Time-Resolved Photoluminescence Spectra of Porous Si

Ｔｉｍｅ－ＲｅｓｏｌｖｅｄＰｈｏｔｏｌｕｍｉｎｅｓｃｅｎｃｅＳｐｅｃｔｒａｏｆＰｏｒｏｕｓＳｉＦＥＩＨａｏ－ｓｈｅｎｇ，ＨＡＮＬｉ，ＣＨＥＹａｎ－ｌｏｎｇ，ＮＩＥＲｕｉ－ｊｕａｎａｎｄＬＩＴｉｅ－ｊｉｎ（ＤｅｐａｒｒｍｅｎｔｏｆＰｈｙｓｉｃｓａｎｄＤ...     

The Difference of Electronic Properties and the Effect of Hydrogen－bondofcis－and trans－Polyazomethine

ＴｈｅＤｉｆｆｅｒｅｎｃｅｏｆＥｌｅｃｔｒｏｎｉｃＰｒｏｐｅｒｔｉｅｓａｎｄｔｈｅＥｆｆｅｃｔｏｆＨｙｄｒｏｇｅｎ－ｂｏｎｄｏｆｃｉｓ－ａｎｄｔｒａｎｓ－ＰｏｌｙａｚｏｍｅｔｈｉｎｅＷＡＮＧＲｏｎｇ－ｓｈｕｎ，ＰＡＮＸｉｕ－ｍｅｉａｎｄＳＵＺｈｏｎｇ...     

Synthesis and Diffuse Reflectance Spectrum of Open－framework Cobalt Phosphate DAF－2 From Alcoholic System

ＳｙｎｔｈｅｓｉｓａｎｄＤｉｆｆｕｓｅＲｅｆｌｅｃｔａｎｃｅＳｐｅｃｔｒｕｍｏｆＯｐｅｎ－ｆｒａｍｅｗｏｒｋＣｏｂａｌｔＰｈｏｓｐｈａｔｅＤＡＦ－２ＦｒｏｍＡｌｃｏｈｏｌｉｃＳｙｓｔｅｍＹＵＪｉ－ｈｏｎｇ;ＣＨＥＮＪｉｅ－ｓｈｅｎｇａｎｄＸＵＲｕ－ｒ...     

Direct Electron－transfer Reaction of Cytochrome C at a Bare Spectrographic Graphite Electrode

ＤｉｒｅｃｔＥｌｅｃｔｒｏｎ－ｔｒａｎｓｆｅｒＲｅａｃｔｉｏｎｏｆＣｙｔｏｃｈｒｏｍｅＣａｔａＢａｒｅＳｐｅｃｔｒｏｇｒａｐｈｉｃＧｒａｐｈｉｔｅＥｌｅｃｔｒｏｄｅＹＵＡｉ－ｍｉｎ，ＣＨＥＮＨｏｎｇ－ｙｕａｎａｎｄＨＡＮＪｉ－ｌｉｎ（Ｄｅｐａｒｔｍｅ...     

On Line Anion Exchange Preconcentration in Microwave Plasma Torch Atomic Emission Spectrometry

ＯｎＬｉｎｅＡｎｉｏｎＥｘｃｈａｎｇｅＰｒｅｃｏｎｃｅｎｔｒａｔｉｏｎｉｎＭｉｃｒｏｗａｖｅＰｌａｓｍａＴｏｒｃｈＡｔｏｍｉｃＥｍｉｓｓｉｏｎＳｐｅｃｔｒｏｍｅｔｒｙＬＩＡＮＧＦｅｎｇ;ＺＨＡＮＧＨａｎ－ｑｉａｎｄＪＩＮＱｉｎ－ｈａｎ（Ｄｅｐａｒｔｍ...     

Synthesis and Evaluation of Aromatic DTPA-bis(amide) Gadolinium Complexes as Magnetic Resonance Imaging Contrast Agents

ＳｙｎｔｈｅｓｉｓａｎｄＥｖａｌｕａｔｉｏｎｏｆＡｒｏｍａｔｉｃＤＴＰＡ┐ｂｉｓ（ａｍｉｄｅ）ＧａｄｏｌｉｎｉｕｍＣｏｍｐｌｅｘｅｓａｓＭａｇｎｅｔｉｃＲｅｓｏｎａｎｃｅＩｍａｇｉｎｇＣｏｎｔｒａｓｔＡｇｅｎｔｓＺＨＵＯＲｅｎ－Ｘｉ＊＊，ＷＥＮＪｉｅ...     

A Highly Stereoselective Synthesis of 2－Carbomethoxy－3－aryl－4－carboethoxy－5－methyl－cis－2，3－dihydrofurans

ＡＨｉｇｈｌｙＳｔｅｒｅｏｓｅｌｅｃｔｉｖｅＳｙｎｔｈｅｓｉｓｏｆ２－Ｃａｒｂｏｍｅｔｈｏｘｙ－３－ａｒｙｌ－４－ｃａｒｂｏｅｔｈｏｘｙ－５－ｍｅｔｈｙｌ－ｃｉｓ－２，３－ｄｉｈｙｄｒｏｆｕｒａｎｓＤＩＮＧＷｅｉ－ｙｕ；ＣＨＥＮＹａ－ｌｉ；ＺＨＡＮＧ...     

Determination of Elements of Groups Ⅲ A and Ⅳ A Using Microwave Plasma Torch Atomic Emission Spectrometry

ＤｅｔｅｒｍｉｎａｔｉｏｎｏｆＥｌｅｍｅｎｔｓｏｆＧｒｏｕｐｓⅢＡａｎｄⅣＡＵｓｉｎｇＭｉｃｒｏｗａｖｅＰｌａｓｍａＴｏｒｃｈＡｔｏｍｉｃＥｍｉｓｉｏｎＳｐｅｃｔｒｏｍｅｔｒｙＺＨＡＮＧＨａｎ－ｑｉ，ＹＵＡＮＸｉａｎｇ－ｌｉｎ，ＬＩＡＮＧＦｅｎｇ，Ｌ...     

Electrochemical Scanning Tunneling Microscopy──An Ex－situ Study of the Growth of Polypyrrole Films on Electrodes

ＥｌｅｃｔｒｏｃｈｅｍｉｃａｌＳｃａｎｎｉｎｇＴｕｎｎｅｌｉｎｇＭｉｃｒｏｓｃｏｐｙ──ＡｎＥｘ－ｓｉｔｕＳｔｕｄｙｏｆｔｈｅＧｒｏｗｔｈｏｆＰｏｌｙｐｙｒｒｏｌｅＦｉｌｍｓｏｎＥｌｅｃｔｒｏｄｅｓＬＩＪｉｎｇａｎｄＷＡＮＧＥｒ－ｋａｎｇ（Ｌａｂｏｒ...     

STUDY ON SYNTHESIS，CHARACTERIZATION AND CATALYSIS OF PILLARED ANION CLAY（Ⅲ）──SYNTHESIS OF ZnAl－BW_（11）O_（39）Z（H_2）~（n－）

ＳＴＵＤＹＯＮＳＹＮＴＨＥＳＩＳ，ＣＨＡＲＡＣＴＥＲＩＺＡＴＩＯＮＡＮＤＣＡＴＡＬＹＳＩＳＯＦＰＩＬＬＡＲＥＤＡＮＩＯＮＣＬＡＹ（Ⅲ）──ＳＹＮＴＨＥＳＩＳＯＦＺｎＡｌ－ＢＷ_（１１）Ｏ_（３９）Ｚ（Ｈ_２）~（ｎ－）ＴｈａｎｋｓｆｏｒｔｈｅｓｕｐｐｏｒｔｏｆＦｏｕｎｄａｔｉｏｎｏｆＣＥＣａｎｄｔｈｅｏｐｅｎｌａｂｏｆＨｙｄｒｏｔｈｅｒｍａｌＳｙｎｔｈｅｓｉｓｉｎＪｉｎｎＵｎｉｖｅｒｓｉｔｙｅｄｄｉｆｆｅｒｅｎｔｋｉｎｄｓｏｆｔｒｉｈｅｔｅｒｏｐｏｌｙｏｘｏｍｅｔａｌａｔｅ（ＴＨ＇ＰＯＭｓ）ｔｏｔｈｅＺｎＡＩｌａｙｅｒｅｄｃｌａｙｓ，ｕｓｉｎｇｔｈｅｅｓｔｅｒｉｆｉｃａｔｉｏｎｏｆｎ－ｂｕｔｙｌａｌｃｏｈｏｌａｎｄａｃｅｔｉｃａｃｉｄａｓｐｒｏｂｅｒｅａｃｔｉｏｎ．ａｎｄｆｏｕｎｄｔｈａｔｔｈｅｐｉｌｌａｒｅｄｃｏｍｐｏｕｎｄｓｗｅｒｅｍｏｒｅａｃｔｉｖｅａｎｄｓｅｌｅｃｔｉｖｅｔｈａｎｔｈｅｓｏｌｉｄａｃｉｄｃａｔａｌｙｓｔｓｓｕｃｈａｓａｃｉｄｉｃｉｏｎ－ｅｘｃｈａｎｇｅｒｅｓｉｎｓｌ４］．Ｏｎｔｈｅｂａｓｉｓｏｆｐｒｅｖｉｏｕｓｗｏｒｋ．ｗｅｎｏｗｅｎｃａｐｓｕｌａｔｅｔｒｉｈｅｔｅｒｏｐｏｌｙｏｘｏｍｅ     

Effect of Column Temperature on the Retention of Inorganic Anions and Organic Acids in Non-Suppressed Anion-Exchange IC

An investigation has been conducted into the effect of column temperature on the retention of inorganic anions and organic acids in non-suppressed ion chromatography on an anion-exchange column. Potassium biphthalate and p-hydroxybenzoic acid–tris–boric acid were used as mobile phases. The column temperature was from 25 to 50 °C. Endothermic and exothermic retention of inorganic anions were both observed when potassium biphthalate was used as mobile phase. When p-hydroxybenzoic acid–tris–boric acid was used as mobile phase, however, endothermic behavior only was observed. Moreover, for the two mobile phases, variation of the retention time of the system peaks with changing temperature was reversed. For retention of the organic acids, only endothermic behavior was observed with the two mobile phases. Variation of retention time was greater when p-hydroxybenzoic acid–tris–boric acid was used as mobile phase than when potassium biphthalate was used. These results indicated the exchange reaction in anion-exchange chromatography could be either endothermic or exothermic, depending on the solute and mobile phase ions involved. Different relative changes of retention time were observed for individual inorganic anions and organic acids with increasing column temperature. In general, variation of retention time with increasing temperature was greater for strongly retained inorganic anions and organic acids than for weakly retained species. Van’t Hoff plots for inorganic anions, organic acids, and system peaks were linear. Selectivity variation of the retention of inorganic anions and organic acids was achieved by changing the temperature. In achieving optimum separation of inorganic anions and organic acids, temperature was a valuable tool. To reduce the retention times of the ions and avoid interference from system peaks in non-suppressed anion-exchange ion chromatography with the two mobile phases, a low column temperature, for example, 35 °C, was best.     

吖啶作为检测试剂脂肪醇和脂肪酸的间接光度高效液相色谱研究

以吖啶作为新型检测试剂,研究C_4～C_(12)脂肪醇、C_6～C_(16)脂肪酸的间接光度高效液相色谱,探讨影响色谱保留和产生间接光度响应的因素,从分离检测机理解释两类化合物色谱行为和检测响应的差别,提出新的分离测定脂肪醇和脂肪酸的间接光度高效液相色谱系统。     

Interaction of amino acids, N-acetyl amino acid esters, thymine and adenine with sephadex LH-20 gel.

N-Acetyl aromatic amino acid esters, tryptophan, adenine and thymine show strong retention in Sephadex LH-20 gel in an aqueous phase. The decreased retention in 6 M urea, the absence of retention in absolute methanol and the increased retention at higher temperatures in the aqueous phase indicate that hydrophobic interaction is responsible for the observed retention of the amino acids and their esters in the gel. Adenine was found to be retained by polar interaction in the gel. The increased retention of the solutes in the presence of different electrolytes suggests that the lyotropic effect is more important than the ionic strength effect. The relevance of the results obtained with amino acids and esters to the conformational aspects of proteins in aqueous solution is discussed.     

Retention modelling of electrostatic and adsorption effects of aliphatic and aromatic carboxylic acids in ion-exclusion chromatography

The retention mechanism of aliphatic and aromatic carboxylic acids in ion-exclusion chromatography has been investigated with consideration of simultaneous electrostatic repulsion effects and hydrophobic adsorption effects. A mathematical relationship between the retention factor of the analyte and the mobile-phase composition (sulfuric acid concentration and percentage of methanol), the type of analyte (pK_a and hydrophobicity) and some physical characteristics of the stationary phase has been derived. Thirteen carboxylic acids (comprising mono- and divalent, aliphatic and aromatic acids) were chosen and used to acquire retention data on three different cation-exchange stationary phases (in which the sulfonate functional groups are bound to polystyrene–divinylbenzene, polymethacrylate or silica) using 14 mobile-phase compositions of varying pH and percent methanol. These retention data were used to derive the parameters necessary to solve the retention model using non-linear regression. In this way, a quantitative measure of the effects of adsorption phenomena on analyte retention were obtained. The model was then used to optimise the separation of nine carboxylic acids.     

Retention behavior of a homologous series and positional isomers of aliphatic amino acids in hydrophilic interaction chromatography

The retention behavior of several series of free α‐ and ω‐amino acids and positional isomers of amino pentanoic acid in the hydrophilic interaction chromatography mode (HILIC) was studied. The study was carried out on three stationary phases followed by post‐column derivatization with fluorescence detection in order to describe the retention mechanism of the tested amino acids. The effect of chromatographic conditions including acetonitrile content in the mobile phase, mobile phase pH (ranging from 3.5 to 6.5) and concentration of buffer in the mobile phase was investigated. The effect of the number of carbon atoms (n_C) in aliphatic chains of the individual homologue of α‐ and ω‐amino acids and the logarithm of the partition coefficient (logD) on retention was also a part of the presented study. A good correlation (r > 0.98) between the logk and logD values of amino acids or n_C, respectively, was observed. The described linear relationships were subsequently applied to predict the retention behavior of individual members of the homologous series of amino acids and to optimize the mobile phase composition in HILIC. The obtained results confirmed that the retention mechanism of α‐amino acids, ω‐amino acids and positional isomers of amino acids was based on the logD values and the number of carbon atoms in the aliphatic chains of amino acids. The elution order of ω‐amino acids and positional isomers of amino pentanoic acid was strongly dependent on the mobile phase pH in the investigated range whereas the retention factors of all α‐amino acids remained essentially unchanged on all tested stationary phases.     

阴离子交换-积分脉冲安培检测法分离测定氨基酸注射液中的氨基酸和葡萄糖

 用阴离子交换 积分脉冲安培检测法测定了氨基酸注射液中 1 7种氨基酸和葡萄糖。研究了氨基酸和葡萄糖在阴离子交换中的保留行为。采用了优化的水、NaOH和NaAc三元梯度淋洗条件。在优化的梯度淋洗条件和积分脉冲安培检测条件下 ,氨基酸和葡萄糖的检出限为 0 3pmol～ 1 0 3pmol,线性范围约为 2个数量级。样品加标回收率为 88 3 %～ 1 0 4 6 %。方法简单、灵敏、准确。     

氨基苯磺酸和氨基萘磺酸在反相离子对色谱和离子色谱中分离行为的比较

本文考察了氨基苯磺酸和氨基萘磺酸染料中间体在反相离子对色谱和离子色谱中的分离行为，结果表明一些异构体在反相色谱中的保留顺序与离子色谱中的顺序发生颠倒。静电作用力在离子色谱中对保留值的贡献比在反相离子对色谱中对保留值的贡献要大，而疏水作用力在反相离子对色谱中对保留值的贡献却较在离子色谱中对保留值的贡献要大。离子对色谱更有利于有机离子的分离分析。     

Analysis of hydrophilic metabolites by high-performance liquid chromatography-mass spectrometry using a silica hydride-based stationary phase

A novel silica hydride-based stationary phase was used to evaluate the retention behavior in the aqueous normal-phase (ANP) mode of standards representing three classes of metabolites. The effects on retention behavior of amino acids, carbohydrates and small organic acids were examined by altering the column temperature, and by adding different additives to both the mobile phase and sample solvent. Gradient mode results revealed the repeatability of retention times to be very stable for these compound classes. At both 15 and 30 degrees C, excellent RSD values were obtained with less than 1% variation for over 50 injections of an amino acid mixture. The ability to separate the 19 nonderivatized amino acid standards, organic acids and carbohydrates was demonstrated as well as the potential for this material to separate polar metabolites in complex fluids such as urine.     

The effects of temperature and mobile phase on the retention of aliphatic carboxylic acids in hydrophilic interaction chromatography on zwitterionic stationary phases

The influence of the mobile phase and temperature, on the retention behavior of seven aliphatic acids (pyruvic, gluconic, 2‐oxoglutaric, tartaric, malic, oxalic, and citric acid) in hydrophilic interaction liquid chromatography on zwitterionic stationary phases with sulfobetaine and phosphorylcholine ligands is investigated. In agreement with the van't Hoff model, most acids show linear ln k versus 1/T plots. However, the retention of structurally symmetrical oxalic and tartaric dicarboxylic acids is almost independent of temperature, or slightly increases at rising temperature. The experimental parameters of the van't Hoff plots suggest positive entropic contributions to the retention of these symmetrical acids, possibly connected with changes in molecular symmetry on their adsorption. The type of the zwitterionic stationary phase and the mobile phase composition (the molar concentration of acetate buffer and the volume fraction of acetonitrile) affect the retention and the selectivity of the separation of the acids.     

Effect of the concentration of organic modifier in an aqueous-ethanol mobile phase on the chromatographic retention and thermodynamic characteristics of the adsorption of enantiomers of α-phenylcarboxylic acids on silica gel with immobilized eremomycin antibiotic

Regularities of the chromatographic retention and thermodynamics of the adsorption of enantiomers of α-phenylcarboxylic acids on a chiral stationary phase with immobilized macrocyclic antibiotic eremomycin under conditions of reversed-phase liquid chromatography with aqueous-ethanol mobile phases are studied. Relationships between the retention characteristics of the acids, the enantioselectivity of their separation, and the concentration of organic modifier in the mobile phase are found. It is shown that the sterical structure of substituents on the chiral atoms of the acids affect the mechanism of retention. The compensation effect in the studied systems is considered.