顶空气相色谱法测定盐酸托莫西汀中有机溶剂残留量的研究

建立了盐酸托莫西汀中有机溶剂残留量的顶空气相色谱分析方法.选用大口径HP-快速GC残留溶剂柱为分离柱,FID为检测器,外标法进行定量,并对顶空平衡温度、平衡时间、供试品溶液的制备方法对残留有机溶剂测定的影响进行了研究.甲醇、乙醚、正己烷、乙酸乙酯、四氢呋喃的线性范围分别为 0.41～8.10 μg/mL(r=0.9999)、0.15～3.00 μg/mL(r=0.9995)、0.20～4.01 μg/mL(r=0.9991)、0.32～6.35 μg/mL(r=0.9999)、0.36～7.11 μg/mL(r=0.9999);平均回收率范围96.30%～105.47%,精密度RSD(n=6)2.1%～3.7%;检出限分别为0.2、0.008、0.003、0.04、0.04 μg/mL.     

铁氧簇合物[Fe11O6(OH)6(O2CCH3)15](C5H5N)6的结构和磁性质

通过三核铁盐[Fe₃O(O₂CCH₃)₆(H₂O)₃]C1在吡啶溶液中水解聚合得到铁氧簇合物[Fe₁₁O₆(OH)₆(O₂CCH₃)₁₅](C₅H₅N)₆。晶体结构表明11个铁离子(Ⅲ)中6个位于扭曲的三棱柱的顶点上，其余5个分别位于三棱柱的每个面之外。铁离子(Ⅲ)之间以氧桥或者羟基氧桥相连。变温磁化率证实铁离子(Ⅲ)之间是反铁磁耦合的。     

The preparation of a cabbage reference material for environmental monitoring and food analysis

 Cabbage is frequently used in environmental monitoring and food control, and, hence, cabbage reference materials (RMs) are required for ensuring quality assurance. A cabbage RM was prepared in view of certification of specific elements from the "black list" of high toxicological interest and nutritive importance. All tasks of the RM production (production of the plant material, cutting and freeze-drying, determination of the residual water content, preparation of the RM, homogeneity testing, stability testing, certification measurements) are described in detail. Received: 12 November 1999 / Accepted: 29 January 2000     

磁性纳米固体酸SO42--TiO2-Fe3O4催化剂的合成、表征及催化性能的研究

首先研究制备了Fe3O4和SO42--TiO2固体酸催化剂,在此基础上采用共沉淀和浸渍的方法制备了磁性和超细SO42--TiO2-Fe3O4固体酸催化剂。利用XRD,TEM和FT-IR等分析测试手段对催化剂的结构和性能进行了表征。测定结果证实该催化剂具有较小的粒度,较高的磁性表现。在乙酸丁酯合成反应中SO42--TiO2-Fe3O4展示了很高的催化活性(酯化率可达82.7%),而且利用Fe3O4的磁性可对催化剂进行分离和回收.     

Structures and magnetic properties of tetranuclear nickel(II) complexes with unusual mu3-1,1,3 azido bridges

Pyrazolate-based dinucleating ligands with thioether-containing chelate arms have been used for the synthesis of a family of novel tetranuclear nickel(II) complexes [L2Ni4(N3)3(O2CR)](ClO4)2 that incorporate three azido bridges and one carboxylate (R = Me, Ph). Molecular structures have been elucidated by X-ray crystallography in four cases, revealing Ni4 cores with a unique topology in which two of the azido ligands adopt an unusual mu3-1,1,3 bridging mode. The compounds were further characterized by mass spectrometry, IR spectroscopy, and variable-temperature magnetic susceptibility measurements. Magnetic data analyses indicate a combination of significant intramolecular ferromagnetic and antiferromagnetic exchange interactions that give rise to an overall S(T) = 0 ground state. The sign and the magnitude of the individual couplings have been rationalized in the framework of the common magnetostructural correlations for end-to-end and end-on azido linkages, suggesting that these correlations also remain valid for the respective fragments of multiply bridging mu3-1,1,3 azido ligands.     

Magnetic and Electrical Properties, Eu Mössbauer Spectroscopy, and Chemical Bonding of REAgMg (RE=La, Ce, Eu, Yb) and EuAuMg

Single-phase samples of REAgMg (RE=La, Ce, Eu, Yb) and EuAuMg were prepared by reacting the elements in sealed tantalum tubes in a high-frequency furnace. LaAgMg and CeAgMg adopt the hexagonal ZrNiAl-type structure, while EuAgMg, YbAgMg, and EuAuMg crystallize with the orthorhombic TiNiSi type. Chemical bonding was exemplarily investigatedfor EuAgMg and EuAuMg on the basis of TB-LMTO-ASAcalculations. Magnetic susceptibility measurements indicatePauli paramagnetism for LaAgMg and YbAgMg with room-temperature susceptibilities of 2.4(1)×10⁻⁹ and 1.5(1)×10⁻⁹ m³/mol, respectively. CeAgMg remains paramagnetic down to 2 K. The experimental magnetic moment of 2.52(2) μ_B/Ce above 50 K is compatible with trivalent cerium. EuAgMg and EuAuMg are paramagnetic above 50 K with experimentalmagnetic moments of 7.99(5) μ_B/Eu for the silver and 7.80(5) μ_B/Eu for the gold compound, indicating divalent europium. Ferromagnetic ordering is detected at T_C=22.0(3) K (EuAgMg) and T_C=36.5(5) K (EuAuMg). At 4.2 K and 5 T the saturation magnetizations are 7.1(1) and 7.3(1) μ_B/Eu for EuAgMg and EuAuMg, respectively. According to the very small hysteresis, EuAgMg and EuAuMg may be classified as soft ferromagnets. All compounds are metallic conductors. For EuAgMg and EuAuMg freezing of spin-disorder scattering is observed below T_C. At 78 K ¹⁵¹Eu Mössbauer spectra show isomer shifts of −9.00(4) and −8.72(8) mm/s for EuAgMg and EuAuMg, respectively. Full magnetic hyperfine field splitting is detected at 4.2 K with hyperfine fields of 17.4(1) and 18.3(2) T at the europium nuclei of EuAgMg and EuAuMg.     

Structural, thermal and magnetic characterization of the manganese oxyhalide layered perovskite, (MnCl)LaNb2O7

Mn-Cl sheets were inserted into the perovskite blocks of a double-layered Dion-Jacobson compound by ion exchange at low temperature (390°C). The Rietveld structural analysis of X-ray powder diffraction data (P4/mmm) indicates that the product, (MnCl)LaNb₂O₇, has the manganese coordinated by two apical oxygens from the perovskite layers and four in-plane chlorines within the interlayer space. On heating, this compound exhibits an exothermic transition between 650°C and 750°C that is consistent with metastability. Magnetic characterization shows Curie-Weiss behavior at higher temperatures (>200 K) with a magnetic moment corresponding to the presence of high-spin Mn²⁺ ion (S=5/2). At lower temperatures, antiferromagnetic interactions become significant and the broad maximum at 63 K reveals the 2-D character of the magnetic behavior. The susceptibility data, fit with the high temperature expansion for a Heisenberg square planar system, show a negative exchange interaction of J/k=−3.77 K.     

电感耦合等离子发射光谱法测定渣油中铁、镍、钙、镁、钠、钒金属元素

用电感耦合等离子发射光谱法（ICP-AES）测定渣油中金属元素铁、镍、钙、镁、钠、钒，考察了不同的酸浓度对分析结果的影响和共存元素间的相互干扰，进行了加标回收率和精密度试验。     

不同类型聚合物溶液对采油残余油的作用机理研究

通过实验测定了HPAM溶液和黄原胶溶液的流变性、在多孔介质中的流变性和残余阻力系数 ,计算了衰竭层效应 .用不同的浓度和注入速度进行了驱油实验 .提出聚合物分子缠结作用的增强不仅引起表观粘度增加或衰竭层厚度降低 ,而且使平行于油水界面的拉动残余油的力增加 ,从而使残余油饱和度降低 ,采收率提高 .随浓度增加 ,HPAM溶液的表观粘度和残余阻力系数增加 ,衰竭层厚度减小 ;黄原胶溶液的浓度高于缠结浓度时 ,衰竭层厚度和表观粘度变化不大 .注入速度增加时 ,两种聚合物溶液的衰竭层厚度均降低 ,HPAM溶液的残余阻力系数不变 ,粘弹性增加 ;而黄原胶溶液的残余阻力系数下降 .不同浓度和注入速度情况下两种聚合物溶液的驱油结果证实了文中提出的聚合物分子缠结作用和衰竭层效应对残余油的作用机理 .分子结构的不同是造成两种聚合物溶液在多孔介质中渗流规律和对残余油作用机理的差别的根本原因 .     

一维链状配位聚合物{[Cu(μ-H_2L)(L)Cl](ClO_4)_3}_∞的合成、结构及磁性研究(L=N,N'-双(吡啶基-3-亚甲基)-1,5-二氮环辛烷)

设计合成了一个新型吡啶基二氮环配体L(N,N'-双(吡啶基-3-亚甲基)-1,5-二氮环辛烷)及其铜配位聚合物{[Cu(滋-H2L)(L)Cl](ClO4)3}∞(1),研究了此配合物的晶体结构、光谱及磁性质。该配合物属正交晶系,Pnma空间群,晶胞参数为a=3.5170(17)nm,b=1.0440(5)nm,c=1.1966(6)nm,V=4.394(4)nm3,Z=4。配体L以顺式螯合和反式桥联两种不同的配位形式将铜离子连接起来形成一维链状阳离子结构。