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1.
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
2.
基于硫酸介质中,柠檬酸作活化剂,钒(Ⅴ)、铬(Ⅵ)催化氯酸钾氧化鸡冠花红褪色的反应,建立了催化光度同时测定痕量钒(V)、铬(Ⅵ)的新方法。研究了影响反应速率的最佳条件。本法测定钒(V)、铬(Ⅵ)的线性范围分别为0 ̄8μg/L和0 ̄0.6mg/L;检出限分别为1.79×10^-7g/L和2.36×10^-5g/L。用于测定环境水样、钢样及废水中的钒(Ⅴ)、铬(Ⅵ),结果令人满意。 相似文献
3.
1引言催化光度法具有灵敏、简便、不需使用复杂仪器等特点,是常见的痕量分析方法之一。本文发现,在弱酸性介质中钒能灵敏地催化溴酸钾氧化H酸生成红色产物,8-羟基喹啉对该反应有强烈的活化作用,据此可建立一个测定超痕量钒的催化动力学光度法。2实验部分2.1仪器和试剂722型分光光度计;501·型超级恒温槽。钒标准溶液:用偏钒酸铵按常规方法配制;0.20mol/L溴酸钾溶液;0.02mol/LH酸溶液:用H酸-钠盐配制,贮于棕色瓶中置暗处存放,可使用5天;0.10mol/L抗坏血酸溶液;2.0g/L8-羟… 相似文献
4.
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,建立了该剂催化荧光测定痕量钒的 新体系,反应在盐酸体系中进行,其λex/λem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。 相似文献
5.
基于硫酸介质中,柠檬酸作活化剂,钒(Ⅴ)、铬(Ⅵ)催化氨酸钾氧化鸡冠花红褪色的反应,建立了催化光度同时测定痕量钒(Ⅴ)、铬(Ⅵ)的新方法。研究了影响反应速率的最佳条件。本法测定钒(Ⅴ)、铬(Ⅵ)的线性范围分别为 0~ 8μm/L和0~0.6mg/L;检出限分别为1.79×10-7g/L和2.36×10-5g/L。用于测定环境水样、钢样及废水中的钒(Ⅴ)、铬(Ⅵ),结果令人满意。 相似文献
6.
本建立了苯素红催化荧光测定痕量钒的新方法。在λex/λem=381/445(nm)由多目标罚函数单纯形法获得最佳实验条件为:1%苯素红6mL,1mol/L盐酸2.1mL,饮和KIO41.8mL,反应温度85℃,反应时间15.30min,钒的检测下限为7×10^-10g/mL,反应对试剂及金属离子均为一极反应。方法用于水样和铬钒钢中钒的测定,结果满意。 相似文献
7.
在碱性介质中,痕量钴(Ⅱ)能显著催化H2O2氧化水杨基荧光酮的指示反应,本文据此建立了测定痕量钴的新催化动力学分析法,方法线性范围为0.1~2.8μg/L,检测限为0.02μg/L。测得反应表现活化能为59.03kJ/mol。测定了人发,茶叶,土壤和水等样品中钴的含量,结果满意。 相似文献
8.
基于稀磷酸介质中,亚硝酸根对溴酸钾氧化酚藏花红反应的催化作用,建立了催化荧光法测定痕量亚硝酸根的新方法。反应在55℃水浴中进行8min,线性范围为0.27~7.3μg/L,其回归方程为ΔF=0.40+10.93c,r=0.9994。用于水样中痕量亚硝酸根的测定,结果良好。 相似文献
9.
本文拟定了一个催化荧光测定痕量钼的新方法,在磷酸介质中,钼(Ⅵ)催化过氧化氢氧化碘化钾的反应,其反应产物使罗丹明6G荧光猝灭。方法检出限1.2μg/L;线性范围2-16μg/L。直接用于豆类、人尿中钼的测定及钼酸铅Ksp的测定,获得满意结果。 相似文献
10.
研究了在pH9.2的硼砂介质中,痕量钒(Ⅴ)催化H2O2氧化桑色素褪色反应体系的新催化光度法。测量范围为0~7.5μg/50mL加标回收率为95%~98.5%,测定2μg钒(Ⅴ),RSD为1.68%,用于水样中痕量钒(Ⅴ)的测定。 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 from Izvestiya 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, (5 E)-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.
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.
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, M o, 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 600-700 oC. 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.
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 from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997. 相似文献
20.
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
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