涂丝型聚氯乙烯膜甲哌卡因选择电极的研制与应用

报导一种以甲哌卡因与碘分子缔合物为电活性物的新型全固态PVC膜甲哌卡因涂丝选择电极,电极的线性响应范围为1.0×10-1~8.1×10-5mol·L~(-1),级差为57m V/pC,检测限为4.32×10-5mol·L~(-1)。该电极响应迅速,重现性好,用此电极以标准曲线法对盐酸甲哌卡因注射液含量进行了测定,此法简便,结果与药典法相符。     

涂丝型PVC膜离子选择电极测定格列齐特缓释片

本文报道了以格列齐特碘化物与碘化铋形成的分子缔合物为电活性物的新型聚氯乙烯(PVC)膜格列齐特涂丝选择电极,电极的线性响应范围为2.1×10~(-6)~2.5×10~(-2)mol·L~(-1),级差电位为59m V/p C,检测限为1.6×10~(-7)mol·L~(-1)。该电极响应迅速,重现性好,用此电极测定了格列齐特缓释片的含量,方法简便,结果与药典法相符。     

聚氯乙烯膜盐酸地尔硫卓离子选择电极测定盐酸地尔硫卓

制备了一种以盐酸地尔硫卓与碘汞酸盐形成的缔合物为电活性物质的聚氯乙烯膜盐酸地尔硫卓选择电极,并对其性能做了测定,结果显示该电极对盐酸地尔硫卓有较好的能斯特响应。盐酸地尔硫卓的线性范围为4.5×10~(-2)～1.0×10~(-4)mol·L~(-1),检出限为3.55×10~(-5)mol·L~(-1)。该电极用于盐酸地尔硫卓片剂的分析,结果与药典法结果相符。     

聚氯乙烯膜曲马多选择电极的研制与应用

报道一种以曲马多与四苯硼的缔合物为电活性物的新型PVC膜曲马多选择电极,电极的Nernst响应范围为1．0×10~(－2)~2．1×10~(－5)mol/L;斜率为57mV/pC;检测限为7．2×10~(-6)mol/L。此电极响应迅速,重视性好,用此电极以标准曲线法对药物中的曲马多进行了测定,此法简便,结果与紫外分光光度法相符。     

Nafion-多壁碳纳米管复合膜修饰玻碳电极测定岩白菜素的研究

研制了以Nafion分散多壁碳纳米管的化学修饰电极,研究了岩白菜素在该修饰电极上的电化学行为和电化学动力学性质.发现修饰电极对岩白菜素有显著的电催化作用,岩白菜素的氧化过程是单电子单质子过程,岩白菜素在该修饰电极上的扩散系数、速率常数分别为6.02×10~(-6) cm~2·s~(-1)、5.54×10~(-3) mol·L~(-1)·s~(-1). 通过优化各项参数,建立了一种直接测定岩白菜素的电分析方法.该方法的线性范围为1.44×10~(-7) ～1.92×10~(-6) mol·L~(-1)和4.18×10~(-5) ～1.06×10~(-4) mol·L~(-1),检出限为1.02×10~(-7) mol·L~(-1),同支电极测定10次的相对标准偏差为4.6%,可用于岩白菜素样品的含量测定.     

安乃近在活化玻碳电极上的电化学行为及测定

制备了活化玻碳电极,并采用循环伏安法研究了安乃近在该电极上的电化学行为。结果表明,该电极过程是一受吸附控制的不可逆过程。用线性扫描伏安法优化了实验参数,测定了浓度与峰电流Ipa的线性关系,在1.0×10~(-6)~5.0×10~(-5)mol·L~(-1)和5.0×10~(-5)~1.0×10~(-3)mol·L~(-1)范围内,有线性方程Ipa(μA)=0.43751+0.15494c(μmol·L~(-1));Ipa(μA)=7.03296+0.02556c(μmol·L~(-1)),检出限可达5.00×10~(-7)mol·L~(-1),回收率为94.0%~103.25%。该方法可用于药物中安乃近含量的测定。     

多壁碳纳米管-十二烷基苯磺酸钠修饰的碳糊电极为工作电极测定磺胺甲噁唑

取1g·L~(-1)多壁碳纳米管悬浮液2μL,滴涂在自制的碳糊电极表面,待溶剂挥发后即得多壁碳纳米管修饰的碳糊电极(MWCT-CPE)。再在其表面滴涂1g·L~(-1)十二烷基苯磺酸钠溶液2μL,即制成MWCT-SDBS-CPE修饰电极。结果表明:碳糊电极经多壁碳纳米管和十二烷基苯磺酸钠修饰后,降低了电荷转移电阻,有利于电子传递。以0.005mol·L~(-1)硝酸钠为支持电解质,在pH 5.0的乙酸-乙酸钠缓冲溶液中进行微分脉冲伏安法(DPV)测定时,该修饰碳糊电极对磺胺甲噁唑(SMZ)具有良好的电化学响应。SMZ的线性范围为2.0×10~(-9)~1.0×10~(-7) mol·L~(-1)和1.0×10~(-7)~1.0×10~(-5) mol·L~(-1),方法的检出限为1.0×10~(-9) mol·L~(-1)。对6.0×10~(-6) mol·L~(-1)SMZ标准溶液连续测定5次,测定值的相对标准偏差为4.9%。     

固体石蜡碳糊—磷钼酸根电极的研制与应用

研究了以固体石蜡作粘和剂的碳糊电极,在磷钼酸溶液中活化一定时间后,该电极对1.0×10~(-6)～5.0×10~(-4)mol·L~(-1)的磷钼酸有能斯特响应,斜率约为30mV,检出限为3.2×10~(-7)mol·L~(-1).电极的稳定性和选择性较好,已用于矿石、水样中磷的测定,结果满意.     

长春地辛在硫化铜纳米花/石墨烯修饰玻碳电极上的电化学行为

通过改进的Hummers法和溶剂热法分别制备了石墨烯和硫化铜纳米花。采用滴涂法进一步依次将石墨烯和硫化铜纳米花修饰于玻碳电极,制备了硫化铜纳米花/石墨烯修饰玻碳电极(Nanoflower CuS/GR/GCE)。利用循环伏安法和差分脉冲伏安法等研究了长春地辛在该修饰电极的电化学行为。结果表明:长春地辛的浓度在1.0×10~(-8)~1.0×10~(-7) mol·L~(-1),1.0×10~(-7)~1.1×10~(-5) mol·L~(-1)及1.1×10~(-5)~1.0×10-4 mol·L~(-1)内与其对应的峰电流的减小量呈线性关系,检出限(3S/N)为4.9×10~(-9 )mol·L~(-1)。对1.0×10~(-6) mol·L~(-1)长春地辛标准溶液连续测定5次,测定值的相对标准偏差为1.2%。方法用于长春地辛药品样品的分析,加标回收率在97.1%~103%之间。     

四苯基硼酸钠手性离子选择性电极对缬氨酸甲酯的手性识别

以质量分数为4%的四苯基硼酸钠为手性选择性识别剂,将其负载于聚氯乙烯膜上制得四苯基硼酸钠手性离子选择性电极,此电极对缬氨酸甲酯对映异构体的识别能力进行检测。结果表明此电极能优先响应L-缬氨酸甲酯。在pH 8.0的缓冲溶液中,所用氯化钾内参比溶液的浓度在0.1mol·L~(-1)的条件下,L-缬氨酸甲酯的线性范围为10~(-3)~10~(-1) mol·L-1,斜率为47mV·dec~(-1),测定下限为5.01×10~(-4) mol·L~(-1),对映异构选择性系数lgKpotL,D为-1.89。     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.