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1.
极谱催化波法测定马蔺子素   总被引:5,自引:0,他引:5  
宋俊峰  何平  过玮 《分析化学》2002,30(8):954-957
报道了在Na2 B4 O7 KH2 PO4 K2 S2 O8体系中马蔺子素的极谱催化波。拟定了测定马蔺子素的新方法。在 8.0× 10 - 3mol/LNa2 B4 O7 1.6× 10 - 2 mol/LKH2 PO4 (pH =7.7) 5 .0× 10 - 3mol/LK2 S2 O8底液中 ,极谱催化波峰电位Ep=-1.2 3V(vs .SCE) ;二阶导数峰峰电流i″p 与马蔺子素浓度在 2 .0× 10 - 9~ 2 .0× 10 - 6 mol/L范围内呈良好线性关系 ,检出限为 1.0× 10 - 9mol/L。催化波灵敏度比相应马蔺子素还原波高 75倍。采用该法测定了胶囊中马蔺子素的含量  相似文献   

2.
本文提出用邻氨基酚 ( OAP) - H2 O2 -辣根过氧化物酶 ( HRP)伏安酶联免疫分析体系测定 HRP和南方菜豆花叶病毒 ( SBMV)。该方法是将 HRP催化 H2 O2 与 OAP的酶催化反应与邻氨基酚的氧化中间产物在滴汞电极上的还原反应相偶合 ,在 BR缓冲溶液中 ,在 - 0 .87V( vs.SCE)左右产生灵敏的伏安峰。利用该极谱波对 HRP的检测限为 5× 10 -12 g/m L,线性范围为 6.0× 10 -12~ 4 .0× 10 -9g/m L。用该方法测定南方菜豆花叶病毒取得了令人满意的结果。  相似文献   

3.
曹维良  唐波  张敬畅  严斌 《分子催化》2001,15(5):335-340
以新型水溶性二磺化 - 1-苯基二苯并膦 (简称 PDBPDS)为配体 ,制备了铑膦配合物 Rh(acac) (CO ) -(PDBPDS) 3.将其负载于高吸水性载体上 ,制得负载水相催化剂 ,并对催化剂的制备条件进行了优化 .以人造沸石为载体 ,在载水量 30 % ,[Rh]=2 .0× 10 - 5、 [P]/ [Rh]=40的条件下 ,筛选出丙烯氢甲酰化反应的最佳工艺条件 .在反应温度 10 0℃、压力 2 .0 MPa、搅拌速度为 5 0 0 r/ m in条件下 ,催化剂活性达 10 12 g丁醛 / (g Rh· h) ;正异比高达 43.5 ;在有机相中铑的浓度为 1.2× 10 - 9,解决了均相反应催化剂回收和循环使用的问题 .实验结果表明 ,新型配体二磺化 - 1-苯基二苯并膦是一性能较好的新配体 ,所制备的新型负载水相催化剂是一有较好开发前景的新型催化剂  相似文献   

4.
复方芦丁片中主要成分的毛细管电泳安培检测   总被引:5,自引:0,他引:5  
用毛细管电泳安培检测法同时测定了复方芦丁片中芦丁和抗坏血酸的含量 ,研究了各种实验条件对分离效果的影响 ,得到了优化的实验条件。以直径为 5 0 μm的碳纤维微电极为工作电极 ,电极电位为+ 0 .80V(vs.Ag AgCl) ,4 0mmol L的Na2 B4O7 H3 BO3 (pH值为 7 5 0 )为缓冲溶液。在此条件下 ,芦丁和维生素C在 1 0min内得到了良好的分离。芦丁和维生素C分别在 5 .0×1 0 - 8~ 5 .0× 1 0 - 4 g mL、8.0× 1 0 - 8~ 5 .0× 1 0 - 4g mL浓度范围内与电泳峰电流呈现良好的线性关系 ;检测下限分别为 2 .0× 1 0 - 8、5 .0× 1 0 - 8g mL。方法应用于实际样品的测定 ,结果令人满意  相似文献   

5.
报道了在适量十六烷基三甲基溴化铵 (CTMAB)存在下 ,高灵敏度测定水体中铅、银离子的化学修饰碳糊电极。在pH 2 .5 0 .1mol LKNO3溶液中 ,铅、银离子在钠型蒙脱石修饰碳糊电极上通过离子交换而富集 ,同时被还原。在阳极扫描过程中 ,分别在 - 0 .5 2V和 0 .2 3V(vs.SCE)处出现灵敏的溶出峰。详细研究了测定水样中铅、银离子的条件 ,如介质的pH、CTMAB用量、修饰剂用量、富集电位和时间等。该修饰电极连续测定铅、银离子的线性范围为 5 .0× 10 - 9mol L~ 1.0× 10 - 7mol L(Pb2 + )和 8.0× 10 - 9mol L~ 1.0× 10 - 7mol L(Ag+ ) ,富集 4min后检出限分别为 1.0× 10 - 1 0 mol L(Pb2 + )和 3.0× 10 - 1 0 (Ag+ )。  相似文献   

6.
刘有芹  沈含熙 《化学学报》2004,62(20):2067-2072,F009
采用一种新方法镀膜 /循环伏安法成功制备了钴氢氧化物修饰玻碳电极 .考察了影响钴氢氧化物膜电催化活性的因素 ,确定最佳富集时间为 2min ,最佳活性单元浓度为 9 90× 10 -4mol·L-1.讨论了成膜过程及机理 .膜氧化峰电流 (i0pa)与扫描速率 (v <0 60V·s-1)成正比 ,具有表面吸附反应特征 ,表面覆盖量约相当于 0 5个单层的氧化还原活性物质 .制得的钴氢氧化物膜修饰电极具有相当的稳定性 ,并对H2 O2 氧化表现出较高的电催化活性 .线性回归方程为 :Δipa( μA) =-2 10 3 6+2 3 72 0× 10 4CH2 O2 (mol·L-1) (R =0 9990 ,n =18) ,线性范围为 :1 43× 10 -5~ 1 80× 10 -2 mol·L-1,检出限为 :9 5 9× 10 -6mol·L-1( 3S/k) .  相似文献   

7.
合成了烯丙基取代的含氮中性配体 [( p-C3H5) C12 H16]2 N3C9H9,然后与 Fe Cl2 反应合成含烯丙基取代的三齿“茂后”烯烃聚合催化剂 [( p-C3H5) ( C12 H16) ]2 N3C9H9Fe Cl2 ,通过 IR,1H NHR,EI-MS对化合物进行了表征 .研究了它催化乙烯聚合的能力 ,这种催化剂与 MAO组成的催化体系可在常压下催化乙烯聚合 ,活性最高达 1 .9× 1 0 6g PE/ ( mol Fe· h) .所得聚乙烯粘均分子量在 5× 1 0 4 ~ 2 .6× 1 0 5之间  相似文献   

8.
在 0 .0 5mol/L氯乙酸 氯乙酸钠 (pH 3.0 )介质中 ,Pb2 + 、In3 + 与二溴邻苯二胺双草酰胺酸酯 (DBAC)生成络合物 ,并吸附于电极表面 ,分别于 - 0 .5 0V、- 0 .6 3V(vs .SCE)得到络合物吸附还原波。其二阶导数峰电流与Pb2 + 、In3 + 浓度分别在 2 .5× 10 -8~ 6 .0× 10 -6mol/L、7.5× 10 -8~ 3.4× 10 -6mol/L内呈良好的线性关系 ;检出限分别为 1.5× 10 -8mol/LPb2 + 和 4 .5× 10 -8mol/LIn3 + 。应用于陶瓷颜料、矿石中微量Pb、In的测定 ,结果满意。  相似文献   

9.
父母职业对幼儿头发中微量元素水平的影响   总被引:1,自引:0,他引:1  
测定了深圳市父母不同职业的 894名 1~ 7岁幼儿头发中的Zn、Cu、Fe、Ca、Mn、Pb的含量。结果表明 ,父母为干部与父母为工人的幼儿头发中的Fe有显著性差异 (P <0 0 5) ,其含量分别为 (2 9 2± 4 9)× 10 -6和 (30 0± 5 6 )× 10 -6;父母为干部与父母为工人的幼儿头发中的Mn有非常显著性差异 (P <0 0 0 1) ,其含量分别为 (1 7± 0 7)× 10 -6和 (1 9± 1 0 )× 10 -6;父母为干部与父母为工人的幼儿头发中的Pb有显著性差异 (P <0 0 5) ,其含量分别为 (12 3±7 6 )× 10 -6和 (13 2± 7 5)× 10 -6。本文还列出了幼儿头发中元素的含量比较图。  相似文献   

10.
阻抑褪色光度法测定微量硫代硫酸根   总被引:2,自引:0,他引:2  
饶志明  黄淑萍  张素清 《分析化学》2004,32(9):1193-1195
基于加热和pH =5 .0~ 6.0条件下 ,硫代硫酸根抑制H2 O2 氧化结晶紫 (CV)的褪色反应 ,建立了一种测定硫代硫酸根的方法。硫代硫酸根在 4.5× 1 0 -5~ 4.5× 1 0 -4g/L范围内服从比耳定律 ;检出限为 3 .2×1 0 -6g/L。本法用于定影废液中硫代硫酸钠含量的测定 ,结果满意。  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.
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   

13.
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   

14.
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   

15.
16.

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   

17.
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   

18.
The kinetics of the interaction between lithium carbonate and silica with various degrees of dispersion was investigated by TG and DTA methods. It was found that the utilization of pyrogenic silica with a specific surface area of about 300 m2g-1 instead of aerosil with one of 175 m2g-1 leads to an increase of the reaction rate between lithium carbonate and silica, which depends on the formation and growth of lithium orthosilicate crystals in the first stage, and is conditioned by the diffusion of lithium and oxygen ions through the lithium orthosilicate layer formed at temperatures above 800 K. This supposition is supported by the kinetic analysis results obtained with the use of the different models. The optimal regime of heating is recommended. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

19.
小环化合物中饱和碳质子化学位移的计算   总被引:3,自引:0,他引:3  
小环化合物由于其张力、构型、构象和各向异性效应等原因,环碳上质子化学位移缺乏规律性,难以预测,对此作者曾提出一种近似算法。本文根据303种小环化合物中饱和碳质子的化学位移实验数据,将适于计算这类质子化学位移的公式表述为:  相似文献   

20.
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   

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