年来碳纳米管基气体传感器的研究成为研究热点.概述了碳纳米管基气体传感器的种类、结构特点、气敏性能和未来的发展方向,着重介绍了纯的碳纳米管包括单壁碳纳米管、多壁碳纳米管和碳纳米管阵列的气敏特性,以及碳纳米管的修饰或碳纳米管与高分子材料、氧化物等复合对其气敏性能的影响.     

盐酸普萘洛尔分子印迹电化学传感器的制备与研究

以盐酸普萘洛尔为目标模板分子,通过电聚合多巴胺,在多壁碳纳米管修饰的玻碳电极表面制备了对目标分子有特异响应的分子印迹电化学传感器.利用扫描电子显微镜、循环伏安法和差示脉冲伏安法对此传感器的表面形貌及性能进行了表征,并且优化了检测条件,研究了印迹传感器对模板分子及其结构类似物的选择性响应.结果表明:此传感器具有较好的选择性响应,而且碳纳米管的存在显著提高了传感器的灵敏度.盐酸普萘洛尔的浓度在0.20～100 μmol/L范围内与峰电流呈良好的线性关系;检出限为2.53×10-8 mol/L(S/N=3).此传感器还具有良好的稳定性和重现性.     

基于稀土材料催化化学发光法检测乙腈气体传感器的研究

基于稀土粉体材料Y2O3催化乙腈气体在其表面发生氧化反应而产生化学发光现象,研制了一种基于化学发光原理检测乙腈的气体传感器。研究结果表明,该传感器具有较高灵敏度和较强的选择性。在温度175℃,波长490 nm条件下,其催化化学发光强度与乙腈浓度在一定范围内呈良好的线性关系,线性范围为2.9~290.0 mg/m3(r=0.9955);检出限为1 mg/m3。该传感器操作简便、性能稳定,实现了对乙腈气体的实时在线检测。     

基于多壁碳纳米管负载金纳米粒子修饰的甲基对硫磷分子印迹电化学传感器的研制

本文以四氨基苯硫酚作为功能单体、甲基对硫磷(MP)作为模板分子,通过电聚合的方法在多壁碳纳米管负载金纳米粒子修饰的玻碳电极表面成功构建了MP分子印迹电化学传感器。借助循环伏安、电化学阻抗和差示脉冲等方法对传感器的电化学性能、选择性、稳定性以及重现性进行了研究。并将所建立的方法应用于黄河水中MP的加标回收检测,结果令人满意。该方法无需进行预处理,选择性好、灵敏度高、重现性好,为分析检测MP分子提供了一种非常有效的方法。     

基于新型纳米传感材料的DNA生物传感器的应用

DNA是构建纳米技术和生物传感技术新设备的良好构建体。DNA生物传感器由于具有灵敏度高、选择性好等特点,近年来获得了飞速发展。研究发现,金属纳米粒子(MNPs)、碳基纳米材料等一系列纳米材料在传感器设计中提高了电化学DNA传感器的传感性能。本文侧重介绍了场效应晶体管、石墨烯、碳纳米管等新型纳米传感材料,以及基于这些材料的DNA生物传感器的最新进展,最后展望了DNA生物传感器的应用前景。     

SAW气体传感器聚合物敏感膜材料研究进展

声表面波(surface acoustic wave,SAW)气体传感器具有灵敏度高、选择性好、响应时间短以及体积小,携带方便等优点,因而被广泛应用于环境监测、医疗卫生、化学侦检等领域中有毒有害气体的现场实时检测。敏感膜材料的特性是决定SAW传感器性能(如灵敏度、选择性、响应时间、寿命等)的关键因素。本文首先简要介绍了SAW气体传感器的响应原理和对敏感膜材料的要求,然后重点阐述了用于SAW气体传感器的有机聚合物敏感膜材料的研究进展,最后对其研究趋势做出简单预测。     

辣根过氧化物酶在金属螯合琼脂糖/CNTs修饰电极表面的固定化及邻苯二酚检测

将辣根过氧化物酶亲和固定在金属螯合功能化的琼脂糖/碳纳米管复合物修饰电极上,构建了一种新型的安培生物传感器,并将其用于邻苯二酚分析检测.金属螯合亲和是利用Ni2＋对辣根过氧化物酶表面的组氨酸或半胱氨酸残基强烈且可逆的亲和键合能力.因此,在分子中有这样残基的酶很容易固定在含有镍螯合的功能化的琼脂糖/碳纳米管复合物上.采用线性扫描伏安法和安培法研究,酶电极对邻苯二酚在-0.05V（vs.SCE）直接还原生物催化其生成的醌类物质而间接测定.对影响生物传感器灵敏度的pH、施加电位和H2O2浓度进行了研究.研究结果表明在pH为7.0,电极电位为-0.05V（vs.SCE）,H2O2浓度为40-M时,传感器有很好的响应.利用构建的生物传感器对邻苯二酚、苯酚、对叔丁基邻苯二酚及2-氯酚进行了测试,显示出高的灵敏度,特别是对邻苯二酚,其线性范围为2.0×10-8～1.05×10-5M,检测限为5.0×10-9M.此外,生物传感器在保存60天后其响应为起始水平的90%,响应时间为3s,并能用于实际水样测定,表明构建的生物传感器有宽的线性范围、高的灵敏度、好的抗干扰能力和长期稳定性.     

二氧化锡气体传感器对有机磷农药残留的动态检测

研究了一种快速检测和识别农药敌百虫、乙酰甲胺磷和乐果气体的新方法,即动态检测方法。这种方法利用单个SnO2气体传感器而非阵列在方波温度调制的状态下可实现3种农药气体的快速检测。实验结果表明：在0．02Hz的调制频率和250—300℃的温度调制范围,传感器表现出高的选择性和稳定性;利用FFT频谱和极坐标构建完成对敌百虫、乙酰甲胺磷和乐果的定性和定量检测。     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.