MnOx在ZrO2上分散状态及对CO氧化的影响

近年，氧化铝载体以其独特性能引起多方面的关注［1］．当将Pt、Rh金属担载在ZrO2上时，在金属和氧化物之间存在着强的相互作用［2，3］，从而提高了CO氧化和NO的还原性能．目前，许多作者曾对ZrO2。负载氧化铜催化剂进行了较系统的研究[4，5]：氧化锰对许多重要的催化反应有广     

Direct determination of manganese in vitamin-mineral tablets using solid sampling electrothermal atomic absorption spectrometry

Manganese in vitamin-minerals tablets was determined by solid sampling electrothermal atomic absorption spectrometry (SS-ETAAS) using three different calibration methods, namely calibration against aqueous standards, standard addition with aqueous standards on solid samples and calibration against solid certified standards. Samples were only finely ground and introduced directly into the furnace by means of solid autosampler system without any dissolving process. Effects of different calibration techniques, temperatures and heating rates of atomization and pyrolysis steps on the accuracy and precision of the analyte elements were investigated. After optimization of the experimental parameters, there is good agreement (at 95% confidence level) between the results obtained by solid sampling and those obtained by acid digestion of samples.     

一种基于形成杂多核络合物的荧光增敏效应的研究 Ⅲ.锰(Ⅱ)、钴(Ⅱ)的混合荧光增敏及其连续测定

本文研究了Mn~(2+)和Co~(2+)对7-(8-羟基-3,6-二磺基萘偶氮)-8-羟基喹啉-5-磺酸-硼砂反应体系的混合荧光增敏作用。实验条件下,荧光增敏强度满足线性加和关系的范围是:Mn~(2+)浓度0～2.9×10~(-7)mol/L;Co~(2+)浓度0～8.8×10~(-7)mol/L;总浓度不超过1.0×10~(-6)mol/L。检出限量为Mn~(2+)4.5×10~(-9)mol/L和Co~(2+)1.4×10~(-8)mol/L。实现了Mn~(2+)和Co~(2+)的连续测定。     

化学发光分析法测定动物蛋白粉等样品中的锰

基于Mn(Ⅱ) 邻菲罗啉对鲁米诺 KIO4化学发光体系的催化作用建立了测定Mn(Ⅱ)的分析方法。Mn(Ⅱ)质量浓度在2.0×10-6～5.0×10-5mg/mL范围与发光强度呈线性响应,回归方程为ICL=0.6+1.39×106ρ(mg/mL),检出限为2.0×10-6mg/mL。Cr3+、Fe2+、Co2+、Au3+等离子有干扰,使用EDTA、F-、8 羟基喹啉等为掩蔽剂可消除或降低干扰。将该法应用于生物化工产品丙酸钙、动物蛋白粉等中痕量锰的测定,加标回收率98%～102%,10次测定RSD为4 6%。将测定的结果与原子吸收法比较,相对偏差≤±3%。     

Enantioselective catalytic epoxidation of nonfunctionalized prochiral olefins by dissymmetric chiral Schiff base complexes of Mn(III) and Ru(III) metal ions II

A series of new dissymmetric chiral Schiff base complexes has been obtained by a systematic condensation of (1S,2S)(+)-diaminocyclohexane and 3-acetyl-4-hydroxy-6-methyl-2-pyrone with salicylaldehyde, 5-chloro-, 5-methoxy-and 5-nitrosalicylaldehyde and by subsequent metallation with manganese and ruthenium. The characterization of the complexes 1–8 was accomplished by physico chemical studies viz. microanalysis, IR-, UV/VIS-, and CD spectral studies, optical rotation, molar conductance measurements and cyclic voltammetry. Enantioselective epoxidation of non functionalised olefins, viz. cis-stilbene, trans-3-nonene and trans-4-octene with iodosyl benzene as oxidant was demonstrated in the presence of catalytic amounts of chiral Mn(III) and Ru(III) dissymmetric Schiff base complexes. Good optical yields of epoxides were obtained for the catalyst 4 with the substrates trans-3-nonene and cis-stilbene.     

测定痕量锰的锰(Ⅱ)-锌试剂-重铬酸钾体系催化分光光度法

在Na2B4O7-NaOH缓冲介质及加热条件下 ,锰 (Ⅱ )对重铬酸钾氧化锌试剂引起褪色 ,有明显的催化作用 ,据此建立了测定痕量锰的新方法 ;该法的线性范围为0.69～40μg/L,检出限为0.22μg/L ,反应表观活化能为87.1kJ/mol,反应表观速率常量1.10×10-3/s,用该法测定蒙药样品中锰含量 ,结果令人满意     

双波长K系数—标准加入吸光光度法同时测定锰和锌

研究应用双波长K系数—标准加入吸光光度法同时测定锰和锌二组分混合物.试验确定了锰和锌测定中K_(Mn)与K_(Zn)的回归方程.对合成试样、人发试样测定,结果满意.     

Monitoring of sources of clinical exposure to nickel

Due to the widespread uses of Ni and Ni alloys, patients undergoing medical treatments can experience inadvertent exposure to the metal, present as a contaminant in fluids for intravenous administration or released from surgical implants and other medical devices. Because of the risk of acute allergic reactions in Ni-sensitive subjects, sources of metal exposure within medical care and its concentrations in biological fluids of potentially exposed patients should be periodically monitored, using reliable analytical procedures, which include strict measures of contamination control. The results of a recent survey on the concentrations of Ni and other potentially toxic metals in human albumin solutions are reported.     

Effect of heat treatment on the physico-chemical properties and catalytic activity of manganese nodules leached residue towards decomposition of hydrogen peroxide

The effect of calcination temperature on the physico-chemical characterization of manganese nodule leached residue (MNLR) and water-washed manganese nodule leached residue (WMNLR) has been investigated on the basis of chemical analysis, XRD, TG-DTA, FTIR, surface hydroxyl groups, surface oxygen, reducing and oxidizing sites, surface area. XRD and IR confirm the presence of amorphous iron oxyhydroxides, delta-MnO2, which are converted to alpha-Fe2O3 and gamma-Mn2O3 phases above 400 degrees C of calcination, respectively. A solid solution of Fe2O3 and Mn2O3 is formed above 700 degrees C. The surface area, surface hydroxyl group, surface oxygen, reducing and oxidizing sites increase with the increase in calcination temperature up to 400 degrees C and then decrease with further rise in calcination temperature up to 700 degrees C. The catalytic activity of the sample towards H2O2 decomposition shows the similar trend as surface properties. A suitable Mn(3+)Mn4+ couple favours H2O2 decomposition reaction. The activity has been correlated with various physico-chemical properties.     

PAN共沉淀富集原子吸收测定饮水和人发中的微量锰

使用PAN-Ni(Ⅱ)共沉淀体系分离富集、微量流向进样火焰原子吸收光谱测定饮水和人发中的微量锰。样品中的共存元素不干扰测定，锰的标准加入回收率90%-108%之间。12次重复测定锰含量为0.15μg/mL的试样溶液的变异系数为4.6%,本法简便快捷,取得了较满意的结果.