Effectiveness of linearization of calibration curves in Zeeman graphite furnace atomic absorption spectrometry

A theoretical analysis is made of the effect of analytical line broadening and of non-absorbable radiation in the light source on the shape of concentration curves in Zeeman graphite furnace atomic absorption spectrometry. These results have been used in a systematic study of the effect of spectrometer slit width and hollow-cathode lamp (HCL) current on linearization of calibration graphs for 11 elements: Ag, Au, Bi, Cd, Co, Cu, Fe, Mn, Ni, Pb, and Sb. The effectiveness of linearization throughout the analytical range covered was estimated experimentally on series of 25–30 solutions. Three solutions in each series were used as standards for constructing the calibration graph, the others serving to evaluate the linearization effectiveness. Increasing the slit width and decreasing the HCL current compared to the standard measurement conditions have permitted us to reach a sufficiently high effectiveness of linearization for all the elements studied, with the exception of Ni. The maximum deviation of experimental points from the linear graph under optimum conditions does not exceed 6%. The effect of the Δ parameter used in the computational algorithm on linearization effectiveness is investigated.     

Synthesis and spectroscopic study of hexadecaalkyl-substituted rare-earth diphthalocyanines

New hexadecaalkyl-substituted diphthalocyanine complexes of lanthanides ^RPc₂Ln (R = Et, or Bu; Ln = Lu, Dy, or Eu) were synthesized by three methods: in solution in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene, in a melt of a mixture of the reagents, and under microwave irradiation. The first of the above-mentioned procedures has an advantage for the preparation of Dy and Eu diphthalocyanines, whereas the melt synthesis is a method of choice for the preparation of Lu complexes. The reaction time decreases in going from the first to the third method. The structures of the complexes were confirmed by mass spectrometry, NMR spectroscopy, and electronic absorption spectroscopy.     

Re_2(edt)_4的电子结构和电子吸收光谱的从头算研究

用密度泛函理论中的B3LYP/CEP-4G方法对Re2（edt）4进行了结构优化和自然键轨道计算,并用单电子激发组态相互作用方法（CIS）计算了Re2（edt）4的分子轨道和激发态。结果表明Re-Re之间不存在明显的三重键,进而很好地解释了Re2（edt）4分子的电子吸收光谱。     

乳化法—火焰原子吸收光谱法测定奶粉中的锌

用乳化剂ＯＰ将奶粉乳化成稳定的乳浊液，喷入空气－乙炔火焰中，以标准加入法测定锌，测定结果与灰化法一致，方法简便，准确。     

碳酸及碳酸酯热消除反应的量子化学研究

用AM1方法研究了碳酸和碳酸酯的热消除反应．发现迁移基团R和基团R’共同制约这类吸热反应的活化能。     

Dicopper(I) oxalate complexes as molecular precursors for the deposition of copper compounds

The synthesis, characterization, and thermal decomposition behavior of dicopper(I) oxalato complexes L₄Cu₂(C₂O₄) (L = CNtBu (2a), CNCMe₂CH₂tBu (2b), CNC₆H₃Me₂-2,6 (2c)) is reported. 2c can be prepared in a straightforward manner by the reaction of stoichiometric amounts of Cu₂O and oxalic acid with four equivalents of CNC₆H₃Me₂-2,6, while those complexes with aliphatic isocyanides are better prepared from a copper(I) oxalato complex with alkine capping ligands (Me₃SiCCSiMe₃)₂Cu₂(C₂O₄) (1) via ligand exchange. Crystallographic and spectroscopic evidence for 2a-c confirms the anticipated dinuclear structure with the oxalate in a μ-1,2,3,4 bridging mode and an essentially σ-character of the terminal isocyanides. In solid form the complexes are stable at room temperature and can be handled in air for some time. Their decomposition was studied by thermal gravimetric analysis coupled with mass spectrometry, and the degradation pathway was shown to depend on the type of isocyanide capping ligand. Decomposition of 2a,b takes place between 150 and 200 °C to give CuCN in a clean process that involves isobutene elimination from the terminal ligands, with elimination of (CN)₂ and conversion to elemental copper at higher temperatures. Heating of 2c leads to CuO (and then to Cu₂O) via release of the intact isocyanide, CO₂, and CO in a well-behaved thermal process around 200-280 °C.     

火焰原子吸收法测定鸡尾木中无机元素的含量

鸡尾木(ExcoecariaVenenataS.LeeetF.N.Wei)属大戟科,海漆属,为民间药用珍贵植物,用于治疗牛皮癣、慢性湿疹等,疗效颇佳[1]。鸡尾木中无机元素,尤其是医学微量元素的测定对其药理效的研究有重要的参考价值。1　实验部分1 1　仪器及试剂TAS 986原子吸收分光光度计(北京普析通用仪器有限责任公司);空心阴极灯:Fe、Cu、Ni、Cr、Cd、Zn、Co、Ba、Ca(北京瑞利普光电器厂);Mg、Pb(北京真空电子技术总公司);Mn(北京市朝阳天宫电器厂);AdventurerTM电子天平(奥豪斯国际贸易〈上海〉有限公司)。标准储备液:配制Zn2+、Mg2+、Fe3+、Mn2…     

Mechanical alloying of a thermoelectric alloy: Pb0.65Sn0.35Te

We report in this paper a study of the mechanical alloying (MA) process for the Pb_0.65Sn_0.35Te alloy. MA has been carried out in a high-energy planetary ball mill. The mechanism of formation has been studied from systematic analyses of mechanically alloyed powders using X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. As it was already observed for the MA of PbTe, this synthesis is associated with an exothermic reaction between the elemental powders. The required time to reach an homogeneous phase Pb_0..65Sn_0.35Te is 31 h.     

流动注射-氢化物发生-原子吸收光谱法测定雪中的微量铅

建立了测定雪中微量铅的流动注射-氢化物发生-原子吸收光谱法。在优化条件下。测定铅的线性范围为0～52．0ng／mL，线性回归方程为A=0．018c 0．016，相关系数r=0．9995，检出限为0．2ng／mL。用于雪中微量铅的测定，加标回收率为94．2％～107．3％，相对标准偏差为1．47％～3．22％。该方法的测定结果与标准加入法基本一致。     

若干1-(N-甲基-4-吡啶鎓基)-3-(N-甲基-4-吡啶亚基)-4-烷基环戊烯-1-酮-5菁化合物可见吸收光谱的溶剂效应

菁是一类很重要的离子型染料和感光材料,也有极少数可用作激光染料,绝大部价菁染料为直链分子。我们最近合成了一系列带有五员桥环的菁,并研究了这些桥环菁化合物的质子化平衡和荧光性质。