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金在脱乙酰壳多糖学修饰电极上的电化学行为及分析应用 总被引:3,自引:1,他引:2
用脱乙酰壳多糖化学修饰电极为工作电极,阳极溶出伏安法测定痕量金。在pH1 ̄2的KCl-HCl底液中,超始电位0.20V,终止电位1.30V,富集时间5min,以-0.1/s扫速阳极溶出,峰电位在1.00V(vs.SCE),Au(Ⅲ)浓度在0.10mg/L ̄10mg/L范围内与峰高呈线性关系。在富集10min时,可检测0.25mig/LAu,大大提高了测定灵敏度,用于矿样测定,无需分离,结果满意。用 相似文献
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Nafion修饰金电极阳极溶出伏安法测定痕量碲 总被引:4,自引:0,他引:4
本文用Nafion修饰金盘电极,在0.04mol/LLiCl和PH2的H2SO4底液中,阳极溶出伏安法测定痕量碲,研究了富集溶出过程的特性和优化条件,碲浓度在0.2-15ng/mL范围内与溶出峰电流呈良好的线性关系。本法灵敏度高,选择性好,用于测定小麦粉和玉米粉中痕量碲,测定标准偏差小于0.07μg/g,与ICP测定结果比较其相对误差小于16%。 相似文献
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蒙脱石修饰碳糊电极测定氨基酸的研究:Ⅱ.酪氨酸的测定 总被引:13,自引:1,他引:13
本文报道蒙脱石修饰碳糊电极测定酪氨酸,在0.001mol/L KCl-HCl(pH=2.0)溶液中开路富集,介质交换后微分脉冲阳极溶出伏安法测定,在0.5-2.5μg/ml范围内有线性,检测限为63ng/ml。可避免其他氨基酸,微量元素和常量金属元素的干扰,直接用于氨基酸药物样品的分析,获得了满意的结果,还对酪氨酸在电极上的反应机理进行了探讨。 相似文献
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药物分子在玻碳电极电的电分析化学研究:Ⅳ.乙酰螺旋霉素的伏安测定 总被引:2,自引:0,他引:2
本文对乙酰螺旋霉素在GCE上的伏安行为进行了研究,发现在磷酸盐缓冲溶液(pH=7.78)中,於+0.85V(vs,Ag/AgCl)左右产生一良好的阳极氧化伏安峰,浓度在0.5~100μg/mL之间与峰电流呈线性关系,分析了制剂中乙酰螺旋霉素的含量,相对标准偏差为4.5%,平均回收率为101%,经循环伏安法验证,电极反应为不可逆反应。 相似文献
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用钼酸盐和罗丹明B光度法测定铂 总被引:3,自引:0,他引:3
本文研究了在聚乙烯醇(PVA)存在下用钼酸盐和罗丹明B(RB)光度法测定铂,铂(Ⅳ)与相酸铵和罗丹明B形成离子缔合物,它的最大吸收波长位于570nm处;摩尔吸光系数6值为6.83×10 ̄5L·mol ̄(-1)·cm ̄(-1),铂量在0~3.5μg/25mL范围内服从比耳定律,缔合物至少稳定1月。报告了41种共存离子的影响,除生成杂多酸元素和Au(Ⅲ)、Os(Ⅷ)、Ru(Ⅲ)外,大多数元素不干扰。测定铂(Ⅳ)的适宜条件为[HClO_4]=0.93mol/L,[RB]=4.2×10 ̄(-5)mol/L,PVA0.8g/L,本法已用于催化剂和某些铂矿中铂的测定,结果满意。缔合物的摩尔比为Pt(Ⅳ):RB=1:2,初步探讨了反应机理。 相似文献
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应用循环伏安法、微分脉冲伏安法对多菌灵在破碳电极上的电化学行为及其测定进行了研究。在pH=9.0的2mol/L NH3-NH4Cl底液中,对其进行循环伏安扫描,发现于0.61V(vs.Ag/AgCl)产生一灵敏的氧化峰。微分脉冲伏安法殉菌灵的检测限为4×10^-8mol/L。多菌灵的浓度在5.0×10^-7 ̄1.0×10^-5mol/L间与微分脉冲伏安峰电流呈线性关系(r=0.9942)。对于1× 相似文献
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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
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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
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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
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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
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Jona Mirnik Eva Pušavec Kirar Sebastijan Ričko Uroš Grošelj Amalija Golobič Franc Požgan Bogdan Štefane Jurij Svete 《Tetrahedron》2017,73(24):3329-3337
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 CuI 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). 相似文献
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George E. Magoulas Thomas Garnelis Constantinos M. Athanassopoulos Dionissios Papaioannou George Mattheolabakis Konstantinos Avgoustakis Dimitra Hadjipavlou-Litina 《Tetrahedron》2012,68(35):7041-7049
(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. 相似文献