碘汞酸钾与CPB反应产物的共振散射光谱及其在分析中的应用

在pH 2~7的溶液中,碘汞酸钾和溴化十六烷基吡啶(CPB)反应生成离子缔合物,在390 nm处有共振散射峰,峰强度随汞(Ⅱ)浓度的增加而急剧增大。在试验条件下,汞(Ⅱ)的线性范围为15~200μg.L-1,检出限为5μg.L-1,用于合成水样和环境水样中汞(Ⅱ)的测定,在4个浓度水平测得结果的RSD均小于1.5%,用标准加入法测得的回收率在94.9%至102.1%之间。     

氢化物发生-原子荧光光谱法测定环境水样中痕量镉

采用氢化物发生-原子荧光光谱法对环境水样中痕量镉进行测定。对分析的条件进行了试验并予以优化。在0.12 mol.L-1盐酸介质中,以1 mg.L-1钴溶液为信号增感剂,10 g.L-1硫脲溶液作为络合剂,当硼氢化钾质量浓度为30 g.L-1时,镉质量浓度在6.0μg.L-1以内与荧光强度值呈线性关系。对空白溶液进行11次测定,其方法检出限(3s/k)为0.18μg.L-1。此方法应用于环境水样的分析,并在此样品基础上,用标准加入法对方法作回收试验,测得平均回收率为96.3%及101.7%。     

化学蒸气发生-多通道原子荧光光谱法同时测定化探样品中的砷、锑、铋、汞

采用氢化物发生-四通道原子荧光光谱仪同时测定化探样品中砷、锑、铋和汞的含量。试样溶于盐酸-硝酸-水(3+1+4)的混合酸中,分取适量试液在盐酸(1+4)溶液和含硫脲10g·L-1的介质中预还原30min。用纯氩气作载气和屏蔽气,流量依次为300,900mL·min-1。仪器采用间歇流动进样方式,硼氢化钾溶液的质量浓度为15g·L-1。上述4种元素的质量浓度在一定范围内呈线性,检出限(3S/N)为0.031μg·L-1(砷)、0.028μg·L-1(锑)、0.024μg·L-1(铋)和0.004 8μg·L-1(汞)。应用此方法分析了化探样品,并用标准加入法对上述4种元素进行回收试验,测得回收率在95.4%~101%之间。     

微波消解-氢化物发生-原子荧光光谱法同时测定土壤及生物样品中铅和汞

应用氢化物发生-原子荧光光谱法测定了土壤及生物样品中铅和汞。样品用硝酸4mL及过氧化氢1mL按微波消解仪的工作参数进行消解,消解后溶液定容至25mL供测定。用30g·L-1柠檬酸溶液和硝酸(1+99)溶液的混合液作载流,根据铅(Ⅱ)离子的反应和试液对酸度的要求,选用含15g·L-1硼氢化钾,10g·L-1铁氰化钾和20g·L-1氢氧化钾的混合溶液作为还原剂。方法的检出限(3s/k)为0.512μg·L-1(铅)和0.067μg·L-1(汞)。应用此方法分析了3种实样并进行加标回收试验,测得回收率分别在91.0%~97.0%(铅)和88.0%~95.5%(汞)之间。     

氢化物发生-原子荧光光谱法同时测定陈皮中砷和汞

采用微波消解法消解陈皮样品,利用氢化物发生-原子荧光光谱法同时测定陈皮中砷和汞.研究并优化了硼氢化钾的用量、消解介质的酸度、共存离子的干扰和消除等试验条件.荧光强度与砷及汞的质量浓度在20.0μg·L-1及2.00 μg·L-1以内呈线性关系,方法的检出限为0.084μg·L-1(砷)和0.022 μg·L-1(汞).应用此法分析了6个陈皮试样,测定值的相对标准偏差均小于7.0%,以标准加入法做回收率试验,平均回收率分别为93.6%(砷)和90.7%(汞).     

硅藻土吸附在线柱富集-火焰原子吸收光谱法测定环境水样中痕量铜

提出了硅藻土吸附在线柱富集-火焰原子吸收光谱法测定环境水样中痕量铜的方法。利用硅藻土对环境水样中痕量铜在线预富集,浓集因子达到27.6,使火焰原子吸收光谱法的检测能力达到测定环境水样中痕量铜的要求。方法检出限为0.32μg.L-1,RSD(20μg.L-1)为3.52%,加标回收率为97.0%~105.0%。     

阳离子交换树脂富集-流动注射-冷原子荧光光谱法测定环境水样中痕量汞

提出了用阳离子交换树脂富集环境水样中痕量汞,用流动注射-冷原子荧光光谱法测定其中汞的含量。对阳离子交换柱的制备、富集时间、介质及洗脱剂的酸度等分析条件做了试验并予以优化。汞的质量浓度在40 ng.L-1以内与其荧光强度呈线性关系,方法的检出限(3s)为0.13 ng.L-1。应用此法对环境水样进行分析,并以此样品为基体作回收试验,测得汞的回收率在72.5%~101.3%之间。     

电化学-汞蒸气-原子荧光光谱法测定中药中可溶性汞

中药安宫牛黄丸(0.3 g试样)中可溶性汞用人工胃液(200 mL)于37℃的恒温水浴中提取4 h,分取其滤液1 mL,用0.5 mol.L-1硫酸溶液定容至25 mL,用电化学-汞蒸气-原子荧光光谱法测定其含汞量。方法中采用断续流动进样法引入试样溶液,进样体积为0.5 mL,试样溶液经过自制的电化学流通池,在阴极发生还原反应生成汞蒸气。文中对电化学流通池的结构作了详细描述,采用的电解电流为1.5 A(或0.54 A.cm-2),所用载气及屏蔽气的流量均为500 mL.min-1。试验结果表明:在所选择的试验条件下无基体效应。方法的检出限(3S/N)为2.1 ng.L-1。在1μg.L-1汞的浓度水平上连续测定11次作精密度试验,求得其相对标准偏差为1.9%。在此中药实样的基础上,分别加入40,50,60μg.g-1汞标准溶液,按方法测定其汞的回收值,算得其回收率在96%~102%之间。     

镍(Ⅱ)-1-(1吡啶偶氮)-2-萘酚-十二烷基苯磺酸钠体系共振光散射法测定痕量镍

在pH 8.0的Tris-盐酸缓冲介质中,利用十二烷基苯磺酸钠(SDBS)增敏镍(Ⅱ)和1-(2-吡啶偶氮)-2-萘酚(PAN)形成离子缔合物体系,使体系共振光散射增强.体系最大散射波长545 nm,在15～500μg·L-1范围内共振散射增强强度(△I)与镍(Ⅱ)质量浓度呈线性关系.检出限(3S/N)为4.57μg·L-1,分别对50,200,400 μg·L-1镍(Ⅱ)标准溶液进行11次平行测定,测定值的相对标准偏差(n=6)依次为3.5%,3.0%,1.7%.据此提出了一种简单而快速的测定镍的方法.应用于测定水样中镍量,测得其平均回收率为98.5%.     

纳米钛酸锶钡粉体吸附富集-火焰原子吸收光谱法测定水样中锰离子

提出了纳米钛酸锶钡粉体吸附富集,火焰原子吸收光谱法测定水中痕量锰的含量。在pH 6的氨性缓冲介质中,采用纳米钛酸锶钡(0.02 g)对水样(10 mL)中的锰离子振荡吸附15 min。优化条件下吸附容量达5.4 mg.g-1。方法检出限(3s/k)为2.1μg.L-1。用0.15 mg.L-1锰(Ⅱ)标准溶液连续测定6次,求得其相对标准偏差(n=6)为3.4%。用于河水和地下水中痕量锰的测定,用标准加入法测得方法的回收率在93.5%~99.7%之间。     

利用手持技术改进测定乙醇分子结构实验

利用压强传感器代替排水集气法,改进测定乙醇分子结构实验的仪器装置,并探索最佳反应条件。另外,设计两个空白实验,结合压强变化曲线对实验误差进行相关讨论。     

Neutral diterpenoids of oleoresins of five species of conifers of Transcarpathia

The compositions of the neutral diterpenoids of the oleoresins of five species of conifers growing in the Transcarpathia have been studied. It has been found that the oleoresins ofAbies alba M.,Larix decidua M., andPicea excelsa L. contain more than 50% of neutral diterpenoids. The group and qualitative compositions of the oxygen-containing diterpenoids have been determined. In the oleoresins ofAbies alba,Picea excelsa, andPicea abies tertiary alcohols — cis-abienol and isocembrol — predominate, while inLarix decidua the main component is the hydroxy ester larixyl acetate. Primary alcohols related to the resin acids have been found in all the oleoresins investigated. Features of the distribution of diterpenoids according to the species of conifers have been revealed. The results obtained are necessary for the chemotaxonomy of conifers of the family Pinceae.Novosibirsk Institute of Organic Chemistry, Siberian Branch, Academy of Sciences of the USSR. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 812–816, November–December, 1988.     

光谱仪测试范围的扩展

由于石化行业的生产需要，其材质的使用具有多样性和广泛性，经常会出现顾客委托的测试样品的一个或几个元素跨越光谱仪现有测试程序测量范围的情况。本法通过对光谱仪测试原理的认识，根据光谱仪的测试能力及标样的采集，实现了一个或几个元素测量范围的扩展，并对其测量的影响因素进行了研究。     

Influence of viscosity of medium on processes of oxygen quenching of excited states of mesoporphyrin

The oxygen quenching rate constants for singlet and triplet excited states of the dimethyl ester of mesoporphyrin IX increase with decreasing viscosity of the medium and reach a maximum at a viscosity of approximately 0.4 mPa·sec, after which the rate constants begin to decrease. The drop in rate constant with increasing fluidity of the medium may be related to a nonequilibrium character of the elementary act in the interaction of the reactants in the solvent cage. In viscous media such as isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol, the reaction radius is greater than the sum of the radii of the reacting particles. The long-range character of these processes is due to the relatively weak dependence of the quenching probability on distance.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 2, pp. 161–167, March–April, 1989.     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

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.     

物质分配系数的测定实验改进

实验教学目的是从解决实际问题出发,以实验技术训练和实验设计思想培养为目标。介绍了将单一的物质分配系数测定实验改进为综合实验,提高了实验效果及实验资源利用率。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

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.

     

Calculation of enthalpies of hydrogenation of hydrocarbons

Sets of hydrogen molecule equivalents have been developed which permit the calculation of hydrogenation of different types of carbon-carbon bonds from ab initio total energies (3-21G and 6-31G* basis sets, and, to a more limited extent, for MP2/6-31G* data) of reactants and products. The calculated enthalpies of hydrogenation are in good agreement with experiment for unstrained molecules, with average errors on the order of 2 kcal/mol. The 6-31G* equivalents allow the enthalpies for strained molecules to be calculated accurately, but the 3-21G equivalents do not. The equivalents for both basis sets have been tested by calculating the enthalpies of hydrogenation of carbon-carbon bonds in nitrogen- and oxygen-containing organic molecules, free radicals, and classical carbocations. The results are in good agreement with experiment in most cases.     

非那雄胺合成工艺改进

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。