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本文采用装有Jones柱的流动注射系统,研究了钒(Ⅱ)-光泽精体系的化学发光反应。在此基础上建立了痕量钒测定的新方法。方法的检出限3×10 ̄(-10)g·mL ̄(-1);对于1.0×10 ̄(-7)g·mL ̄(-1)钒标准溶液测定的相对标准偏差为2%(n=11);线性范围1.0×10 ̄(-9)~9.0×10 ̄(-5)g·mL ̄(-1),相关系数大于0.9980。该方法已用于水样中痕量钒的测定。对于反应机理,本文也进行了探讨。 相似文献
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催化还原褪色光度法测定痕量铜的研究 总被引:13,自引:0,他引:13
本文在少量氯化钠存在下的磷酸-磷酸二氢钾缓冲溶液(pH=2.7)中,以铜(Ⅱ)催化次磷酸钠还原罗丹明B褪色为指示反应,建立了痕量铜的动力学光度分析新方法,在沸水浴中加热反应10min,测定的线性范围在0~0.40μg/25mL铜(Ⅱ)回归方程为△A=1.975c+0.003,相关系数为0.9999,以△A=0.01计算得测定下限为0.005μg/25mL。方法应用于铅基合金,纯铅粉和标准镁合金中铜 相似文献
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催化动力学分析法测定痕量铜 总被引:7,自引:0,他引:7
研究了在氨性介质中,Cu(Ⅱ)催化H2O2氧化噻嗪红R的退色反应,据此建立了催化动力学光度测定Cu(Ⅱ)的新方法,方法的线性范围为0.005-0.5μg/25ml。曾应用于水、猪肝和小麦粉标准物质中痕量铜的测定,获得满意结果。 相似文献
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本文报道了新荧光试剂3-对甲苯基-5-(2’-羧基苯偶氨)绕丹宁(PM-PRACP)的合成。用元素分析、红外光谱、核磁共振氢谱和质谱确证了其结构,研究了其荧光性质。在pH5.6时,该试剂与Cu ̄(2+)形成稳定的荧光螯合物,且在λ_(ex)/λ_(em)=305nm/405nm产生强烈荧光。其荧光强度与Cu ̄(2+)的浓度在0~1.6μg/25mL范围内呈线性关系,检测限为5×10 ̄(-4)μg/g。已用于痕量铜(Ⅱ)的荧光分光光度法测定。测定了蚕茧、蚕丝和丝绸中的痕量铜,结果满意。 相似文献
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烟草中Fe,Co一阶导数分光光度法同时测定的研究 总被引:4,自引:0,他引:4
本文研究了在pH4.0时,meso-四(4-磺酸基苯基)卟啉与铁、钴同时络合显色的反应条件以及一阶导数光谱行为。此体系一阶导数的灵敏度比零阶导数灵敏度高。Fe ̄(3+)~0.18μg/mL、Co ̄(2+)0~0.24μg/ml,范围内符合比耳定律;检测限为:Fe ̄(3+)=0.48ng/mL,Co ̄(2+)=0.2ng/mL。回收率为:Fe98.5%~100.8%,Co99.2%~101.3%。此方法用于烟草中痕量Fe、Co测定,与AAS值相比较,结果令人满意。 相似文献
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本文研究了在硫酸介质中,Cu(Ⅰ)-SCN ̄-罗丹明B体系当有明胶和聚乙醇辛基苯基醚存在时的显色反应。该反应的λmax=595nm,ε=2.0×105L·mol ̄(-1)·cm ̄(-1),铜在0~5.00μg/25mL范围内具有良好的线性关系。据此拟定的分析方法,用于测定绿茶中的痕量铜,选择性好,灵敏度高,结果满意。 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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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. 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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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. 相似文献
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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. 相似文献