原子荧光光谱法测定镉锭中锡的含量

采用氢化物发生-原子荧光光谱法测定镉锭中锡含量,研究了基体镉对锡的干扰及消除方法,优化了氢化物的发生条件,建立了镉锭中锡含量的快速分析方法。实验证明,原子荧光光谱法对锡的检出限为0.08mg/kg,回收率为99.0%～104.0%,方法准确、可靠,用于日常样品分析,取得了很好的效果。     

石墨炉原子吸收光谱法测定钢中痕量锡

锡通常是作为有害杂质存在于钢中,一部分锡形成固溶体存在于碳化铁中。锡可以增加钢的抗拉强度却降低了钢的冲击值和冲击性能,不利于钢的加工。一般应严格控制其含量。因此,准确测定钢铁中痕量锡的含量很重要。目前,测定锡的方法有苯基荧光酮十六烷基三甲基溴化铵(CTMAB)直接光度法、原子荧光光谱法和石墨炉原子吸收光     

地质样品中总锡测定方法的研究进展

综述了地质样品中总锡分析方法(包括容量法、分光光度法、氢化物发生-原子荧光光谱法、原子吸收光谱法、极谱法、原子发射光谱法、电感耦合等离子体原子发射光谱法、电感耦合等离子体质谱法、X射线荧光光谱法)的研究进展。     

Determination of Tin in Canned Food by Microwave Digestion and HG - AFS

为建立微波消解-氢化物原子荧光光谱法测定罐头食品中锡含量的方法.样品在HNO3+HCl或HNO3+ HCl+H2O2体系中经微波消解处理后,以硫脲-抗坏血酸混合液作预还原剂,用氢化物原子荧光光谱法测定罐头食品中锡.结果表明,在优化的条件下,锡质量浓度在0～ 100μg/L范围内线性关系良好,相关系数为0.9998,方法最低检出限为0.067 mg/kg,加标回收率在99.7％～108.3％之间,方法变异系数为2.67％(n=6).该法具有准确度高、精密度好、灵敏快速且安全环保等优点,适用于罐头食品中锡的测定.     

微波消解一氢化物原子荧光光谱法测定罐头食品中锡

为建立微波消解-氢化物原子荧光光谱法测定罐头食品中锡含量的方法。样品在HNO3＋HC1或HN03＋HCl＋H2O2体系中经微波消解处理后,以硫脲-抗坏血酸混合液作预还原剂,用氢化物原子荧光光谱法测定罐头食品中锡。结果表明,在优化的条件下,锡质量浓度在0～100μg／L范围内线性关系良好,相关系数为0．9998,方法最低检出限为0．067mg／kg,加标回收率在99．7％～108．3％之间,方法变异系数为2．67％（n=6）。该法具有准确度高、精密度好、灵敏快速且安全环保等优点,适用于罐头食品中锡的测定。     

原子荧光光谱法测定锡精矿中汞

建立了原子荧光光谱法测定锡精矿中汞的分析方法。试样经王水（1＋1）溶解,以盐酸（5%）为载流,氯化亚锡（200g/L）溶液为还原剂,用原子荧光光谱法测定样品中的汞。考察了测定的最佳条件、锡及共存元素对测定的影响。方法相对标准偏差为5.9%-6.3%,与冷原子吸收光谱法对比结果令人满意。方法的准确度和精密度均能满足分析需要,具有较强的实用性。     

粉末压片-X射线荧光光谱法测定矿石中钨、锡

将样品与微晶纤维素混匀后置于模具中,以32 MPa压力制成外径40 mm、内径32 mm的样片。用X射线荧光光谱法测定矿石中钨和锡的含量。钨、锡的检出限为4.9,3.8 mg·kg^-1。方法用于矿石样品分析,钨和锡的测定值相对标准偏差（n=6）分别为1.7%,0.37%。测定值与国家标准方法测定值相一致。     

微波消解氢化物发生-原子荧光光谱法测定罐头食品中汞和锡

建立了一种微波消解、氢化物发生-原子荧光光谱法同时测定罐头食品中汞和锡的方法。研究了测定汞、锡时介质的酸度和硼氢化钾的用量对汞、锡测定的影响。优化了样品消解和测定的条件,采用硫脲-抗坏血酸为掩蔽剂,以酒石酸为载流,消除了影响锡测定的干扰因素。汞和锡的检出限、相对标准偏差、回收率分别为:0.005μg.L-1和0.20μg.L-1;5.0%~6.5%和4.0%~7.3%;93.0%~101.0%和92.5%~94.0%。     

氢化物发生-原子荧光光谱法测定化探样品中痕量锡

锡在钨钼矿石中是最常见的伴生有益元素。目前测定该矿石中锡的方法主要有碘量法、分光光度法和极谱法等。碘量法和分光光度法存在锡的干扰元素较多,终点难辨的缺点;极谱法灵敏度较高,但操作条件要求严格,各实验室现行操作手续差异较大,且对操作人员且环境危害较大,应减少使用。近十年来,氢化物发生与原子荧光光谱法联用     

标准加入-原子荧光光谱法测定罐头中的痕量锡

用微波消解处理样品,采用标准加入-原子荧光光谱法测定罐头中的锡.通过实验探讨了样品预处理条件、仪器条件、微波消解程序、还原剂浓度等对锡测定的影响.锡浓度(X)在1～100 μg/L范围内与荧光强度(Y)呈线性关系,线性方程为Y=50.15X+12.13,相关系数r=0.9995.用该法对水果和蔬菜罐头样品进行了测定,并...     

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.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。