反胶束萃取分离生物分子及相关领域的研究进展

综述了反胶束有关的概念、理论；反胶束萃取蛋白质的传质机制、选择性分离过程及工艺流程；反胶束对氨基酸、抗生素及核酸的萃取分离；反胶束与其他方法、技术相结合的应用状况。     

Formation and Characterization of Reversed Micelles Composed of Phospholipids and Fatty Acids

The formation of reversed micellar systems composed of phosphatidylcholine (PC) and fatty acid was newly demonstrated by a significant increase in water content in the organic ethyl oleate phase when the micelles were prepared by the contact method. The solubilized water concentration in the reversed micellar organic phase reached 3 wt%. The new systems are expected to be used as highly biocompatible reversed micellar systems. The structure of the reversed micelles composed of PC and oleic acid was characterized by determining the water concentration and by small-angle X-ray scattering analysis. The reversed micelles composed of PC and oleic acid formed in ethyl oleate were spherical. The radius of gyration was between 30 and 50 Å. The size of the reversed micelles decreased with an increase in the oleic acid concentration and was independent of the PC concentration. Experimental results indicated that the structure of the reversed micellar system was determined by the oleic acid concentration. An increase in the PC concentration caused an increase in the number of reversed micelles of the same size. These reversed micellar systems are expected to be used as solubilization media in pharmaceutical and food industries because they are not toxic.     

Micellar kinetics in aqueous acetonitrile. Part A. Sodium-hydrogen ion-exchange constant for 1-dodecanesulfonate surfactant. Part B. Substrate structural effects for micellar catalysis by perfluorooctanoic acid as reactive counterion surfactant

The sodium-hydrogen ion exchange constant for the system sodium 1-dodecanesulfonate-hydrochloric acid in aqueous acetonitrile has been determined from the pseudo-phase ion exchange model for surfactant catalytic effects. The results indicate that the micellar system behaves similarly for the aqueous and the aqueous acetonitrile (2.106 M) solvent systems. The influence of substrate molecular structure on micellar catalysis by perfluorooctanoic acid of the hydrolysis of hydroxamic acids (R—CO—NHOH) in aqueous acetonitrile has been explored. Data for substrate structures of fifteen compounds with R=alkyl, aralkyl, alicyclylalkyl, phenylalkyl, alkyl-substituted phenylalkyl, and with chain branching at the α, β, and γ positions are compared. Relative binding constant values indicate that substrates with aromatic groups are less well solubilized in the perfluoro micellar environment than are substrates with saturated groups. There is now evidence for specific micellar effects on the reaction rate as well as general micellar catalysis. © 1997 John Wiley & Sons, Inc.     

Micellar ultrafiltration preconcentration of strontium by anionic micellar solution

Th anionic micellar system of the sodium dodecylsulphate (SDS) with di-2-ethylhexylphosphoric acid (D2EHPA) chelating ligand reagent in acctate buffer solutions was studied. The influence of the concentration and the composition of the micellar system for strontium preconcentration was determined. Different pH values of solutions as well as different concentration ratios of the ligand to the surfactant were used.     

Interphase Transport in a Salicylic Acid Emulsion

Selected pairs of phases in the system, not in equilibrium, were brought into contact and the transport between them was evaluated from the changes in volumes with time. The results showed the rate determining factors to be the extremely slow absorption of compounds into the solid acid layer and of water into the surfactant inverse micellar solution. The former factor was referred to the protracted process of modifying the crystalline structure and the latter to the minute diffusion coefficient of the inverse micelles. In the same manner the contact between the lamellar phase liquid crystalline phase and a solid solution of the surfactant in the acid led to the formation of two inverse micellar solutions of different composition separated by a liquid crystalline layer instead of the expected aqueous liquid and one inverse micellar solution, which appeared first after significantly extended times. The equilibration was significantly retarded by the slow diffusion of acid molecules through one of the liquid layers.     

Phase Equilibria in Systems of Water,Naphthenic Acids,and Phenols

A partial phase diagram has been determined for the system based on 5‐phenylvalerate, 4‐pentyphenol, and water at 25 °C. The system showed a very rich phase behavior in which many different isotropic solutions and liquid crystals were found. Both normal and reverse self‐assembly structures of the micellar and hexagonal types were noted. In the middle of the phase diagram, a lamellar liquid crystalline phase with a large swelling capacity was observed. When the aromatic alcohol was replaced by a long‐chain alcohol the reverse hexagonal structure disappeared. The effect of temperature and salinity on the phase behavior was also studied. Raising the temperature increased the micellar regions, while the lamellar phase was slightly reduced and the reverse hexagonal phase disappeared. Addition of salt gave the lamellar phase a smaller region of existence and the large extension towards the water apex disappeared. Introduction of an acid to the system resulted in a remarkable change of the phase behavior: both the normal micellar and lamellar regions were significantly reduced, while the reverse micellar region was significantly increased.     

TODGA based w/o microemulsion in dodecane: an insight into the micellar aggregation characteristics by dynamic light scattering and viscometry

N,N,N',N'-tetraoctyl diglycolamide abbreviated as TODGA, is one of the most promising extractant for actinide partitioning from high level nuclear waste. It forms reverse micelles in non polar solvents on equilibration with aqueous HNO(3) solutions. This reverse micellar system undergoes phase separation into dilute and concentrated reverse micellar solutions at high aqueous acid concentration. Small angle neutron scattering (SANS) studies reported in the literature explained this phenomenon based on gas-liquid type phase transition in the framework of Baxter adhesive hard sphere theory in the presence of a strong inter-micellar attractive interaction. The present investigation attempts to throw further light on this system by carrying out systematic dynamic light scattering (DLS) and viscometry studies, and their modeling on the TODGA reverse micellar solutions in the dodecane medium. The variation of the diffusion coefficient with the micellar volume fraction observed from the DLS studies is suggestive of the presence of an attractive interaction between the TODGA reverse micelles, which weakens at the high micellar volume fraction due to the increased dominance of the excluded volume effect. It is suggested that this weakened interaction is responsible for the absence of phase separation in this system at high TODGA concentration. The results thus highlight the importance of the presence of an attractive interaction between the TODGA micelles in determining the observed phase separation in the TODGA reverse micellar systems. The modeling of the DLS and viscosity data, however, suggest that the characteristic stickiness parameter of this system could be smaller than the critical value required for inducing a gas-liquid type phase transition.     

Two-dimensional fluorescence correlation spectroscopy II: spectral analysis of derivatives of anthracene and pyrene in micellar solutions

Generalized two-dimensional (2D) correlation spectroscopy has been applied to the analysis of fluorescence spectra in two micellar systems: (1) a mixture of pyrene and 1,3,6,8-pyrenetetrasulfonic acid in the cationic micellar solutions of cetyltrimethylammonium chloride (CTAC) and (2) a mixture of pyrene and 9-anthracencepropionic acid in anionic micellar solutions of sodium dodecyl sulfate (SDS). Fluorescence quenching is employed as a perturbation mode for causing intensity changes in fluorescence bands (quenching perturbation). Iodide ion (I-) is used as a quencher in the former system, and cetyl pridinium chloride (CPC) is used in the latter. Vibronic bands in the complicated fluorescence spectra of the mixture of the analytes were successfully resolved. It is shown that asynchronous maps are especially useful for spectral resolution enhancement when the quenching perturbation is employed in 2D fluorescence correlation spectroscopy. Furthermore, the information about the order of response of the bands to quenching is obtained by comparing the signs of synchronous and asynchronous cross-peaks.     

Molecular organization and dynamics of micellar phase of polyelectrolyte-surfactant complexes: ESR spin probe study

Molecular dynamics and organization of the micellar phase of complexes of linear polyelectrolytes with ionogenic and non-ionogenic surfactants was studied by the ESR spin probe method. Complexes of polyacrylic acid (PAA) and sodium polystyrenesulfonate (PSS) with alkyltrimethylammonium bromides (ATAB), as well as complexes of poly-N,N'-dimethyldiallylammonium chloride (PDACL) with sodium dodecylsulfate (SDS) were studied. The micellar phase of such complexes is highly organized molecular system, molecular ordering of which near the polymeric chain is much higher than in the 'center' of the micelle, it depends on the polymer-detergent interaction, flexibility of polymeric chain and length of carbonic part of the detergent molecule. Complexes of polymethacrylic acid (PMAA) with non-ionic detergent (dodecyl-substituted polyethyleneglycol), show that the local mobility of surfactant in such complexes is significantly lower than in 'free' micelles and depends on the number of micellar particles participating in formation of complexes.     

Hyphenated techniques in anticancer drug monitoring. II. Liquid chromatography-mass spectrometry and capillary electrophoresis-mass spectrometry

A micellar electrokinetic chromatographic (MEKC) method was developed for the separation of ten phenolic acids including cichoric acid and caftaric acids, specific marker phytochemicals of Echinacea purpurea. The MEKC method involved the use of 70 mM sodium deoxycholate (SDC) in 40 mM borate (pH 9.2) buffer and UV detection at 300 nm. The bile acid was used as biosurfactant able to provided a micellar system with different and more selective properties than sodium dodecyl sulfate. The effects of SDC and borate concentration and buffer pH on the analyte resolution were evaluated. The validated method was applied to the determination of cichoric acid and related compounds in E. purpurea root extracts, and in commercial E. purpurea based dried extracts and tablets.     

Direct serum injection in micellar liquid chromatography. Recovery of serum proteins and assay of hydrophilic drugs

The recovery of serum proteins from reversed-phase and internal-surface reversed-phase (ISRP) silica supports following direct serum injection was investigated using an eluent containing a micellar solution of sodium dodecyl sulphate (SDS). The results indicated that the recoveries of serum proteins were 98-103% for both supports. On the basis of the above findings, the separation and recovery of hydrophilic drugs (cephalosporins and salicylic acid) from human serum were investigated using acidic eluents including micellar solutions of SDS. They were completely separated from the components of serum, and the recoveries were 94-98% despite protein binding. Although the recommended eluent pH range is 6.0-7.5 for the ISRP support, eluents of pH 2-8 can be used with the micellar chromatographic system.     

色谱法研究杂多酸 Ⅴ.杂多酸的胶束液相色谱分析

本文研究了杂多酸阴离子在正丁胺柠檬酸盐胶束液相色谱中的保留行为, 考察了胶束浓度,有机修饰剂种类和含量,柱温,pH 值等因素对杂多酸阴离子保留行为及柱效的影响,与反相离子对色谱比较,本体系具有柱效高等优点, 这对分离有较大分子量的杂多酸是有利的,运用此方法进行杂多酸定量分析,得到满意的结果     

Enhanced Electron Transfer Ability via Coordination in Block Copolymer/Porphyrin/Fullerene Micelle

Inspired by structures of antenna-reaction centers in photosynthesis,the complex micelle was prepared from zinc tetra-phenyl porphyrin (ZnTPP),fullerene derivative (PyC60) and poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-bPCL).The core-shell structure made the hydrophobic donor-acceptor system work in aqueous.In micellar core,coordination interaction occurred between ZnTPP and PyC60 molecules which ensured the enhanced energy migration from the donor to the acceptor.The enhanced interaction between porphyrin and fullerene was confirmed by absorption,steady-state fluorescence and transient fluorescence.The generation of singlet oxygen and superoxide radical was detected by iodide method and reduction of nitro blue tetrazolium,respectively,which confirmed that electron transfer reaction in the complex micellar core occurred.Moreover,the complex micelle exhibited effective electron transfer performance in photodebromination of 2,3-dibromo-3-phenylpropionic acid.The complex micellar structure endowed the donor-acceptor system with improved stability under irradiation.This strategy could be helpful for designing new electron transfer platform and artificial photosynthetic system.     

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.     

An Insight into Peak‐Splitting Phenomenon in On‐Column Concentration‐Micellar Electrokinetic Capillary Chromatography for Aqueous Sample Solution

Abstract

A detailed study was carried out to investigate the origin of the peak‐splitting phenomena in on‐column concentration‐micellar electrokinetic capillary chromatography for aqueous sample solution. The system studied was a basic phosphate and borax mixed buffer with sodium dodecyl sulfate (SDS) as micellar phase. Phenol, benzyl alcohol, phenyl ethanol, salicylic acid, and p‐hydroxy benzyl acid were selected as the analytes. Several factors that affect peak splitting were investigated. The injection time, SDS micellar concentration, hydrophobicity of the analytes, and analytes concentration were the most important factors. A hypothesis was proposed to explain the peak‐splitting phenomena. Several means to avoid peak‐splitting phenomena were proposed, such as controlling sample injection time and hydrophobicity of the analyte, decreasing SDS concentration and increasing sample concentration. However, the most practical method for avoiding peak splitting was to control the sample injection time.     

Simultaneous determination of antioxidants, preservatives and sweeteners permitted as additives in food by mixed micellar electrokinetic chromatography.

A micellar electrokinetic chromatography method was developed to simultaneously analyse commonly used food additives. The additive mixture, comprising propyl gallate, octyl gallate, dodecyl gallate, butylated hydroxyanisole, butylated hydroxytoluene, tertiary butylhydroquinone, p-hydroxybenzoic acid methyl ester, p-hydroxybenzoic acid ethyl ester, benzoic acid, sorbic acid, saccharin, aspartame and acesulfame-K, was not resolved using single surfactant micellar systems consisting of sodium dodecyl sulfate (SDS), sodium cholate (SC) or sodium deoxycholate (SDC). The separation of these additives using mixed micellar systems, involving SDS/SC, SDS/SDC and SC/SDC, was investigated. Organic solvents were added to the mixed micellar phases to optimise the separation. The mixture was successfully separated using a 20 mM borate buffer with 35 mM SC, 15 mM SDS and 10% methanol added at pH 9.3. Additives in cola beverages and low-joule jam were investigated and quantified using this method.     

Analysis of antiepileptic drugs in human plasma using micellar electrokinetic capillary chromatography.

We describe a method for the simultaneous determination of antiepileptic drugs (ethosuccimide, phenytoin, primidone, phenobarbital, carbamazepine and valproic acid) by micellar electrokinetic capillary chromatography using sodium dodecyl sulphate as the micellar phase. Factors affecting the micellar electrokinetic separation were studied for the quantitative determination of these drugs in human plasma. The confirmation of the peaks and the specificity of the method were investigated by combining multiwavelength detection with micellar electrokinetic capillary chromatography.     

High-performance liquid chromatographic determination of diuretics in urine by micellar liquid chromatography.

The use of micellar liquid chromatography for the determination of diuretics in urine by direct injection of the sample into the chromatographic system is discussed. The retention of the urine matrix at the beginning of the chromatograms was observed for different sodium dodecyl sulphate (SDS) mobile phases. The eluent strengths of a hybrid SDS-methanol micellar mobile phase for several diuretics were compared and related to the stationary phase/water partition coefficient with a purely micellar mobile phase. The urine band was appreciably narrower with a mobile phase of 0.05 M SDS-5% methanol (v/v) at 50 degrees C (pH 6.9). With this mobile phase the determination of bendroflumethiazide and chlorthalidone was adequate. Acetazolamide, ethacrynic acid, furosemide, hydrochlorothiazide and probenecid were overlapped by the urine matrix, and the retention of amiloride and triamterene was too long.     

Interfacial Rheological Property and Rheokinetics of a Novel Photoreversible Micellar System

A new photorheologically reversible micelle composed of a polymerizable cationic surfactant N-cetyl dimethylallyl ammonium chloride (CDAAC) and trans-4-phenylazo benzoic acid (trans-ACA) was prepared. Exposing the CDAAC/trans-ACA (14 mM/10 mM) micellar system to the UV light (365 nm) resulted in a decrease in the relative viscosity, and in turn, the relative viscosity increases to its initial value when the micellar system was exposed to visible light (460 nm), which is caused by the photoisomerization of ACA. The interfacial tension and modulus of the micellar system change significantly after UV irradiation and show the reversible interfacial rheological properties when irradiated by visible light. Furthermore, for the first time the dynamic changing of the rheological properties, i.e., the decreasing of viscosity and viscoelasticity during the UV irradiation, has been studied and well described by a rheokinetics model.     

Selenium-mediated micellar catalyst: an efficient enzyme model for glutathione peroxidase-like catalysis

Mimicking the properties of the selenoenzyme glutathione peroxidase (GPx) has inspired great interest. In this report, a selenium-containing micellar catalyst was successfully constructed by the self-assembly of the cationic surfactant hexadecyltrimethylammonium bromide (CTAB) with benzeneseleninic acid (PhSeO2H) through hydrophobic and electrostatic interaction in water. The selenium-containing micellar catalyst demonstrated substrate specificity for both 3-carboxy-4-nitrobenzenethiol (ArSH, 2) and cumene hydroperoxide (CUOOH), and their complexation was confirmed by UV and fluorescence spectra. More importantly, it demonstrated high GPx activity in two assay systems. It is about 126 times more effective than the well-known GPx mimic ebselen in the classical coupled reductase assay system; however, by using hydrophobic substrate ArSH (2) as an alternative of glutathione (GSH, 1), the micellar catalyst exhibited remarkable 500-fold and 94 500-fold rate enhancements compared with that of PhSeO2H and PhSeSePh.