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1.
低温堆水样中微量氢的测定   总被引:1,自引:1,他引:0  
本文以氩载气洗提,气相色谱法测定低温核供热反应堆环路冷却水中的微量氢,可测定氢气最低浓度为0.20mL/LH2O,在此浓度下,分析10次的精密度(相对标差)为10%。  相似文献   

2.
偶合反应化学发光法测定痕量银的研究   总被引:6,自引:0,他引:6  
耿征  武竟存 《分析化学》1995,23(4):401-403
本将Ag(Ⅰ)催化S2O^2-8氧化Mn(Ⅱ)生成MnO^-4的催化反应与LuminolMnO^-4-OH^-的化学发光反应相偶合,建立起一种新的灵敏测定痕量银的化学发光分析法,在所研究的优化条件下,该法测定银的选择性较好,检测限达到3.2×10^-12g/mLAg线性浓度范围为1.0×10^-11-1.0×10^-5g/mLAg,用于水样分析,结果较为满意。  相似文献   

3.
偏最小二乘催化极谱法同时测定铂,钯,铑   总被引:6,自引:0,他引:6  
应用M273A电化学系统中的线性扫描技术,确定了0.75mol/LH2SO4-1.5%NH4Cl-2.8mmol/L(CH2)6N4-0.0025%N2H4.H2SO4为偏最小二乘极谱法同时测定Pt、Pd、Rh的最佳极谱体系。Pt、Pd、Rh的线性范围为3.2mg/L、0-15.0mg/L和0-1.0mg/L。模拟样品及实际样品的回收率在90.3-107.7%之间。  相似文献   

4.
本文通过对NO3-和NO2-的一阶导数光谱研究,提出利用它们各自导致光谱峰值的两种解析方法测定相互干扰的两组份含量,由于利用尽可能最大信息量和导数谱的特有功能,使测定NO3-和NO2-灵敏度分别为0.005μg/mL、0.009μg/mL(峰高-截矩比f校正系数法)及0.004μg/ml、0.006μg/mL(双峰k系组合导致法),线性范围皆为0~1.0μg/mL方法用于水样分析,结果令人满意。  相似文献   

5.
基于微波消解和正相液相色谱-荧光检测测硒法,实现了对环境水样中亚纳克级硒的测定。考察了HNO3和H2SO4-H2O2两种消化体系及其工作条件,方法检出限分别可达 7.2和 10.4 pg Se,对标准参考物质的回收率分别为99.4±2.0和97.8±2.5%,在0~1.5ngSe范围内有线性关系(R2<0.996)。对北京地区 4种不同类型水体水样含硒量进行了分析测定(2mL样品),其浓度范围为 0.20~0.90μg/L,标准加入回收率为99.1%~103.4%。  相似文献   

6.
在催化显色体系中引入合适的活化剂能显著地提高其反应灵敏度,通过实验,我们观察到,乙醇对Cu-邻苯二酚-H2O2的催化显色反应有明显的活化增敏作用。研究了该体系的实验条件,并成功应用于食品和发样中痕量铜的测定。1 试剂与仪器7230型分光光度计;pHS-2型酸度计。铜(Ⅱ)标准贮备液浓度1mg/mL,工作液稀释为1μg/mL;邻苯二酚溶液0.2mol/L;30%H2O2溶液、pH5.5,HAc-NH4Ac缓冲溶液。试剂均为分析纯,水为去离子水。2 实验方法在25mL比色管中分别加入2.5mL的邻苯…  相似文献   

7.
催化动力学光度法测定痕量钒(Ⅴ)的研究   总被引:1,自引:0,他引:1  
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   

8.
NaIO4-肾上腺色腙体系化学发光法测定肾上腺色腙   总被引:3,自引:0,他引:3  
利用NaIO4-H^+-H2O2-肾上腺色腙化学发光体系,结合流动注射技术建立了一种测定肾上腺色腙的化学发光新方法。方法的线性范围为8.0*10^-9-1.0*10^-6g/mL肾上腺色腙,检出限为2.7*10^-9g/mL,相对标准偏差为0.97%。  相似文献   

9.
18-冠-6修饰碳糊电极测定金的研究   总被引:2,自引:0,他引:2  
本文研究了18-冠-6修饰碳糊电极测定金的条件,金在0.5mol/LHC1-0.005mol/LKC1底液中富集,介质交换到0.01mol/LHC1中进行测定。金(Ⅲ)浓度在0.1~1.0μg/mL范围内呈线性关系,相对标准偏差为9.7%,检出限为20ng/mL。可不经预先分离直接测定矿样中的金,结果良好。并研究了Au(Ⅲ)在18-冠-6碳糊修饰电极上的还原机理。  相似文献   

10.
在0.2mol/LNaOH-0.04mol/LH3PO4-0.02mol/L(NH4)2SO4-0.04mol/LCH3COOH溶液中,精氨酸(Arg)在苯甲醛存在下产生一灵敏的吸附波。实验证明电活性物质为α-苯亚甲基精氨酸,其电极反应机理是分子内α->C=N基团被还原为亚胺。用该吸附波可在1×10(-3)~2×10(-6)mol/L范围内分析蛋白质中的Arg。  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.
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   

19.
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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