电感耦合等离子体原子发射光谱法测定核纯海绵锆中微量铪

应用标准加入-电感耦合等离子体原子发射光谱法(ICP-AES)对核纯海绵锆中微量铪进行测定.当试样中锆的质量浓度为10 g·L-1时,铪的测定范围为50～400μg·g-1,回收率为103%～110%,相对标准偏差(n=6)为4.2%～6.5%.     

电感耦合等离子体质谱法测定核级海绵锆及锆合金中16种痕量杂质元素北大核心CSCD

取样品0.600 0 g,加入10 mL水润湿后,用5 mL氢氟酸和5 mL硝酸溶解,用水定重至60.0 g。选择灵敏度高且干扰小的同位素,以标准加入法补偿基体效应制作工作曲线,在射频功率1 100 W,雾化气流量0.87 L·min^(-1)等条件下,采用电感耦合等离子体质谱法同时测定核级海绵锆及锆合金中16种杂质元素的含量。结果表明,16种元素的检出限(3s)为0.007~0.26μg·g^(-1)。测定核级海绵锆样品11次,各元素测定值的相对标准偏差(RSD)为2.2%~8.0%。按照标准加入法进行回收试验,回收率为90.0%~111%。     

高温高压消解-电感耦合等离子体原子发射光谱法测定锆钇粉体中钇与6种杂质元素

锆钇粉体样品经高温高压消解后,采用电感耦合等离子体原子发射光谱法测定其中钇和6种杂质元素(铝、铁、钠、镁、铪、硅)的含量。选择铝、铁、钠、镁、铪、硅、钇的分析谱线依次为396.152,238.204,589.592,279.553,277.336,288.158,371.029nm。钇的线性范围在75.0mg·L-1以内,6种杂质元素的线性范围均在30.0mg·L-1以内,方法的检出限(3s)在0.2~2μg·g-1之间。方法用于锆钇粉体样品的分析,加标回收率在80.0%~120%之间,测定值的相对标准偏差(n=5)在3.1%~5.2%之间。     

ICP–AES测定铌铪合金中的铪、钛、锆、钨、钽

采用氢氟酸–硝酸溶解铌铪合金样品,建立电感耦合等离子体原子发射光谱法(ICP–AES)测定铌铪合金中铪、钛、锆、钨、钽元素的分析方法。铪、钛、锆、钨、钽的分析谱线分别为232.247,368.519,339.197,224.876,248.870nm,通过基体匹配法消除基体铌的干扰。在优化条件下对铌铪合金样品进行测定,各元素的质量浓度在其线性范围内与其光谱强度呈良好的线性关系,线性相关系数大于0.998,定量限为0.003 6%~0.007 4%。测定结果的相对标准偏差(n=11)小于1%,回收率为96.8%~105.0%。该方法快速、准确,可以满足实际生产中铌铪合金样品的测定要求。     

氢化物发生-原子荧光光谱法测定中药材中痕量锑

采用微波消解法消解中药样品,以L-半胱氨酸作为预还原剂与掩蔽剂,利用氢化物发生-原子荧光光谱法测定中药中痕量锑的含量;优化了仪器的工作条件以及样品酸度、栽流酸度、硼氢化钾的用量等因素对荧光强度的影响;在最佳工作条件下,锑的质量浓度与荧光强度在10 μg·L-1以内呈线性关系,检出限达(3S/N)到0.038 4 μg·L-1.测定了两种中药样品中的锑量,5次测定的平均值分别为0.083及0.038 μg·g-1,其相对标准偏差依次为3.69%及4.12%.在两种已测定其锑量的中药样品中分别加入锑标准溶液作回收试验,测得回收率为96.0%.     

TBP柱上分离—ICP—AES法测定二氧化铀中微量杂质元素

用ICP-AES法对二氧化铀中23个微量杂质元素进行了测定.取样量100mg时铝、钡、钙、钴、铬、铜、饵、铁、铪、铟、镁、锰、钼、铌、钛、铅、锡、钽、镍、钒、钇、锌和锆的测定范围是20～800μg·g~(-1),回收率为94%～106%,RSD(n=8)为0.2%～1.6%.     

氢化物发生-原子吸收光谱法测定萤石粉中砷

提出了以氢化物发生-原子吸收光谱法测定萤石粉中砷的方法,研究了酸介质、还原剂、载气流量等因素对测定的影响,并选择出最佳工作条件.砷的检出限为0.052μg·g-1,线性范围为0.10～6.00 μg·L-1,回收率在90.0%～102.0%之间,相对标准偏差为9.8%.     

萃取分离-高效液相色谱法同时测钢铁及合金中的锆和铪

锆和铪在钢中主要用来制作特殊用途的合金钢，它们可以改善钢的性能，提高钢的强度、导热性和导电性。而如何测定锆和铪的含量一直是研究的重要课题。锆和铪的化学性质极为相似，测定时相互严重干扰，同时由于钢铁及合金中的复杂的基体干扰，同时测定非常困难。本实验建立了一种离子对反相色谱法同时测定钢铁及合金中锆和铪的方法，采用钽试剂-苯萃取、硫酸反萃取排除共存离子W、Nb的干扰，用于钢铁及合金中锆和铪的同时测定，结果令人满意。     

沉淀分离-离子色谱法测定氧化镧中氯和溴

采用硫酸溶解La2O3,以Ba(OH)2为沉淀剂,沉淀分离法同时除去干扰测定的La3+和SO42-离子.并选用AS15(250 mm×4 mm i.d.)分离柱,电导检测器测定Cl和Br的含量.通过正交实验,优化了色谱条件.Cl和Br的检出限分别为2和8 μg·g-1;测定下限分别为7和26 μg·g-1.样品加标回收率为97%～104%,方法精密度RSD为1.0%～2.5%.Cl测定结果与AgNO3比浊法相一致.     

氢化物发生-原子吸收光谱法测定锑(Ⅲ)和锑(Ⅴ)

提出在酸性条件下以氟化钠为掩蔽剂测定锑(Ⅲ),在碱性介质中加入氟化钠消除价态的影响测定锑总量,两者相减求出锑(Ⅴ),实现对锑(Ⅲ)和锑(Ⅴ)的分别测定.研究了在酸性介质中测定锑(Ⅲ)及碱性介质中测定锑总量的条件及共存离子的干扰和消除.工作曲线的线性范围为：0～20 μg·L-1锑(Ⅲ);0～80 μg·L-1锑(Ⅴ),相关系数大于0.999,方法的检出限为0.31 μg·L-1锑(Ⅲ),0.69 μg·L-1锑(Ⅴ).对水样和土壤样品进行了测定,相对标准偏差(RSD)小于5%.     

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.     

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.

     

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。     

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。