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1.
陈虹  黄湘源 《分析化学》2003,31(1):87-91
在pH=3.2乙酸-乙酸钠缓冲介质中,研究了铬(Ⅵ)催化过氧化氢氧化对-氨基二甲替苯胺盐酸盐和N,N-二甲基苯胺的氧化偶联反应及其机理,建立了催化光度法测定痕量铬(Ⅵ)的新方法.该方法线性范围为0~0.12 mg/L;检出限为1.0×10-7 g/L;相对标准偏差为0.12%,直接用于水中铬(Ⅵ)的测定,结果满意.  相似文献   

2.
甲苯胺蓝褪色指示反应动力学光度法测定痕量铁   总被引:10,自引:0,他引:10  
研究了在硫酸介质中 ,痕量铁催化 H2 O2 和 K2 Cr O7联合氧化甲苯胺蓝褪色反应及其动力学条件 ,建立了催化动力学测定痕量铁的新方法。检出限为9.6 6× 10 -9g· m L-1 ,测定的线性范围为 0~ 0 .6μg/2 5 m L。方法已用于矿泉水、莱服子、菊花、大米和花生中铁的测定  相似文献   

3.
测定超痕量铁的高灵敏指示反应   总被引:4,自引:0,他引:4  
在稀 H2 SO4 介质中 ,1 ,1 0 -邻菲 口罗啉存在下基于 Fe( )催化过氧化氢氧化棉红的新指示反应建立了测定超痕量铁的一个新方法。方法检出限 1 .0× 1 0 - 11g/m L ,线性范围 0 .0 0~ 1 .2 ng/m L。用于井水、一次蒸馏水、黄豆、芹菜中痕量及超痕量铁的测定获得满意结果  相似文献   

4.
催化光度法测定痕量钴的研究   总被引:6,自引:0,他引:6  
李竹云  崔孟忠 《化学通报》2001,64(5):309-311,292
研究了钴 (Ⅱ )离子在碱性介质中催化H2 O2 氧化 2 ,2′ 二甲基 4 ,4′ 二氨基联苯 (o Tolidine)的显色反应 ,发现当Co2 +浓度在 0 8~ 3 6ng mL时具有强烈的催化显色作用 ,而当Co2 +浓度在 0 0 4~0 2 4 μg mL时则对显色作用具有抑制效应。基于此研究了测定痕量Co(Ⅱ )离子的影响因素 ,建立了测定痕量Co2 +离子的催化光度法。测定的线性范围Co(Ⅱ )的浓度在 0 0 4~ 0 2 4 μg mL时 ,灵敏度为 3 1 6× 1 0 -6g L ;Co(Ⅱ ) 0 8~ 3 6ng mL时 ,灵敏度为 1 78× 1 0 -6g L。实验操作简便 ,应用于工业污水中痕量Co2 +离子的监测 ,结果满意。  相似文献   

5.
考马斯亮蓝G动力学光度法测定痕量铁的研究   总被引:3,自引:0,他引:3  
研究了在稀盐酸介质中 ,α,α-联吡啶存在下 ,铁催化溴酸钾氧化考马斯亮蓝G,使其褪色这一新的指示反应及其动力学条件 ,建立了测定痕量铁的新方法。方法的检出限为 2 .2 6× 1 0 - 10 g/ m L,线性范围 0~ 0 .2 4μg/ 2 5 m L,用于食品及水中痕量铁的测定 ,结果满意  相似文献   

6.
催化动力学分光光度法测定微量铁的研究   总被引:4,自引:0,他引:4  
在 Na2 HPO4介质中 ,研究了 Fe( )催化 H2 O2 氧化甲基百里酚蓝褪色指示反应及其动力学条件 ,建立了测定痕量铁的新方法。方法的线性范围为 0 .0 2~ 0 .2 5μg/2 5m L,检出限为 0 .0 1 2 μg/2 5m L。用以测定过氧化碳酸钠 ( 2 Na2 CO3· 3H2 O2 )中的铁 ,结果令人满意。  相似文献   

7.
李建国  张敏  郁晓峰 《分析化学》2003,31(2):252-252
1 引  言碘是生命科学、水文环境研究和地质找矿的重要元素。尽管分析方法较多 ,但由于在样品中的含量低 ,且易于氧化还原和挥发 ,给测定带来一定困难。我们观察到 ,4 ,4′ 对 (二甲氨基 ) 二苯基甲烷在稀盐酸介质中被氧化生色的反应进行的非常缓慢 ,痕量碘离子的存在对此反应有极好的催化效应 ,从而建立了催化动力学测定痕量碘的新方法。该法线性范围宽 ,检出限达 0 .4 5 μg/L ,且测定体系无须加热 ,是目前测定碘最简便、快速、灵敏的方法之一。2 实验部分2 1 仪器和试剂  75 3 0G紫外可见分光光度计 (上海惠普公司 ) ;72 1分…  相似文献   

8.
新体系催化动力学光度法测定痕量亚硝酸根   总被引:13,自引:0,他引:13  
基于增敏剂吐温 - 80存在下亚硝酸根催化过氧化氢氧化中性红的反应 ,建立了测定痕量亚硝酸根的新催化动力学光度法。方法的灵敏度较常规方法提高了 2 .2倍 ,测定的线性范围为 2~ 1 0 μg/L,检出限为 2 .7× 1 0 - 10 g/m L。已用于测定水样中 NO2 - 的含量  相似文献   

9.
基于在弱硫酸介质中及活化剂邻菲罗啉存在下 ,微量铁对溴酸钾氧化胭脂红的褪色反应有强烈的催化作用 ,由此建立了催化光度法测定微量铁的方法。该方法的检出限为 1.2× 10 - 10 g·ml- 1,测定范围为 0~ 0 .2 μg/2 5ml ,催化反应的表观活化能为 15 2 .7kJ·mol- 1。方法应用于大米、水样中微量铁的测定 ,结果满意。  相似文献   

10.
铁-过氧化氢-变色酸催化动力学光度法测定痕量铁   总被引:6,自引:0,他引:6  
本文研究了在H3PO4介质中,痕量铁(Ⅲ)催化过氧化氢氧化变色酸的褪色指示反应及最佳实验条件条件和动力学参数,建立了测定痕量铁的新方法。方法的灵敏度为6.18×109g/L;测定范围0~30μg/L。用于各种水平痕量铁的测定获得满意结果。  相似文献   

11.
The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.  相似文献   

12.
非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。  相似文献   

13.

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

  相似文献   

14.
Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.  相似文献   

15.
针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。  相似文献   

16.
翟宗玺  刘树深  夏树屏 《化学学报》1990,48(10):946-950
用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。  相似文献   

17.
In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.  相似文献   

18.
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

19.
袁丽秋 《化学教育》2006,27(5):8-10
面对日益枯竭的能源危机,氢能是一种洁净、最有前景的替代能源。目前在各种制氢的方法中光催化分解水制氢的研究最多,光解水过程中催化剂最关键,本文对利用太阳能光解水的途径、提高光催化反应效率以及光催化剂的开发研究进行了综述。  相似文献   

20.
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