Enhancing the organic dye adsorption on porous xerogels

We investigate the adsorption of four different organic dyes (i.e., methyl orange, alizarin red S, brilliant blue FCF, and phenol red) on porous xerogels. To understand the factors affecting the adsorption capacity of the xerogels, we vary the hydrophobicity and the textural properties of the xerogels as well as the solution pH. We control the hydrophobicity by mixing two different precursors (i.e., vinyltriethoxysilane (VTES) and tetraethoxysilane (TEOS)) and the textural properties by using cetyltrimethylammonium bromide (CTAB) as a templating agent. We find that the adsorption capacity is enhanced as the organic/inorganic hybrid xerogel or the templated xerogel is used instead of the purely inorganic or the untemplated xerogel. In all the cases studied, adsorption decreases as the pH is increased due to the electrostatic repulsion between the dyes and the xerogel surface. We find that both the hydrophobic surface and larger pore size/volume are required to enhance the adsorption capacity significantly.     

气相色谱法测定饮料酒中的低沸点有机酸

在非质子极性溶剂-二甲基乙酰胺中,室温下用碘乙烷与C_1—C_6脂肪酸及乳酸的四甲基铵盐反应制备各酸相应的乙酯。乙酯在15%的邻苯二甲酸二壬酯与6%的土温-80混合固定液填充柱上获得满意分离。用本法测定饮料酒中的低沸点有机酸含量,简便、快速、准确。     

检测易爆气体的催化发光传感器研究

报道了一种用于定量分析易爆气体混合物丙烷和异丁烷的基于碳酸锶纳米材料的催化发光传感器。基于该传感器在不同温度下对两种气体的灵敏度不同，在320℃和342℃两个工作温度下，两种气体的浓度范围均为1000mL／m^3～10000mL／m^3时，分别建立了混合组分浓度相对催化发光强度的两个线性回归方程。在342℃时，丙烷和异丁烷的检出限（3σ）分别为50mL／m^3和20mL/m^3。可通过解上述两个联立方程式求得未知混合物中两组分的浓度。外来物质甲烷、乙烷、CO、氨气通过传感器时，甲烷和乙烷分别引起5．6％和17．2％的干扰，其它气体不干扰测定。20000mL／m^3的水蒸气不干扰2000mL／m^3丙烷和异丁烷气体的测定。用该法分析了人工合成样品中两种气体的浓度。     

超声波作用下的糖精相转移催化N—苄基化反应的研究

超声波作用下的糖精相转移催化Ｎ－苄基化反应的研究嵇学林刘华黄昆（江苏镇江医学院有机化学教研室镇江２１２００１）关键词超声波相转换催化糖精苄基化有机声化学近年来，由于超声波（Ｕｌｔｒａｓｏｕｎ，缩写Ｕ．Ｓ）在有机合成中应用的不断发展，逐渐形成了一门新兴...     

Drying dissipative patterns of colloidal crystals of silica spheres in organic solvents

Drying dissipative structural patterns formed in the course of drying colloidal crystals of silica spheres (110 nm in diameter) in water, methyl alcohol, ethyl alcohol, 1-propyl alcohol, diethyl ether, and in the mixtures of ethyl alcohol with the other solvents above have been studied on a cover glass. The macroscopic broad rings were formed in the outside edges of the dried film for all the solvents examined. Furthermore, much distinct broad rings appeared in the inner area when the solvents were ethyl alcohol, methyl alcohol, and their mixtures. Profiles of the thickness of the dried films were sensitive to the organic solvents and explained well with changes in the surface tensions, boiling points, and viscosities of the solvents. The macroscopic and microscopic spoke-like crack patterns formed. The drying area (or the drying time) increased (or decreased) as the surface tension of the solvent decreased. However, the absolute values of these drying parameters are determined also by the boiling points of the solvents. Importance of the fundamental properties of the solvents is supported in addition to the characteristics of colloidal particles in the drying dissipative pattern formation.     

有机链状分子的定域分子轨道的研究

利用Foster-Boys定域化程序和STO-3G ab initio方法,对含有C、H、O、N原子的100多个有机链状分子进行了研究,得到定域分子轨道能量及其相互作用参数。应用这些参数和定域分子轨道模型,对于众多的含有C、H、O、N原子的有机链状分子,可得到相应的正则分子轨道能量及其与定域分子轨道的关系。以此预测它们的电离能,结果与实验值符合较好。     

Sample preparation for organic acids in biological fluids

A review of sample preparation methods for organic acids in biological fluids, in particular serum and urine, is presented. It covers techniques on organic acid determination without sample preparation, release of organic acids from binding locations, removal of proteins by protein precipitation and ultrafiltration, isolation of the organic acids by liquid-liquid and liquid-solid extraction, purification of the extract, derivatization and pre-fractionation. The various alternative sample preparation steps are compared and critically discussed. Examples of applications including profile analysis of organic acids by gas chromatography (GC), determination of particular organic acids by GC or liquid chromatography and determination of fatty acids as a distinct chemical class of acids demonstrate that the kind of sample preparation chosen depends strongly on the analytical aims.     

有机溶剂对镧和钇ICP光谱信号的增敏机理研究

本文考察了有机溶剂（乙酸丁酯）及有机试剂（PMBP）引入ICP－AES对稀土元素镧和钇光谱信号的影响。实验结果表明，有机溶剂的引入明显增大了待测物的传质效率，从而导致分析灵敏度的改善。与水相相比，有机相的引入对ICP激发温度未产生明显影响，但使线对强度比（LogI^ /I)增强，有利于待测物的电离。     

Syntheses of per-N labeled etioporphyrins I-IV and a related tetrahydrobenzoporphyrin for applications in organic geochemistry and vibrational spectroscopy

Nitrogen-15 labeled pyrroles have been prepared from commercially available ¹⁵N glycine or sodium nitrite using the Barton-Zard, Knorr, and Kleinspehn approaches. These pyrroles were used as intermediates in the synthesis of per-¹⁵N labeled porphyrins needed for the analysis and assignment of vibrational spectra for sedimentary porphyrins. Etioporphyrin-I was prepared via pyrromethene intermediates, while etioporphyrins II-V and a related tetrahydrobenzoporphyrin were synthesized via stepwise routes involving the copper(II) mediated cyclization of a,c-biladienes as the key step. Detailed analyses of both the proton and carbon-13 NMR spectra provide nitrogen-15 coupling constants for these important structures.     

反相毛细管电色谱中中性化合物的保留及有机改性剂对其保留值的影响

以硫脲作为电渗流标记物测定的死时间和以苯同系物线性回归方法测定的死时间为基础，将液相色谱中溶质保留值方程应用到电色谱中，得到了容量因子与二元流动相体系中有机改性剂含量之间的关系曲线；通过实验数据说明了一些极性的电中性化合物在电场作用下也会发生迁移而引起保留值的变化，且这种变化还受有机改性剂含量的影响。