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1.
钒(Ⅴ)-亚铁氰化钾-鲁米诺化学发光体系测定钒   总被引:1,自引:0,他引:1  
本文利用钒(Ⅴ)-亚铁氰化钾-鲁米诺化学发光体系建立了痕量钒的化学发光测定法。方法检出限是2×10~(-10)g/mL钒,线性范围是4×10~(-10)~1×10~(-7)g/mL钒,测定的相对标准偏差小于2%,考察了26种常见离子的干扰情况。方法已用于水样中痕量钒的测定。  相似文献   

2.
测定化探样品中痕量钒的流动注射光泽精化学发光法   总被引:4,自引:1,他引:3  
用配有Jones还原器的流动注射系统,研究了光泽精与钒(Ⅱ)的化学发光反应,并建立了钒的流动注射化学发光分析法。该法线性范围为1×10-6~1×10-2 g/L ,检出限为3×10-7 g/L,相对标准偏差为2.0 %(1×10-4 g/L,n=11),相关系数在0.9988以上。已用于化探样品中痕量钒的测定,结果令人满意。  相似文献   

3.
合成了新型席夫碱类试剂茚三酮缩7-氨基-8-羟基喹啉-5-磺酸,建立了该试剂催化荧光测定痕量钒(Ⅴ)的新体系,反应在盐酸体系中进行,其λex/λm为325/448(nm),钒(Ⅴ)的量在0~40.0μg/L、40.0~160.0μg/L呈良好线性关系,检测下限为1.7μg/L,方法用于水样痕量钒的测定,结果令人满意。此外,还详细探讨了反应机理和动力学方程。  相似文献   

4.
研究了在活化剂柠檬酸的存在下 ,钒 催化溴酸钾氧化三溴偶氮胂褪色反应特性 ,测定了反应级数和反应速率方程 ,拟定了反应的最佳条件 ,建立了测定痕量钒的新方法。该法灵敏度为 7.78× 10 -12 g mL ,线性范围为 0~ 8× 10 -9g mL ,用于测定人发中的痕量钒 ,结果令人满意。  相似文献   

5.
双波长双指示剂催化光度法测定食品中痕量钒   总被引:1,自引:0,他引:1  
研究了在0.2 mol/L柠檬酸介质中,利用钒酸根对溴酸钾氧化乙基紫和萘酚绿B褪色反应同时具有强烈的催化作用,通过650 nm和720 nm波长下测量催化体系和非催化体系的吸光度,建立了一种双指示剂、双波长催化动力学光度法测定钒(V)的新方法。最佳实验条件下,测定钒的线性范围为1.00~80.0μg/L,检出限为1.1×10-10g/mL。对20.0μg/L钒进行12次平行测定的相对标准偏差为2.2%。方法用于面粉和大米中痕量钒的测定,结果令人满意。  相似文献   

6.
催化动力学褪色光度法测定痕量钒   总被引:15,自引:0,他引:15  
刘长增 《分析化学》2000,28(12):1481-1484
基于磷酸和棉红在沸水发色条件下反应生成的产物在钒(Ⅴ)催化下被KBrO3氧化而建立了一个测定超痕量钒的新方法,方法选择性好;测定范围是0.00-0.70μg/L,检测出限量7.3*10^-12g/mL,方法用于芹菜、人体血清和井水中超痕量钒的测定,获得了满意结果。  相似文献   

7.
流动注射催化光度法测定化探样品中痕量钒   总被引:3,自引:0,他引:3  
利用痕量钒对铍试剂Ⅲ-抗坏血酸体系的催化作用,建立了一个流动注射-分光光度法测定化探样品中痕量钒的方法。该方法具有灵敏度高,分析速度快的特点。选择反应温度为90℃时,反应速度加快,测量时间由普通光度法1h减少到约1min,分析速度为60样次/h。方法的检测限为7μg/L,对于含钒0.4mg/L的试样,RSD为0.6%(n=30),用于化探样品,分析结果满意。  相似文献   

8.
在硫酸介质中,以抗坏血酸作活化剂,痕量钒(Ⅴ)能灵敏地催化溴酸钾氧化偶氮胂Ⅰ褪色的指示反应。研究了该反应的最佳实验条件和动力学参数,建立了一种测定痕量钒(Ⅴ)的新方法,该方法的线性范围为0~4.0μg L钒(Ⅴ),方法检出限为2.8×10-12g mL,本方法已用于生物样品中痕量钒(Ⅴ)的测定。  相似文献   

9.
吖啶橙催化荧光法测定痕量钒   总被引:9,自引:0,他引:9  
李书存  石生勋 《分析化学》2001,29(10):1170-1173
研究了在酸性介质中柠檬酸存在下,痕量钒(V)催化溴酸钾氧化吖啶橙退色及其动力学条件,建立了催化荧光法测定痕量钒(V)的新方法。钒(V)的线性范围为 0.2~2.8 μg/L,检出限为 5.8× 10-8g/L。30多种离子基本不干扰测定,将方法用于矿泉水,枸杞和人发样品中钒(V)的含量的测定,结果满意。此外,还对反应机理进行了初步探讨。  相似文献   

10.
在硫酸介质中,痕量钒能灵敏地催化溴酸钾氧化偶氮胭脂红B而褪色.研究了该催化褪色反应的最佳条件及动力学参数,建立了一种测定痕量钒(Ⅴ)的新方法.该法的线性范围为0~1.0 μg/10 mL,检出限为1.40×10-9 g/mL.用于水和小麦试样中钒(Ⅴ)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.
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.
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   

16.
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   

17.
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   

18.
19.
The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.  相似文献   

20.
设计了铁的锈蚀实验,说明了铁钉的处理方法,增加了温度、酸、碱的影响条件,实现了铁跟蒸馏水及空气中氧气快速反应而生锈,使实验在5 min左右就能够得到准确的结果。  相似文献   

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