固态进样方式石墨炉原子吸收光谱法测定沙痕量金

报道了地质样品中痕量金用表面涂有磷酸三丁酯的聚氨酯泡沫塑料(PUPF)吸附富集后用石墨炉原子吸收光谱法(GF-AAS)测定,测定中采用外形改变的热解石墨管,表面吸附有金离子的PUPF毋需经过解吸操作,直接引入石墨管中进行测定.将吸附有金的PUPF固体物直接进样的方式的特点反映在两方面:①避免了因解吸操作而引起的金的损失;②降低方法的检出限至沙痕量级.在3个浓度水平上作了精密度试验,测得方法的RSD(n=11)值≤3.6%.用标准加入法作回收率试验,所得结果在102%～107%之间.该方法的检出限为10 pg·g-1,应用此法分析了一件标准物质样品(GBW 07242),测出的金含量与证书值相符,进一步证明了方法的准确性.     

快速石墨炉原子吸收光谱法测定尿铊

尿样用硫酸-硝酸混合酸消化,并用溴水将溶液中铊(Ⅰ)氧化至铊(Ⅲ),用盐酸(1 4)介质使铊(Ⅲ)以络阴离子Tl(Cl)4-状态存在。用聚氨酯泡沫塑料吸附铊(Ⅲ),从而与尿液分离,且达到消除尿液中无机盐的干扰和一定的富集效果。将聚氨酯泡沫塑料取出并洗净后置于沸水中使铊(Ⅲ)从泡沫塑料上解吸,所得溶液供石墨炉原子吸收光谱法(GF-AAS)测定。在方法中不加任何基体改进剂且在石墨平台升温程序中省略了灰化步骤,使测定达到快速的要求。方法的测定限达到0.1μg.L-1,测得回收率在91%~97%之间。     

泡沫塑料吸附分离石墨炉原子吸收测定地质样品中微量铊

地球化学样、单矿物及一些岩石样品常需分析微量铊,其含量有时小于10~(-5) ％。测定这样微量的铊尚无很好的方法。石墨炉原子吸收法灵敏度高,适于微量铊的测定,但已有方法都使用有机溶剂萃取分离,效果差。用泡沫塑料吸附方法作为一种分离富集手段,能解脱制备为水性溶液,很适合于石墨炉原子吸收分析,目前,已应用于测金、砷及稀土等。本文就聚氨醋泡沫塑料富集分离微量铊进行了研究,在含适量卤素离子(Br~-、Cl~-或F~-)的稀     

石墨炉原子吸收法测定化探样品中痕量金

提出了泡沫塑料富集—石墨炉原子吸收光谱法测定化探样品中痕量金的过程中存在的问题,结合实际情况给予相应的解决办法。通过标准溶液或采用国家标准物质同步操作进行补偿,提高了方法的精密度,重现性好,适合大批量化探样品中痕量金的分析测定。     

化探样品中痕量金和钯的火焰原子吸收分析

金和钯在地壳中含量甚微,克拉克值分别为5ppb和3ppb。其矿样经王水溶解所得溶液,必须预先富集分离后,才能测定痕量金和钯。作者选用聚氨酯泡沫塑料吸收金,以717型强碱性阴离子交换树脂吸附钯,火焰原子吸收测定金与钯。本法在同一份样品中连续测定金与钯,分析速度快,成本低,宜于大批量化探样品中的应用。     

水浴加热密闭溶样石墨炉原子吸收光谱法测定化探样品中的痕量金

以王水、氟化钾、Fe3+溶液为溶剂,对化探样品进行水浴加热分解1.5 h,经泡沫塑料吸附后,于90℃以上硫脲溶液中解吸20 min,然后采用石墨炉原子吸收光谱仪测定其中的金含量。对仪器分析条件进行了优化。金的质量分数在0.1~100.0 ng/g范围内与吸光度呈良好的线性,线性相关系数r2=0.999 3,检出限为0.100 ng/g。该方法对金标准物质测定结果的相对标准偏差为5.96%~9.25%(n=12),对国家一级标准物质进行分析,测定结果与标准值相符合。该方法满足1∶50 000化探样品中痕量金的分析要求。     

金测定的方法验证及质量控制图的建立

对DZ/T 0279.19–2016 《区域地球化学样品分析方法第19部分:金量测定泡沫塑料富集–石墨炉原子吸收光谱法》进行了实验室方法验证,并建立了相应的质量控制图。结果表明,实验室具备采用泡沫塑料富集–石墨炉原子吸收光谱法测定金的资源和技术能力,建立的质量控制图能够对分析系统进行有效核查。     

石墨炉原子吸收光谱法测定地质样品中的微量金

石墨炉原子吸收光谱法测定地质样品中的微量金已有不少报导。该法由于受试样注入量的限制,金的相对灵敏度并不太高,故不能满足地质科研的要求。我们设想,如将金的化学富集物全部原子化,就能充分发挥石墨炉法绝对灵敏度高的这一特点。经试验,选择适宜的富集剂是关键的一步。本文采用了巯基棉富集法。测定金的灵敏度可达6×10~(-11)克/(富集物)1％。如用1克样品富集,测金范围为0.01～0.0005克/吨,方法的回收率为90-115％,满足了地质上对微量金的测定要求。 (一)仪器与试剂 1.原子吸收分光光度计。     

聚氨酯泡沫塑料富集-电感耦合等离子体发射光谱法测定地质样品中的金

建立聚氨酯泡沫塑料富集–电感耦合等离子体发射光谱法测定地质样品中金的方法。泡沫塑料预处理:用5%NaOH溶液浸泡60 min,再用10%HCl溶液浸泡120 min。金矿样品用王水溶解,再用预处理的泡沫塑料吸附其中的金,灰化后用王水溶解,在选定的仪器工作条件下进行测定。金的质量浓度在0.00~20.00μg/mL范围内与光谱强度呈良好的线性关系,相关系数为0.999 5,方法的检出限为9.9 ng/mL。测定结果的相对标准偏差为1.15%~3.99%(n=10),用该法测定金矿石国家标准物质,测定值与标准值基本一致。该方法准确、可靠,能够满足地质样品中金的分析测试要求。     

浊点萃取富集-石墨炉原子吸收光谱法同时测定环境水样和中药中超痕量铅和镉

提出了石墨炉原子吸收光谱法同时测定环境水样和中药中超痕量铅与镉的方法.以双硫腙为络合剂,在pH 7.0时,用Triton X-114非离子表面活性剂浊点萃取富集样品溶液中痕量铅和镉.用硝酸镁和磷酸二氢铵的混合液作为基体改进剂测定铅和镉,铅和镉的检出限(3s/k)分别为0.138,0.007μg·L-1,相对标准偏差(n=7)分别为1.90%,2.08%.对于10 mL样品溶液的富集倍数分别为18.3,17.7.应用所提出的方法测定了杨树叶(GBW 07604)和小麦粉(GBW08503)国家标准样品,测定结果与标准值相符.铅和镉的加标回收率分别为97.8%,94.0%(水样);98.0%,94.0%(中药样).     

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。     

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。     

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.     

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。