痕量雌二醇的吸附方波伏安法检测

本文报道一种简便、快速、灵敏检测痕量雌激素的吸附溶出方波伏安法。该法先将雌二醇在玻碳电极上吸附富集一定时间 ,然后以方波伏安溶出法检测其氧化电流。介质为含有 8× 1 0 - 5mol· L- 1溴化十六烷基三甲铵 ( CTAB)的 0 .1 mol· L- 1磷酸盐缓冲溶液 ( p H=1 0 .0 )。该法检出限为 5× 1 0 - 8mol· L- 1,线性范围为 5 .2× 1 0 - 7～ 5× 1 0 - 5mol· L- 1。研究了雌二醇的电极反应机理     

单扫示波极谱法同时测定钴与镍

在 pH 9.70的Na2 CO3 NaHCO3、亚硝基红盐和氯代十四烷基吡啶体系中 ,镍和钴均有灵敏的络合物吸附波 ,其二阶导数峰电位分别为 - 0 .6 4V (vs .SCE) (镍 )和 - 0 .80V (vs .SCE)(钴 ) ,电流峰高与浓度在 3.4× 10 - 9～ 3.74× 10 - 6 mol·L- 1(镍 )和 7.0× 10 - 11～ 6 .0× 10 - 6 mol·L- 1(钴 )范围内呈线性关系 ,检出限分别为 2 .4× 10 - 9mol·L- 1(14 1ng·L- 1镍 )和 3.2× 10 - 11mol·L- 1(1.9ng·L- 1钴 )。方法应用于水样和生物样品中微量钴和镍的测定 ,结果满意     

钴氢氧化物修饰玻碳电极的镀膜/循环伏安法制备及其电化学行为

采用一种新方法镀膜 /循环伏安法成功制备了钴氢氧化物修饰玻碳电极 .考察了影响钴氢氧化物膜电催化活性的因素 ,确定最佳富集时间为 2min ,最佳活性单元浓度为 9 90× 10 -4mol·L-1.讨论了成膜过程及机理 .膜氧化峰电流 (i0pa)与扫描速率 (v <0 60V·s-1)成正比 ,具有表面吸附反应特征 ,表面覆盖量约相当于 0 5个单层的氧化还原活性物质 .制得的钴氢氧化物膜修饰电极具有相当的稳定性 ,并对H2 O2 氧化表现出较高的电催化活性 .线性回归方程为 :Δipa( μA) =-2 10 3 6+2 3 72 0× 10 4CH2 O2 (mol·L-1) (R =0 9990 ,n =18) ,线性范围为 :1 43× 10 -5～ 1 80× 10 -2 mol·L-1,检出限为 :9 5 9× 10 -6mol·L-1( 3S/k) .     

二次微分简易示波伏安法直接测定酒样中半胱氨酸

在 0 .2mol·L- 1NaOH支持电解质溶液中 ,半胱氨酸在二次微分简易示波伏安图阴极支- 0 .4 9V(vs .SCE)处产生一灵敏的峰 ,研究了半胱氨酸在此底液中的示波伏安行为 ,并据上述示波特性建立了二次微分简易示波伏安法直接测定酒中半胱氨酸含量的新方法。校正曲线的线性范围为 3.0× 10 - 6 ～ 5 .0× 10 - 5mol·L- 1,相关系数为 0 .9995 ,检出限为 1× 10 - 6 mol·L- 1,对 1.0×10 - 5mol·L- 1半胱氨酸进行 6次测定的RSD为 1.8%。利用此法测定了啤酒、黄酒及加饭酒中半胱氨酸的含量 ,样品的回收率分别为 94 .2 %、10 1.6 %和 10 2 .2 %。方法具有仪器装置简单、经济 ,方法简便快速、无需通氮除氧以及对样品进行前处理的优点     

方波吸附溶出伏安法同时测定水中痕量铜和镉

报道了应用方波吸附溶出伏安法 (OSWSV)同时测定Cu(Ⅱ )和Cd(Ⅱ )。在 0 .0 1mol·L- 1酒石酸钾钠 2 .0× 10 - 4mol·L- 1水杨醛肟溶液中 (pH 11.75 ) ,Cu(Ⅱ )和Cd(Ⅱ )分别与水杨醛肟形成的络合物均产生非常灵敏的还原波 ,峰电位分别为 - 0 .5 5 6V和 - 0 .70 4V (vs.Ag/AgCl以下均同 )。峰电流与Cu(Ⅱ )、Cd(Ⅱ )浓度分别在 9.0× 10 - 74 .0× 10 - 8mol·L- 1和 2 .0× 10 - 6 6 .0×10 - 8mol·L- 1范围内呈线性关系 ,检出限均为 1.0× 10 - 8mol·L- 1。该法用于同时测定水样中痕量Cu(Ⅱ )和Cd(Ⅱ ) ,所得结果满意。通过对该体系的初步研究 ,Cu(Ⅱ )、Cd(Ⅱ )与水杨醛肟形成的络合物的还原峰具有明显的吸附性。     

Cd2+用于复合维生素B片剂中烟酰胺的示波测定

在0.05mol·L-1Na2B4O7-0.05 mol·L-1KNO3溶液中,Cd2+能够产生灵敏切口且该切口深度随烟酰胺-Cd2+络合物量的增加而变浅.根据Cd2+的这一示波特性,建立了用二次微分简易示波伏安法间接测定烟酰胺含量的新方法.在选定实验条件下,测得Cd2+在二次微分简易示波图上的峰高与烟酰胺浓度在3.0×10-6～6.5×10-5mol·L-1范围内呈线性关系,检出限为1.5×10-6mol·L-1;对于3.0×10-5mol·L-1烟酰胺测定的相对标准偏差为2.3%(n=5).与其他方法相比,本方法具有仪器简单、方法简便快速、无需通氮除氧等特点.     

胆红素的伏安特性及其微分脉冲伏安法测定

建立中成药中胆红素定量测定的微分脉冲伏安法。在多种介质中研究胆红素在玻碳电极上的电化学行为 ,全面优化条件后 ,采用标准加入法对中成药中胆红素进行测定 ,并通过与药典中标准方法对照和干扰实验及回收率实验对本方法进行评价。在 0 .2mol·L-1HAc NaAc 5 0 %EtOH和 1 1 5mol·L-1KH2 PO4 Na2 HPO4 溶液中 ,峰电流与胆红素浓度分别在 6.2 5× 1 0 -7～ 1 .0 0× 1 0 -5mol·L-1(r=0 .9976)和 5 .0 0× 1 0 -8～ 3.0 0× 1 0 -6mol·L-1(r=0 .9939)范围内呈良好的线性关系 ,检测下限分别为 5 .0× 1 0 -8mol·L-1和 5 .0× 1 0 -9mol·L-1。众生丸和牛黄解毒片中胆红素的质量分数分别为 0 .0 86%和 0 .1 0 9% ,RSD分别为 3 4%和 3.0 % ,回收率为 96.6%～ 1 0 4 .1 % ,其结果与药典中标准方法测定结果基本一致。     

β-环糊精-二次微分简易示波伏安法测定苯巴比妥

在NaOH底液中 ,β 环糊精能够产生灵敏切口 ,且该切口深度随苯巴比妥 β 环糊精包结物量的增加而变浅。根据 β 环糊精的示波特性 ,建立了用二次微分简易示波伏安法间接测定苯巴比妥注射液中苯巴比妥含量的新方法。苯巴比妥的浓度在 2 .5× 10 - 6 ～ 4 .5× 10 - 5mol·L- 1范围内的回归方程为h(V) =4 .5 5 9- 1.381× 10 4 c(mol·L- 1) ,相关系数为 - 0 .9976 ,检出限为 1.5×10 - 6 mol·L- 1。对于 2 .5× 10 - 5mol·L- 1苯巴比妥 5次测定的相对标准偏差为 2 .7% ,回收率为10 2 .1%。与高效液相色谱和其他方法相比 ,此法具仪器简单、简便快速、无需通氮除氧等特点     

铁(Ⅲ)-2-(5是′-溴-2′-吡啶偶氮)-5-二乙氨基苯酚配合物1.5、2.5阶微分吸附伏安法研究

本文讨论了铁(Ⅲ)-2-(5＇-溴-2＇-吡啶偶氮)-5-二乙氨基苯酚配合物1.5、2.5阶微分吸附伏安法电流1.5、2.5阶微分峰峰值的表达式。实验结果表明,1.5、2.5阶吸附伏安法的线性范围为1×10~(-10)～1×10~(-7)mol/L,对2.5阶微分吸附伏安法,富集2min的检测下限为5×10~(-11)mol/L。用此法测定了人发中的痕量铁。     

表面活性剂增敏2.5次微分极谱测定香豆素

拟定了表面活性剂增敏、2 .5次微分极谱测定香豆素的方法。在含 6.0× 10 -6 mol·L-13 氯 2 羟丙基 三甲基氯化铵的 0 .1mol·L-1KH2 PO4 Na2 HPO4 (pH 6.8)缓冲液中 ,香豆素还原波 [峰电位Ep=- 1.60V(vs .SCE) ]的 2 .5次微分极谱峰峰电流e″p 与其浓度在 4 .0× 10 -7～ 6.0× 10 -5mol·L-1范围内呈良好线性关系 (r =0 .9998,n =10 ) ,检出限为 1.2× 10 -7mol·L-1。 13次平行测量 8.0× 10 -6 mol·L-1香豆素的峰电流 ,RSD为 1.5 %。该方法可用于中药白芷中香豆素的直接测定     

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.