基于聚硫堇和纳米金共修饰的过氧化氢生物传感器的研究

用循环伏安法将电子媒介体硫堇电聚合在铂电极上,使其表面形成均匀的带负电的聚合膜层,通过静电吸附作用固定表面带正电荷的辣根过氧化物酶,接着吸附纳米金,然后再利用纳米金吸附固定一层辣根过氧化物酶,制成了新型过氧化氢生物传感器。实验发现,该传感器增加了酶的吸附量,响应快、灵敏度高、稳定性好,对H2O2表现出良好的响应特性。检测范围为5.2×10-7~2.0×10-3mol/L,检出限为1.7×10-7mol/L,并具有抗尿酸、抗坏血酸等干扰的特点。     

基于等离子体聚合膜固定酶的H2O2生物传感器

以玻碳电极为基础电极,用微波等离子体技术聚合沉积聚乙二胺等离子体膜,使之形成带氨基功能团的表面,再通过戊二醛交联共价固定辣根过氧化物酶,制得H2O2生物传感器.探讨了等离子体聚合膜的形成条件(如放电功率、单体流速、单体气压和聚合时间),讨论了工作电位、介体浓度和pH值对传感器响应的影响.此外,用红外光谱对等离子体聚合膜进行了表征.该传感器在5×10-7～1.1×10-3mol/LH2O2浓度范围内有线性响应,最低检测限为0.3μmol/L.将此传感器用于实际试样回收率的测定,结果良好.     

基于层层静电吸附天青Ⅰ和纳米金固定过氧化物酶生物传感器的研究

在玻碳电极(GCE)上,构造了一种以对氨基苯磺酸电聚合膜(PABSA)为基底,利用层层静电自组装技术固定多层天青Ⅰ(AI)和纳米金(nano-Au)制备的复合薄膜(nano-Au/AI)n,然后通过静电吸附辣根过氧化物酶(HRP)制得过氧化氢生物传感器[HRP/(nano-Au/AI)n/PABSA/GCE].采用循环伏安法和计时电流法考察了该传感器的电化学性质,并且研究了该修饰电极对H2O2的催化还原作用.在优化的实验条件下,该传感器的响应电流与其浓度在3.5×10-6～3.6×10-3 mol/L范围内呈现良好的线性关系,检出限为1.2×10-6 mol/L.该传感器的米氏常数为1.5 mmol/L,表明所固定的酶具有较高的生物活性.     

基于聚硫堇和纳米银固定酶的葡萄糖生物传感器

用循环伏安法将电子媒介体硫堇电聚合在玻碳电极表面上,使其表面形成均匀的带负电的聚硫堇膜,通过静电吸附作用吸附表面带正电荷的纳米银溶胶,接着通过静电吸附带负电的葡萄糖氧化酶,最后用聚硫堇包埋电极,从而制得性能优良的葡萄糖氧化酶(GOD)生物传感器。实验发现传感器氧化峰电流与葡萄糖的浓度在1.0×10-8~5.0×10-6mol/L(r=0.9963)范围内呈良好线性关系,检出限为5.0×10-9mol/L(S/N=3)。     

溶胶-凝胶壳聚糖/二氧化硅杂化复合膜固定辣根过氧化酶的H2O2电化学生物传感器的研制

利用溶胶 凝胶法制备壳聚糖 二氧化硅有机无机复合杂化膜,用于对辣根过氧化酶进行固定,制得测定H2O2的电流型生物传感器。以1mmol/LK4Fe(CN)6作为电子媒介体。研究了各种因素如壳聚糖与二氧化硅的比率、pH、温度、工作电位等对传感器响应电流的影响。计时电流法测定H2O2的线性范围为2.0×10-6～6.8×10-4mol/L,检出限为8.0×10-7mol/L。测得酶催化动力学参数米氏常数Km=0 87mmol/L。用该法对实际样品进行了测定。     

基于Nafion-氧化石墨烯复合物/硫堇/纳米金构建过氧化氢传感器的研究

利用Nafion(全氟聚苯乙烯磺酸溶液)-氧化石墨烯复合物、硫堇和纳米金构建了H2O2酶传感器。首先将氧化石墨烯分散在体积分数0.2%Nafion溶液中制得Nafion-氧化石墨烯的复合物,并将其固定在玻碳电极表面,通过静电吸附将带正电荷的硫堇吸附到Nafion-氧化石墨烯复合膜修饰的玻碳电极表面,再利用静电吸附将纳米金修饰于电极上,通过纳米金来固定辣根过氧化物酶从而制得H2O2传感器。用循环伏安法和计时电流法考察该修饰电极的电化学特性。H2O2浓度为5.5×10-6~1.0×10-3mol/L时,酶电极的响应电流值与H2O2的浓度呈良好的线性关系,检出限为1.80×10-6mol/L。     

巯基丁二胺镍(Ⅱ)自组装单分子层H2O2传感器研究

采用巯基丁二胺镍(Ⅱ)(NiL-SH)自组装单分子层修饰金电极,制得测定H2O2的电流型生物传感器.NiL-SH在电极表面有一对可逆的氧化还原峰.传感器对H2O2的还原显示出快速电催化响应(＜10 s),采用电子扫描电镜(SEM)和光电子能谱(XPS)对电极表面进行了表征,且计算了其自身电化学反应性质.研究了各种因素如pH、工作电位等对传感器响应电流的影响.循环伏安法测定H2O2的线性范围为5.0×10-6～3.0×10-3 mol/L(r=0.999),检出限为2.0×10-6 mol/L.该电极显示出模拟酶特性,测定米氏常数KMapp＝2.78 mmol/L.对传感器的稳定性,灵敏度和选择性进行研究,并应用于实际样品测定.     

普鲁士蓝和苝四甲酸二酐衍生物膜修饰的过氧化氢生物传感器

以玻碳电极(GCE)为基底,采用恒电位法沉积一层普鲁士蓝(PB),然后将苝四甲酸二酐衍生物(PTC-NH2)自组装到其表面,形成既带氨基功能团,又可有效防止PB渗漏的导电膜.通过静电吸附和共价键合作用固定纳米金和辣根过氧化物酶(HRP)的复合物,从而制得性能优良的过氧化氢(H2O2)生物传感器.采用循环伏安法(CV)和计时电流法,考察了传感器的电化学性能.实验表明,本传感器具有灵敏度高、线性范围宽、检出限低、稳定性好、抗干扰能力强等特点.其线性范围为2.0×10-6～1.4×10-3mol/L;检出限为8.3×10-7mol/L(S/N=3).     

基于层层自组装技术制备石墨烯/多壁碳纳米管共修饰的过氧化氢传感器的研究

利用阳离子型聚合物聚二烯丙基二甲基氯化铵(PDDA)和功能化的带负电荷的多壁碳纳米管(MWNTs)及石墨烯(GR)之间的静电吸附,通过层层自组装的方法在玻碳电极的表面制备了均一、稳定的(PDDA/GR/PDDA/MWNTs)5多层膜。以交流阻抗及循环伏安等方法对修饰电极的性质进行了表征。结果表明,该电极对过氧化氢(H2O2)的氧化显示出较好的电催化活性,在工作电位为1.0 V,0.067 mol/L磷酸盐缓冲溶液(PBS)中对H2O2响应灵敏度高,检测范围宽,测定H2O2的线性范围为6×10-6~1.4×10-2mol/L(相关系数为0.997)。检出限为1.2×10-7mol/L(S/N=3)。并且表现出良好的稳定性和高选择性。该电极用于实际样品中H2O2的测定,结果令人满意。     

基于静电吸附多层膜固定酶的过氧化氢生物传感器的研究

以玻碳电极为基底,电聚合2,6-吡啶二甲酸(PDC),使形成一带负电的界面,再通过静电吸附自组装一层聚阳离子聚丙烯胺(PAH),用于静电吸附固定辣根过氧化物酶并以此方法固定多层酶膜制备过氧化氢传感器.探讨了工作电位、介体浓度、pH对电极响应的影响,考察了电极的重现性、干扰及使用寿命.该传感器在H₂O₂浓度4.6×10^-6～3.5×10^-3 mol/L范围内有线性响应, 检出限为2×10^-6 mol/L.电极在用于实际试样回收率的测定中,结果良好.     

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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.