共查询到20条相似文献,搜索用时 781 毫秒
1.
电聚合修饰碳纤维电极及乳酸脱氢酶活性的测定 总被引:4,自引:0,他引:4
用电聚合方法将亚甲基绿 (MG)修饰在碳纤维电极 (直径 7μm)上 ,并用该修饰电极测定了乳酸脱氢酶 (LDH)活性。在烟酰胺腺嘌呤二核苷酸 (NAD+ )浓度为 6 .0× 10 - 4mol L ,乳酸浓度为 5 .0× 10 - 3mol/L的pH7.0NaOH KH2 PO4 缓冲介质中 ,电位恒定在 +0 .10V下 ,用电流法测定乳酸脱氢酶活性 ,线性范围为 15~ 2 4 0U/mL ,检测限为 10U/mL ,响应时间为 15s。该修饰微电极稳定性好、灵敏度高、测定干扰小 相似文献
2.
新型纳米银-磷酸锆-中性红复合膜修饰电极对过氧化氢电催化还原 总被引:3,自引:0,他引:3
制备了新型纳米银 磷酸锆复合材料 ,对中性红有强烈吸附。吸附的中性红表现出更强的氧化还原性 ,氧化还原中点电位与溶液中 (pH 7)相比正移约 2 0 0mV。将辣根过氧化酶与复合材料共同修饰在电极表面制成酶电极 ,对H2 O2 有显著电催化还原作用。催化电流在 2 .5× 1 0 - 6 ~ 2 .0× 1 0 - 3mol L范围内与H2 O2 浓度成正比 ;H2 O2 检出限为 2 .0× 1 0 - 7mol L(S N =3 ) ;传感器对 1 .0× 1 0 - 5mol LH2 O2 响应时间 <1 5s;RSD为1 4% (n=1 0 )。4℃保存 6个月该电极仍有 85 %以上初始响应。传感器有效消除了抗坏血酸等共存物质的干扰 ,回收率实验结果令人满意。 相似文献
3.
4.
5.
在塑料基片上制备了金薄膜的两电极系统的生物传感器.集成化的Ag|AgCl参比电极采用丝网印刷在薄膜电极上.以聚乙二醇二缩水甘油醚(PEGDGE)为交联剂,将辣根过氧化酶(HRP)和谷氨酸氧化酶(GLOD)固定到聚乙烯吡啶与2,2'-双吡啶锇形成的氧化还原复合物中,滴在电极表面形成传感器的工作电极.实验结果表明,该生物传感器在谷氨酸溶液的浓度为1.0×10-6~4.0×10-4 mol/L的范围内,具有很好的线性关系(r=0.9998,n=9),灵敏度为37.5 mA(mol/L)-1cm-2;谷氨酸检出限为1.0×10-6 mol/L;传感器响应时间为10 s且有良好的一致性和稳定性,使用一个月后仍能保持其初始活性的90%.该传感器可以用于食品工业中的谷氨酸的快速检测和在线监测等. 相似文献
6.
7.
8.
聚吡咯固定胆固醇氧化酶/普鲁士蓝安培传感器的研制 总被引:3,自引:0,他引:3
利用电聚合吡咯的方法将胆固醇氧化酶固定在普鲁士蓝 (PB)修饰玻碳电极表面 ,制成了一种新型胆固醇安培传感器。PB膜修饰电极催化过氧化氢电还原 ,于 0V(vs.Ag ACl)产生灵敏还原峰 ,利用安培法可对胆固醇进行间接测定。胆固醇的测定范围为 0~ 2× 10 - 4mol L ,检出限为 6× 10 - 7mol L ,灵敏度较当前胆固醇传感器有明显的提高。同时该传感器对胆固醇的测定避免了常规电化学传感器测定中样品所含大量的易氧化物质带来的干扰 相似文献
9.
10.
以溴化S 十六烷基双硫腙载体制备了碳酸氢根离子选择性电极 ,选择性次序为 :ClO-4 >SCN->I-~HCO-3 >ClO-3 ~NO-3 >Ac->NO-2 >Cl->H2 PO-4 >SO2 -4 。膜配比 (质量百分比 )为溴化S 十六烷基双硫腙 (SHDTZ)·HCO-3 ∶邻苯二甲酸二异辛酯∶PVC =2 .5∶65.0∶32 .5电极性能最佳。 32℃时 ,在pH 8 30 .1mol/L三乙醇胺 硫酸缓冲溶液中 ,HCO-3 离子浓度在 1 .0× 1 0 -2 ~ 1× 1 0 -5mol/L范围与电极电位呈线性响应 ,检测限为 5.0× 1 0 -6mol/L;斜率为 54± 2mV/decade。研究了HCO-3 离子与载体的作用机理。用该法测定了人体血清中HCO-3 ,结果与滴定法一致。 相似文献
11.
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%. 相似文献
12.
Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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. 相似文献
13.
Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
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. 相似文献
14.
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. 相似文献
15.
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. 相似文献
16.
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. 相似文献
17.
Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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. 相似文献
18.
N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
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. 相似文献
19.
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%). 相似文献
20.
Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
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. 相似文献