长链烷基(2-羟乙基)二甲基氯化铵用作分析增敏试剂

合成了3种含季氮原子及羟基的同系列分析增敏试剂十六烷基(2-羟乙基)二甲基氯化铵(HEMAC)、十四烷基(2-羟乙基)二甲基氯化铵(TEMAC)和十二烷基(2-羟乙基)二甲基氯化铵(DEMAC),测试其基本物性,并用作测定微量钪、铁(Ⅲ)、锗的增敏试剂,获得了与阳离子表面活性剂及醇类有机溶剂联用时相仿的增敏效果。     

反胶束萃取醇脱氢酶的研究

本文报道了用反胶束体系萃取醇脱氢酶(ADH)的研究结果。在此萃取体系中,以十六烷基三甲基溴化铵(CTAB)作为表面活性剂,辛烷和己醇作为溶剂及助溶剂。考察了振荡时间、水相pH值和离子强度、表面活性剂及助溶剂浓度等因素对醇脱氢酶萃取率的影响,确定了最佳萃取条件。     

TLC－FTIR联用方法的应用

本文利用TLC-FTIR联用技术在Analect公司出品的RFX-65型PTIR仪上，检测了未知混合物样品A的四种组份，未知样品B的两个组份，以及对3微克和5微克标样的均三硝基苯(1，3，5-TRINITROBENZENE)进行测定，均得到了可以认可的红外光谱图。本方法操作较简便且灵敏，但功能的应用范围有待开发。     

A General Protocol for Robust Sonogashira Reactions in Micellar Medium

A robust and general protocol for a sustainable copper‐free Sonogashira cross coupling under micellar aqueous reaction conditions with high turnover was developed. By using the commercially available catalyst CataCXium A Pd G3 and THF as co‐solvent, various alkyne substrates were efficiently cross‐coupled with a broad range of aryl halides, providing improved yields and low catalyst loadings. The reaction parameters were optimized to render the process operationally simple, robust and scalable. The method gives access to alkynylated arenes, heterocyclic compounds, and monofunctionalized products from dihalogenated substrates with an improved selectivity achieved by the micellar aqueous reaction conditions.     

Behavior of Humic Acid as a Micellar Phase in Micellar Electrokinetic Chromatography (MEKC)

The possibility of humic acids acting as micellar phase in micellar electrokinetic chromatography was evaluated. We investigated the separation of naphthalene in capillary electrophoresis using various samples of humic acids as micellar phase under different pH conditions, concentrations of humic acid, and temperature. The humic acid samples studied were from different origins including peat, vermicompost and a commercial sample acquired from Aldrich. Methanol was used as a marker for the electroosmotic flow. The results indicate that the formation of micelle depends on the number and nature of the hydrophobic association sites in an aqueous humic acid solution and on the origin and concentration of the humic acid at a defined pH. At lower pH values, the possibility of the humic acid molecule forming pseudomicelles increases due to a combination of neutralized and dissociated charged sites.     

胶束微多相中生物催化反应的研究及其分析应用

本文对研究胶束微多相中的生物催化反应进行了讨论,并对过氧化物酶及其模拟酶在微多相中的分析应用作了评述。     

Selectivity Control in Micellar Electrokinetic Chromatography by Modification of Micellar Surface with Cyclohexanol

Abstract

The effect of cyclohexanol added to the micellar solution of sodium dodecyl sulfate in the micellar electrokinetic chromatography of several aromatic compounds was investigated. Cyclohexanol (0.05–-0.10 M) diminished the capacity factors (k') of the solutes possessing hydrophilic functional groups which were solubilized near the micellar surface, whereas little changed the k' of the hydrophobic solutes solubilized in the micellar core. This selective effect was ascribed to the saturation of the micellar surface with cyclohexanol.     

Application of Catalyzed Reactions in Analytical Chemistry

Catalyzed reactions are becoming increasingly improtant in analytical chemistry, and especially in trace analysis. The acceleration of a particular reaction (indicator reaction) promoted by the catalyst provides information about the catalyst concentration. Substances which lower or raise the activity of a catalyst (inhibitors or activators, respectively) can likewise be determined in this way. The course of a reaction is usually monitored by physical measuring techniques. Various methods of conducting these kinetic-catalytic studies are discussed in this article.—Use of catalyzed reactions for end point detection in volumetric analysis is also feasible.     

Orthogonal Enzymatic Reactions to Control Supramolecular Hydrogelations

Enzyme‐responsive hydrogels have great potential in applications of controlled drug release, tissue engineering, etc. In this study, we reported on a supramolecular hydrogel that showed responses to two enzymes, phosphatase which was used to form the hydrogels and esterase which could trigger gel‐sol phase transitions. The gelation process and visco‐elasticity property of the resulting gel, morphology of the nanostructures in hydrogel, and peptide conformation in the self‐assembled nanostructure were characterized by rheology, transmission electron microscope (TEM), and circular dichroism (CD), respectively. Potential application of the enzyme‐responsive hydrogel in drug release was also demonstrated in this study. Though only one potential application of drug release was proved in this study, the responsive hydrogel system in this study might have potentials for the applications in fields of cell culture, controlled‐drug release, etc.     

分析化学计量学中的新方法─—小波分析

小波分析在分析信号处理中具有诸多显著的优点。本文介绍了小波分析的一般描述，综述了化学计量学在的小波新方法，并展望了小波分析在分析化学计量学中的应用前景。     

Micellar Extraction of Polycyclic Aromatic Hydrocarbons from Certified Marine Sediment

Abstract

In the present study the extraction of polycyclic aromatic hydrocarbons from a certified marine sediment (SRM 1941a) with a micellar medium of polyoxyethylene 10 lauryl ether by micro-wave- and ultrasound-assisted method has been evaluated. The analysis of extracts has been carried out by HPLC with fluorimetric detection and wavelength programming. Hydrocarbons with more than three rings gave average recoveries of 77.4% and 86.5%, by microwave- and ultrasound-assisted methods respectively, with a mean relative standard deviation better than 6.2%.     

Headspace Single Drop Microextraction Using Micellar Ionic Liquid Extraction Solvents

A headspace single drop microextraction (SDME) method using extraction solvents comprised of micellar ionic liquids (ILs) was used to perform the extraction of 17 aromatic compounds from aqueous solution and coupled with liquid chromatography. The effects of various experimental parameters including type of micellar IL extraction solvent, stir rate, extraction time, volume of the microdroplet, and addition of organic solvent were investigated and optimized. Two different micellar solutions were formed by dissolving 1-decyl-3-methylimidazolium bromide ([DMIM][Br]) and sodium dodecyl sulfate (SDS) in 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]). It was observed that the enrichment factors of the 17 studied compounds were all enhanced with the micellar ionic liquid extraction solvent compared to the neat [BMIM][Cl] IL. The highest sensitivity was obtained with the [BMIM][Cl]–[DMIM][Br] micellar solution for polycyclic aromatic hydrocarbons (PAHs) with high molecular weight and fused rings while the [BMIM][Cl]–SDS micellar solution was proven to be more sensitive for smaller, more polar molecules. The detection limits were lower when utilizing the [BMIM][Cl]–SDS and [BMIM][Cl]–[DMIM][Br] extraction solvents compared to the neat [BMIM][Cl] extraction solvent. The reproducibility of the extraction method at 20 °C using extraction solvents composed of [BMIM][Cl]–SDS and [BMIM][Cl]–[DMIM][Br] ranged from 6.7 to 14.0 and 4.2 to 14.7%, respectively.     

Effect of Chaotropes on Lipase Back Extraction Recovery in the Process of Reverse Micellar Extraction

Chaotropes could significantly enhance lipase activity recovery in reverse micellar back extraction. However, the mechanism of chaotropes promoting the release of enzyme from reverse micelles was not clear. In this study, chaotropes were added in the process of lipase reverse micellar extraction, and back extraction recovery was improved. In back extraction, at 0.6 M urea in stripping solution, 94.60 % total extraction recovery was obtained. Meanwhile at 0.3 M guanidine hydrochloride, nearly 65 % lipases were released into the stripping solution. DLS and Karl Fischer method results showed that the presence of urea in stripping solution could weaken the electrostatic interaction between lipase and cetyltrimethylammonium bromide molecules, promoting lipase release from reverse micelles, and guanidine hydrochloride could stimulate lipase and free water molecules enwrapped in reverse micelle release into the stripping solution. These experimental results provide a clue for understanding the mechanism of chaotropes influencing on protein recovery in reverse micelle back extraction.     

Analytical Azo Coupling Reactions: A Quantum-Chemical Consideration

Azo coupling reactions of 1-aminonaphthalene with naphthalene-1-diazonium and 4-sulfobenzene-diazonium cations are studied by quantum chemistry. It is found that the reactions are orbital controlled and their regioselectivity is unambiguously governed by the thermodynamic properties of the intermediate σ-complexes and by the effect of the aqueous medium. The latter causes high site selectivity, providing the choice of one of the two possible reaction channels predicted on the basis of quantum-chemical calculations of the isolated molecular systems. As a result, azo coupling occurs at the 4-position of the 1-aminonaphthalene molecule. Additionally, the aqueous medium provides the selection of analytical forms, namely, the protonated azo coupling products that have the quinone-hydrazone structure. On the basis of the quantum-chemical study, the analytical performances of the two azo coupling reactions mentioned above are discussed.     

利用催化方法的动力学分析法动态

催化动力学分析法虽甚多,但具特色的方法极少,本文对两例方法作出评述. 1 胶束系催化动力学测定法     

Surface Diels–Alder Reactions as an Effective Method to Synthesize Functional Carbon Materials

The post‐synthesis chemical modification of various porous carbon materials with unsaturated organic compounds is reported. By this method, amine, alcohol, carboxylate, and sulfonic acid functional groups can be easily incorporated into the materials. Different carbonaceous materials with surface areas ranging from 240 to 1500 m² g^?1 and pore sizes between 3.0 and 7.0 nm have been studied. The resulting materials were analyzed by elemental analysis, nitrogen sorption, FTIR spectroscopy, zeta‐potential measurements, thermogravimetric analysis, photoelectron spectroscopy, and small‐angle X‐ray scattering. These analyses indicated that the degree of functionalization is dependent on the nature of the dienophile (reactivity, steric hindrance) and the porosity of the carbon material. As possible applications, the functionalized carbonaceous materials were studied as catalysts in the Knoevenagel reaction and as adsorbents for Pb²⁺ from aqueous solution.     

A Simple Method for Determining the Critical Micellar Concentration of a Surfactant

This paper will present a simple method for critical micellar concentration (cmc) determination based on light scattering using a turbidimeter. The method does not require the optical clarification of the surfactant solution. The surfactant solutions were prepared from distilled water after boiling. Distinct cmc values were observed for polyoxyethylene mono n-dodecylether, sodium taurodeoxycholate and sodium dodecyl sulfate. The cmc values obtained using the turbidity method were compared with cmc values obtained by the surface tension method and with data given in the literature. Values obtained by our simple method have comparable accuracy with data obtained from more elaborate experiments.     

Analytical Method Development for 19 Alkyl Halides as Potential Genotoxic Impurities by Analytical Quality by Design

Major issues in the pharmaceutical industry involve efficient risk management and control strategies of potential genotoxic impurities (PGIs). As a result, the development of an appropriate method to control these impurities is required. An optimally sensitive and simultaneous analytical method using gas chromatography with a mass spectrometry detector (GC–MS) was developed for 19 alkyl halides determined to be PGIs. These 19 alkyl halides were selected from 144 alkyl halides through an in silico study utilizing quantitative structure–activity relationship (Q-SAR) approaches via expert knowledge rule-based software and statistical-based software. The analytical quality by design (QbD) approach was adopted for the development of a sensitive and robust analytical method for PGIs. A limited number of literature studies have reviewed the analytical QbD approach in the PGI method development using GC–MS as the analytical instrument. A GC equipped with a single quadrupole mass spectrometry detector (MSD) and VF-624 ms capillary column was used. The developed method was validated in terms of specificity, the limit of detection, quantitation, linearity, accuracy, and precision, according to the ICH Q2 guideline.