基于Ru(bpy)2+3/AuNPs/SWCNTs/腺苷适配体电化学发光生物传感器用于腺苷的检测

利用AuNPs/Nafion复合膜技术固定Ru(bpy)2+3,采用羧基化碳纳米管固定氨基化腺苷适配体,制备腺甘电化学发光生物传感器.采用循环伏安法和电化学发光法对传感器进行表征.结果表明,此传感器具有良好的稳定性和重现性.腺苷与传感器作用后,腺苷与其适配体形成G四面体结构,Ru(bpy)2+3的电化学发光强度降低.在最佳实验条件下,电化学发光强度降低量与腺苷浓度的负对数在1.0×10-11~1.0×10-7 mol/L范围内呈良好的线性关系,线性方程为ΔIECL=-890lgC-5050,检出限(S/N=3)为5.0 × 10-12 mol/L.对1.0 × 10-10 mol/L腺苷平行测定11次,相对标准偏差为2.7%.用于尿液中腺苷的测定,加标回收率在 97.1%~110.0%之间.     

乳酸氧化酶共价交联于蛋膜上制备乳酸传感器

以牛血清白蛋白 戊二醛为交联剂 ,将乳酸氧化酶固定于鸡蛋膜上 ,氧电极作电化学敏感元件 ,制成乳酸氧化酶电极。传感器的线性响应范围为 5 .0×1 0 - 5～ 2 .5× 1 0 - 2 mol/L ,检测限为 2 .0× 1 0 - 5mol/L ,RSD为 1 .4% (n =1 1 ) ,回收率为 97.5 %～ 1 0 4 .0 %。该传感器可用于临床乳酸的测定。     

流动注射电化学发光法测定半胱氨酸和谷胱甘肽

采用流动注射分析技术研究了半胱氨酸和谷胱甘肽对鲁米诺微弱电化学发光的增敏行为。对影响电化学发光的各因素进行了试验和探讨 ,提出了可能的反应机理 ,并建立一种电化学发光测定半胱氨酸和谷胱甘肽的新方法。半胱氨酸和谷胱甘肽的浓度在 1 .0× 1 0 - 6 mol/L～ 5 .0× 1 0 - 5 mol/L和 1 .0× 1 0 - 6mol/L～ 2 .0× 1 0 - 5 mol/L之间呈良好的线性关系 ,相关系数分别为 0 .993和0 998,检出限分别为 0 .67μmol/L和 0 .72 μmol/L。对 1 .0× 1 0 - 5mol/L的半胱氨酸和谷胱甘肽进行 1 1次平行测定 ,相对标准偏差分别为 4.5 %和 3.7%。     

流动注射化学发光发测定葡萄糖

β-D-葡萄糖的检测是临床化学的常规分析项目 .化学发光分析法测定葡萄糖具有线性范围宽、灵敏度高等优点[1～ 3] .我们曾研究了鲁米诺 ( L uminol) -KIO4 -H2 O2 化学发光反应体系[4 ] ,发现 H2 O2 浓度在 2 .0× 1 0 - 7～ 6.0× 1 0 - 4mol/L范围内与发光强度有良好的线性关系 .本文将生成 H2 O2 的葡萄糖 -葡萄糖氧化酶 ( GOD)的酶促反应与鲁米诺 -KIO4 -H2 O2 的化学发光反应相偶合 ,结合流动注射技术 ,建立了一种流动注射化学发光测定葡萄糖的新方法 .方法的线性范围为 0 .6～ 1 1 0 mg/L ,相关系数为 0 .9997,检出限为 0 .0…     

磷脂-月桂酸膜修饰玻碳电极测定多巴胺及其电化学行为

本文报道了多巴胺 (DA)在磷脂 -月桂酸修饰的玻碳电极上的电化学行为 ,在+ 0 .7～ -0 .4V(vs.Ag/ Ag Cl)电位范围内 ,于 p H 6.4的 0 .0 1 mol/ L的 KH2 PO4 -Na2 HPO4 底液中 ,多巴胺产生很灵敏的氧化峰电流。氧化峰电流与多巴胺浓度在 3 .1× 1 0 - 7～ 1 .2× 1 0 - 4mol/ L范围内呈良好线性关系。该电极可作为检测多巴胺的新型的高灵敏度电化学生物传感器     

基于Ru(bpy)32+/AuNPs/Nafion电化学发光传感器检测已烯雌酚

利用柠檬酸钠还原氯金酸制得金纳米粒子(AuNPs),基于AuNPs/Nafion与Ru(bpy)32+之间的静电引力,制备了Ru (bpy) 32+/AuNPs/Nafion电化学发光传感器.采用循环伏安法和电化学发光法对该传感器进行了表征,结果表明该传感器具有良好的稳定性和重现性,可实现对已烯雌酚的检测.在pH=7.0的0.1 mol/L磷酸盐缓冲溶液(PBS,含0.05 mol/L三正丙胺)中,当已烯雌酚与修饰电极作用15 min时,电化学发光强度减少值与已烯雌酚浓度的负对数在1.0×10-10～5.0×10-7 mol/L范围内呈良好的线性关系,检出限为6.0 X 10-11 mol/L.对1.0×10-8 mol/L已烯雌酚平行测定11次,相对标准偏差为2.7％.测定已烯雌酚实际样品的加标回收率在98.0％～104.5％之间.     

噻吩甲酰三氟丙酮的电化学性质及应用

在 0 .5mol/LHCl和 0 .2g/L的明胶溶液中 ,利用线性扫描极谱法测定噻吩甲酰三氟丙酮 (简称TTA) ,发现有一还原峰 ,其峰电位是 - 1 .0 0V (vs.SCE)。峰电流与TTA浓度在 2 .5× 1 0 - 5mol/L～ 2 .0× 1 0 - 3mol/L之间存在线性关系 (r=0 .9986) ,检测下限为 1 .0× 1 0 - 5mol/L。利用单扫描极谱法和循环伏安法对极谱峰的电化学性质进行了研究     

基于电还原鲁米诺电化学发光分析法测定水样中钼(Ⅵ)

基于钼 对鲁米诺电化学发光体系的电还原发光信号的增敏作用 ,建立了一种测定钼 的电化学发光新方法。在最佳的实验条件下 ,相对电化学发光强度与钼 的浓度在 5 .0× 1 0 - 4～ 1 .0× 1 0 - 2 g L范围内呈线性关系 ;检出限为 0 .1 3mg L ;相关系数为 0 .992 0。     

L-半胱氨酸自组装膜电极对米吐尔的电催化及其分析应用

研究了米吐尔在L 半胱氨酸自组装膜修饰金电极上的电化学行为。米吐尔在该修饰电极上的CV曲线仅出现一对峰 ,其峰形对称 ,ΔEp =42mV ,氧化还原峰电流之比约等于 1,为可逆反应 ;扩散系数D =2 .2 4× 10 - 6 cm2 ·s- 1 。初步探讨了电催化机理。差分脉冲伏安法测定其氧化峰电流与米吐尔浓度在 5 .0× 10 - 7～ 2 .0× 10 - 5mol/L和 5 .0× 10 - 5～ 1.0× 10 - 3 mol/L范围内分段呈线性关系 ;相关系数分别为 0 .9987和 0 .9972 ;检测限 1.0× 10 - 8mol/L     

利用粉末微电极检测谷胱甘肽及L-半胱氨酸

本文研究了谷胱甘肽 ( GSH)和 L-半胱氨酸 ( L- cys)在碳粉末微电极上的电化学行为 ,并分别用乙炔黑粉末和 Ketjenblack粉末填充的微电极检测了溶液中GSH和 L- cys的浓度。 GSH和 L- cys在粉末微电极上的检出限分别为 3.4× 1 0 - 6mol/ L和 2 .5× 1 0 - 6 mol/ L,线性范围分别为 3.6× 1 0 - 5～ 4.5× 1 0 - 3mol/ L和 1 .5×1 0 - 5～ 5 .0× 1 0 - 3mol/ L。采用粉末微电极技术完全避免了尿酸和对 -乙酰氨基苯酚对测量谷胱甘肽的干扰 ;0 .0 6mmol/ L的抗坏血酸引起的干扰约为 8%。     

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.     

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.     

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.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.