DNA-HRP/聚L-酪氨酸共修饰电极的制备及其电化学性能的研究

以聚L-酪氨酸膜为载体,固载DNA和辣根过氧化物酶(HRP)制备过氧化氢生物传感器.该传感器对H2O2表现出良好的催化还原特性,具有灵敏度高,稳定性好且易于制作等特点.其线性响应范围为: 2.0×10-6～1.1×10-2 mol/L,检出限为8.0×10-7 mol/L (S/N=3).     

DNA-HRP/聚M-酪氨酸共修饰电极的制备及其电化学性能的研究

以聚L-酪氨酸膜为载体,固载DNA和辣根过氧化物酶(HRP)制备过氧化氢生物传感器.该传感器对H2O2表现出良好的催化还原特性,具有灵敏度高,稳定性好且易于制作等特点.其线性响应范围为:2.0×10-6～1.1×10-2 mol/L,检出限为8.0×10-7 mol/L (S/N=3).     

新型脱氧核糖核酸光纤生物传感器的研制及其性能评价

研制了一种新型脱氧核糖核酸(DNA)光纤生物传感器,以带尾纤的脉冲半导体激光器为激发光源,结合流动进样系统,能够快速方便地对光纤传感器表面发生的DNA杂交反应进行测定.研究表明:通过链霉亲和素/生物素作用修饰到传感器表面的DNA探针对Dylight 680荧光标记的完全互补DNA有良好的响应,而对非互补的DNA基本没有响应.系统检测灵敏度可达到4.5×10-10 mol/L;线性范围为1×10-9～3×10-8 mol/L.光纤传感器具有良好的再生性能.     

高效液相色谱-柱后化学发光法检测人体尿液中的卡托普利

在酸性条件下,Ce?氧化Ru(bipy)32+生成Ru(bipy)33+,同时氧化卡托普利生成二硫化物中间活性态([RS-SR]*),Ru(bipy)33+和二硫化物中间活性态之间相互反应产生强烈的化学发光。基于此,根据发光试剂Ru(bipy)32+水溶性好、试剂稳定等特点,将其加入到流动相中,通过高效液相色谱分离,建立了柱后化学发光快速灵敏检测卡托普利的方法。在以甲醇-0.01mol/L KH2PO4-1g/L Ru(bipy)32+(80∶20∶2,V/V)为流动相,流速为0.9mL/min,8.0×10-4 mol/L Ce?的优化实验条件下,方法的线性范围为2.0×10-7～1.0×10-4 mol/L(R2=0.9988),检出限为6.0×10-8 mol/L(S/N=3),并对1×10-5 mol/L卡托普利平行测定11次,相对标准偏差(RSD)为1.8%。将本方法用于人体尿液中卡托普利含量的测定,结果令人满意。结合化学发光光谱,对该体系发光机理进行了探讨。     

二甲基姜黄素对Fe~(3+)的选择性识别研究

以姜黄素和碘甲烷为原料,一步合成了二甲基姜黄素分子探针L,其结构经X-射线单晶衍射、~1H NMR,~(13)C NMR和ESI-MS等分析手段确证。该化合物晶体属单斜晶系,空间群C2/c,晶胞参数:a=22.317(6)nm,b=8.703 8(19)nm,c=23.039(5)nm,β=93.378(10)°,V=4 467.4(18)nm3,Z=4,Dc=1.206 g·cm-3,F(000)=1 720,μ(MoKα)=0.088 mm-1,R=0.080 9,ωR=0.216 3。探针L在甲醇-水溶液(体积比9∶1,Tris-HCl缓冲溶液,p H 7.2)中对Fe~(3+)具有选择性识别和较强的抗干扰能力。通过紫外滴定以及质谱确证探针L与Fe~(3+)形成1∶1配合物,结合常数(K)为1.089×106L/mol。该识别体系在Fe~(3+)浓度为5.5×10-6~3×10~(-5)mol/L范围内具有较好的线性关系(r2=0.997 8),检出限为2.2×10~(-6)mol/L。     

2-(2-羟基-3-甲氧基苯基)-5-(1-羟甲基)C_(60)吡咯烷衍生物的合成及其在DNA电化学传感器中的应用

以L-丝氨酸、邻香兰素及C60为原料通过1,3-偶极环加成反应,合成并分离纯化得到一种新型的2-(2-羟基-3-甲氧基苯基)-5-(1-羟甲基)C60吡咯烷衍生物(FPD)。通过质谱、红外光谱、紫外-可见光谱、氢核磁和元素分析等检测手段对其结构进行表征。采用滴涂法将FPD修饰在玻碳电极表面,然后在其表面组装Al3+,并进一步利用Al3+与磷酸骨架的静电相互作用,将探针DNA固定到修饰电极表面,组建了一种新型DNA电化学生物传感器。以亚甲基蓝(MB)为杂交指示剂,考察了该DNA传感器的分析性能。实验结果表明,在1.0×10-15~1.0×10-9mol/L浓度范围内,互补序列DNA的浓度对数值(lgcS2)与该传感器上的峰电流值(Ip)具有良好的线性关系,其线性方程为Ip(10-6A)=0.106 lg(cS2,mol/L)+0.735,检出限(S/N=3)为5.4×10-16mol/L。选择性实验表明该传感器能有效识别互补序列和碱基错配序列DNA片段。     

基于胆碱修饰层为基底的纳米金固定过氧化物酶修饰电极的研究

玻碳电极上共价修饰上单分子层胆碱(Ch)可以显著提高电极的活性。本研究利用该电极上胆碱层带有的正电荷,牢固吸附带负电荷的纳米金溶胶,继而利用纳米金颗粒良好固载辣根过氧化物酶(HRP),制备出了基于HRP酶直接电化学的H2O2传感器。以阻抗谱、循环伏安等方法表征了修饰电极的性质。结果显示,该电化学传感器具有良好的催化活性,电活性HRP的表面浓度(Γ*)为1.2×10-9mol/cm2,米氏常数KMapp=1.55±0.11 mmol/L。该修饰电极在H2O2浓度1.2×10-6~3.2×10-3mol/L范围内有线性响应,检出限(S/N=3)为4.0×10-7mol/L。本修饰电极制备简单,选择性高,稳定性好,可以作为进一步构筑生物传感器的基础。     

辣根过氧化酶在磁性纳米修饰的离子注入电极上的电化学和电催化行为

辣根过氧化酶(HRP)在Co/NH2/ITO离子注入电极上有一对良好的氧化还原峰,峰电位分别为Epc=-0.2 V,Epa=-0.01 V(vsAg/AgCl)。该修饰电极对H2O2具有催化作用,可以用作H2O2的生物传感器,峰电流与H2O2的浓度分别在1.0×10-10~2.0×10-8mol/L和2.0×10-8~1.0×10-7mol/L范围内呈线性关系,线性回归方程分别为Ip(mA)=2.2986+0.06632c(nmol/L)和Ip(mA)=3.5788+7.3053E-4c(nmol/L),相关系数分别为0.9972和0.9688。检出限为1.0×10-10mol/L。     

石墨烯-铁卟啉复合材料的制备及其H2O2传感器应用研究

本文通过π-π非共价键的方式合成了具有仿生功能的石墨烯-铁卟啉复合材料,并将其修饰在玻碳电极上,制备成一种新型的无酶H2O2传感器。利用傅里叶变换红外(FT-IR)光谱、紫外-可见吸收光谱(UV-Vis)及电化学阻抗谱(EIS)对合成材料进行了表征,并研究了该传感器对H2O2的电催化还原性能。实验结果表明,该传感器对H2O2具有较好的催化还原效果,能够在-0.24V电位下对H2O2进行测定;其对H2O2的线性检测范围为5.0×10-7～1.975×10-4 mol/L,检测限为4.1×10-7 mol/L。     

电聚合茜素黄R构建辣根过氧化物酶传感器的研究

利用电聚合茜素黄R(AYR)的方法,将辣根过氧化物酶(HRP)和细胞色素c(Cyt c)固载于通过一步法电沉积的碳纳米管-金纳米粒子(MWCNTsAu NPs)复合纳米材料修饰电极表面,构筑PAYR-HRP-Cyt c/M WCNTs-Au NPs修饰电极,并利用HRP对H2O2的直接电化学催化行为对H2O2进行检测。采用扫描电镜对MWCNTs-Au NPs和PAYR-HRP-Cyt c的表面形貌进行表征。利用电化学阻抗对修饰电极的构筑过程进行了监测。采用循环伏安法和计时电流法对修饰电极的电化学行为进行了研究。探讨了p H和电位对该修饰电极测定H2O2的性能的影响。该传感器对H2O2在5.0×10-7~3.14×10-3mol/L范围内呈良好的线性响应,相关系数为0.9997,灵敏度为0.50 A·L/mol,检出限(S/N=3)为9.6×10-8mol/L。     

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%.     

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.     

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.     

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.     

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 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.     

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.     

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.