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本文从反应产物, 化学反应计量关系, 电化学模拟和动力学测定诸方面对氧铵盐与dl-半胱氨酸在盐酸水溶液中的反应作了研究. 相似文献
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本文报道2-羟基-4-(1-甲基庚氧基)二苯甲酮肟(N530)在盐酸介质中萃取钯(II)的平衡和动力学研究结果.用分配法测定了N530的基本常数.平衡研究表明,N530萃取钯反应的表现平衡常数K~ex为10~[16.88±0.04]氯仿作稀释剂)和10~[18.00±0.01](正十二烷作稀释剂).动力学研究表明,水相中的取代反应为决速步骤,K,1为2.42x10~2L.mol^-1.s^-1.测得萃取反应活化能为30.0±3.2(氯仿)和28.9±1.9KJ.mol^-1(正十二烷),与稀释剂无明显关系.界面特性研究表明,界面饱和时有机相体相浓度为10^-2mol.L^-1,小于测定速率方程时的浓度,这些都进一步证实了水相反应机理而排斥了界面反应机理. 相似文献
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有机金属钼催化下的甲基萘氧化反应 总被引:4,自引:0,他引:4
本文研究了在液相条件下用有机金属钼作均相催化剂,叔丁基过氧化氢作氧化剂,把甲基萘氧化成甲基萘醌的反应。讨论了溶剂、催化剂、反应温度、氧化剂与甲基萘的配比以及萘环上不同取代基对反应的影响, 相似文献
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1,5-二(2-羟基-5-氯苯基)-3-氰基甲 催化动力学光度法测定痕量锰(II) 总被引:4,自引:0,他引:4
The aerial oxidation of 1, 5-bis (2-hydroxy-5-chlorophenyl)- 3-cyanoformazan (HCPCF) in ammoniacal medium catalyzed by Mn(II) has been investigated and used for spectrophotometric determination of trace Mn(II) in water. The effect of various experimental factors was studied and the optimal conditions for Mn(II) determination were found. It has been shown that the reaction follows the rate expression: 相似文献
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A kinetic method is described for the determination of trace amounts of manganese(II) based on its catalytic effect on the aerial oxidation of 1,4-dihydroxyphthalimide dithiosemicarbazone. The reaction is followed spectrophotometrically by measuring the rate of change in absorbance at 594 nm. The calibration graph (rate constant vs. manganese concentration) is linear in the range 10–90 ng Mn ml-1. The preparation and properties of the reagent are described and the kinetic parameters of the reaction are reported. There are few interferences. 相似文献
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A catalytic method is described for the determination of trace amounts of manganese(II) based on its catalytic effect on the hydrogen peroxide oxidation of an anthraquinone dye, Acid blue 45 (C.I. 63010). The reaction is followed spectrophotometrically by measuring the rate of change in absorbance of the dye at 595 nm. The calibration graph (rate constant (tg α) vs. manganese concentration) is linear in the range 4–25 ng Mn ml?1, the relative standard deviation being 1.9% at the 13 ng Mn ml?1 level. There are few interferences. The kinetic parameters of the reaction were investigated and the role of hydrogen peroxide and hydrogencarbonate ions is discussed. 相似文献
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meso-四(3-氟-4-磺酸基苯基)卟啉的合成及微分分光光度法同时测定痕量铜锌 总被引:6,自引:0,他引:6
本文报道一种新的高灵敏度水溶性卟啉显色剂meso-四(3-氟-4-磺酸基苯基)卟啉的合成方法. 研究了该试剂与Cu(II)、Zn(II)的反应条件. 在PH6.4的HOAc-NaOAc缓冲介质中, Hg(II)催化下, 室温反应30min即完成. 采用四阶微分分光光度法可同时测定痕量Cu(II)、Zn(II). 表观微分摩尔吸光系数分别达8.13×10^5和1.59×10^6. 本方法灵敏度高, 选择性好, 可不用分离直接测定茶叶、血液等样品中痕量Cu(II)、Zn(II), 操作简便. 相似文献
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The catalytic effect of manganese(II) on the oxidation of barium diphenylamine sulfonate (BDAS) with potassium bromate in sulfuric acid was studied. Progress of the reaction was monitored, spectrophotometrically, by measuring absorbance changes at 547.5 nm. A highly sensitive, selective and simple method was accordingly developed for the determination of trace amounts of Mn(II), with no need for a separation or pre‐concentration step. Effects of reaction time, concentration of reagents, temperature and ionic strength on the reaction rate were studied. In the optimized conditions, manganese could be determined in a range of 1 to 60 ng mL?1 with a detection limit of 0.2 ng mL?1. The proposed method was successfully applied to the determination of manganese in tea leaves. 相似文献
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The chromogenic agent, 1-(2-pyridylazo)-2-naphthol (PAN) was included in g -Cyclodextrin polymer ( g -CDP) and the modified polymer of inclusion of PAN ( g -CDP-PAN) was obtained. Based on the fact that g -CDP-PAN can adsorb Mn (II) in solution to form Mn (II)-PAN complex, a sensitive and selective solid phase spectrophotometric method for the determination of trace amounts of Mn (II) has been developed. The maximum absorbance of Mn (II)-PAN complex in g -CDP was at 514 nm. The working range of the calibration graph was 2-12 w g of Mn (II). The interference of molybdenum, lead, cobalt, chromium, iron, nickel, zinc, tin, cadmium, and copper that form colored species with PAN in the polymer phase was investigated. The method was applied to the determination of Mn (II) in black rice and tea samples. A new method for the determination of trace amounts of manganese by polymer phase spectrophotometry is described. Manganese reacted with 1-(2-pyridylazo)-2-naphthol (PAN) that was included in a g -cyclodextrin polymer. The absorbance of the colored polymer, packed into a 5 mm quartz cell, was determined directly at 514 nm. The proposed method was applied to the determination of manganese in black rice and tea samples. 相似文献
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A kinetic—spectrophotometric method for the detemination of traces of cobalt(II) and manganese(II) based on their catalytic effect on the tiron—hydrogen peroxide indicator reaction is proposed. Optimal conditions for determination of Co(II) are deduced from response surface studies, considering the sensitivity and the blank absorbance as responses. The detection limit is 0.05 ng Co ml?1. The Mn(II)-catalyzed reaction was optimized for 1,10-phenanthroline as the activator by the simplex method and for 2,2′-bipyridine as the activator by response surface methodology on the basis of a previously described mechanistic model of the catalytic reaction. In the presence of 2,2′-bipyridine, the detection limit is 0.2 ng Mn ml?1. The influence of foreign metal ions on both determinations is discussed and is related in the case of the 2,2′-bipyridine—activated Mn(II)-catalyzed reaction with model generated effects of these metal ions. 相似文献
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Zheng HL Xiong WQ Gong YK Peng DJ Li LC 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,66(4-5):1243-1247
A new catalytic spectrophotometric method is described for the determination of trace amounts of Al(III). The methods based on catalytic action of Al(III) on the oxidation of indigo carmine (IC) by ammonium persulfate in hexamethylene tetramine-hydrochloric acid ((CH2)6N4-HCl) buffer medium (pH 5.4) and in the presence of surfactant-TritonX-100. The effects of some factors on the reaction speed were investigated. Aluminium concentration is linear for 0-1.2x10(-7) g/ml in this method. The detection limit of the proposed method is 1.96x10(-8) g/ml. Most of the foreign ions except for Cu(II), Fe(III) do not interfere with the determination, and the interference of Cu(II) and Fe(III) in this method can be removed by extraction with sodium diethyldithiocarbamate-carbon tetrachloride (DDTC-CCl4). This system is a quasi-zero-order reaction for Al(III), but it is a quasi-first-order reaction for IC. The apparent rate constant is 2.62x10(-5) s-1 and the apparent activation energy is 6.60 kJ/mol in the system. The proposed method was applied to the determination of trace aluminium(III) in real samples with satisfactory results. 相似文献
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A kinetic-catalytic spectrophotometric flow-injection method was developed for the rapid and sensitive determination of trace amounts of copper(II). The method is based on the catalytic effect of copper(II) on the redox reaction of cysteine with iron(III). Iron(II) produced by the catalytic reaction reacts with 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPTZ) to form the iron(II)-TPTZ complex (lambda(max) = 593 nm). By measuring an absorbance of the complex, one could determine 0.05-8 ppb copper(II) with the relative standard deviations (n = 10) of 1.6%, 1.3%, and 0.8% for 0.5 ppb, 1 ppb, and 2 ppb copper(II), respectively. The limit of detection (S/N = 3) was 0.005 ppb. The sample throughput was 30 h(-1). The proposed method was successfully applied to the determination of copper in natural water and serum samples. 相似文献