Au-Pd合金纳米管修饰的尼古丁分子印迹膜传感器的研究

基于Au-Pd合金修饰的玻碳电极为工作电极,采用循环伏安法将邻氨基酚与尼古丁电沉积在工作电极上,制备了尼古丁分子印迹膜传感器。采用差分脉冲伏安法研究尼古丁在尼古丁分子印迹膜传感器上的电化学行为,考察了模板溶解时间、富集时间和溶液pH值对尼古丁测定的影响。在优化实验条件下,尼古丁分子印迹膜传感器的线性范围为1.2×10~(-7)~2.5×10~(-3) mol/L,检出限为4.6×10~(-8) mol/L。用该传感器对吸烟者血液中尼古丁的含量进行检测,结果表明,该传感器具有灵敏度高、线性范围宽、重现性及稳定性好等优点。     

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。     

固体接触式聚合物敏感膜电位型传感器检测海水中碳酸根

以CO_3~(2-)为检测对象,发展了聚合物敏感膜电位型碳酸根传感器。采用3-辛基噻吩(POT)作为传导层的固体接触式电极技术,通过优化实验条件,构建了聚合物敏感膜CO_3~(2-)选择性电极,该电极对CO_3~(2-)检出限为7.0μmol/L,线性范围为1.0×10~(-5)~1.0×10~(-3)mol/L,能斯特响应斜率为-29.6 m V/decade。传感器已用于海水中CO_3~(2-)的测定。     

石墨烯修饰电化学适配体传感器测定双酚A

构建了一种检测双酚A(BPA)的电化学适配体传感器。利用在线电化学方法将氧化石墨烯还原为石墨烯,通过石墨烯与单链DNA之间的相互作用,将BPA适配体单链DNA吸附固定在修饰电极上,制备了BPA电化学适配体传感器。以铁氰化钾-亚铁氰化钾平衡电对为电化学探针,利用电化学循环伏安法和差分脉冲伏安法对BPA传感器的性能进行了研究。结果表明,在最优化实验条件下,传感器对BPA的检测线性范围在1.0×10~(-15)~1.0×10~(-10)mol/L之间,检出限为3.3×10~(-16)mol/L(S/N=3)。     

碳纳米管修饰电极对对苯二酚和邻苯二酚的电催化研究

用循环伏安法(CV)和交流阻抗技术(EIS),研究了对苯二酚(HQ)和邻苯二酚(CC)在多壁碳纳米管(MWCNT)修饰电极上的电化学行为。分析和比较了修饰电极对这两种酚的催化反应。修饰电极对两种多酚类化合物都有强烈的电催化作用,电极过程受扩散控制。在pH 5.8的HAc-NaAc缓冲溶液中,HQ在修饰电极上的线性范围是10×10-4~1.0×10-2mol/L,检出限为1.0×10-5mol/L;在pH 4.4的HAc-NaAc缓冲溶液中,CC在修饰电极上的线性范围是4.0×10-5~2.0×10-3mol/L,检出限为8.0×10-6mol/L。该修饰电极可对HQ和CC同时进行测定。     

二茂铁巯基化合物/金纳米粒子/还原石墨烯修饰电化学传感器检测Cu~(2+)

通过Hummer法进一步还原合成还原石墨烯(RGO),Shifft碱反应合成新型二茂铁巯基化合物(FcSH)。利用还原石墨烯吸附性将石墨烯修饰在玻碳电极(GCE)上,在石墨烯表面电沉积金纳米粒子(AuNPs),通过自组装制备还原石墨烯和二茂铁巯基修饰电化学传感器(FcSH/AuNPs/RGO/GCE),该电化学传感器具有大的比表面积和富电子性能。实验显示,在0.01 mol/L HCl中,富集时间为180s,Cu~(2+)浓度在1.0×10~(-12)~1.0×10~(-11)mol/L与1.0×10~(-11)~1.0×10~(-10)mol/L范围内与方波伏安峰电流分别呈现良好的线性关系,检出限为0.94×10~(-12)mol/L。该电化学传感器对Cu~(2+)的检测表现出较好的选择性、高的稳定性和灵敏性,可用于环境中痕量Cu~(2+)的测定。     

二茂铁修饰碳黑微电极同时测定多巴胺和抗坏血酸

研究了神经递质多巴胺(DA)和抗坏血酸(AA)在二茂铁修饰碳黑微电极上的电化学行为。实验结果表明,在pH4.5的磷酸盐中,DA在该电极上的线性范围为2.0×10-6～4.0×10-3mol/L,检出限(3σ)为1.0×10-6mol/L;AA在该电极上的线性范围为6.0×10-6～1.0×10-3mol/L,检出限(3σ)为2.0×10-6mol/L;用这种电极可以同时测定多巴胺,抗坏血酸。     

流动注射化学发光法测定曲克芦丁

基于曲克芦丁对Luminol-K_2S_2O_化学发光体系的强烈抑制作用,结合流动注射技术,建立了流动注射化学发光法测定曲克芦丁的新方法.在优化的实验条件下,该法的线性范围为1.0 ×10~(-7)～6.7×10~(-5)mol/L,检出限为8.0×10~(-8)mol/L,对4.0×10~(-7)mol/L曲克芦丁进...     

MoS_2中空纳米球的制备及在超灵敏microRNA电化学生物传感器中的应用

采用模板法制备了二硫化钼中空球纳米材料,利用扫描电子电子显微镜、X射线衍射仪和Raman光谱仪对材料的形貌和结构进行表征.将适配体固定在金纳米粒子和二硫化钼共同修饰的电极上构建了一种新型的微小核糖核酸(microRNA)电化学生物传感器,采用循环伏安、微分脉冲伏安和电化学阻抗等技术对构筑的传感器进行表征.结果表明,microRNA浓度在1.0×10~(-10)~1.0×10~(-16)mol/L范围内峰电流(I)与microRNA浓度的负对数(-lgc)呈良好的线性,目标miRNA的检出限为0.55×10~(-16)mol/L.构建出的传感器具备选择性好、灵敏度高、稳定性强等特性,具有广阔的应用前景.     

L-丝氨酸/壳聚糖/石墨烯/纳米金修饰电极的制备及应用

将L-丝氨酸(L-Serine)电聚合到裸金电极表面,再将壳聚糖(CS)、纳米金(Nano-Au)、石墨烯(GO)混合液滴涂在L-丝氨酸修饰的金电极上,制成L-Serine/GO/Nano-Au/CS/Au/CME电化学传感器.考察了胞嘧啶在该传感器上的电化学行为,优化了实验条件.结果表明,该传感器对胞嘧啶有良好的选择性和灵敏度,胞嘧啶的浓度在1.0×10~(-7)~1.0×10~(-3)mol/L范围内与峰电流的减小量呈现良好的线性关系,检出限为3.2×10~(-8)mol/L(S/N=3).将该传感器应用于实际样品中测定胞嘧啶,结果令人满意.     

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%.     

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.     

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.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

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.     

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.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

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.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

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.