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催化褪色光度法测定痕量铜——胭脂红—铜—过氧化氢体系 总被引:13,自引:2,他引:13
研究了在磷酸二氢钾-四硼酸钠介质中,用邻菲罗啉作活化剂,CU(Ⅱ)催化过氧化氢氧化胭脂红的褪色反应及反应活化能的测定,建立了测定痕量铜的新方法.铜的测定范围为0~0.4μg/25ml,方法灵敏度为2.35×10~(-11)g·ml~(-1),用于合成水样及人发样中的痕量铜测定,结果满意. 相似文献
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铜是人体必需的微量元素之一,人体内铜的含量为100~150mg。铜在人体中具有造血,促进骨骼、血管和皮肤健康的生理功能,是人体中超氧化物歧化酶(SOD)的重要成分。因此建立高灵敏度测定水、食物、药物中铜的方法十分重要。催化动力学光度法测定痕量铜的研究报道较多〔1-3〕,但利用KIO4氧化结晶紫(CV)作为测定铜的方法则未见报道。笔者发现在pH5.0的HAc-NaAc缓冲体系中,痕量铜对KIO4氧化CV的褪色反应有明显的催化作用,探讨了反应的最佳条件,建立了催化动力学光度法测定铜的新方法,研究了动力学参数。该法可应用于水、食物、中草药中痕… 相似文献
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胶束增敏催化光度法测定痕量铜(Ⅱ) 总被引:1,自引:0,他引:1
基于铜(Ⅱ)对过氧化氢还原中性红褪色反应的强烈催化作用,建立了在表面活性剂氯化十六烷基吡啶(CPC)存在下测定痕量铜(Ⅱ)的方法。在pH 8.1氨水-氯化铵缓冲溶液介质中,以454 nm为测定波长,在120μg·L~(-1)以内吸光度ΔA(A_0—A)与铜(Ⅱ)浓度呈线性关系,方法的检出限(3S/N)为2.15×10~(-8)g·L~(-1)。方法应用于水样中铜的测定,所得结果与原子吸收光谱法测得结果相符,加标回收率在97.9%~105.7%之间。 相似文献
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催化褪色反应动力学法测定痕量铜 总被引:18,自引:1,他引:18
作者发现铜(Ⅱ)对过氧化氢在硫酸介质中氧化甲基橙的褪色反应有催化作用,找到了影响催化褪色反应的最佳条件,建立了测定痕量铜(Ⅱ)的新方法。灵敏度为9.22×10~(-11)g/ml,测定范围0~2.0μgCu~(2+)/50ml。用于测定几种实物样品中的痕量铜,得到满意的结果。相对标准偏差0.2%~2.3%。 相似文献
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铜修饰电极上铜(Ⅱ)的示波电位滴定法 总被引:1,自引:0,他引:1
齐同喜 《理化检验(化学分册)》2007,43(4):323-324,326
用示波电位滴定法测定铜,已有文献报道[1,2],大多数是用铂电极和自制的碳糊电极作为指示电极。笔者研究了用铜(Ⅱ)为修饰物,对铜电极进行吸附修饰,使铜电极产生一定的电位响应,对铜(Ⅱ)进行示波电位滴定,根据示波器上的荧光点最大位移为终点。结果表明,铜(Ⅱ)在0.50-350.00 mg范围内均能准确测定。该法用于含铜样品中铜的测定,结果与标准值吻合较好。1试验部分1.1主要仪器与试剂SR8型双踪示波器;磁力加热搅拌器;甘汞电极和铜修饰电极。EDTA标准溶液:0.01 mol·L-1,按文献[3]配制;铜(Ⅱ)标准溶液:1.000 0 g·L-1。1.2铜修饰电极的制备将… 相似文献
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林海山 《中国无机分析化学》2013,3(Z1):50-52
建立了火焰原子吸收光谱法测定废杂铜中银量的新方法,研究了在盐酸介质或氨水介质中测定银的条件,并对两种介质中测定的结果与行业标准分析方法的结果进行比对。研究表明,盐酸(15%)介质适用于废杂铜中Ag≤1 300g/t的样品测定,氨水(10%)介质适用于废杂铜中Ag≥500g/t的样品测定,火焰原子吸收光谱法测得结果与标准分析方法测得的结果吻合。方法已应用于废杂铜中银量的测定,结果满意。 相似文献
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基于在氨水-氯化铵缓冲介质中,铜(Ⅱ)催化过氧化氢氧化靛蓝胭脂红,导致反应体系的荧光增强,提出了荧光光度法测定痕量铜(Ⅱ)的一种灵敏的方法。在320 nm(eλx)及391 nm(eλm)波长处,反应体系的ΔF(F-F0)与铜(Ⅱ)的质量浓度在0.2~100μg.L-1范围内呈线性关系。方法的检出限(3σ)为0.05μg.L-1。该方法用于大米、面粉和茶叶中铜的测定,测得方法的回收率在96.2%~104.9%之间,测定值的相对标准偏差(n=5)在0.72%~1.5%之间。 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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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
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Xi-Liu YunWen-Ying Bi Jian-Hui HuangYu Liu Daisy Zhang-NegrerieYun-Fei Du Kang Zhao 《Tetrahedron letters》2012,53(38):5076-5080
A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd2(dba)3-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring. 相似文献
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Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles. 相似文献
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An efficient and benign method for the preparation of aminomethyl-substituted fullerenes has been developed. The process, involving catalyst free, visible-light irradiation of 10% EtOH-toluene solutions containing fullerene C60 and N-trimethylsilylmethyl-substituted amines by using a 20 W compact fluorescent lamp, leads to formation of aminomethyl-substituted fullerene adducts in a highly efficient manner. The photoaddition reaction takes place via a pathway initiated by visible light absorption by C60, followed by SET from the amine to the triplet excited state of C60. Ethanol-promoted desilylation of the resulting a minimum radical then generates the corresponding α-amino radical which couples with the C60 radical anion to form the anion precursor of the fullerene adducts. The new approach using visible-light takes place under mild conditions and it does not require the use of photocatalysts. Thus, the method developed in this effort could broadens the range of functionalized fullerene derivatives that can be readily prepared. 相似文献
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Viktor A. Dmitriev Mariia M. Efremova Alexander S. Novikov Vladimir V. Zarubaev Alexander V. Slita Anastasia V. Galochkina Galina L. Starova Andrey V. Ivanov Alexander P. Molchanov 《Tetrahedron letters》2018,59(24):2327-2331
The reactions of various nitrones with indolyl- and pyrrolylacrylates proceeds regioselectively with high diastereoselectivity in the case of aldonitrones, and represents an effective method for obtaining new indolyl- and pyrrolyl-substituted isoxazolidine carboxylates stabilized by weak (CH?O) and moderate (NH?N) strength intramolecular hydrogen bonding. The resulting cycloadducts exhibit promising in vitro anti-influenza activities. 相似文献
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A transition metal-free method for the direct amination of benzoxazoles using formamides as nitrogen sources is reported, which was mediated by an inexpensive and environmentally friendly tetrabutylammonium iodide/tert-butyl hydroperoxide system and gave the 2-aminobenzoxazole derivatives with moderate to good yields. 相似文献
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Multifunctionalized 1,2,3,4-tetrahydropyridines are concisely synthesized in good yields via l-proline-catalyzed or l-proline/FeCl3-cocatalyzed one-pot multicomponent reactions (MCRs). The MCRs involve a domino hydroamination/prins reaction/Mannich-type reaction/intramolecular dehydration-cyclization process. The molecular structure of 5baa, one of multifunctionalized 1,2,3,4-tetrahydropyridines, was confirmed by single-crystal X-ray diffraction. 相似文献
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Yin Shuhui Liu Hongping Zhang Jianyang Jiang Bo Wang Li Sha Guohe Lou Nanquan 《化学物理学报(中文版)》2003,16(1):3-8
The multi-photon dissociative photoionization dynamics of CF3I has been studied with femtosecond two-color pump-probe time of flight mass spectra at a pump pulse of 265 nm and a probe pulse of 398 nm. The life constants of CF3I+ and its fragment ions CF3+ and I+ are obtained as (96±7), (198±130) and (167±6)fs, respectively. The multi-photon dynamics leading to these ions differ. CF3I+ corresponds to a (1+2′) transition with one-photon pump excitation to the A band of CF3I. CF3+ are mainly formed by a tow-photon probe excitation to the CF3+ with subsequent dissociation of parent ions. I+ are produced in (2+2′) combined with (1+1′+2′) process. The results provide information on the multi-photon pathways involved. 相似文献