溶胶凝胶溴离子选择电极的研制与应用

报道了一种以溶胶凝胶为载体的溴离子选择电极。电极信号响应线性范围为1 .0× 1 0 - 1～ 1 .0× 1 0 - 5mol/L,斜率为 5 7m V/pc;检出限为 2 .5× 1 0 - 6 mol/L。该电极响应快 ,体积小 ,稳定性和重现性好。电极用作测定溴离子浓度 ,结果令人满意     

聚氯乙烯膜苯海拉明选择电极的研制与应用

报道了一种以苯海拉明碘化物与碘化铋形成的分子缔合物为电活性物的新型PVC膜苯海拉明选择电极。电极的线性响应范围为 1 0× 10 -1～ 2 .6× 10 -5mol/L ;级差为 4 8mV/pC ;检出限为 1 9× 10 -5mol/L。该电极响应迅速 ,重现性好 ,用此电极以校准曲线法对片剂中的苯海拉明进行了测定 ,此法简便 ,结果与药典法相符     

表面活性剂敏化的铽离子荧光探针对氧氟沙星的测定

稀土Tb3 +能与氧氟沙星形成络合物 ,并发出Tb3 +的特征荧光 ;加入表面活性剂SDBS能大大增强体系的荧光强度 ,由此建立了表面活性剂敏化的Tb3 +荧光探针测定氧氟沙星的方法。用 1cm石英比色池在激发波长为 30 0nm ,发射波长为 5 4 5nm处测定其荧光强度。在pH =5 .5～ 6 .5 ,Tb3 +浓度为 5 .0× 10 -5mol/L ,SDBS浓度为 5 .0× 10 -4mol/L的最佳测试条件下 ,氧氟沙星的浓度与体系的荧光强度呈线性关系 ,线性范围为 5 .0× 10 -8～ 2 .0× 10 -6mol/L ;检出限为 6 .0× 10 -9mol/L。该法可用于氧氟沙星药物的测定     

微渗析活体取样与液相色谱安培检测法联用测定鼠脑中黄嘌呤和次黄嘌呤

采用微渗析活体取样技术和高效液相色谱安培检测法 ,测定了鼠脑纹状体中的黄嘌呤和次黄嘌呤。安培检测以玻碳电极为工作电极 ,检测电位为 0 .9V。在 5 .0× 1 0 - 7～ 1 .0× 1 0 - 4 mol/L浓度范围内 ,黄嘌呤和次黄嘌呤的浓度分别与峰电流呈良好的线性关系 ,检出限分别为 8 0× 1 0 - 8mol/L和 3 0× 1 0 - 7mol/L。该方法为生命科学的研究提供了一种新的分析手段     

基于尼古丁对胆碱氧化酶的抑制作用测定尼古丁的研究

基于尼古丁对胆碱氧化酶(CHOD)的抑制作用,将胆碱氧化酶电极用于微量尼古丁的测定。酶电极制作中,先在铂电极表面修饰一层壳聚糖膜,再用戊二醛交联CHOD。采用这种酶固定化方法,电极在4. 0×10-6 ~ 3×10-3 mol/L胆碱的浓度范围呈线性关系。探讨了工作电位、pH、底物浓度等实验条件对酶电极性能及抑制过程中响应电流的影响,测定了电极的重现性、干扰及使用寿命。电极检测尼古丁的线性范围为1. 5×10-5 ~3×10-3 mol/L;检出限为1. 25×10-5 mol/L。将电极用于实际样品烟草中尼古丁回收率的测定,结果良好。     

聚氯乙烯膜普鲁卡因选择电极的研制与应用

研制了一种以普鲁卡因碘化物与碘化铋形成的缔合物为电活性物质的PVC(聚氯乙烯 )膜普鲁卡因选择电极 ,测定了普鲁卡因注射液的含量 ;电极的线性响应范围1.0×10 -1～6.3×10 -5mol/L,级差电位为45mV/pc ,检出限为3.4×10-5 mol/L ;该电极响应迅速 ,测定结果与药典法相符     

尿酸在普鲁士蓝修饰电极上的电化学行为及其分析应用

用恒电位电解法制备了普鲁士蓝修饰玻碳电极,研究了尿酸(UA)在该电极上的电化学行为,并提出了一种新的用于检测UA的方法。在 0. 1mol/L(pH5. 0 )的醋酸缓冲溶液中, 0. 100mol/LKCl作为支持电解质,UA在普鲁士蓝修饰电极上于 0. 470V处产生一灵敏的氧化峰,方波伏安法测定其氧化峰电流与UA浓度在 2. 5×10-6 ~2. 0×10-4 mol/L范围内呈良好的线性关系,相关系数为 0. 9986,检出限为 1. 1×10-6 mol/L。该电极制作简单,重现性良好,可用于UA的测定。     

嵌入式超薄碳膜电极的伏安行为及其应用

以镍铬合金为基体,在其表面嵌入碳膜或碳纳米管,制备了超薄碳膜电极,并用于酚磺乙胺(ETA)的测定。超薄碳膜电极对ETA有良好的电催化作用和增敏作用,与玻碳电极相比,氧化峰电位负移120mV,还原峰电位正移160mV,电流响应明显增大。在最优条件下,ETA浓度在5×10-7 ~9×10-6 mol/L和9×10-6~6×10-5 mol/L之间与其氧化峰电流呈良好的线性关系,相关系数分别为0. 9967和0. 9979。该电极制备简便,价格低廉,用于酚磺乙胺的测定结果令人满意。     

化学发光法测定氧氟沙星的含量

利用氧氟沙星对碱性Luminol H2O2 化学发光体系的增敏作用,建立了一种测定氧氟沙星的新方法。方法的线性范围为5.53×10-9 ~2.21×10-5 mol/L,检出限(3σ)为5.08×10-10 mol/L,RSD为2.23%(cs=1.38×10-5 mol/L,n=8)。该法用于针剂、片剂及胶囊中氧氟沙星含量的测定,结果令人满意。     

聚L-谷氨酸/石墨充蜡修饰电极测定多巴胺

用充蜡石墨电极 (WGE)在L 谷氨酸 (GA)无水乙醇溶液中恒电位于 1.6V(vs.SCE)氧化制备了一种聚GA修饰电极 (GA/WGE) ,该电极可用于肾上腺素 (EP)和抗坏血酸 (AA)共存下对多巴胺 (DA)的测定。该电极的灵敏度和选择性主要取决于阳极极化电位与极化时间、富集电位和溶液的pH。DA在该电极上呈现一对循环伏安峰 ,Em=0 .14 5V ,为 1电子 / 1质子的准可逆氧化还原过程。AA和EP也能够在电极上富集和催化氧化 ,伏安峰分别在 0 .30V和 0 .17V。当AA浓度小于 0 .1mmol/L时 ,电极对AA基本不响应 ,可以用DA的氧化峰电流做定量分析。线性范围为 2 .0× 10 -4～ 5 .0× 10 -7mol/L ;检出限为 2 .5× 10 -7mol/L。当AA的浓度较大或在AA、EP共存下 ,可利用DA氧化的再还原峰电流做定量分析。线性范围为 1.0× 10 -4～ 2 .5× 10 -6mol/L ;检出限为 7.5× 10 -7mol/L。该电极制作简便 ,重现性良好 ,定量结果也令人满意     

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.