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1.
金利通  刘彤 《分析化学》1993,21(10):1117-1121
本文介绍了1:12磷钼杂多酸修饰电极的制备及其对IO^-3、BrO^-3的催化还原作用。本文还研究了在涂敷十六烷基三甲基溴化铵的C18键合固定相上IO^-3与BrO^-3的分离方法,并采用修饰电极色谱电化学的方法对IO^-3与BrO^-3进行定量测定。IO^-3、BrO^-3的量分别在8.0×10^-10~1.0×10^-1mol和1.6×10^-9~3.0×10^-7mol范围内与峰高呈良好的线  相似文献   

2.
林志红  吴蒙 《分析化学》1994,22(8):833-836
由于香蕉组织中含有的氧化酶能够生物催化氧化多巴胺,去甲肾上腺素,L-多巴等,大大地提高了植物组织电极的灵敏度;又由于茄子组织中所含有的氧化酶在催化氧化儿茶酚的同时,能有效地抑制抗坏血酸在电极上的反应,将上述两种植物组织混合制成电极,使其更适于神经递质的测定,线性范围:2.4×10^-6--9.8×10^-4mol/L;检出下限3.2×10^-7mol/L。  相似文献   

3.
高锰酸钾—抗坏血酸化学发光体系测定抗坏血酸   总被引:6,自引:0,他引:6  
本文研究了高锰酸钾-抗坏血酸化学发光体系,建立了测定抗坏血酸的化学发光分析新方法,线性响应的浓度范围为5.0×10^-7mol/L~4.0×10^-5mol/L,检出限为3.0×10^-7mol/L,对2.5×10^-6mol/L抗坏血酸进行10次平行测定,相对标准偏差为1.6%,考察了22种物质的干扰情况。用于维生素C片剂及注射液中抗坏血酸含量测定,结果令人满意。  相似文献   

4.
砷在1.5×10^-4mol/L Co-0.1mol/L KCNS-1%抗坏血酸-0.7mol/L Na2SO4-4×10^-3mol/L NaBr介质中产生一灵敏催化波,峰电位为-1.1V。采用微分脉冲极谱法研究了各项实验条件,建立了直接测定硫中微量砷的方法。该法简便快速,结果满意。  相似文献   

5.
催化动力学法测定化探样品中的痕量铬   总被引:7,自引:0,他引:7  
本对在弱酸性介质中铬(VI)强烈催化H2O2氧化铬蓝黑R褪色反应进行了一系列研究,拟定了用催化动力学法测定铬(VI)的最佳条件。该法检出限为3.2×10^-9g/mL,测定线性范围0~1.5μg/25mL铬(VI),用于化探样品中痕量铬的测定,结果良好。  相似文献   

6.
银微盘电极上碘离子的示差脉冲溶出伏安法   总被引:6,自引:0,他引:6  
方宾  方惠群 《分析化学》1997,25(1):59-62
基于I能与Ag生成难溶出化合物特性,在银微盘电极上研究了I的示差脉冲溶出伏安法(DPSV)。该法不需镀汞,不要搅拌,可在较稀稀的支持电解质溶液中实施。于0.08mol/LHAc-NaC及0.01mol/LEDTA介质中,能检出1.00×10^-8mol/L的I,I的浓度为5.00×10^-6--1.20×10^-8mol/L范围与峰电流有良好的线性关系。该法用于自来水中I的测定,相对偏差为4.3%  相似文献   

7.
大蒜中抗坏血酸的半微分伏发法测定   总被引:2,自引:0,他引:2  
韩树波  袁倬斌 《分析化学》1997,25(3):338-340
将工作电极直接插入大蒜瓣中,采用半微分伏安法研究了抗坏血酸的测定方法。用微铂盘电极作为工作电极,在ph6.8的磷酸氢二钠-柠檬酸介质中,抗坏血酸在7.0×10^-2-3.2×10^2mg/L范围内与半微分伏安曲线阳极峰的峰高呈线性关系,其最低检出浓度为4.9×10^2mg/L。  相似文献   

8.
研究了在酸性介质中,抗坏血酸对溴酸钾、次甲基绿、钒催化体系具有显著的活化作用建立了测定抗坏血酸的新方法。线性范围为0.002~0.06μg.ml^-1,方法检出限为1.25×10^-9g.ml^-1,用于药品、尿液中抗坏血酸的测定,结果满意。  相似文献   

9.
头孢噻肟钠的降解及其产物伏安行为的研究   总被引:18,自引:1,他引:18  
头孢噻肟钠在NaOH溶液中降解后,于0.1mol/LNaOH中得一灵敏的吸附伏安原峰,Ep=-0.78V(νsAg/AgCl),ip与头孢噻肟钠浓度在1.0×10^-^9-1.0×10^-^8,1.0×10^-^8-1.0×10^-^7,1.0×10^-^7-1.0×10^-^6mol/L范围内呈线性关系,检出限为5.0×10^-^1^0mol/L。用多种电化学手段研究其降解产物的伏安行为,测定了  相似文献   

10.
测定超氧化物歧化酶活性的一种新的极谱分析方法   总被引:3,自引:0,他引:3  
杨天鸣  黎瑞珍 《分析化学》1998,26(11):1342-1345
报道一种测定超氧化物歧化酶活生的新极谱分析方法,在0.125mol/LNH3.H2O-0.75MOL/l nh4cL-2.5%,Na2SO3-0.5%,吐温-80-的介质中,SOD在-0.52V处产生一氧极谱催化波。SOD在1.0×10^3U/L-4.0×10^3U/L的活性含量范围内与催化电流呈线性关系,检出限为8.0×10^2U/L。  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.
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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