微波消解-微波等离子体炬原子发射光谱法测定膨化食品中铅和铝

膨化食品样品经微波消解处理,用微波等离子体炬原子发射光谱法(MPT-AES)测定其中铅和铝的含量。详细考察了分析谱线、微波功率、载气流量、工作气流量等实验参数对元素测定的影响,在最佳条件下测得铅和铝的检出限分别为4.7ng/mL和20.8ng/mL,其线性范围分别为0.01~20μg/mL和0.5~300μg/mL,样品加标回收率为96.4%~104.1%,精密度为1.06%~4.65%。结果表明,MPT-AES测定膨化食品中铅和铝的含量方法简便、高效、消耗试剂少、污染少、准确度高。     

石墨炉原子吸收光谱法测定新疆出口番茄酱中的铅和镉

报道了微波消解石墨炉原子吸收光谱法测定番茄酱中的铅、镉。研究了石墨炉原子吸收测定的最佳条件。该方法测定铅和镉的线性范围分别为0.00~25 ng/mL、0.00~8 ng/mL;相对标准偏差分别为2.15%、3.10%;回收率分别为98.6%、104.5%。利用国家标准物质番茄叶(ESP-1)验证了方法的准确度,测定值与标准值基本吻合。研究表明,该方法具有很好的准确度和精密度。     

微波消解石墨炉原子吸收法测定人发中的铅、镉

采用石墨炉原子吸收分光光度法(GFAAS)测定人发中的铅、镉含量.采用微波消解法消解样品,加入(NH4)2SO4+KH2PO4基体改进剂消除干扰,对消化剂种类、消解压力、仪器条件等进行了探索.方法简便、准确度高,Pb和Cd的平均回收率分别为101.8%和107.1%,相对标准偏差(RSD)为5.14%和6.80%,方法检出限Pb为9.53 ng/mL,Cd为0.78 ng/mL.     

原子荧光光谱法测定蛇粉中汞的方法研究

用微波消解仪消解、氢化物发生-原子荧光光谱法测定蛇粉中的微量Hg,优化了仪器的工作条件。测定汞的检出限为0.7pg/mL。测定0.3及1ng/L Hg标准溶液,相对标准偏差分别为4.1%及0.9%,加标回收率为87%~110%。     

微波消解-GFAAS法测定菠菜粉和蘑菇粉中微量镉的研究

应用微波消解-石墨炉原子吸收光谱法对菠菜粉和蘑菇粉中微量镉的含量进行测定。菠菜粉和蘑菇粉经HNO3+H2O2微波消解体系消解后,采用磷酸二氢铵作为基体改进剂,灰化温度为900℃,原子化温度为1 350℃,镉含量在0~2 ng/mL范围内与吸光度呈线性关系,线性相关系数为0.999 4,检出限为0.02 mg/kg。该法测定结果的相对标准偏差小于4%(n=6),加标回收率为96.7%~103.2%。     

微波消解–ICP–OES法测定陶土中铅和镉含量

建立微波消解–ICP–OES法测定陶土中铅和镉含量的方法。采用氢氟酸–硝酸作为消解液,微波消解法处理样品,消解液定容后直接进入耐氢氟酸的进样系统,用ICP–OES法测定陶土中重金属铅和镉的含量。结果表明,Pb和Cd检出限分别为0.027μg/m L和0.011μg/m L,回收率分别为90.5%~98.8%和95.0%~98.4%,测定结果相对标准偏差分别为1.38%和2.17%(n=7)。该方法具有快速、准确、灵敏度高等优点,适用于陶土中铅和镉含量的检测。     

螺旋藻中铅镉的ICP-MS测定

采用微波消解、高压罐消化以及HNO3 HClO4消化3种方法对螺旋藻样品进行处理,比较了不同方法产生的空白值和加标回收率。建立了微波消解-电感耦合等离子体质谱法测定螺旋藻样品中的铅镉的方法。铅镉检出限分别为0.06ng mL和0.05ng mL,RSD均小于3%,加标回收率在98%～101%之间。方法用于实际样品分析。     

微波消解样品-电感耦合等离子体原子发射光谱法测定铅精矿中铅、砷、镉、汞

采用微波消解样品-电感耦合等离子体原子发射光谱法同时测定铅精矿中主体元素铅及有毒有害元素砷、镉、汞的含量。0.20g试样置于消解罐中,先后加入硝酸9mL、盐酸3mL、氟硼酸2mL及过氧化氢2.5mL,密闭罐盖按设定的微波消解程序进行消解。试验选择铅、砷、镉和汞的分析线分别为220.351,189.042,228.802,184.950nm以消除基体干扰。铅、砷、镉、汞的检出限分别为16.0,2.2,0.4,0.8μg.g-1。方法用于铅精矿标准样品(GBW 07617)和铅精矿实际样品分析,此方法的测定值与认定值及原子吸收光谱法或原子荧光光谱法的测定值相一致。方法的相对标准偏差(n=10)在0.15%～3.9%之间。     

微波消解-ICP-AES测定食品塑料包装中钛、铅、铬和镉

采用微波消解技术,电感耦合等离子体原子发射光谱法(ICP-AES)同时测定食品塑料包装中钛、铅、铬和镉.研究了消解程序和消解试剂,建立了塑料样品的微波消解方法.测定了三种不同的食品包装用塑料,方法回收率为73.3%~101.7%,相对标准偏差为0.3%~10.7%,钛、铅、铬和镉在塑料中的检出限分别为1.50、7.38...     

电感耦合等离子体质谱法测定有机肥料中砷、镉、铅、铬、汞的含量

提出了用微波消解-电感耦合等离子体质谱法测定有机肥料中砷、镉、铅、铬、汞等5种元素的方法。有机肥料样品(0.200 0~0.500 0g)加入硝酸10mL和过氧化氢溶液1mL,按程序升温微波消解,将消解液蒸发至2mL,用硝酸(1+99)溶液定容至50mL。用电感耦合等离子体质谱法测定上述样液中的砷、镉、铅、铬、汞等元素。各元素的检出限(3.3s/k)为0.015~0.040mg·kg~(-1),测定值的相对标准偏差(n=6)均小于5.0%。按标准加入法进行回收试验,测得回收率在98.0%~101%之间。     

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.     

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。     

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.

     

Synthesis of phenolic components of Grains of Paradise

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.     

Summary of development of the theory of stability of colloids and thin films

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.     

Study of hydration of two cements of different strengths

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, M_o, 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 600-700^oC. 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.     

氯氧化镁生成热的研究

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^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

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.     

探究“铁的锈蚀条件”实验创新设计

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。