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951.
952.
流动注射在线共沉淀预富集火焰原子吸收法测定痕量铜 总被引:3,自引:0,他引:3
研究了以Ni^2+-DDTC为共沉淀载体,流动注射在线共沉淀预富集-火焰原子吸收光谱法测定痕量铜的体系,在0.3mol.L^-1的硝酸介质中,铜离子在编织反应器中与Ni^2+-DDTC(产生共沉淀,并被收集在编织器内壁上,用甲基异丁基酮(MIBK)在线洗脱沉积物并引入火争原子化器中测定。当富集时间为40s时,40μg.L^-1的铜10次测定的相对标准偏差为3.0%,灵敏度提高60倍,检出限(3σ) 相似文献
953.
Yimin Jin J. Bonilla Ye-Gang Lin J. Morgan Linda McCracken J. Carnahan 《Journal of Thermal Analysis and Calorimetry》1996,46(3-4):1047-1059
Two poly(butylene terephthalate)/polycarbonate (PBT/PC) blends with different formulations were analyzed by modulated DSC (MDSC) and conventional DSC to determine differences in crystallization behavior. A significant difference (30°C in cold crystallization temperature) between the two samples was detectable by MDSC while no significant difference was seen by conventional DSC. That indicatesthe total heat flow from MDSC is not always equivalent to the heat flow from conventional DSC as we have assumed or seen before. The reason has not been fully understood, but may be related to unusual nucleation and crystallization induced by modulation. Alternative conventional DSC methods were developed and compared to the MDSC results.Dedicated to Professor Bernhard Wunderlich on the occasion of his 65th birthdayThe authors like to thank Drs. Bernhard Wunderlich and Robert Gallucci for helpful discussion, David Shaker and Mary Parsonage for some DSC experiments. Technical support from TA Instruments is also greatly appreciated. 相似文献
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酰胺是肽的基本结构单元, 而且在蛋白质的二级结构中与酰胺联系的氢键对蛋白质的稳定起着十分重要的作用. 作为蛋白质模型化合物热力学性质研究的一部分, 报道了甲酰胺在乙二醇水溶液中的稀释焓. 相似文献
958.
A new series of bisthiosemicarbazone derivative receptors(1,2 and 3)have been synthesized by simple steps ingood yields.Their anion recognition properties were studied by UV-Vis and ~1H NMR spectroscopy.The resultshowed that the receptors 1,2 and 3 all had a better selectivity to F~-,CH_3COO~- and H_2PO_4~-,but no evidentbinding with Cl~-,Br~-,I~-,NO_3~- and HSO_4~-.Upon addition of the three anions to the receptors in DMSO,thesolution acquired a color change from colorless to dark yellow that can be observed by the naked-eyes,thus the re-ceptors can act as fluoride ion sensors even in the presence of other halide ions.The data showed that it was regularthat the three receptors had different binding ability with the three anions.For the same anion,the association con-stants followed the trend:receptor 1>3>2.The UV-Vis data indicates that a 1:1 stoichiometry complex isformed through hydrogen bonding interactions between compound 1,2 or 3 and anions. 相似文献
959.
纳米CoHCF修饰电极的制备及其对血红蛋白的电化学测定研究 总被引:1,自引:0,他引:1
A cobalt hexacyanoferrate (CoHCF) nanoparticle (size ca. 60 nm) chemically modified electrode (CME) was fabricated and the electrochemical behavior of hemoglobin (Hb) at this nanosized CoHCF CME was studied. In comparison with a bare glassy carbon electrode (GCE) and a general CoHCF CME electrodeposited in a traditional manner, the present nanosized CoHCF CME performed efficiently electrocatalytic reduction for Hb with relatively high sensitivity, stability, and longlife, Combined with liquid chromatography (LC), the nanosized CoHCF CME was used as the electrochemical detector of Hb in the established flow injection analysis-electrochemical determination (FIA-ECD) system. The peak current was a linear function of concentrations in the range from 2.5×10^-8 to 5.0×10^-6mol/L for Hb, with detection limit of 1.4×10^-8 mol/L. The FIA-ECD system has been successfully applied to assess the Hb content of clinic blood samples with advantages of sensitiveness, speediness, easy control and small sample-consumption. 相似文献
960.
本文描述了一个倾斜交叉、差分式激光热透镜光谱法。采用本方法可消除较高的溶剂空白的影响。文章讨论了调制频率和泵浦光功率对热透镜信号的影响,给出了检测Cu~(2+)的工作曲线,讨论了影响方法灵敏度的诸因素,提出了可能的改进方案。 相似文献