Preparation of BaMgAl10O17∶Eu2+ and Its Phase Behavior in Microemulsion System

BaMgAl10O17∶Eu2 (BAM) was prepared in the microemulsion system and its phase behavior was studied. There exists a small region in the reverse microemulsion system where the dispersed particles are of spherical form. In this way, BAM blue phosphor with good dispersion can be synthesized. The microemulsion phase diagrams of the pseudo-ternary system (Triton X-100/cosurfactant-oil-BAM brine) were first established intuitively by the dilution method. The microstructure of microemulsions was determined through eyeballing, conductance technique, and polar optical microscopy. Its phase behavior is affected by various factors, such as temperature (room temperature, 30, 40 ℃), oil, surfactants, and cosurfactants in microemulsions. According to the phase diagrams, the microemulsion system of Triton X-100/1-hexanol-hexane-BAM brine was chosen to prepare the precursor. The BAM phosphor can be obtained via sintering the precursor at a comparatively low temperature. The phosphors were characterized by XRD and vacuum ultraviolet (VUV) spectra.     

Preparation of BaMgAl10O17 ：Eu^2＋ and Its Phase Behavior in Microemulsion System

BaMgAl10O17 ： Eu^2＋ （BAM） was prepared in the microemulsion system and its phase behavior was studied. There exists a small region in the reverse microemulsion system where the dispersed particles are of spherical form. In this way, BAM blue phosphor with good dispersion can be synthesized. The microemulsion phase diagrams of the pseudo-ternary system （Triton X-100/cosuffactant-oil-BAM brine） were first established intuitively by the dilution method. The microstructure of microemulsions was determined through eyeballing, conductance technique, and polar optical microscopy. Its phase behavior is affected by various factors, such as temperature （room temperature, 30, 40 ℃）, oil, surfactants, and cosurfactants in microemulsions. According to the phase diagrams, the microemulsion system of Triton X-100/1-hexanol-hexane-BAM brine was chosen to prepare the precursor. The BAM phosphor can be obtained via sintering the precursor at a comparatively low temperature. The phosphors were characterized by XRD and vacuum ultraviolet （VUV） spectra.     

Synthesis of SmOHCO3 micro/nano particles from the coupling route of homogeneous precipitation with microemulsion

SmOHCO3 micro/nano particles were prepared in water/oil(W/O) reverse microemulsion composed of cetyltrimethyl ammonium bromide(CTAB), n-octane, n-butanol, Sm(NO3)3·6H2O and urea aqueous solution by the coupling route of homogeneous precipitation with microemulsion. The nanoparticles were characterized and analyzed by X-ray powder diffraction(XRD), thermal gravimetric and differential thermal gravimetric analysis(TG-DTG), Fourier transform infrared absorption spectra(FT-IR) and scanning electron microscope(SEM). The results showed that the phase SmOHCO3 micro/nano particles was in agreement with pure orthorhombic phase. The different morphologies of SmOHCO3 micro/nano particles with good monodispersity and size were obtained by regulating the reaction temperature and reaction time. Possible formation mechanisms of the morphological structure of SmOHCO3 were proposed and discussed.     

Study on Properties of Microemulsion AEO-9/Butanol/Cyclohexane/Salt Aqueous Solution

The microemulsion AEO-9/butanol/cyclohexane/nitrate aqueous solution (or ammonium salt aqueous solution) was studied, which was used as 'micro-reactor' in preparing long afterglow phosphor materials SrAl2O4: Eu2 ,Dy3 . The phase behavior of microemulsion was investigated. The radius of inner water droplet Rw and the change of standard free energy ΔG*o→i were obtained by means of dilution method and theoretical calculation. The result shows that with the increase of W/S, the area of microemulsion region decreases, Rw and ΔG*o→i increase and the microemulsion stability decreases. The structure change and formation area of microemulsion AEO-9/butanol/cyclohexane/nitrate aqueous solution ( or ammonium salt aqueous solution) were offered for the adoption of a synthesis method with newly high efficiency and utility. The particular size and its distribution theory gist, fluorescence life-span, and quenching concentration parameter data were expected. A new approach was explored for finding a new preparation method of rare earths afterglow materials and increasing luminescence intensity without crashing.     

Separation of neutral compounds by capillary electrokinetic chromatography using polyethyleneimine as replaceable cationic pseudostationary phase

Polyethyleneimine (PEI, molecular weight 6 x 10(5) - 1 x 10(6)) is applied as a positively charged pseudostationary phase for electrokinetic chromatography (EKC) of uncharged mono- and oligophenols. EKC is carried out in PEI-coated fused-silica capillaries (with electroosmotic flow directed towards the anode) in 2-(N-morpholino)ethanesulfonic acid (MES) buffer (pH 7.0, 20 mM) with PEI added to the solution in concentrations up to 0.70% w/v. The pseudostationary phase leads to a retardation of the solutes mainly according to the number (and the position) of the OH-groups of the separands, and is not influenced significantly by methyl groups. For 0.70% w/v PEI solution, for instance, the relative retention, rho, has values between 0.33 and 0.53. For the systems with the highest resolution of the separands (0.25-0.30% PEI) 190,000 plates per meter are observed. The results indicate that the separation selectivity is mainly caused by ion-dipole interactions between the OH-groups of the solutes and the pseudostationary phase.     

DTAB微乳液体系溶水性能研究

研究了阳离子表面活性剂DTAB与不同助表面活性剂、油相形成的微乳液体系的溶水能力,并考察温度、pH对微乳液体系稳定性的影响。分别绘制了不同体系的拟三元相图。结果表明:当DTAB与正丁醇质量比为13∶7,(DTAB+正丁醇)与环己烷质量比为3∶1时,DTAB/正丁醇/环己烷/水微乳液体系具有较大的稳定区域,其最大溶水量在50%左右。该微乳液体系在温度低于80℃时,稳定区域受温度影响较小;pH对该体系稳定性影响不大。     

UNIFAC Modeling of Cosolvent Phase Partitioning in Nonaqueous Phase Liquid-Water Systems

In this study, an existing thermodynamic model was used to predict equilibrium phase partitioning behavior of a cosolvent in a two-phase nonaqueous phase liquid (NAPL)–water system. The activity coefficients are calculated using the universal quasichemical functional group activity coefficient (UNIFAC) method. We examined an assortment of cosolvent–NAPL pairs of environmental interest and compared the UNIFAC-predicted ternary phase diagrams against published experimentally derived ternary phase diagrams. Results show that the UNIFAC model is a promising method for predicting equilibrium cosolvent partitioning behavior in NAPL–water systems, and thus can be useful in estimating the potential for NAPL solubilization and mobilization in remediation processes. The cosolvent partitioning behavior is interpreted with regard to changes in the physical properties of the NAPL-water system. Changes in interfacial tension between the two phases were estimated using an existing correlation. A viscosity experiment was conducted for selected mixtures of ethanol, toluene, and water; and the viscosity was found to increase with increasing amounts of the cosolvent.     

A quantitative relationship between capacity factor and selector concentration in capillary electrophoresis and high performance liquid chromatography: evidence from the enantioselective resolution of benzoin using human serum albumin as a chiral selector

Many selectors are used both in pressure-driven liquid chromatography (LC) and in electrokinetic chromatography (EKC), particularly chiral species such as cyclodextrins and proteins. It should be possible to readily apply information gleaned using one technique to the other, since in both techniques the underlying molecular interactions which lead to separations are expected to be the same. Superficially this may be the case, but an exact transfer of operating conditions, i.e., background electrolyte (BGE) composition/mobile phase composition, assuming that these meet certain minimum requirements for each technique, is not often possible. To investigate the reason for this we have measured retention (k') of a neutral solute (racemic benzoin) in HPLC and EKC using an identical range of BGE/mobile phase conditions in both techniques. The selector used was human serum albumin. The k' measurements obtained for each benzoin enantiomer were consistently higher in HPLC than in EKC. This can be explained very simply if one considers that retention in both systems is related to the selector concentration [S], by the expression k'=K[S], where K is the affinity constant. In EKC, [S] is simply the concentration of free selector in the BGE, while in LC, [S] = m(p)/Vo, where m(p) is the number of moles of accessible selector, and Vo is the column void volume. In LC, [S] is generally considerably higher than in EKC, leading to larger values of k'.     

Separation of cardiac glycosides by micellar electrokinetic chromatography and microemulsion electrokinetic chromatography

The interest of micellar electrokinetic chromatography (MEKC) and microemulsion electrokinetic chromatography (MEEKC) for the resolution of four cardiac glycosides is demonstrated. First, the influence of some parameters on the resolution of the solutes in MEKC such as the concentration of the surfactant, pH, addition of organic modifiers and urea is discussed. Then, results are compared with those obtained in MEEKC using different microemulsion compositions. Results indicate that MEEKC possesses several advantages over MEKC for the separation of relatively hydrophobic compounds such as digitalic compounds. First, microemulsions allow a better manipulation of the migration time window and of the retention of the solutes. Moreover, efficiency is improved with shorter analysis time.     

Linear solvation energy relationships in micellar liquid chromatography and micellar electrokinetic capillary chromatography

Linear solvation energy relationships (LSERs) were used to evaluate and characterize chemical interactions that influence retention behavior in micellar liquid chromatography (MLC) and micellar electrokinetic capillary chromatography (MEKC). High correlations were found between solutes' capacity factors in MLC and in MEKC, as well as binding constants to micelles and their solvatochromic parameters using two anionic surfactants, sodium dodecyl sulfate (SDS) and sodium cholate (SC), and one cationic surfactant, tetradecyltrimethylammonium bromide (C14TAB). Surprisingly, in the C14TAB MLC system capacity factor (k') vs. solvatochromic parameters gives better correlation than log k' vs. solvatochromic parameters, which is an opposite behavior to that observed in the SDS MLC system. The capacity factors in the C14TAB MLC system were characterized using LSERs with and without organic modifiers. It was found that the addition of a small amount of short-chain alcohols (e.g., 7% 2-propanol or 5% butanol) does not significantly change the high correlations between k' vs. solvatochromic parameters. The changes in the coefficients with the volume fraction of organic solvents were explained by comparing the differences in chemical natures between mobile phase and stationary phase. Stationary phase shows a significant effect on the chemical interactions in MLC through LSER study using a diphenyl column and a C8 column. LSERs were also used to characterize retention behavior in MEKC. High correlations between the logarithm of solutes' capacity factors and their solvatochromic parameters were observed for a group of 25 uncharged substituted aromatic compounds and polycyclic aromatic hydrocarbons with SDS and SC micelles. It was found that solutes' size and basicity are the two dominant factors that influence the migration behavior in MEKC.     

氨皂化的P507微乳液导电行为及FT-IR光谱研究

利用电导法研究了氨皂化的P507形成的微乳液体系，Ea-VH20％关系曲线表明，溶水率VH20％29％时微乳体系最稳定。利用FT-IR光谱研究了P507皂化时的分子结构变化、微乳液中水的存在形式及微乳液的相变化。增溶水过程发现，P507阴阳离子先发生水化，之后形成微液滴的内相，W／O型微乳液内相增溶水阶段出现渗透现象，再加入水使得分散相联通形成双连续相微乳液，最后发生相变，形成O／W型乳浊液。     

Administrative issues in health team development: report of a workshop

Conventional microbiological assay procedures for cephalosporins in serum do not allow the determination of serum concentrations if more than one cephalosporin is present in a single sample. An HPLC procedure has been developed which permits the simultaneous quantitative determination of cefazolin sodium and cephalothin sodium in serum. Reverse phase chromatography using methanol in 0.2 M ammonium acetate as the mobile phase was employed to separate and quantitate the two cephalosporins in a trichloroacetic acid supernatant solution prepared from serum.     

The use of microemulsion electrokinetic chromatography in pharmaceutical analysis

The use of a single set of microemulsion electrokinetic chromatography (MEEKC) separation conditions has been assessed for its applicability in the analysis of a range of pharmaceutical compounds. Particular emphasis was placed on neutral or very hydrophobic compounds, which can be difficult to analyse by conventional capillary electrophoresis. The microemulsion employed for the majority of separations consisted of 0.81% w/w octane, 6.61% w/w 1-butanol, 3.31% w/w sodium dodecyl sulphate and 89.27% w/w 10 mM sodium tetraborate buffer. Good separations of methyl, ethyl, butyl and propyl hydroxybenzoates, and a range of ionic and neutral water soluble and insoluble compounds was achieved using a single set of separation conditions. A number of novel applications of MEEKC were developed included the simultaneous determination of the active components and preservatives in liquid formulation and determination of drug related impurities. Improved performance was obtained through use of internal standards and preparation of the samples dissolved in the microemulsion solution. Validation aspects such as linearity, repeatability, accuracy, injection precision and sensitivity were successfully assessed.     

Metal ion separations in polyethylene glycol-based aqueous biphasic systems: correlation of partitioning behavior with available thermodynamic hydration data

Solvent extraction utilizing an oil-water mixture (e.g., chloroform-water) and a suitable complexant, is a proven technology for the selective removal and recovery of metal ions from aqueous solutions. Aqueous biphasic systems (ABS), formed by mixing certain inorganic salts and water-soluble polymers, or by mixing two dissimilar water-soluble polymers, have been studied for more than 40 years for the gentle, non-denaturing separation of fragile biomolecules, yet ABS have been virtually ignored as a possible extraction technology for metal ions. In this report we review our metal ion partitioning work and discuss the three major types of partitioning: (1) those rare instances that the metal ion species present in a given solution partitions to the PEG-rich phase without an extractant; (2) the use of halide salts which produce a metal anion complex that partitions to the PEG-rich phase; and (3) the use of a water-soluble extractant which distributes to the PEG-rich phase. In addition, we correlate the partitioning behavior we observed with available thermodynamic data for metal ions and their complexes.     

Solid-phase extraction and liquid chromatographic quantitation of the antiarrhythmic drug L-768673 in a microemulsion formulation

A sensitive and specific method based in solid-phase extraction and reverse-phase liquid chromatography was developed and validated for the quantitation of L-768673 in a microemulsion formulation. Following a water wash, the drug was eluted from the extraction column with acetonitrile and was analyzed on a reverse-phase C18 column with UV detection at 245 nm. The mobile phase consisted of acetonitrile-0.2% trifluoroacetic acid, 0.1% triethylamine (53:47 v/v). The retention time L-768673 was approximately 28 min with a flow rate of 1.5 ml min-1.     

Deterioration of goat spermatozoa in skimmed milk-based extenders as a result of oleic acid released by the bulbourethral lipase BUSgp60

The migration behavior and separation of six tetracyclines (TCs) were investigated by micellar electrokinetic chromatography (MEKC) in the pH range 5.0-9.0 using ammonium acetate buffer with the addition of sodium dodecyl sulfate (SDS). Mixed SDS-Brij 35, sodium cholate (SC) and tetradecyltrimethylammonium bromide (TTAB) were also used as surfactants. The influences of surfactant concentration and buffer pH on the separation of TCs were examined and the separations of TCs were optimized. Complete separation of six TCs was achieved within 8 min with 15 mM ammonium acetate buffer containing 20 mM SDS, with or without the addition of Brij 35 (0.135%, w/v), at pH 6.5 using a fused-silica capillary (42 cm x 75 microns I.D.) at 15 kV. In general, good linear correlations of the logarithm of migration factor (log k') versus the logarithm of octanol-water partition coefficient (log P(ow)) in these micellar systems, except for the TTAB-MEKC system, were obtained. The results indicate that the migration of TCs in MEKC is mainly based on hydrophobic interactions. However, hydrogen bonding interactions also play a significant role in influencing the chemical selectivity of TCs. In addition, the micelle-water partition coefficients (Pmw) of TCs, which are pH-dependent in the SDS-MEKC micellar system, are reported.     

Drug delivery systems for cyclosporine: achievements and complications

The review deals with the preparation, properties, and analysis of different kinds of cyclosporine delivery systems, such as solid formulations, liposomes, emulsions and microemulsions and targeted cyclosporine formulations. The review points out a key role of delivery systems in increasing the therapeutic effectiveness of cyclosporine. Comparative studies of the prior marketed formulation, Sandimmune, with a new microemulsion formulation, Neoral, are discussed including some data on clinical development of Neoral.     

Study on Properties and Structural Parameters of Microemulsion CTAB／Butanol／Cyclohexane／Salt Aqueous Solution

SrAl2 O4∶Eu2 ,Dy3 isanewlongafterglowlu minescencematerialdevelopedinthe 1990s .Owingtoitsexcellentpropertiessuchashighluminescencein tensity ,longafterglowtime ,goodstability ,longsur vivalandwiderangeofexcitationband ,etc .,thema terialhasreceiveda…     

Synthesis and Fluorescence of Europium-Doped Barium Fluoride Cubic Nanocolumns

Europium-doped barium fluoride cubic nanocolumns were synthesized from the quaternary water in oil reverse microemulsions. In this process, the aqueous cores of water/cetyl trimethyl ammonium bromide (CTAB)/n-butanol/n-oe-tane reverse mieroemulsions were used as mieroreaetors for the precipitation of europium doped barium fluoride. XRD analysis shows that under the dopant concentration of 0.06% (molar fraction), the products are single phase. The result products are cubic column-like with about 30 - 50 nm edge length of cross section, and about 200 nm of length obtained from the transmission electron microscopy (TEM), and atomic force microscopy (AFM). Under the 0.06% (molar fraction) of dopant concentration, the fluorescence of Eu^2 and Eu^3 under the 589 of excitation wavelength is observed.     

Fungal Biofiltration of Toluene on Ceramic Rings

Fungal biofilters attain higher toluene elimination rates compared to bacterial systems. However, strong mycelia growth can cause clogging. In the present work, toluene biofiltration with the fungus Paecilomyces variotii CBS 115145 was tested with two rigid packing materials that allow high mycelia growth. The reactor had two 4.25?L sections, each packed with ceramic Raschig rings differing in water retention capacity and internal porosity. After optimizing nutrient solution delivery, an overall maximum elimination capacity of 245?g/m3/h was obtained. Higher elimination capacity (290?g/m3/h) was measured in the ceramic ring with lower water content, indicating the interest of such packing material for treating hydrophobic pollutants in fungal biofilters. Additional experiments with this support in a 2?L biofilter showed bacterial contamination, but the fungal activity was responsible for about 70% of the total removal. The support with less humidity showed greater aerial growth, which possibly improves removal efficiency by favoring the direct transfer of pollutants from the gas phase to the microorganism.