石墨炉原子吸收光谱法测定冶金材料中痕量钛

本文研究了不同石墨管测钛的特点,用热解石墨管测定钛灵敏度较高,并可消除某些共存元素的干扰。探讨了在高温石墨炉中钛的原子化机理,提出了TiO_2被碳还原的可能性。方法适用于测定冶金材料中痕量钛,测定钛的特征含量可达3.76×10~(-10)克/1%吸收,相对标准偏差为3.8%。该法准确、简便、快速。     

色谱－质谱－红外光谱联用系统研究原煤浸取液及燃煤烟气中环烃类有机污染物

采用美国惠普公司色谱－质谱－红外三联仪，研究了我国典型煤种──青山烟煤中二氯甲烷（ＣＨ２Ｃｌ２）的４１ｈ浸取液和８００℃燃烧排放烟气中脂环烃、苯系物、多环芳烃（ＰＡＨｓ）等环烃类有机污染物的种类、组成及含量。并用ＰＡＨｓ标样对原煤浸取液和烟气中ＰＡＨｓ排放进行了定量评价。通过两种排放源中各有机污染物的组成和含量比较，获得了原煤及燃后烟气中环烃类有机污染物排放的一般规律。     

痕量砷的形态分析进展

痕量砷的形态分析进展范华均，张薇（四川轻化工学院化学工程系自贡，６４３０３３）施文赵（华中理工大学化学系武汉，４３００７４）关键词：砷，形态分析不同化合形态的砷化合物其性质往往不同．毒性差异很大，而且随着各种经常发生的化学的和生物化学的氧化还原反应而...     

用重质蜡膏制医药凡士林工艺条件的研究

生产凡士林主要有三种方法:硫酸磺化法、三氯化铝法和加氢法。我们对三氯化铝法作了一点改进,把机油和蜡膏合在一起,用三氯化铝处理,省去硫酸对机油的处理。主要原料、仪器及工艺路线 1 主要原料和仪器减压四线蜡膏(茂名石油公司提供);无水三氯化铝(广州化工厂);机油40号;烧碱(天津化学试剂三厂);活性白土(抚顺产);增粘剂;滴点测定仪;紫外分光光度计;离心机;恒     

Cyanex923对稀土元素硝酸盐的萃取

研究了Ｃｙａｎｅｘ９２３在正庚烷溶液中对１５种稀土元素硝酸盐的萃取，计算了分离系数，得出了反应机理，考察了温度对萃取平衡的影响以及萃合物的红外光谱，发现ｙａｗｎｅｘ９２３遥可能应用于从在土中分离镧以及从重稀土中分离钇。     

Ion Channel Behavior of a Supported Bilayer Lipid Membrane Composed of 5,5－Ditetradecyl－2－ （2－trimethyl－ammonioethyl）－l, 3－dioxane Bromide Modified Glassy Carbon Electrode

A synthetic cationic surfactant, 5,5-ditetradecyl-2-(2-trimethyl-ammonioethyl)-l,3-dioxane bromide (DTDB), was used to construct a supported bilayer lipid membrane (s-BLM) coatedon an underlying glassy carbon electrode (GCE). Electrochemical impedance spectroscopy (EIS), small-angle X-ray diffraction (SAXD) and cyclic voltammetry were used to characterize the s-BLM. Both EIS and SAXD data indicated that the synthetic lipid exists as a well-oriented bilayer in the membrane.The voltammetric study showed that the lipid membrane can open ion channels in the presence of ClO4^- stimulant with Ru(bpy)3^2 as marker ions and give distinct channel currents.The channels can be dosed and open up again many times by removing or introducing ClO4^- anions.     

Direct Electrochemistry of Horseradish Peroxidase Embedded in Nano－Fe304 Matrix on Paraffin Impregnated Graphite Electrode and Its Electrochemical Catalysis for H2O2

Fe3O4 particles coated with acrylic copolymer (ACP) of about 5--8 nm in diameter were synthesized and used for immobilization of horseradish peroxidase (HRP). Direct electrochemistry of HRP embedded in the nanosized Fe304 solid matrix modified paraffin impregnated graphite electrode (PIGE) was achieved,which is related to the heine Fe(Ⅲ)/Fe(Ⅱ) conversion of HRP. Cyclic voltammetry gave a pair of reproducible and welldefined redox peaks at about Ea of -0.295 V vs. SCE. The standard rate constant k, was determined as 2.7 s^-1. It demonstrated that the nano-Fe3O4 solid matrix offers a friendly platform to assemble the HRP protein molecules and enhance the electron transfer rate between the HRP and the electrode. UV-Vis absorption spectra and WrIR spectra studies revealed that the embedded HRP retained its native-like structure. The HRP/Fe3O4/PIGE showed a strong catalytic activity toward H2O2. The voltammetric response was a linear function of H2O2 concentration in the range of 10-140μmol/L with detection limit of 7.3 μmol/L (s/n = 3 ). The apparent Michaelis-Menten constant is calculated to be 0.42 mmol/L.     

二价铜离子在CuNaX分子筛中的迁移

在石油化工催化反应中,作为催化剂的低交换度的CuNaX分子筛,在反应过程中经常发生掉铜现象。我们应用多晶X-射线衍射方法,测定了三个具有不同吸附水量的CuNaX分子筛的结构,并用Rietveld方法进行了修正。从结构测定结果发现,随着吸附水量的增大,Cu~(2 )离子发生迁移,在饱和吸水状态下,Cu~(2 )离子迁移入超笼。随着吸附水的减少,Cu~(2 )离子又可逆地返回S(Ⅱ)位置。催化剂理想的活性中心应为定位于S(Ⅱ)位置上的Cu~(2 )离子。掉铜的机理是由于迁移至超笼的Cu~(2 )离子失去了骨架氧原子的制约,与反应物生成中间产物而流失。因此在反应前对分子筛进行焙烧予处理,以及对反应物进行脱水,均可阻止铜的流失,延长催化剂寿命。