Sample records for micellar pmca showed

  1. Cellular and subcellular localization of the neuron-specific plasma membrane calcium ATPase PMCA1a in the rat brain.

    Kenyon, Katharine A; Bushong, Eric A; Mauer, Amy S; Strehler, Emanuel E; Weinberg, Richard J; Burette, Alain C


    Regulation of intracellular calcium is crucial both for proper neuronal function and survival. By coupling ATP hydrolysis with Ca(2+) extrusion from the cell, the plasma membrane calcium-dependent ATPases (PMCAs) play an essential role in controlling intracellular calcium levels in neurons. In contrast to PMCA2 and PMCA3, which are expressed in significant levels only in the brain and a few other tissues, PMCA1 is ubiquitously distributed, and is thus widely believed to play a "housekeeping" function in mammalian cells. Whereas the PMCA1b splice variant is predominant in most tissues, an alternative variant, PMCA1a, is the major form of PMCA1 in the adult brain. Here, we use immunohistochemistry to analyze the cellular and subcellular distribution of PMCA1a in the brain. We show that PMCA1a is not ubiquitously expressed, but rather is confined to neurons, where it concentrates in the plasma membrane of somata, dendrites, and spines. Thus, rather than serving a general housekeeping function, our data suggest that PMCA1a is a calcium pump specialized for neurons, where it may contribute to the modulation of somatic and dendritic Ca(2+) transients.

  2. GABA-shunt enzymes activity in GH3 cells with reduced level of PMCA2 or PMCA3 isoform

    Kowalski, Antoni, E-mail: [Department of Molecular Neurochemistry, Medical University of Lodz, 6/8 Mazowiecka Str., 92-215 Lodz (Poland); Zylinska, Ludmila, E-mail: [Department of Molecular Neurochemistry, Medical University of Lodz, 6/8 Mazowiecka Str., 92-215 Lodz (Poland); Boczek, Tomasz, E-mail: [Department of Molecular Neurochemistry, Medical University of Lodz, 6/8 Mazowiecka Str., 92-215 Lodz (Poland); Rebas, Elzbieta, E-mail: [Department of Molecular Neurochemistry, Medical University of Lodz, 6/8 Mazowiecka Str., 92-215 Lodz (Poland)


    Highlights: {yields} Suppression of PMCA2 or PMCA3 slows down proliferation of GH3 cells. {yields} PMCA2 suppression lowers the activity of GABA-shunt enzymes. {yields} PMCA3 suppression increases the expression of glutamate decarboxylase 65. {yields} PMCA2 and PMCA3 function appears to be linked to regulation of GABA metabolism. -- Abstract: GABA ({gamma}-aminobutyric acid) is important neurotransmitter and regulator of endocrine functions. Its metabolism involves three enzymes: glutamate decarboxylase (GAD65 and GAD67), GABA aminotransferase (GABA-T) and succinic semialdehyde dehydrogenase (SSADH). As many cellular processes GABA turnover can depend on calcium homeostasis, which is maintained by plasma membrane calcium ATPases (PMCAs). In excitable cells PMCA2 and PMCA3 isoforms are particularly important. In this study we focused on GABA-metabolizing enzymes expression and activity in rat anterior pituitary GH3 cells with suppressed expression of PMCA2 or PMCA3. We observed that PMCA3-reduced cells have increased GAD65 expression. Suppression of PMCA2 caused a decrease in total GAD and GABA-T activity. These results indicate that PMCA2 and PMCA3 presence may be an important regulatory factor in GABA metabolism. Results suggest that PMCA2 and PMCA3 function is rather related to regulation of GABA synthesis and degradation than supplying cells with metabolites, which can be potentially energetic source.

  3. Molecular cloning of a plasma membrane Ca²⁺ ATPase (PMCA) from Y-organs of the blue crab (Callinectes sapidus), and determination of spatial and temporal patterns of PMCA gene expression.

    Chen, Hsiang-Yin; Roer, Robert D; Watson, R Douglas


    Existing data indicate that a stage-specific increase in intracellular free Ca(2+) stimulates ecdysteroid production by crustacean molting glands (Y-organs). The concentration of Ca(2+) in cytosol is controlled mainly by proteins intrinsic to the plasma membrane and to the membranes of organelles. Several families of proteins are involved, including Ca(2+) channels, Ca(2+) pumps (ATPases), and Ca(2+) exchangers. The family of Ca(2+) pumps includes plasma membrane calcium ATPases (PMCAs). As a step toward understanding the involvement of calcium signaling in regulation of ecdysteroidogenesis, we used a PCR-based cloning strategy (RT-PCR followed by 3'- and 5'-RACE) to clone from Y-organs of the blue crab (Callinectes sapidus) a cDNA encoding a putative PMCA. The 4292 base pair (bp) cDNA includes a 3510 bp open reading frame encoding a 1170-residue protein (Cas-PMCA). The conceptually translated protein has a relative molecular mass of 128.8×10(3) and contains all signature domains of an authentic PMCA, including ten transmembrane domains and a calmodulin binding site. The predicted membrane topography of Cas-PMCA is as expected for an authentic PMCA protein. A phylogenetic analysis of nonredundant amino acid sequences of PMCA proteins from different species showed Cas-PMCA clusters with other arthropod PMCA proteins. An assessment of tissue distribution showed the Cas-PMCA transcript to be broadly distributed in both neural and non-neural tissues. Studies using quantitative real-time PCR revealed stage-specific changes in Cas-PMCA abundance during the molting cycle, with peak expression occurring during premolt stage D2, a pattern consistent with the hypothesis that Cas-PMCA functions to maintain cellular Ca(2+) homeostasis in Y-organs. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Cross talk among PMCA, calcineurin and NFAT transcription factors in control of calmodulin gene expression in differentiating PC12 cells.

    Boczek, Tomasz; Lisek, Malwina; Ferenc, Bozena; Zylinska, Ludmila


    Brain aging is characterized by progressive loss of plasma membrane calcium pump (PMCA) and its activator - calmodulin (CaM), but the mechanism of this phenomenon remains unresolved. CaM encoded by three genes Calm1, Calm2, Calm3, works to translate Ca(2+) signal into changes in frequently opposite cellular activities. This unique function allows CaM to affect gene expression via stimulation of calcineurin (CaN) and its downstream target - nuclear factor of activated T-cells (NFAT) and to terminate Ca(2+) signal by stimulation of its extrusion. PMCA, which exists in four isoforms PMCA1-4, may in turn shape the pattern of Ca(2+) transients and control CaN activity by its direct binding. Therefore, the interplay between PMCA, CaM and CaN/NFAT is highly plausible. To verify that, we used differentiated PC12 cells with reduced expression of PMCA2 or PMCA3 to mimic the potential changes in aged brain. Manipulation in PMCAs level decreased CaM protein in PMCA2 or PMCA3-reduced lines that was accompanied by down-regulation of Calm1 and Calm2 in both lines, but Calm3 only in PMCA2-reduced cells. Further studies showed substantially higher NFATc2 nuclear accumulation and increased NFAT transcriptional activity. Blocking of CaN/NFAT signalling resulted in almost full CaM recovery, mainly due to up-regulation of Calm2 and Calm3 genes. Moreover, higher occupancy of Calm2 and Calm3 promoters by NFATc2 and increased expression of these genes in response to NFATc2 silencing were demonstrated in PMCA2 and PMCA3-reduced lines. Our results indicate that decrease in CaM level in response to PMCAs downregulation can be driven by CaN/NFAT pathway. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. The plasma membrane Ca(2+) pump PMCA4b inhibits the migratory and metastatic activity of BRAF mutant melanoma cells.

    Hegedũs, Luca; Garay, Tamás; Molnár, Eszter; Varga, Karolina; Bilecz, Ágnes; Török, Szilvia; Padányi, Rita; Pászty, Katalin; Wolf, Matthias; Grusch, Michael; Kállay, Enikõ; Döme, Balázs; Berger, Walter; Hegedũs, Balázs; Enyedi, Agnes


    Oncogenic mutations of BRAF lead to constitutive ERK activity that supports melanoma cell growth and survival. While Ca(2+) signaling is a well-known regulator of tumor progression, the crosstalk between Ca(2+) signaling and the Ras-BRAF-MEK-ERK pathway is much less explored. Here we show that in BRAF mutant melanoma cells the abundance of the plasma membrane Ca(2+) ATPase isoform 4b (PMCA4b, ATP2B4) is low at baseline but markedly elevated by treatment with the mutant BRAF specific inhibitor vemurafenib. In line with these findings gene expression microarray data also shows decreased PMCA4b expression in cutaneous melanoma when compared to benign nevi. The MEK inhibitor selumetinib-similarly to that of the BRAF-specific inhibitor-also increases PMCA4b levels in both BRAF and NRAS mutant melanoma cells suggesting that the MAPK pathway is involved in the regulation of PMCA4b expression. The increased abundance of PMCA4b in the plasma membrane enhances [Ca(2+) ]i clearance from cells after Ca(2+) entry. Moreover we show that both vemurafenib treatment and PMCA4b overexpression induce marked inhibition of migration of BRAF mutant melanoma cells. Importantly, reduced migration of PMCA4b expressing BRAF mutant cells is associated with a marked decrease in their metastatic potential in vivo. Taken together, our data reveal an important crosstalk between Ca(2+) signaling and the MAPK pathway through the regulation of PMCA4b expression and suggest that PMCA4b is a previously unrecognized metastasis suppressor. © 2016 UICC.

  6. PMCA4 (ATP2B4 mutation in familial spastic paraplegia.

    Miaoxin Li

    Full Text Available Familial spastic paraplegia (FSP is a heterogeneous group of disorders characterized primarily by progressive lower limb spasticity and weakness. More than 50 disease loci have been described with different modes of inheritance. In this study, we identified a novel missense mutation (c.803G>A, p.R268Q in the plasma membrane calcium ATPase (PMCA4, or ATP2B4 gene in a Chinese family with autosomal dominant FSP using whole-exome sequencing and confirmed with Sanger sequencing. This mutation co-segregated with the phenotype in the six family members studied and is predicted to be pathogenic when multiple deleteriousness predictions were combined. This novel R268Q mutation was not present in over 7,000 subjects in public databases, and over 1,000 Han Chinese in our database. Prediction of potential functional consequence of R268Q mutation on PMCA4 by computational modeling revealed that this mutation is located in protein aggregation-prone segment susceptible to protein misfolding. Analysis for thermodynamic protein stability indicated that this mutation destabilizes the PMCA4 protein structure with higher folding free energy. As PMCA4 functions to maintain neuronal calcium homeostasis, our result showed that calcium dysregulation may be associated with the pathogenesis of FSP.

  7. Cavitation during the protein misfolding cyclic amplification (PMCA) method – The trigger for de novo prion generation?

    Haigh, Cathryn L., E-mail: [Department of Pathology, The University of Melbourne, Victoria 3010 (Australia); Drew, Simon C., E-mail: [Florey Department of Neuroscience and Mental Health, The University of Melbourne, Victoria 3010 (Australia)


    The protein misfolding cyclic amplification (PMCA) technique has become a widely-adopted method for amplifying minute amounts of the infectious conformer of the prion protein (PrP). PMCA involves repeated cycles of 20 kHz sonication and incubation, during which the infectious conformer seeds the conversion of normally folded protein by a templating interaction. Recently, it has proved possible to create an infectious PrP conformer without the need for an infectious seed, by including RNA and the phospholipid POPG as essential cofactors during PMCA. The mechanism underpinning this de novo prion formation remains unknown. In this study, we first establish by spin trapping methods that cavitation bubbles formed during PMCA provide a radical-rich environment. Using a substrate preparation comparable to that employed in studies of de novo prion formation, we demonstrate by immuno-spin trapping that PrP- and RNA-centered radicals are generated during sonication, in addition to PrP-RNA cross-links. We further show that serial PMCA produces protease-resistant PrP that is oxidatively modified. We suggest a unique confluence of structural (membrane-mimetic hydrophobic/hydrophilic bubble interface) and chemical (ROS) effects underlie the phenomenon of de novo prion formation by PMCA, and that these effects have meaningful biological counterparts of possible relevance to spontaneous prion formation in vivo. - Highlights: • Sonication during PMCA generates free radicals at the surface of cavitation bubbles. • PrP-centered and RNA-centered radicals are formed in addition to PrP-RNA adducts. • De novo prions may result from ROS and structural constraints during cavitation.

  8. Association of CD147 and Calcium Exporter PMCA4 Uncouples IL-2 Expression from Early TCR Signaling.

    Supper, Verena; Schiller, Herbert B; Paster, Wolfgang; Forster, Florian; Boulègue, Cyril; Mitulovic, Goran; Leksa, Vladimir; Ohradanova-Repic, Anna; Machacek, Christian; Schatzlmaier, Philipp; Zlabinger, Gerhard J; Stockinger, Hannes


    The Ig superfamily member CD147 is upregulated following T cell activation and was shown to serve as a negative regulator of T cell proliferation. Thus, Abs targeting CD147 are being tested as new treatment strategies for cancer and autoimmune diseases. How CD147 mediates immunosuppression and whether association with other coreceptor complexes is needed have remained unknown. In the current study, we show that silencing of CD147 in human T cells increases IL-2 production without affecting the TCR proximal signaling components. We mapped the immunosuppressive moieties of CD147 to its transmembrane domain and Ig-like domain II. Using affinity purification combined with mass spectrometry, we determined the domain specificity of CD147 interaction partners and identified the calcium exporter plasma membrane calcium ATPase isoform 4 (PMCA4) as the interaction partner of the immunosuppressive moieties of CD147. CD147 does not control the proper membrane localization of PMCA4, but PMCA4 is essential for the CD147-dependent inhibition of IL-2 expression via a calcium-independent mechanism. In summary, our data show that CD147 interacts via its immunomodulatory domains with PMCA4 to bypass TCR proximal signaling and inhibit IL-2 expression.

  9. NFAT1 and NFAT3 cooperate with HDAC4 during regulation of alternative splicing of PMCA isoforms in PC12 cells.

    Michalina Kosiorek

    Full Text Available The bulk of human genes undergo alternative splicing (AS upon response to physiological stimuli. AS is a great source of protein diversity and biological processes and is associated with the development of many diseases. Pheochromocytoma is a neuroendocrine tumor, characterized by an excessive Ca2+-dependent secretion of catecholamines. This underlines the importance of balanced control of calcium transport via regulation of gene expression pattern, including different calcium transport systems, such as plasma membrane Ca2+-ATPases (PMCAs, abundantly expressed in pheochromocytoma chromaffin cells (PC12 cells. PMCAs are encoded by four genes (Atp2b1, Atp2b2, Atp2b3, Atp2b4, whose transcript products undergo alternative splicing giving almost 30 variants.In this scientific report, we propose a novel mechanism of regulation of PMCA alternative splicing in PC12 cells through cooperation of the nuclear factor of activated T-cells (NFAT and histone deacetylases (HDACs. Luciferase assays showed increased activity of NFAT in PC12 cells, which was associated with altered expression of PMCA. RT-PCR experiments suggested that inhibition of the transcriptional activity of NFAT might result in the rearrangement of PMCA splicing variants in PC12 cells. NFAT inhibition led to dominant expression of 2x/c, 3x/a and 4x/a PMCA variants, while in untreated cells the 2w,z/b, 3z,x/b,c,e,f, and 4x/b variants were found as well. Furthermore, chromatin immunoprecipitation experiments showed that NFAT1-HDAC4 or NFAT3-HDAC4 complexes might be involved in regulation of PMCA2x splicing variant generation.We suggest that the influence of NFAT/HDAC on PMCA isoform composition might be important for altered dopamine secretion by PC12 cells.

  10. Pressure-induced melting of micellar crystal

    Mortensen, K.; Schwahn, D.; Janssen, S.


    Aqueous solutions of triblock copolymers of poly(ethylene oxide) and poly(propylene oxide) aggregate at elevated temperatures into micelles which for polymer concentrations greater-than-or-equal-to 20% make a hard sphere crystallization to a cubic micellar crystal. Structural studies show...... that pressure improves the solvent quality of water, thus resulting in decomposition of the micelles and consequent melting of the micellar crystal. The combined pressure and temperature dependence reveals that in spite of the apparent increase of order on the 100 angstrom length scale upon increasing...... temperature (decreasing pressure) the overall entropy increases through the inverted micellar crystallization characteristic....

  11. Effects of Cerium Nitrate on Expression of CaM Ⅰ and PMCA Ca2+-ATPase mRNA in Rat Liver

    杨维东; 王艇; 刘洁生; 雷衡毅; 杨燕生


    The effect of cerium nitrate on expression of CaM Ⅰ and PMCA1b in rat liver was studied by means of reverse transcription-polymerase chain reaction (RT-PCR). The result shows that neither a high dose (50 mg*kg-1) nor a low dose (1 mg*kg-1) of cerium nitrate induces any alterations of expression of CaM Ⅰ and PMCA 1b mRNA after recurrent intraperitoneal injection of cerium nitrate, which suggests that effect of cerium nitrate on CaM and Ca2+-ATPase might be at posttranscription level.

  12. Enhanced Micellar Catalysis LDRD.

    Betty, Rita G.; Tucker, Mark D; Taggart, Gretchen; Kinnan, Mark K.; Glen, Crystal Chanea; Rivera, Danielle; Sanchez, Andres; Alam, Todd Michael


    The primary goals of the Enhanced Micellar Catalysis project were to gain an understanding of the micellar environment of DF-200, or similar liquid CBW surfactant-based decontaminants, as well as characterize the aerosolized DF-200 droplet distribution and droplet chemistry under baseline ITW rotary atomization conditions. Micellar characterization of limited surfactant solutions was performed externally through the collection and measurement of Small Angle X-Ray Scattering (SAXS) images and Cryo-Transmission Electron Microscopy (cryo-TEM) images. Micellar characterization was performed externally at the University of Minnesotas Characterization Facility Center, and at the Argonne National Laboratory Advanced Photon Source facility. A micellar diffusion study was conducted internally at Sandia to measure diffusion constants of surfactants over a concentration range, to estimate the effective micelle diameter, to determine the impact of individual components to the micellar environment in solution, and the impact of combined components to surfactant phase behavior. Aerosolized DF-200 sprays were characterized for particle size and distribution and limited chemical composition. Evaporation rates of aerosolized DF-200 sprays were estimated under a set of baseline ITW nozzle test system parameters.

  13. Micellar Electrokinetic Chromatography

    Bald, Edward; Kubalczyk, Paweł

    Since the introduction of micellar electrokinetic chromatography by Terabe, several authors have paid attention to the fundamental characteristics of this separation method. In this chapter the theoretical and practical aspects of resolution optimization, as well as the effect of different separation parameters on the migration behavior are discussed. These among others include fundamentals of separation, retention factor and resolution equation, efficiency, selectivity, and various surfactants and additives. Initial conditions for method development and instrumental approaches such as mass spectrometry detection are also mentioned covering the proposals for overcoming the difficulties arising from the coupling micellar electrokinetic chromatography with mass spectrometry detection.

  14. The role of the calcium transporter protein plasma membrane calcium ATPase PMCA2 in cerebellar Purkinje neuron function.

    Empson, R M; Akemann, W; Knöpfel, Thomas


    Genetic deletion of the plasma membrane calcium ATPase type 2 (PMCA2), a calcium transporter protein, is associated with an overtly ataxic phenotype in mice. PMCA2 is expressed at high levels in cerebellar Purkinje neurons (PNs) where functional integrity is essential for normal cerebellar function. Indeed, loss of PN function accompanies cerebellar ataxia in humans and mouse models. In the ataxic PMCA2 knockout (PMCA2-/-) mouse the ability of the PNs to control their cytosolic calcium levels was severely impaired; basal calcium levels were high and calcium recovery kinetics slow. Whole cell patch clamp recordings from PMCA2-/- PNs revealed that they possessed hyperpolarised membrane potentials, reduced frequency and increased irregularity of spontaneous action potential firing, curtailed complex spikes and sustained calcium-dependent outward K+ currents. We propose that these alterations limit pathological excursions in PN cytosolic calcium as an aid to survival but that they are insufficient to prevent loss of functional cerebellar output.

  15. Micellar liquid chromatography

    Basova, Elena M.; Ivanov, Vadim M.; Shpigun, Oleg A.


    Background and possibilities of practical applications of micellar liquid chromatography (MLC) are considered. Various retention models in MLC, the effects of the nature and concentration of surfactants and organic modifiers, pH, temperature and ionic strength on the MLC efficiency and selectivity are discussed. The advantages and limitations of MLC are demonstrated. The performance of MLC is critically evaluated in relationship to the reversed-phase HPLC and ion-pair chromatography. The potential of application of MLC for the analysis of pharmaceuticals including that in biological fluids and separation of inorganic anions, transition metal cations, metal chelates and heteropoly compounds is described. The bibliography includes 146 references.

  16. A micellar solution

    Jewulski, J.


    The subject of the invention is a micellar solution used in oil extraction when flooding a deposit and washing out the critical zone. It contains ethanolamine salt of alkylobenzolsulfonic acid (10 to 56 percent by mass), higher alcohol (4 to 56 percent) an organic solvent and water (2.4 to 57.2 percent) and is distinguished by the fact that an amyl alcohol of the third series is used as the higher alcohol, while oil in a volume of 19 to 71 percent or gasoline in a volume of 6 to 16 percent) is used as the solvent.

  17. The contribution of the sodium-calcium exchanger (NCX) and plasma membrane Ca(2+) ATPase (PMCA) to cerebellar synapse function.

    Roome, Chris J; Empson, Ruth M


    The cerebellum, a part of the brain critically involved in motor learning and sensory adaptation, expresses high levels of the sodium-calcium exchanger (NCX) and the plasma membrane calcium ATPase (PMCA). Both these transporters control calcium dynamics at a variety of synapses, and here, we draw upon the available literature to discuss how NCX and PMCA work together to shape pre-synaptic calcium dynamics at cerebellar synapses.

  18. Flow-induced structured phase in nonionic micellar solutions.

    Cardiel, Joshua J; Tonggu, Lige; de la Iglesia, Pablo; Zhao, Ya; Pozzo, Danilo C; Wang, Liguo; Shen, Amy Q


    In this work, we consider the flow of a nonionic micellar solution (precursor) through an array of microposts, with focus on its microstructural and rheological evolution. The precursor contains polyoxyethylene(20) sorbitan monooleate (Tween-80) and cosurfactant monolaurin (ML). An irreversible flow-induced structured phase (NI-FISP) emerges after the nonionic precursor flows through the hexagonal micropost arrays, when subjected to strain rates ~10(4) s(-1) and strain ~10(3). NI-FISP consists of close-looped micellar bundles and multiconnected micellar networks as evidenced by transmission electron microscopy (TEM) and cryo-electron microscopy (cryo-EM). We also conduct small-angle neutron scattering (SANS) measurements in both precursor and NI-FISP to illustrate the structural transition. We propose a potential mechanism for the NI-FISP formation that relies on the micropost arrays and the flow kinematics in the microdevice to induce entropic fluctuations in the micellar solution. Finally, we show that the rheological variation from a viscous precursor solution to a viscoelastic micellar structured phase is associated with the structural evolution from the precursor to NI-FISP.

  19. Chloromethylation of 2-chloroethylbenzene catalyzed by micellar catalysis

    LIU QiFa; LU Ming; WEI Wei


    The chloromethylation reaction of 2-chloroethylbenzene was performed successfully by micellar catalysis in the biphasic oil/water system.The effects of anionic,cationic and non-ionic surfactants on the reaction were compared.The mechanism of chloromethyiation reaction and the mechanism of micellar catalysis were investigated.The results show that the micellar catalysis is an effective way to realize the chloromethylation of 2-chloroethylbenzene,and the cationic surfactant shows the most effectiveness.The longer the hydrophobic chain of the cationic surfactant is,the better the catalysis effect will be,and the addition of inorganic electrolyte into the aqueous phase can markedly promote the catalysis effect.

  20. Glassy states in attractive micellar systems

    Mallamace, F.; Broccio, M.; Faraone, A.; Chen, W. R.; Chen, S.-H.


    Recent mode coupling theory (MCT) calculations show that in attractive colloids one may observe a new type of glass originating from clustering effects, as a result of the attractive interaction. This happens in addition to the known glass-forming mechanism due to cage effects in the hard sphere system. MCT also indicates that, within a certain volume fraction range, varying the external control parameter, the effective temperature, makes the glass-to-liquid-to-glass re-entrance and the glass-to-glass transitions possible. Here we present experimental evidence and details on this complex phase behavior in a three-block copolymer micellar system.

  1. Hydrogels with micellar hydrophobic (nanodomains

    Miloslav ePekař


    Full Text Available Hydrogels containing hydrophobic domains or nanodomains, especially of the micellar type, are reviewed. Examples of the reasons for introducing hydrophobic domains into hydrophilic gels are given; typology of these materials is introduced. Synthesis routes are exemplified and properties of a variety of such hydrogels in relation with their intended applications are described. Future research needs are identified briefly.

  2. Detection of Molecular Weight of PMCA Isoform with 20 cm SDS PAGE Electrophoresis:Compared with 8 cm SDS PAGE

    Hui Yang; Junwen Zeng


    Purpose: To compare the effect of 20 cm SDS-PAGE electrophoresis, which is most widely used in proteomic research, in identifying human lens epithelium B3 (HLE B3) cells plasma membrane calcium ATPase (PMCA) isoform's apparent molecular weight (MW), with that of 8 cm SDS-PAGE electrophoresis.Method: HLE B-3 cells were cultured and membrane protein sample was collected. Part of the sample is electrophoresised with 20 cm gel, 16 mA/gel for 1.5 hrs and then 24 mA/gel for 4~5 hrs. The same sample is electrophoresised with 8cm mini gel, 200V for 2 hrs. Protein marker of known MW was run with the sample in the same gel. The resulting separated proteins were transferred to polyvinylidene difluoride (PVDF) membrane and Western blot were used to identify the PMCA isoform with specific antibody against PMCA 1, 2, 4. The apparent MW was calculated in reference to the known protein marker that was electrophoresised in the same gel.Result: In 8 cm gel the distance between 208 kDa and 126 kDa band was about 6.1 mm,while that of 20 cm gel was 32.8 mm. The distance between 126 kDa and 97 kDa was about 5.2 mm, while that of 20 cm gel was 20.2 mm. The migration distance differences of protein bands were significantly much longer in 20 cm gel than in 8 cm gel (P < 0.005).But the bands were generally more condensed in 8 cm gel. The apparent MW of PMCA1,2, 4 were 153.8, 153.5 and 152.9 kDa respectively. In the 20 cm gel, the apparent MW for PMCA1, 2, 4 was 153.1, 125.5 and 147.4 kDa respectively.Conclusion: Both the 20 cm gel and 8 cm gel successful identified PMCA 1,2, 4 in HLE B-3 cells. The apparent MW for PMCA1, 2, 4 was 153.8, 153.5 and 152.9 kDa respectively in 8 cm gel,and 153.1,125.5 and 147.4 kDa respectively in 20 cm gel.PMCA2 probably had some kinds of degradation during the long electrophoresis time in 20 cm gel.

  3. Micellar systems: Novel family for drug carriers

    Rana, Meenakshi; Chowdhury, Papia


    Micellar systems have attracted a great deal of interest, especially in the field of biomedical sciences. The paper deals with the encapsulation behavior of Pyrrole-2-carboxyldehyde (PCL) an anti-cancer drug in different micellar systems. The inculsion capability of PCL is verified experimentally (UV-Vis, Photoluminescence and Raman spectroscopy) in polymer matrix. Two-micellar systems sodium dodecyl sulfate (SDS) and Polysorbate 80 (TWEEN 80) have been studied with a poorly water soluble PCL. The present work provides the effects of biocompatible organic PCL molecule entrap in micellar system in polymer phase due to its vast applicability in drug industry.

  4. Micellar electrokinetic chromatography on microchips.

    Kitagawa, Fumihiko; Otsuka, Koji


    This review highlights the methodological and instrumental developments in microchip micellar EKC (MCMEKC) from 1995. The combination of higher separation efficiencies in micellar EKC (MEKC) with high-speed separation in microchip electrophoresis (MCE) should provide high-throughput and high-performance analytical systems. The chip-based separation technique has received considerable attention due to its integration ability without any connector. This advantage allows the development of a multidimensional separation system. Several types of 2-D separation microchips are described in the review. Since complicated channel configurations can easily be fabricated on planar substrates, various sample manipulations can be carried out prior to MCMEKC separations. For example, mixing for on-chip reactions, on-line sample preconcentration, on-chip assay, etc., have been integrated on MEKC microchips. The application of on-line sample preconcentration to MCMEKC can provide not only sensitivity enhancement but also the elucidation of the preconcentration mechanism due to the visualization ability of MCE. The characteristics of these sample manipulations on MEKC microchips are presented in this review. The scope of applications in MCMEKC covers mainly biogenic compounds such as amino acids, peptides, proteins, biogenic amines, DNA, and oestrogens. This review provides a comprehensive table listing the applications in MCMEKC in relation to detection methods.

  5. CASK interacts with PMCA4b and JAM-A on the mouse sperm flagellum to regulate Ca2+ homeostasis and motility.

    Aravindan, Rolands G; Fomin, Victor P; Naik, Ulhas P; Modelski, Mark J; Naik, Meghna U; Galileo, Deni S; Duncan, Randall L; Martin-Deleon, Patricia A


    Deletion of the highly conserved gene for the major Ca(2+) efflux pump, Plasma membrane calcium/calmodulin-dependent ATPase 4b (Pmca4b), in the mouse leads to loss of progressive and hyperactivated sperm motility and infertility. Here we first demonstrate that compared to wild-type (WT), Junctional adhesion molecule-A (Jam-A) null sperm, previously shown to have motility defects and an abnormal mitochondrial phenotype reminiscent of that seen in Pmca4b nulls, exhibit reduced (P JAM-A on the proximal principal piece, acts as a common interacting partner of both. Importantly, CASK binds alternatively and non-synergistically with each of these molecules via its single PDZ (PDS-95/Dlg/ZO-1) domain to either inhibit or promote efflux. In the absence of CASK-JAM-A interaction in Jam-A null sperm, CASK-PMCA4b interaction is increased, resulting in inhibition of PMCA4b's enzymatic activity, consequent Ca(2+) accumulation, and a ∼6-fold over-expression of constitutively ATP-utilizing CASK, compared to WT. Thus, CASK negatively regulates PMCA4b by directly binding to it and JAM-A positively regulates it indirectly through CASK. The decreased motility is likely due to the collateral net deficit in ATP observed in nulls. Our data indicate that Ca(2+) homeostasis in sperm is maintained by the relative ratios of CASK-PMCA4b and CASK-JAM-A interactions.

  6. Pseudomyxoma peritonei – two novel orthotopic mouse models portray the PMCA-I histopathologic subtype

    Wiig Johan N


    Full Text Available Abstract Background Pseudomyxoma peritonei (PMP is a rare malignant disease, most commonly originating from appendiceal lesions and characterized by accumulation of mucinous tumor tissue in the peritoneal cavity. Since the disease is infrequent, the task of carrying out studies of treatment efficacy and disease biology in the clinical setting is challenging, warranting the development of relevant in vitro and in vivo PMP models. Methods Human tumor tissue was implanted in the peritoneal cavity of nude mice to establish two orthotopic models exhibiting noninvasive intraperitoneal growth without metastasis development. Results Xenograft tissues have retained essential properties of the original human tumors, such as macro- and microscopic growth patterns, mucin production as well as expression of carcinoembryonal antigen, cytokeratins 20 and 7 and the proliferation marker pKi67. Upon microscopic examination, the human tumors were categorized as the PMCA-I (peritoneal mucinous carcinomatosis of intermediate features subtype, which was conserved through 14 examined passages in mice, for the first time modeling this particular histopathologic category. Conclusion In conclusion, two novel orthotopic models of human PMP have been established that consistently portray a distinct histopathologic subtype and reflect essential human tumor properties. Xenografts can easily and reproducibly be transferred to new generations of mice with acceptable passage periods, rendering the models as attractive tools for further studies of PMP biology and treatment.

  7. Capillary Separation: Micellar Electrokinetic Chromatography

    Terabe, Shigeru


    Micellar electrokinetic chromatography (MEKC), a separation mode of capillary electrophoresis (CE), has enabled the separation of electrically neutral analytes. MEKC can be performed by adding an ionic micelle to the running solution of CE without modifying the instrument. Its separation principle is based on the differential migration of the ionic micelles and the bulk running buffer under electrophoresis conditions and on the interaction between the analyte and the micelle. Hence, MEKC's separation principle is similar to that of chromatography. MEKC is a useful technique particularly for the separation of small molecules, both neutral and charged, and yields high-efficiency separation in a short time with minimum amounts of sample and reagents. To improve the concentration sensitivity of detection, several on-line sample preconcentration techniques such as sweeping have been developed.

  8. Catalysis in micellar and macromoleular systems

    Fendler, Janos


    Catalysis in Micellar and Macromolecular Systems provides a comprehensive monograph on the catalyses elicited by aqueous and nonaqueous micelles, synthetic and naturally occurring polymers, and phase-transfer catalysts. It delineates the principles involved in designing appropriate catalytic systems throughout. Additionally, an attempt has been made to tabulate the available data exhaustively. The book discusses the preparation and purification of surfactants; the physical and chemical properties of surfactants and micelles; solubilization in aqueous micellar systems; and the principles of

  9. Quantification of Lipophilicity of 1,2,4-Triazoles Using Micellar Chromatography.

    Janicka, Małgorzata; Stępnik, Katarzyna; Pachuta-Stec, Anna


    High-performance liquid chromatography (HPLC), over-pressured-layer chromatography (OPLC) and thin-layer chromatography (TLC) techniques with micellar mobile phases were proposed to evaluate the lipophilicity of 21 newly synthesized 1,2,4-triazoles, compounds of potential importance in medicine or agriculture as fungicides. Micellar parameters log k(m) were compared with extrapolated R(M0) values determined from reversed-phase (RP) TLC experimental data obtained on RP-8 stationary phases as well as with log P values (Alog Ps, AClog P, Alog P, Mlog P, KowWin, xlog P2 and xlog P3) calculated from molecular structures of solutes tested. The results obtained by applying principal component analysis (PCA) and linear regression showed considerable similarity between partition and retention parameters as alternative lipophilicity descriptors, and indicated micellar chromatography as a suitable technique to study lipophilic properties of organic substances. In micellar HPLC, RP-8e column (Purospher) was applied, whereas in OPLC and TLC, RP-CN plates were applied, which was the novelty of this study and allowed the use of micellar effluents in planar chromatography measurements.

  10. Effect of mixed micellar lipid on the absorption of cholesterol and vitamin D3 into lymph

    Thompson, Gilbert R.; Ockner, Robert K.; Isselbacher, Kurt J.


    The absorption of endogenous cholesterol, labeled with tracer doses of cholesterol 14C or cholesterol-3H and of near physiological doses of vitamin D3-3H was studied in rats with cannulated intestinal lymphatics. The effects of administering mixed micellar solutions of fatty acid, monoglyceride, and bile salt on the absorption of these labeled sterols was determined. It was observed that the specific activity of free cholesterol and the amounts of vitamin D3 appearing in lymph were significantly increased during the intraduodenal administration of mixed micellar solutions of either linoleic or palmitic acid, in contrast to control rats receiving a micellar solution of taurocholate. These increases were related linearly to the lymph triglyceride level. In addition it was observed that when the linoleic acid solution was administered there was a more marked increase in the ratio of the specific activities of free and esterified cholesterol in lymph than with either the palmitic acid or taurocholate solutions. Additional studies in rats with intact lymphatics showed that the uptake of labeled cholesterol and vitamin D3 from the intestinal lumen into the wall was similar whether the sterols were administered in taurocholate or in mixed micellar solution. These findings suggest that mixed micellar lipid increased the rate of appearance of labeled free cholesterol and vitamin D3 in lymph by enhancing their transport out of the intestinal mucosa, rather than by an effect on uptake. PMID:4303790

  11. Use of micellar liquid chromatography to analyze darunavir, ritonavir, emtricitabine, and tenofovir in plasma.

    Peris-Vicente, Juan; Villarreal-Traver, Mónica; Casas-Breva, Inmaculada; Carda-Broch, Samuel; Esteve-Romero, Josep


    Danuravir, ritonavir, emtricitabine, and tenofovir are together prescribed against AIDS as a highly active antiretroviral therapy regimen. Micellar liquid chromatography has been applied to determine these four antiretroviral drugs in plasma. The sample preparation is shortened to the dilution of the sample in a micellar solution, filtration, and injection. Clean-up steps are avoided, due to the solubilization of plasma matrix in micellar media. The drugs were analyzed in 0.995), accuracy (89.3-103.2%), precision (<8.2%) and robustness (<7.5%). Real plasma sample from patients taking this therapy were analyzed. This is the first paper showing the simultaneous detection of this four drugs. Therefore, the methodology was proven useful for the routine analysis of these samples in a hospital laboratory for clinical purposes.

  12. Wheat alkylresorcinols reduce micellar solubility of cholesterol in vitro and increase cholesterol excretion in mice.

    Horikawa, Kazumasa; Hashimoto, Chiaki; Kikuchi, Yosuke; Makita, Miki; Fukudome, Shin-Ichi; Okita, Kimiko; Wada, Naoyuki; Oishi, Katsutaka


    Epidemiological studies have shown that the consumption of whole grains can reduce risk for metabolic disorders. We recently showed that chronic supplementation with wheat alkylresorcinols (ARs) prevents glucose intolerance and insulin resistance with hepatic lipid accumulation induced in mice by a high-fat high-sucrose diet (HFHSD). This study examines the effects of ARs on the micellar solubility of cholesterol in vitro, as well as the effects of transient AR supplementation on faecal lipid excretion and plasma lipid levels in mice. We found that ARs formed bile micelles with taurocholate independently of phospholipids, and dose-dependently decreased the micellar solubility of cholesterol in a biliary micelle model. Transient AR supplementation with HFHSD increased faecal cholesterol and triglyceride contents and decreased plasma cholesterol concentrations. These suggest that one underlying mechanism through which ARs suppress diet-induced obesity is by interfering with the micellar cholesterol solubilisation in the digestive tract, which subsequently decreases cholesterol absorption.

  13. Conformational transition and mass transfer in extraction of proteins by AOT--alcohol--isooctane reverse micellar systems.

    Hong, D P; Lee, S S; Kuboi, R


    We examined quantitatively the effect of alcohols on protein and reverse micellar structure. We used circular dichroism (CD) to compare the effects of various alcohols on the protein structure, and percolation phenomena to evaluate the effects of various alcohols on reverse micellar structure. Upon the addition of alcohols to the bulk aqueous phase, proteins were denatured significantly, depending on the alcohol species and concentration, suggesting that use of alcohol directly to the stripping solution is not effective in back-extraction processes of proteins. In the present study, a new method, a small amount of alcohol is added to the surfactant-organic solution to improve the back-extraction behaviors of proteins. Practically, in the back-extraction process, the alcohols suppressing the cluster formation of reverse micelles (high value of beta1), remarkably improved the back-extraction behavior of proteins. In addition, the same alcohol molecules showed a positive effect on the rate and fraction of protein back-extraction. From a result of the CD measurement of the back-extracted proteins, it was known that the alcohols added to reverse micellar solution allowed the proteins to back-extract safely without causing structural changes. These results show that the values of beta(t), defined by the variation of percolation processes, and the back-extraction behaviors of proteins have a good relationship, suggesting that the back-extraction processes were controlled by the micellar-micellar and protein-micellar interactions.

  14. Functional Characterization of an Aspergillus fumigatus Calcium Transporter (PmcA) that Is Essential for Fungal Infection

    Dinamarco, Taísa Magnani; Freitas, Fernanda Zanolli; Almeida, Ricardo S.; Brown, Neil Andrew; dos Reis, Thaila Fernanda; Ramalho, Leandra Naira Zambelli; Savoldi, Marcela; Goldman, Maria Helena S.; Bertolini, Maria Célia; Goldman, Gustavo Henrique


    Aspergillus fumigatus is a primary and opportunistic pathogen, as well as a major allergen, of mammals. The Ca+2-calcineurin pathway affects virulence, morphogenesis and antifungal drug action in A. fumigatus. Here, we investigated three components of the A. fumigatus Ca+2-calcineurin pathway, pmcA,-B, and -C, which encode calcium transporters. We demonstrated that CrzA can directly control the mRNA accumulation of the pmcA-C genes by binding to their promoter regions. CrzA-binding experiments suggested that the 5′-CACAGCCAC-3′ and 5′-CCCTGCCCC-3′ sequences upstream of pmcA and pmcC genes, respectively, are possible calcineurin-dependent response elements (CDREs)-like consensus motifs. Null mutants were constructed for pmcA and -B and a conditional mutant for pmcC demonstrating pmcC is an essential gene. The ΔpmcA and ΔpmcB mutants were more sensitive to calcium and resistant to manganese and cyclosporin was able to modulate the sensitivity or resistance of these mutants to these salts, supporting the interaction between calcineurin and the function of these transporters. The pmcA-C genes have decreased mRNA abundance into the alveoli in the ΔcalA and ΔcrzA mutant strains. However, only the A. fumigatus ΔpmcA was avirulent in the murine model of invasive pulmonary aspergillosis. PMID:22649543

  15. Adsorption characteristics of zinc ions on sodium dodecyl sulfate in process of micellar-enhanced ultrafiltration


    To separate zinc ions from aqueous solution efficiently, micellar-enhanced ultrafiltration(MEUF) of hollow ultrafiltration membrane was used with sodium dodecyl sulfate(SDS) as surfactant. The formation of micellar and the adsorption mechanism were investigated, including the influence of the ratio of SDS to zinc ions on the micelle quantity, the micelle ratio, the gross adsorptive capacity, the rejection of zinc ions and the adsorption isotherm law. The results show that the rejection rate of zinc ions reaches 97% and the adsorption of zinc ions on SDS conforms to the Langmuir adsorption isotherm and the adsorption is a chemical adsorption process.

  16. Brownian Dynamics Simulation of Microstructures and Elongational Viscosities of Micellar Surfactant Solution

    WEI Jin-Jia; KAWAGUCHI Yasuo; YU Bo; LI Feng-Chen


    @@ Brownian dynamics simulation is conducted for a dilute surfactant solution under a steady uniaxial elongational flow.A new inter-cluster potential is used for the interaction among surfactant micelles to determine the micellar network structures in the surfactant solution.The micellar network is successfully simulated.It is formed at low elongation rates and destroyed by high elongation rates.The computed elongational viscosities show elongation-thinning characteristics.The relationship between the elongational viscosities and the microstructure of the surfactant solution is revealed.

  17. Hydrogels with Micellar Hydrophobic (Nano)Domains

    Pekař, Miloslav


    Hydrogels containing hydrophobic domains or nanodomains, especially of the micellar type, are reviewed. Examples of the reasons for introducing hydrophobic domains into hydrophilic gels are given; typology of these materials is introduced. Synthesis routes are exemplified and properties of a variety of such hydrogels in relation with their intended applications are described. Future research needs are identified briefly.

  18. Hydrogels with micellar hydrophobic (nano)domains

    Miloslav ePekař


    Hydrogels containing hydrophobic domains or nanodomains, especially of the micellar type, are reviewed. Examples of the reasons for introducing hydrophobic domains into hydrophilic gels are given; typology of these materials is introduced. Synthesis routes are exemplified and properties of a variety of such hydrogels in relation with their intended applications are described. Future research needs are identified briefly.

  19. Hydrogels with micellar hydrophobic (nano)domains

    Pekař, Miloslav


    Hydrogels containing hydrophobic domains or nanodomains, especially of the micellar type, are reviewed. Examples of the reasons for introducing hydrophobic domains into hydrophilic gels are given; typology of these materials is introduced. Synthesis routes are exemplified and properties of a variety of such hydrogels in relation with their intended applications are described. Future research needs are identified briefly.

  20. Micellar lipid composition affects micelle interaction with class B scavenger receptor extracellular loops.

    Goncalves, Aurélie; Gontero, Brigitte; Nowicki, Marion; Margier, Marielle; Masset, Gabriel; Amiot, Marie-Josèphe; Reboul, Emmanuelle


    Scavenger receptors (SRs) like cluster determinant 36 (CD36) and SR class B type I (SR-BI) play a debated role in lipid transport across the intestinal brush border membrane. We used surface plasmon resonance to analyze real-time interactions between the extracellular protein loops and various ligands ranging from single lipid molecules to mixed micelles. Micelles mimicking physiological structures were necessary for optimal binding to both the extracellular loop of CD36 (lCD36) and the extracellular loop of SR-BI (lSR-BI). Cholesterol, phospholipid, and fatty acid micellar content significantly modulated micelle binding to and dissociation from the transporters. In particular, high phospholipid micellar concentrations inhibited micelle binding to both receptors (-53.8 and -74.4% binding at 0.32 mM compared with 0.04 mM for lCD36 and lSR-BI, respectively, P < 0.05). The presence of fatty acids was crucial for micelle interactions with both proteins (94.4 and 81.3% binding with oleic acid for lCD36 and lSR-BI, respectively, P < 0.05) and fatty acid type substitution within the micelles was the component that most impacted micelle binding to the transporters. These effects were partly due to subsequent modifications in micellar size and surface electric charge, and could be correlated to micellar vitamin D uptake by Caco-2 cells. Our findings show for the first time that micellar lipid composition and micellar properties are key factors governing micelle interactions with SRs.

  1. Micellar liquid chromatography of terephthalic acid impurities.

    Richardson, Ashley E; McPherson, Shakeela D; Fasciano, Jennifer M; Pauls, Richard E; Danielson, Neil D


    The production of terephthalic acid (TPA) by oxidation of p-xylene is an important industrial process because high purity TPA is required for the synthesis of polyethylene terephthalate, the primary polymer used to make plastic beverage bottles. Few separation methods have been published that aim to separate TPA from eight major aromatic acid impurities. This work describes a "green" micellar liquid chromatography (MLC) method using a C18 column (100×2.1mm, 3.5μm), an acidic 1% sodium dodecyl sulfate (SDS) mobile phase, and a simple step flow rate gradient to separate TPA and eight impurities in less than 20min. The resulting chromatogram shows excellent peak shape and baseline resolution of all nine acids, in which there are two sets of isomers. Partition coefficients and equilibrium constants have been calculated for the two sets of isomers by plotting the reciprocal of the retention factor versus micelle concentration. Quantitation of the nine analytes in an actual industrial TPA sample is possible. Limits of detection for all nine acids range from 0.180 to 1.53ppm (2.16-19.3 pmoles) and limits of quantitation range from 0.549 to 3.45ppm (6.48-43.0 pmoles). In addition, the method was tested on two other reversed phase C18 columns of similar dimensions and particle diameter from different companies. Neither column showed quite the same peak resolution as the original column, however slight modifications to the mobile phase could improve the separation. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Conductivity measurements in a shear-banding wormlike micellar system.

    Photinos, Panos J; López-González, M R; Hoven, Corey V; Callaghan, Paul T


    Shear banding in the cetylpyridinium chloride/sodium salicylate micellar system is investigated using electrical conductivity measurements parallel to the velocity and parallel to the vorticity in a cylindrical Couette cell. The measurements show that the conductivity parallel to the velocity (vorticity) increases (decreases) monotonically with applied shear rate. The shear-induced anisotropy is over one order of magnitude lower than the anisotropy of the N(c) nematic phase. The steady-state conductivity measurements indicate that the anisotropy of the shear induced low-viscosity (high shear rate) phase is not significantly larger than the anisotropy of the high viscosity (low shear rate) phase. We estimate that the micelles in the shear induced low viscosity band are relatively short, with a characteristic length to diameter ratio of 5-15. The relaxation behavior following the onset of shear is markedly different above and below the first critical value γ1, in agreement with results obtained by other methods. The transient measurements show that the overall anisotropy of the sample decreases as the steady state is approached, i.e., the micellar length/the degree of order decrease.

  3. Micellar Enzymology for Thermal, pH, and Solvent Stability.

    Minteer, Shelley D


    This chapter describes methods for enzyme stabilization using micellar solutions. Micellar solutions have been shown to increase the thermal stability, as well as the pH and solvent tolerance of enzymes. This field is traditionally referred to as micellar enzymology. This chapter details the use of ionic and nonionic micelles for the stabilization of polyphenol oxidase, lipase, and catalase, although this method could be used with any enzymatic system or enzyme cascade system.

  4. Worming Their Way into Shape: Toroidal Formations in Micellar Solutions

    Cardiel Rivera, Joshua J.; Tonggu, Lige; Dohnalkova, Alice; de la Iglesia, Pablo; Pozzo, Danilo C.; Shen, Amy


    We report the formation of nanostructured toroidal micellar bundles (nTMB) from a semidilute wormlike micellar solution, evidenced by both cryogenicelectron microscopy and transmission electron microscopy images. Our strategy for creating nTMB involves a two-step protocol consisting of a simple prestraining process followed by flow through a microfluidic device containing an array of microposts, producing strain rates in the wormlike micelles on the order of 105 s^1. In combination with microfluidic confinement, these unusually large strain rates allow for the formation of stable nTMB. Electron microscopy images reveal a variety of nTMB morphologies and provide the size distribution of the nTMB. Small-angle neutron scattering indicates the underlying microstructural transition from wormlike micelles to nTMB. We also show that other flow-induced approaches such as sonication can induce and control the emergence of onion-like and nTMB structures, which may provide a useful tool for nanotemplating.

  5. [Solubilization of nitrobenzene in micellar solutions of Tween 80 and inorganic salts].

    Li, Sui; Zhao, Yong-sheng; Xu, Wei; Dai, Ning


    The solubilization of nitrobenzene by a nonionic surfactant Tween 80 was investigated at 10 degrees C. Experimental results indicated that the solubility of nitrobenzene in water was greatly enhanced by Tween 80 at surfactant concentration above CMC(critical micelle concentration) and a linear relationship was obtained between surfactant concentration and nitrobenzene concentration from the solubility curve. The molar solubilization ratio (MSR) value was 5.093 and IgKm was 3.499. The solubilization was attributed to the ethoxylation group in Tween 80 micellar. Effect of four inorganic salts such as NaCl, KCl, CaCl2 , MgCl2 on water solubilities of nitrobenzene in Tween 80 micellar solutions was also investigated by a matrix of batch experiments. Mix the Tween 80-inorganic salts at the total mass ratios of 2:1, 5:1 and 10:1. The results show that the inorganic salts at a high concentration( > or = 500 mg x L(-1)) can enhance the solubilization capacities of Tween 80 micellar solution and increase the value of MSR and IgKm . Because of the salting-out effect between the micellar of Tween 80 and inorganic salts, the volume of micelle turns bigger, which may provide larger solubility volume for nitrobenzene. The mixture of nonionic surfactant and inorganic salts can be used in subsurface remediation as a flushing solution.

  6. El Dorado Micellar-Polymer Demonstration Project third annual report, June 1976--August 1977

    Rosenwald, G.W.; Miller, R.J.; Vairogs, J. (eds.)


    The primary objectives of this project are to determine the economic feasibility of improved oil recovery using two micellar-polymer processes and to determine the associated benefits and problems of each process. The El Dorado Demonstration Project is designed to allow a side-by-side comparison of two distinct micellar-polymer processes in the same field so that the reservoir conditions for the two floods are as nearly alike as possible. Selection of sulfonates and polymers for both patterns was completed. Salinity changes in produced fluids and in observation well samples have shown that breakthrough of preflush (or preflood) has occurred at some wells in both patterns. Observation well sampling and logging data showed that preflush arrived earlier at the observation wells in the north pattern than the south pattern. Injectivities of the micellar system designed for the south pattern and components of that system were tested in three monitoring wells. Similarly, extensive injectivity testing of the surfactant and polymer slugs designed for the north pattern was conducted using two monitoring wells. Recommended preflush volumes for the south pattern were revised to reflect corrections in reservoir data (primarily due to the lack of the upper zone at well MP-213). Reservoir pressure forecasts of the superposition-of-line-sources simulator were compared with observed monitoring well pressures. Injection of the chemical preflush for the south pattern began on June 20, 1976. The micellar fluid injection began in the south pattern on March 22, 1977. (LK)

  7. Effect of the salt-induced micellar microstructure on the nonlinear shear flow behavior of ionic cetylpyridinium chloride surfactant solutions

    Gaudino, D.; Pasquino, R.; Kriegs, H.; Szekely, N.; Pyckhout-Hintzen, W.; Lettinga, M. P.; Grizzuti, N.


    The shear flow dynamics of linear and branched wormlike micellar systems based on cetylpyridinium chloride and sodium salicylate in brine solution is investigated through rheometric and scattering techniques. In particular, the flow and the structural flow response are explored via velocimetry measurements and rheological and rheometric small-angle neutron scattering (SANS) experiments, respectively. Although all micellar solutions display a similar shear thinning behavior in the nonlinear regime, the experimental results show that shear banding sets in only when the micelle contour length L ¯ is sufficiently long, independent of the nature of the micellar connections (either linear or branched micelles). Using rheometric SANS, we observe that the shear banding systems both show very similar orientational ordering as a function of Weissenberg number, while the short branched micelles manifest an unexpected increase of ordering at very low Weissenberg numbers. This suggests the presence of an additional flow-induced relaxation process that is peculiar for branched systems.

  8. A theory of phase separation in asphaltene-micellar solutions

    Pacheco Sanchez, Juan H. [Instituto Mexicano del Petroleo, Mexico D.F. (Mexico)


    A theory of phase separation in micellar solutions of asphaltene in aromatic hydrocarbons was reported in this paper, based on both the approach of the phase behavior of amphiphile/water micelles, and the self-association of asphaltene in aromatic core. Several experimental techniques have been used by different investigators showing the existence of some kind of critical micellar concentration (CMC) on asphaltenes in aromatic solutions. So, at least asphaltene-monomer and asphaltene-micellar phases are experimentally demonstrated facts. These two phases are the main purpose in this report on a theoretical model. Some results show the temperature versus asphaltene concentration phase diagram. The phase diagram is examined against the limited critical micelle concentration data for asphaltenes-in-toluene systems. Such phase diagram is also qualitatively examined against an experimental demonstration of phase separation. The asphaltene-micelle growth depends on the parameter K responsible for the shape and size of it. At the same time, parameter K depends on both the number of asphaltene-monomer associated in the asphaltene-micelle, and the chemical potentials in the interior and in the periphery of the micelle. An expression for getting the number of asphaltene-monomers self-associated in the asphaltene-micelle was obtained. [Spanish] Se reporta una teoria de separacion de fases en soluciones micelares de asfalteno en hidrocarburos aromaticos, basada tanto en la conducta de fase de micelas formadas por anififilos en agua como en la autoasociacion de asfaltenos en nucleos aromaticos. Se han usado diversas tecnicas experimentales por diferentes investigadores que demuestran la existancia de algun tipo de concentracion micelar critica (CMC) de soluciones de asfaltenos en aromaticos. Entonces, al menos las fases de asfalteno-monomerico y de asfalteno-micelar son hechos experimentalmente demostrados. Esta dos fases son el principal proposito de este reporte en un modelo

  9. Dielectric relaxation spectroscopy shows a sparingly hydrated interface and low counterion mobility in triflate micelles.

    Lima, Filipe S; Chaimovich, Hernan; Cuccovia, Iolanda M; Buchner, Richard


    The properties of ionic micelles are affected by the nature of the counterion. Specific ion effects can be dramatic, inducing even shape and phase changes in micellar solutions, transitions apparently related to micellar hydration and counterion binding at the micellar interface. Thus, determining the hydration and dynamics of ions in micellar systems capable of undergoing such transitions is a crucial step in understanding shape and phase changes. For cationic micelles, such transitions are common with large organic anions as counterions. Interestingly, however, phase separation also occurs for dodecyltrimethylammonium triflate (DTATf) micelles in the presence of sodium triflate (NaTf). Specific ion effects for micellar solutions of dodecyltrimethylammonium chloride (DTAC), bromide (DTAB), methanesulfonate (DTAMs), and triflate (DTATf) were studied with dielectric relaxation spectroscopy (DRS), a technique capable of monitoring hydration and counterion dynamics of micellar aggregates. In comparison to DTAB, DTAC, and DTAMs, DTATf micelles were found to be considerably less hydrated and showed reduced counterion mobility at the micellar interface. The obtained DTATf and DTAMs data support the reported central role of the anion's -CF3 moiety with respect to the properties of DTATf micelles. The reduced hydration observed for DTATf micelles was rationalized in terms of the higher packing of this surfactant compared to that of other DTA-based systems. The decreased mobility of Tf(-) anions condensed at the DTATf interface strongly suggests the insertion of Tf(-) in the micellar interface, which is apparently driven by the strong hydrophobicity of -CF3.

  10. Pseudo Peak Phenomena in Micellar Electrokinetic Capillary Chromatography by Using Ionic Surfactant


    The origin of pseudo peak was studied by means of micellar electrokinetic capillary chromatography with cetyltrimethylaminium bromide as the pseudo stationary phase. It has been pointed that two peaks may appear for one component under certain conditions. Experiments showed that the relative areas of the two peaks of analyte depended on the time and the temperature of reaction between analyte and surfactant, and the concentration of surfactant in the sample solution. It means that the interaction between the analyte and the surfactant is a slow process, and a stable substance can be produced from the interaction. It is the substance and the analyte that may lead to the formation of two peaks. The fast interaction mechanism between the solute and the micellar should be queried from the experiment result.

  11. Pseudo Peak Phenomena in Micellar Electrokinetic Capillary Chromatography by Using Ionic Surfactant

    CHENGuan-hua; YANGGeng-liang; TIANYi-ling; CHENYi


    The origin of pseudo peak was studied by means of micellar electrokinetic capillary chromatography with cetyltrimethylaminium bormide as the pseudo stationary phase.It has been pointed that two peaks may appear for one component under certain conditions.Experiments showed that the relative areas of the two peaks of analyte depended on the time and the temperature of reaction between analyte and surfactant,and the concentration of surfactant in the sample solution.It means that the interaction between the analyte and the surfactant is a slow process,and a stable substance can be produced from the interaction.It is the substance and the analyte that may lead to the formation of two peaks.The fast interaction mechanism between the solute and the micellar should be queried from the experiment result.

  12. A core cross-linked polymeric micellar platium(IV) prodrug with enhanced anticancer efficiency.

    Hou, Jie; Shang, Jincai; Jiao, Chengbin; Jiang, Peiyue; Xiao, Huijie; Luo, Lan; Liu, Tongjun


    A core cross-linked polymeric micellar cisplatin(IV) conjugate prodrug is prepared by attaching the cisplatin(IV) to mPEG-b-PLL biodegradable copolymers to form micellar nanoparticles that can disintegrate to release the active anticancer agent cisplatin(II) in a mild reducing environment. Moreover, in vitro studies show that this cisplatin(IV) conjugate prodrug displays enhanced cytotoxicity against HepG2 cancer cells compared with cisplatin(II). Further studies demonstrate that the high cellular uptake and platinum-DNA adduct of this cisplatin(IV) conjugate prodrug can induce more cancer-cell apoptosis than cisplatin(II), which is responsible for its enhanced anticancer activity.

  13. Mixed-micellar proliposomal systems for enhanced oral delivery of progesterone.

    Potluri, Praveen; Betageri, Guru V


    The objective of our study was to develop a mixed-micellar proliposomal formulation of poorly water-soluble drug progesterone and evaluate the dissolution profile and membrane transport. Several formulations of proliposomes were prepared by mixing different concentrations of lipid, progesterone, polysorbate 80, and microcrystalline cellulose. The mixed-micellar formulation of drug:dimyristoyl-phosphatidycholine:polysorbate 80 (1:20:3.3) exhibited the maximum dissolution (75.27%), while pure progesterone resulted in low dissolution. The above formulation showed a 4-fold increase in transport in Caco-2 cells and a 6-fold increase in transport across the everted rat intestinal sac experiments compared with control. Proliposomal formulations enhance the extent of dissolution and membrane transport of progesterone and serve as ideal carriers for oral delivery of drugs with low water solubility.

  14. Glutathione transferase mimics : Micellar catalysis of an enzymic reaction

    Lindkvist, Björn; Weinander, Rolf; Engman, Lars; Koetse, Marc; Engberts, Jan B.F.N.; Morgenstern, Ralf


    Substances that mimic the enzyme action of glutathione transferases (which serve in detoxification) are described. These micellar catalysts enhance the reaction rate between thiols and activated halogenated nitroarenes as well as alpha,beta-unsaturated carbonyls. The nucleophilic aromatic substituti

  15. Small-angle neutron scattering from micellar solutions

    V K Aswal; P S Goyal


    Micellar solutions are the suspension of the colloidal aggregates of the surfactant molecules in aqueous solutions. The structure (shape and size) and the interaction of these aggregates, referred to as micelles, depend on the molecular architecture of the surfactant molecule, presence of additives and the solution conditions such as temperature, concentration etc. This paper gives the usefulness of small-angle neutron scattering to the study of micellar solutions with some of our recent results.

  16. Dye-sensitized photo-oxidation of amino acids in reversed micellar membrane mimetic system

    刘剑波; 张复实; 赵瑜; 赵福群; 唐应武; 宋心琦


    The photochemistry of a novel photosensitizer H[TBC(O’Pr)4P(OH)],and the photo-oxidation of amino acids sensitized by H[TBC(OiPr)4P(OH)] have been investigated in the AOT/H2O/toluene reversed micellar system.Absorption and fluorescence measurements indicate that H[TBC(O’Pr)4P(OH)] can interact with the re versed micelles by adsorption to the micellar surface,resulting in the disaggregation of the sensitizer and the enhance ment of its photoactivity.In micellar solutions,H[TBC(O’Pr)4P(OH)] can efficiently photo-generate O2(Type Ⅱ mechanism) and O2(Type Ⅰ mechanism) as shown by stationary photolysis and ESR spin-trapping techniques Amino acids dissolved in water pools of reversed micelles can be photo-oxidized via Type Ⅱ mechanism as sensitized by H[TBC(O’Pr)4P(OH)].The photo-oxidation of tryptophan follows the first-order kinetics,while that of tyrosine is much slower.Kinetic studies of the photodynamic behavior in this microheterogeneous system shows that the micro-heterogeneity can alter the mechani

  17. Simultaneous isocratic separation of phenolic acids and flavonoids using micellar liquid chromatography.

    Hadjmohammadi, Mohammad Reza; Nazari, S Saman S J


    The simultaneous isocratic separation of a mixture of five phenolic acids and four flavonoids (two important groups of natural polyphenolic compounds with very different polarities) was investigated in three different RPLC modes using a hydro-organic mobile phase, and mobile phases containing SDS at concentrations below and above the critical micellar concentration (submicellar LC and micellar LC (MLC), respectively). In the hydro-organic mode, methanol and acetonitrile; in the submicellar mode methanol; and in the micellar mode, methanol and 1-propanol were examined individually as organic modifiers. Regarding the other modes, MLC provided more appropriate resolutions and analysis time and was preferred for the separation of the selected compounds. Optimization of separation in MLC was performed using an interpretative approach for each alcohol. In this way, the retention of phenolic acids and flavonoids were modeled using the retention factors obtained from five different mobile phases, then the Pareto optimality method was applied to find the best compatibility between analysis time and quality of separation. The results of this study showed some promising advantages of MLC for the simultaneous separation of phenolic acids and flavonoids, including low consumption of organic solvent, good resolution, short analysis time, and no requirement of gradient elution.

  18. Mixtures of lecithin and bile salt can form highly viscous wormlike micellar solutions in water.

    Cheng, Chih-Yang; Oh, Hyuntaek; Wang, Ting-Yu; Raghavan, Srinivasa R; Tung, Shih-Huang


    The self-assembly of biological surfactants in water is an important topic for study because of its relevance to physiological processes. Two common types of biosurfactants are lecithin (phosphatidylcholine) and bile salts, which are both present in bile and involved in digestion. Previous studies on lecithin-bile salt mixtures have reported the formation of short, rodlike micelles. Here, we show that lecithin-bile salt micelles can be further induced to grow into long, flexible wormlike structures. The formation of long worms and their resultant entanglement into transient networks is reflected in the rheology: the fluids become viscoelastic and exhibit Maxwellian behavior, and their zero-shear viscosity can be up to a 1000-fold higher than that of water. The presence of worms is further confirmed by data from small-angle neutron and X-ray scattering and from cryo-transmission electron microscopy (cryo-TEM). We find that micellar growth peaks at a specific molar ratio (near equimolar) of bile salt:lecithin, which suggests a strong binding interaction between the two species. In addition, micellar growth also requires a sufficient concentration of background electrolyte such as NaCl or sodium citrate that serves to screen the electrostatic repulsion of the amphiphiles and to "salt out" the amphiphiles. We postulate a mechanism based on changes in the molecular geometry caused by bile salts and electrolytes to explain the micellar growth.

  19. Prion disease detection, PMCA kinetics, and IgG in urine from sheep naturally/experimentally infected with scrapie and deer with preclinical/clinical chronic wasting disease.

    Rubenstein, Richard; Chang, Binggong; Gray, Perry; Piltch, Martin; Bulgin, Marie S; Sorensen-Melson, Sharon; Miller, Michael W


    Prion diseases, also known as transmissible spongiform encephalopathies, are fatal neurodegenerative disorders. Low levels of infectious agent and limited, infrequent success of disease transmissibility and PrP(Sc) detection have been reported with urine from experimentally infected clinical cervids and rodents. We report the detection of prion disease-associated seeding activity (PASA) in urine from naturally and orally infected sheep with clinical scrapie agent and orally infected preclinical and infected white-tailed deer with clinical chronic wasting disease (CWD). This is the first report on PASA detection of PrP(Sc) from the urine of naturally or preclinical prion-diseased ovine or cervids. Detection was achieved by using the surround optical fiber immunoassay (SOFIA) to measure the products of limited serial protein misfolding cyclic amplification (sPMCA). Conversion of PrP(C) to PrP(Sc) was not influenced by the presence of poly(A) during sPMCA or by the homogeneity of the PrP genotypes between the PrP(C) source and urine donor animals. Analysis of the sPMCA-SOFIA data resembled a linear, rather than an exponential, course. Compared to uninfected animals, there was a 2- to 4-log increase of proteinase K-sensitive, light chain immunoglobulin G (IgG) fragments in scrapie-infected sheep but not in infected CWD-infected deer. The higher-than-normal range of IgG levels found in the naturally and experimentally infected clinical scrapie-infected sheep were independent of their genotypes. Although analysis of urine samples throughout the course of infection would be necessary to determine the usefulness of altered IgG levels as a disease biomarker, detection of PrP(Sc) from PASA in urine points to its potential value for antemortem diagnosis of prion diseases.

  20. Solubilization of parabens in aqueous Pluronic solutions: investigating the micellar growth and interaction as a function of paraben composition.

    Khimani, M; Ganguly, R; Aswal, V K; Nath, S; Bahadur, P


    The influence of methyl paraben (MP) and butyl paraben (BP) on the aggregation characteristics of Pluronics in an aqueous medium has been investigated by DLS, SANS, viscometry, and fluorescence measurement techniques. Parabens are extensively used as preservatives in cosmetic, pharmaceutical, and food products. In this paper, we show that their influence on the restructuring and growth of Pluronics micelles vary quite significantly with their aqueous solubility and with the composition of Pluronics. In the case of P105 and P104, MP reduces the sphere-to-rod transition temperature down to room temperature, but BP with significantly less aqueous solubility than MP suppresses such micellar transition and leads to the formation of micellar clusters due to the onset of intermicellar attractive interaction. In the case of more hydrophobic Pluronic P103, on the other hand, both MP and BP are able to induce rapid room temperature sphere-to-rod micellar growth, which is not observed in the presence of water structure making salts like NaCl and Na(3)PO(4). These observations have been attributed to modulation of growth and restructuring processes of the Pluronic micelles arising due to different locations of parabens within the micellar corona as determined by their aqueous solubility and the hydrophobicity of the Pluronics.

  1. Micellar Copolymerization:the State of the Arts

    FENG Yu-jun


    Over the past two decades, hydrophobically modified water-soluble polymers (HMWSPs),particularly hydrophobically associating polyacrylamides (HAPAMs), have attracted increased interest owing to their practical and fundamental importance[1]. This system usually consists of a hydrophilic backbone with a small proportion (generally less than 2 mol %) of hydrophobic pendent groups. When dissolved in aqueous solutions, the apolar moieties tend to exclude water and are held together by intra- and intermolecular hydrophobic associations. This leads to a transitional network structure that induces a substantial increase in solution viscosity. Such viscosity-building ability is further elevated upon adding salt or increasing temperature due to the enhanced polarity.Additionally, the dynamic associating junctions can be ruptured upon high shear stress, but re-formed when the force ceases. All these unique properties enable HAPAMs attractiveness to various industrial uses in which the control of fluid theology is required.However, it is a great challenge to synthesize HAPAMs since acrylamide and hydrophobic comonomers are mutually incompatible. After attempts using heterogeneous, inverse emulsion,microemulsion, and precipitation copolymerization processes, the commonly accepted method is micellar free radical copolymerization in which an appropriate surfactant is used to solubilize the hydrophobic comonomer[2].In this paper, the sate of the arts for micellar copolymerization is comprehensively reviewed:1. the mechanism of micellar copolymerization;2. parameters affecting micellar copolymerization, including:(1) nature and level of hydrophobic comonomer;(2) nature and content of surfactant used;(3) initiator and temperature.3. structural characteristics of HAPAMs prepared via micellar copolymerization;4. properties of HAPAMs prepared via micellar copolymerization:(1) dilute solution properties;(2) semi-dilute solution properties.5. applications of micellar copolymerization

  2. Crystallization in Micellar Cores: confinement effects and dynamics

    Lund, Reidar; Zinn, Thomas; Willner, Lutz; Department of Chemistry, University of Oslo Team; Forschungszentrum Jülich Collaboration

    It is well known that liquids confined to small nanoscopic pores and droplets exhibit thermal behavior very different from bulk samples. Here we demonstrate that n-alkanes forming 2-3 nm small micellar cores are considerably affected by confinement in analogue with hard confined systems. We study micelles form by self-assembly of a series of well-defined n-Alkyl-PEO polymers in aqueous solutions. By using small-angle X-ray scattering (SAXS), densiometry and differential scanning calorimetry (DSC), we show that n-alkane exhibit a first-order phase transition i.e. melting. Correlating the structural and thermodynamic data, we find that a melting depression can be accurately described by the Gibbs-Thomson equation. ∖f1 The effect of core crystallinity on the molecular exchange kinetics is investigated using time-resolved small-angle neutron scattering (TR-SANS). We show that there are considerable entropic and enthalpic contributions from the chain packing that affect the kinetic stability of micelles. ∖pard

  3. Principles of micellar electrokinetic capillary chromatography applied in pharmaceutical analysis.

    Hancu, Gabriel; Simon, Brigitta; Rusu, Aura; Mircia, Eleonora; Gyéresi, Arpád


    Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

  4. Principles of Micellar Electrokinetic Capillary Chromatography Applied in Pharmaceutical Analysis

    Árpád Gyéresi


    Full Text Available Since its introduction capillary electrophoresis has shown great potential in areas where electrophoretic techniques have rarely been used before, including here the analysis of pharmaceutical substances. The large majority of pharmaceutical substances are neutral from electrophoretic point of view, consequently separations by the classic capillary zone electrophoresis; where separation is based on the differences between the own electrophoretic mobilities of the analytes; are hard to achieve. Micellar electrokinetic capillary chromatography, a hybrid method that combines chromatographic and electrophoretic separation principles, extends the applicability of capillary electrophoretic methods to neutral analytes. In micellar electrokinetic capillary chromatography, surfactants are added to the buffer solution in concentration above their critical micellar concentrations, consequently micelles are formed; micelles that undergo electrophoretic migration like any other charged particle. The separation is based on the differential partitioning of an analyte between the two-phase system: the mobile aqueous phase and micellar pseudostationary phase. The present paper aims to summarize the basic aspects regarding separation principles and practical applications of micellar electrokinetic capillary chromatography, with particular attention to those relevant in pharmaceutical analysis.

  5. Micellar kinetics of a fluorosurfactant through stopped-flow NMR.

    Yushmanov, Pavel V; Furó, István; Stilbs, Peter


    19F NMR chemical shifts and transverse relaxation times T2 were measured as a function of time after quick stopped-flow dilution of aqueous solutions of sodium perfluorooctanoate (NaPFO) with water. Different initial concentrations of micellar solution and different proportions of mixing were tested. Previous stopped-flow studies by time-resolved small-angle X-ray scattering (TR-SAXS) detection indicated a slow (approximately 10 s) micellar relaxation kinetics in NaPFO solutions. In contrast, no evidence of any comparable slow (>100 ms) relaxation process was found in our NMR studies. Possible artifacts of stopped-flow experiments are discussed as well as differences between NMR and SAXS detection methods. Upper bounds on the relative weight of a slow relaxation process are given within existing kinetic theories of micellar dissolution.

  6. Monte Carlo simulation for the micellar behavior of amphiphilic comb-like copolymers

    冯莺; 隋家贤; 赵季若; 陈欣方


    Micellar behaviors in 2D and 3D lattice models for amphiphilic comb-like copolymers in water phase and in water/oil mixtures were simulated. A dynamical algorithm together with chain reptation movements was used in the simulation. Three-dimension displaying program was pro-grammed and free energy was estimated by Monte Carlo technigue. The results demonstrate that reduced interaction energy influences morphological structures of micelle and emulsion ??stems greatly; 3D simulation showing can display more direct images of morphological structures; the amphiphilic comb-like polymers with a hydrophobic main chain and hydrophilic side chains have lower energy in water than in oil.

  7. Effect of acidity of drugs on the prediction of human oral absorption by biopartitioning micellar chromatography


    Biopartitioning micellar chromatography(BMC)is a potentially high throughput and low cost alternative for in vitro prediction of drug absorption,which can mimic the drug partitioning process in biological systems.In this paper,a data set of 56 compounds representing acidic,basic,neutral and amphoteric drugs from various structure classes with human oral absorption(HOA)data available were employed to show the effect of acidity of drugs in oral absorption prediction.HOA was reciprocally correlated to the nega...

  8. First-principles investigation of the structural, dynamical, and dielectric properties of kesterite, stannite, and PMCA phases of Cu2ZnSnS4

    Ramkumar, S. Poyyapakkam; Gillet, Y.; Miglio, A.; van Setten, M. J.; Gonze, X.; Rignanese, G.-M.


    Cu2ZnSnS4 (CZTS) is a promising material as an absorber in photovoltaic applications. The measured efficiency, however, is far from the theoretically predicted value for the known CZTS phases. To improve the understanding of this discrepancy, we investigate the structural, dynamical, and dielectric properties of the three main phases of CZTS (kesterite, stannite, and PMCA) using density functional perturbation theory (DFPT). The effect of the exchange-correlation functional on the computed properties is analyzed. A qualitative agreement of the theoretical Raman spectrum with measurements is observed. However, none of the phases correspond to the experimental spectrum within the error bar that is usually to be expected for DFPT. This corroborates the need to consider cation disorder and other lattice defects extensively in this material.

  9. Preparation of TiO2 nanometer thin films with high photocatalytic activity by reverse micellar method


    Two kinds of TiO2 nanometer thin films were prepared on stainless steel by the reverse micellar and sol-gelmethods, respectively. The calcined TiO2 thin films were characterized by X-ray diffraction (XRD), atomic force micros-copy (AFM), BET surface area and X-ray photoelectron spectroscopy (XPS). Photocatalytic activity was evaluated byphotocatalytic decoloration of methyl orange aqueous solution. The results showed that the TiO2 thin films prepared by re-verse micellar method (designated as RM-TiO2 films) showed higher photocatalytic activity than those by sol-gel method(designated as SG-TiO2 films). This is attributed to the fact that the former is composed of smaller monodispersed sphericalparticles with a size of about 15 nm and possesses higher surface areas.

  10. Ordering fluctuations in a shear-banding wormlike micellar system

    Angelico, R.; Rossi, C. Oliviero; Ambrosone, L.;


    We present a first investigation about the non-linear flow properties and transient orientational-order fluctuations observed in the shear-thinning lecithin–water–cyclohexane wormlike micellar system at a concentration near to the zero-shear isotropic–nematic phase transition. From rheological...


    The combination of micellar electrokinetic chromatography (MEKC) with mass spectrometry (MS) is very attractive for the direct identification of analyte molecules, for the possibility of selectivity enhancement, and for the structure confirmation and analysis in a MS-MS mode. The...

  12. Use of a fluorosurfactant in micellar electrokinetic capillary chromatography.

    de Ridder, R; Damin, F; Reijenga, J; Chiari, M


    A fluorosurfactant, the anionic N-ethyl-N-[(heptadecafluorooctyl)sulfonyl]glycine potassium salt, trade name FC-129 [CAS 2991-51-7] was investigated for possible application in micellar electrokinetic capillary chromatography (MEKC). The surfactant was characterized with conductometric titration and test sample mixtures were investigated in MEKC systems, and compared with sodium dodecylsulphate. An increased efficiency and interesting selectivity differences were observed.

  13. Analysis of Some Biogenic Amines by Micellar Liquid Chromatography

    Irena Malinowska


    Full Text Available Micellar liquid chromatography (MLC with the use of high performance liquid chromatography (HPLC was used to determine some physicochemical parameters of six biogenic amines: adrenaline, dopamine, octopamine, histamine, 2-phenylethylamine, and tyramine. In this paper, an influence of surfactant’s concentration and pH of the micellar mobile phase on the retention of the tested substances was examined. To determine the influence of surfactant’s concentration on the retention of the tested amines, buffered solutions (at pH 7.4 of ionic surfactant—sodium dodecyl sulfate SDS (at different concentrations with acetonitrile as an organic modifier (0.8/0.2 v/v were used as the micellar mobile phases. To determine the influence of pH of the micellar mobile phase on the retention, mobile phases contained buffered solutions (at different pH values of sodium dodecyl sulfate SDS (at 0.1 M with acetonitrile (0.8/0.2 v/v. The inverse of value of retention factor (1/ versus concentration of micelles ( relationships were examined. Other physicochemical parameters of solutes such as an association constant analyte—micelle (ma—and partition coefficient of analyte between stationary phase and water (hydrophobicity descriptor (swΦ were determined by the use of Foley’s equation.

  14. Mobilization and micellar solubilization of NAPL contaminants in aquifer rocks

    Javanbakht, Gina; Goual, Lamia


    Surfactant-enhanced aquifer remediation is often performed to overcome the capillary forces that keep residual NAPL phases trapped within contaminated aquifers. The surfactant selection and displacement mechanism usually depend on the nature of NAPL constituents. For example, micellar solubilization is often used to cleanup DNAPLs from aquifers whereas mobilization is desirable in aquifers contaminated by LNAPLs. Although the majority of crude oils are LNAPLs, they often contain heavy organic macromolecules such as asphaltenes that are classified as DNAPLs. Asphaltenes contain surface-active components that tend to adsorb on rocks, altering their wettability. Previous studies revealed that surfactants that formed Winsor type III microemulsions could promote both mobilization and solubilization. However the extent by which these two mechanisms occur is still unclear, particularly in oil-contaminated aquifers. In this study we investigated the remediation of oil-contaminated aquifers using an environmentally friendly surfactant such as n-Dodecyl β-D-maltoside. Focus was given on asphaltenes to better understand the mechanisms of surfactant cleanup. Through phase behavior, spontaneous imbibition, dynamic interfacial tension and contact angle measurements, we showed that microemulsions formed by this surfactant are able to mobilize bulk NAPL (containing 9 wt.% asphaltenes) in the porous rock and solubilize DNAPL (i.e., 4-6 wt.% adsorbed asphaltenes) from the rock surface. Spontaneous imbibition tests, in particular, indicated that the ratio of mobilized to solubilized NAPL is about 6:1. Furthermore, aging the cores in NAPL beyond 3 days allowed for more NAPL to be trapped in the large pores of the rock but did not alter the amount of asphaltenes adsorbed on the mineral surface.

  15. Inhibitory effect of post-micellar SDS concentration on thermal aggregation and activity of papain.

    Qadeer, A; Zaman, M; Khan, R H


    Papain, a cysteine protease isolated from the latex of Carica papaya, is known to undergo irreversible thermal unfolding. In this study, we found that thermal unfolding of papain is accompanied by a simultaneous self-assembly process where this protein is observed to aggregate above 50°C. The extent of aggregation increased with increasing protein concentration from 3-40 µM. The aggregation was confirmed by enhanced turbidity, light scattering intensity, 1-anilino-8-naphthalene sulfonate (ANS) fluorescence intensity and by transmission electron microscopy. Furthermore, we noted that post-micellar concentration of sodium dodecyl sulfate (SDS) remarkably suppresses the thermal aggregation of papain. Far-UV circular dichroism studies revealed that SDS significantly enhances α-helical content of the protein and also tends to prevent its unfolding, and thus inhibits aggregation. Additionally, papain showed maximal activity at 65°C in neutral buffer. However, in the presence of 6 mM SDS (above its critical micellar concentration), the enzyme lost activity by about 10-fold. Thus, promoting the helical propensity of the protein does not appear to be a suitable strategy to overcome the aggregation related problems of industrially important proteins such as papain, which are not only required to be protected against aggregation but also need to remain functionally active in the presence of aggregation inhibitors.

  16. Aliphatic carboxylic acids and alcohols as efficiency and elution strength enhancers in micellar liquid chromatography.

    Boichenko, Alexander P; Berthod, Alain


    Micellar liquid chromatography (MLC) uses surfactant solutions as mobile phases with added organic additives to enhance both the elution strength and the chromatographic efficiency. Two aliphatic carboxylic acids (1-butanoic and 1-pentanoic) were used as MLC additives and compared with the two corresponding alcohols (1-butanol, 1-pentanol) in terms of elution strength, efficiency and selectivity. A set of 11 phenol derivatives was used as probe compounds. All micellar mobile phases were prepared with sodium dodecylsulfate (SDS) with concentration ranging from 0.05 to 0.15M and the modifier content within 1.0 and 5.0% (v/v). The elution strength of different mobile phases containing a constant amount of SDS and different amounts of modifiers; and mobile phases containing a constant amount of modifier and different SDS concentration were determined and discussed. The effect of the acid modifiers on efficiency was studied constructing van Deemter plots that showed no minimum within the 0.01-0.7mL/min flow rate range studied. Temperature effects were also studied constructing the classical van't Hoff plots. The slight curvature of the plots in the 25-70 degrees C range may indicate some modification of the surfactant-bonded moiety layer on the stationary phase surface. Since no definitive advantage of the use of aliphatic acids were established compared to their alcohol counterpart, their terrible smell will probably preclude their use as MLC organic modifiers.

  17. Micellar cathodes from self-assembled nitroxide-containing block copolymers in battery electrolytes.

    Hauffman, Guillaume; Maguin, Quentin; Bourgeois, Jean-Pierre; Vlad, Alexandru; Gohy, Jean-François


    This contribution describes the synthesis of block copolymers containing electrochemically active blocks, their micellization, and finally their use as micellar cathodes in a lithium battery. The self-assembly of the synthesized poly(styrene)-block-poly(2,2,6,6-tetramethylpiperidinyloxy-4-yl methacrylate) (PS-b-PTMA) diblock copolymers is realized in a typical battery electrolyte made of 1 m lithium trifluoromethanesulfonate dissolved in a mixture of ethylene carbonate/diethyl carbonate/dimethyl carbonate(1:1:1, in volume). Dynamic light scattering and atomic force micro-scopy indicate the formation of well-defined spherical micelles with a PS core and a PTMA corona. The electrochemical properties of those micelles are further investigated. Cyclic voltammograms show a reversible redox reaction at 3.6 V (vs Li(+) /Li). The charge/discharge profiles indicate a flat and reversible plateau around 3.6 V (vs Li(+) /Li). Finally, the cycling performances of the micellar cathodes are demonstrated. Such self-assembled block copolymers open new opportunities for nanostructured organic radical batteries. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Photodegradation in Micellar Aqueous Solutions of Erythrosin Esters Derivatives.

    Herculano, Leandro Silva; Lukasievicz, Gustavo Vinicius Bassi; Sehn, Elizandra; Caetano, Wilker; Pellosi, Diogo Silva; Hioka, Noboru; Astrath, Nelson Guilherme Castelli; Malacarne, Luis Carlos


    Strong light absorption and high levels of singlet oxygen production indicate erythrosin B as a viable candidate as a photosensitizer in photodynamic therapy or photodynamic inactivation of microorganisms. Under light irradiation, erythrosin B undergoes a photobleaching process that can decrease the production of singlet oxygen. In this paper, we use thermal lens spectroscopy to investigate photobleaching in micellar solutions of erythrosin ester derivatives: methyl, butyl, and decyl esters in low concentrations of non-ionic micellar aqueous solutions. Using a previously developed thermal lens model, it was possible to determine the photobleaching rate and fluorescence quantum efficiency for dye-micelle solutions. The results suggest that photobleaching is related to the intensity of the dye-micelle interaction and demonstrate that the thermal lens technique can be used as a sensitive tool for quantitative measurement of photochemical properties in very diluted solutions.

  19. Terahertz absorption spectroscopy of protein-containing reverse micellar solution

    Murakami, H.; Toyota, Y.; Nishi, T.; Nashima, S.


    Terahertz time-domain spectroscopy has been carried out for AOT/isooctane reverse micellar solution with myoglobin at the water-to-surfactant molar ratios ( w0) of 0.2 and 4.4. The amplitude of the absorption spectrum increases with increasing the protein concentration at w0 = 0.2, whereas it decreases at w0 = 4.4. The molar extinction coefficients of the protein-filled reverse micelle, and the constituents, i.e., myoglobin, water, and AOT, have been derived by use of the structural parameters of the micellar solution. The experimental results are interpreted in terms of hydration onto the protein and surfactant in the reverse micelle.

  20. Flow-induced gelation of living (micellar) polymers

    Bruinsma, Robijn; Gelbart, William M.; Ben-Shaul, Avinoam


    The effect of shear velocity gradients on the size (L) of rodlike micelles in dilute and semidilute solution is considered. A kinetic equation is introduced for the time-dependent concentration of aggregates of length L, consisting of 'bimolecular' combination processes L + L-prime yield (L + L-prime) and unimolecular fragmentations L yield L + (L - L-prime). The former are described by a generalization (from spheres to rods) of the Smoluchowski mechanism for shear-induced coalesence of emulsions, and the latter by incorporating the tension-deformation effects due to flow. Steady-state solutions to the kinetic equation are obtained, with the corresponding mean micellar size evaluated as a function of the Peclet number P (i.e., the dimensionless ratio of the flow rate and the rotational diffusion coefficient). For sufficiently dilute solutions, only a weak dependence of the micellar size on P is found. In the semidilute regime, however, an apparent divergence in the micellar size at P of about 1 suggests a flow-induced first-order gelation phenomenon.

  1. Phosphatidylcholine embedded micellar systems: enhanced permeability through rat skin.

    Spernath, Aviram; Aserin, Abraham; Sintov, Amnon C; Garti, Nissim


    Micellar and microemulsion systems are excellent potential vehicles for delivery of drugs because of their high solubilization capacity and improved transmembrane bioavailability. Mixtures of propylene glycol (PG) and nonionic surfactants with sodium diclofenac (DFC) were prepared in the presence of phosphatidylcholine (PC) as transmembrane transport enhancers. Fully dilutable systems with maximum DFC solubilization capacity (SC) at pH 7 are presented. It was demonstrated that the concentrates underwent phase transitions from reverse micelles to swollen reverse micelles and, via the bicontinuous transitional mesophase, into inverted O/W microstructures. The SC decreases as a function of dilution. DFC transdermal penetration using rat skin in vitro correlated with SC, water content, effect of phospholipid content, presence of an oil phase, and ethanol. Skin penetration from the inverted bicontinuous mesophase and the skin penetration from the O/W-like microstructure were higher than that measured from the W/O-like droplets, especially when the micellar system containing the nonionic surfactant, sugar ester L-1695, and hexaglycerol laurate. PC embedded within the micelle interface significantly increased the penetration flux across the skin compared to micellar systems without the embedded PC at their interface. Moreover, the combination of PC with HECO40 improved the permeation rate (P) and shortened the lag-time (T(L)).

  2. Implementation of gradients of organic solvent in micellar liquid chromatography using DryLab(®): separation of basic compounds in urine samples.

    Rodenas-Montano, J; Ortiz-Bolsico, C; Ruiz-Angel, M J; García-Alvarez-Coque, M C


    In micellar liquid chromatography (MLC), chromatographic peaks are more evenly distributed compared to conventional reversed-phase liquid chromatography (RPLC). This is the reason that most procedures are implemented using isocratic elution. However, gradient elution may be still useful in MLC to analyse mixtures of compounds within a wide range of polarities, decreasing the analysis time. Also, it benefits the determination of moderately to low polar compounds in physiological fluids performing direct injection: an initial micellar eluent with a low organic solvent content, or a pure micellar (without surfactant) solution, will provide better protection of the column against the proteins in the physiological fluid, and once the proteins are swept away, the elution strength can be increased using a positive linear gradient of organic solvent to reduce the analysis time. This work aims to encourage analysts to implement gradients of organic solvent in MLC, which is rather simple and allows rapid analytical procedures without pre-treatment or the need of re-equilibration. The implementation of gradient elution is illustrated through the separation of eight basic compounds (β-blockers) in urine samples directly injected into the chromatograph, the most hydrophobic showing large retention in both conventional RPLC and MLC. The use of the DryLab(®) software to optimise gradients of organic solvent with eluents containing a fixed amount of surfactant above the critical micellar concentration is shown to provide satisfactory predictions, and can facilitate greatly the implementation of gradient protocols.

  3. Nonequilibrium Fluctuation Relation for Sheared Micellar Gel in a Jammed State

    Majumdar, Sayantan; Sood, A. K.


    We show that the shear rate at a fixed shear stress in a micellar gel in a jammed state exhibits large fluctuations, showing positive and negative values, with the mean shear rate being positive. The resulting probability distribution functions of the global power flux to the system vary from Gaussian to non-Gaussian, depending on the driving stress, and in all cases show similar symmetry properties as predicted by the Gallavotti-Cohen steady state fluctuation relation. The fluctuation relation allows us to determine an effective temperature related to the structural constraints of the jammed state. We have measured the stress dependence of the effective temperature. Further, experiments reveal that the effective temperature and the standard deviation of the shear-rate fluctuations increase with the decrease of the system size.

  4. Dynamic fluorescence quenching of quinine sulfate dication by chloride ion in ionic and neutral micellar environments

    Joshi, Sunita; Varma Y, Tej Varma; Pant, Debi D.


    Fluorescence quenching of Quinine sulfate dication (QSD) by chloride-ion (Cl-) in micellar environments of anionic, sodium dodecyl sulfate (SDS), cationic, cetyltrimethylammonium bromide (CTAB) and neutral, triton X-100 (TX-100) in aqueous phase has been investigated by time-resolved and steady- state fluorescence measurements. The quenching follows linear Stern-Volmer relation in micellar solutions and is dynamic in nature.

  5. Effects of divalent ions on displacement of oil from porous media by micellar solutions

    Mobarak, S.A.M.


    Micellar solutions are currently being investigated by a number of oil companies and research institutes as potential candidates for tertiary oil recovery processes. Micellar solutions can be used in either secondary or tertiary recovery operations. The process is being tested in some fields, but the results are inconclusive. In general, the limited field trials indicate that micellar solutions do not work as effectively as predicted from laboratory data. This research was to investigate the effect of presence of calcium ions in formation water on oil recovery using micellar solutions. Adsorption of surfactant on sand grain surfaces as a function of calcium ions concentrations also was investigated. A series of laboratory experiments was conducted in which oil was displaced from porous media by micellar solution (Amoco Floodaid 131) driven by viscous water and plain water, respectively. Based on the experimental results, micellar solutions proved to be very effective in displacing oil from porous media. The recovery of oil from porous media by micellar solution in the presence of calcium ions in formation water was improved when ethylene diamene tetracetic acid was added to the micellar solution. (Longer abstract available)

  6. Show Time


    <正> Story: Show Time!The whole class presents the story"Under the Sea".Everyone is so excited and happy.Both Leo and Kathy show their parentsthe characters of the play."Who’s he?"asks Kathy’s mom."He’s the prince."Kathy replies."Who’s she?"asks Leo’s dad."She’s the queen."Leo replieswith a smile.

  7. Snobbish Show



    @@ The State Administration of Radio,Film and Television (SARFT),China's media watchdog,issued a new set of mles on June 9 that strictly regulate TV match-making shows,which have been sweeping the country's primetime programming. "Improper social and love values such as money worship should not be presented in these shows.Humiliation,verbal attacks and sex-implied vulgar content are not allowed" the new roles said.

  8. Separation of Aniline Derivatives by Micellar Electrokinetic Capillary Chromatography

    Jun LI; Zhuo Bin YUAN


    A micellar electrokinetic capillary chromatography (MECC) was developed for the determination of aniline and 6 substituted anilines.The seven components were separated within 25 min in the buffer solution of 40 mmol/L sodium borate and 100 mmol/L SDS.It was found that the separation was dependent on operating voltage, pH value, borate and SDS concentrations.The analytical performance was examined in terms of linear response and reproducibility.Wastewater was determined by the established method.

  9. Analysis of anthraquinones in Rumex crispus by micellar electrokinetic chromatography.

    Başkan, Selda; Daut-Ozdemir, Ayşe; Günaydin, Keriman; Erim, F Bedia


    A micellar electrochromatographic method was performed for the analysis of the pharmaceutically important anthraquinones from the root of Rumex crispus. The separation of 1,5-dihydroxy-3-methylanthraquinone (1); 1,3,5-trihydroxy-6-hydroxymethylanthraquinone (2); 1,5-dihydroxy-3-methoxy-7-methylanthraquinone (3) was achieved in 6min using a running buffer containing 10mmol/l sodium borate, 50mmol/l sodium dodecylsulfate, and 25% acetonitrile at pH 10.6. The method is simple, rapid, and reproducible.

  10. Importance of critical micellar concentration for the prediction of solubility enhancement in biorelevant media.

    Ottaviani, G; Wendelspiess, S; Alvarez-Sánchez, R


    This study evaluated if the intrinsic surface properties of compounds are related to the solubility enhancement (SE) typically observed in biorelevant media like fasted state simulated intestinal fluids (FaSSIF). The solubility of 51 chemically diverse compounds was measured in FaSSIF and in phosphate buffer and the surface activity parameters were determined. This study showed that the compound critical micellar concentration parameter (CMC) correlates strongly with the solubility enhancement (SE) observed in FaSSIF compared to phosphate buffer. Thus, the intrinsic capacity of molecules to form micelles is also a determinant for each compound's affinity to the micelles of biorelevant surfactants. CMC correlated better with SE than lipophilicity (logD), especially over the logD range typically covered by drugs (2 media, thereby enhancing oral bioavailability of drug candidates.


    WANG Erjian; FANG Peiji; FENG Xinde


    A kind of cationic compounds, having benzophenone end group and various length chain (PKT) (BP-CH2N + R2R'·X-, R&R' different chain length alkyl group)were used as photosensitizers. Various BP/TEA systems have been used for study, The efficiency of MMA photopolymerization initiated by them shows PKT > BP in homogeneous water solution and PKT> BP/CTAB in micellar water solution. The results obtained indicate that catalytic effects of PKT type functional micelles are far greater than that of common micelle with the enhancement of polymerization rate over 10 times compared with BP in water solution. The catalytic role,reaction character of PKT, effect of counter ions and retarding effect of oxygen have also been discussed.

  12. Two-peak phenomena and formation origin in micellar electrokinetic capillary chromatography

    陈冠华; 杨更亮; 田益玲; 陈义


    The formation origin of two peaks in micellar electrokinetic capillary chromatography by using cetyltrimethylaminium bromide (or sodium dodecyl sulfate) as pseudo stationary phase is studied. It is pointed out that two peaks may appear for one component in certain conditions. Experiments show that the relative areas of the two peaks of the corresponding component depend on the time and temperature of reaction between the analyte and the surfactant, and the concentration of surfactant in the sample solution. One of the two peaks increase with the increase of surfactant concentration in the sample solution while reverse for another peak. Temperature can accelerate the reaction process. This means that the interaction between analyte and surfactant is a slow process, and a stable substance can be produced from the interaction and leads to the formation of two peaks. The standpoint is confirmed by the infrared and nuclear magnetic resonance spectra of the product from the reaction between cetyltrimethylaminium bromide and m-hydroxyl benzoic acid.

  13. Chiral cyclodextrin-modified micellar electrokinetic chromatography and chemometric techniques for green tea samples origin discrimination.

    Pasquini, Benedetta; Orlandini, Serena; Goodarzi, Mohammad; Caprini, Claudia; Gotti, Roberto; Furlanetto, Sandra


    Catechins and methylxanthines were determined in 92 green tea (GT) samples originating from Japan and China by using micellar electrokinetic chromatography with the addition of (2-hydroxypropyl)-β-cyclodextrin. GT samples showed high concentrations of (-)-epigallocatechin gallate and caffeine, with (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epicatechin in relevant content and (+)-catechin, (-)-catechin and theobromine in much lower amounts. The amount of all the considered compounds was higher for Chinese GTs, with the exception of (-)-epicatechin gallate. Pattern recognition methods were applied to discriminate GTs according to geographical origin, which is an important factor to determine quality and reputation of a commercial tea product. Data analysis was performed by principal component analysis and hierarchical cluster analysis as exploratory techniques. Linear discriminant analysis and quadratic discriminant analysis were utilized as discrimination techniques, obtaining a very good rate of correct classification and prediction.

  14. Influence of boundary conditions and confinement on nonlocal effects in flows of wormlike micellar systems.

    Masselon, Chloé; Colin, Annie; Olmsted, Peter D


    In this paper we report on the influence of different geometric and boundary constraints on nonlocal (spatially inhomogeneous) effects in wormlike micellar systems. In a previous paper, nonlocal effects were observable by measuring the local rheological flow curves of micelles flowing in a microchannel under different pressure drops, which appeared to differ from the flow curve measured using conventional rheometry. Here we show that both the confinement and the boundary conditions can influence those nonlocal effects. The role of the nature of the surface is analyzed in detail using a simple scalar model that incorporates inhomogeneities, which captures the flow behavior in both wide and confined geometries. This leads to an estimate for the nonlocal "diffusion" coefficient (i.e., the shear curvature viscosity) which corresponds to a characteristic length from 1 to 10 microm.

  15. Micellar-polymer joint demonstration project, Wilmington Field, California. Annual report, 1976--1977

    Wade, J.E.


    Work accomplished under the contract during the first year of operation consisted of Micellar-Polymer laboratory systems design; Test Pattern Model Studies; Drilling and coring injection well FT-1; Pressure Transient Tests of Wells Z-81, Z1-16and FT-1; as well as design and construction of a portion of the surface facilities. Radial core floods conducted by Marathon Research Center using reservoir rock and fluid samples from the Wilmington Field demonstrated that Micellar-Polymer systems showing good recovery efficiency could be made from several different commercially available sulfonates. Residual oil saturations obtained were as low as 7 to 10% pore volume. Sulfonates made from Wilmington crude oil also proved to be effective. Polyacrylamides, both liquid and dry, as well as polysaccharides proved equally effective as a mobility buffer. Test pattern model studies were conducted on seven different arrays of wells. These studies showed that the pattern originally proposed exhibited poor areal sweep efficiency and was seriously affected by waterflood operations in the North Flank of the fault block. An E-W staggered line drive backed-up against the Pier A Fault appeared to be the best pattern studied, assuming the Pier A Fault to be a pressure barrier. Injection well FT-1 was drilled, cored and completed in the Hx/sub a/ sand. Cores were taken using low-solids, polymer drilling fluid and were frozen on site. The frozen cores from the project area will be used in the Phase B laboratory work. Pressure Transient Tests run in Z-81 and Z1-16 indicated the Pier A Fault to be pressure competent. The plant site was located adjacent to a railroad siding near the injection wells. The site was graded and seven 2000 barrel tanks were erected. The tanks were internally plastic coated on site. Mixing, filtering and injection facilities are being installed.



    Visitors look at plane models of the Commercial Aircraft Corp. of China, developer of the count,s first homegrown large passenger jet C919, during the Singapore Airshow on February 16. The biennial event is the largest airshow in Asia and one of the most important aviation and defense shows worldwide. A number of Chinese companies took part in the event during which Okay Airways, the first privately owned aidine in China, signed a deal to acquire 12 Boeing 737 jets.

  17. Study of interaction of proflavin with triethylamine in homogeneous and micellar media: Photoinduced electron transfer probed by magnetic field effect

    Chakraborty, Brotati; Basu, Samita


    Interaction of triethylamine (TEA) with cationic proflavin (PF +) in homogeneous and micellar media is studied using absorption spectroscopy, steady-state as well as time-resolved fluorescence spectroscopy and laser flash photolysis in conjunction with an external magnetic field. The two prime phenomena that have been highlighted in this study are photoinduced electron transfer (PET) and ground-state complex formation. This study shows that it is the medium which determines the reaction pathways to be followed. Magnetic field effect (MFE) helps to elucidate the reaction mechanism involved and this work also highlights the distance dependence factor associated with MFE.

  18. Two-phase aqueous micellar systems: an alternative method for protein purification

    Rangel-Yagui C. O.


    Full Text Available Two-phase aqueous micellar systems can be exploited in separation science for the extraction/purification of desired biomolecules. This article reviews recent experimental and theoretical work by Blankschtein and co-workers on the use of two-phase aqueous micellar systems for the separation of hydrophilic proteins. The experimental partitioning behavior of the enzyme glucose-6-phosphate dehydrogenase (G6PD in two-phase aqueous micellar systems is also reviewed and new results are presented. Specifically, we discuss very recent work on the purification of G6PD using: i a two-phase aqueous micellar system composed of the nonionic surfactant n-decyl tetra(ethylene oxide (C10E4, and (ii a two-phase aqueous mixed micellar system composed of C10E4 and the cationic surfactant decyltrimethylammonium bromide (C10TAB. Our results indicate that the two-phase aqueous mixed (C10E4/C10TAB micellar system can improve significantly the partitioning behavior of G6PD relative to that observed in the two-phase aqueous C10E4 micellar system.

  19. The use of micellar solutions for novel separation techniques

    Roberts, Bruce Lynn [Univ. of Oklahoma, Norman, OK (United States)


    Surfactant based separation techniques based on the solubilization of organic compounds into the nonpolar interior of a micelle or electrostatic attraction of ionized metals and metal complexes to the charged surface of a micelle were studied in this work. Micellar solutions were used to recover two model volatile organic compounds emitted by the printing and painting industries (toluene and amyl acetate) and to investigate the effect of the most important variables in the surfactant enhanced carbon regeneration (SECR) process. SECR for liquid phase applications was also investigated in which the equilibrium adsorption of cetyl pyridinium chloride (CPC) and sodium dodecyl sulfate (SDS) on activated carbon were measured. Micellar-enhanced ultrafiltration (MEUF) was investigated using spiral wound membranes for the simultaneous removal of organic compounds, metals and metal complexes dissolved in water, with emphasis on pollution control applications. Investigations of MEUF to remove 99+ per cent of trichloroethylene (TCE) from contaminated groundwater using criteria such as: membrane flux, solubilization equilibrium constant, surfactant molecular weight, and Krafft temperature led to the selection of an anionic disulfonate with a molecular weight of 642 (DOWFAX 8390). These data and results from supporting experiments were used to design a system which could clean-up water in a 100,000 gallon/day operation. A four stage process was found to be an effective design and estimated cost for such an operation were found to be in the range of the cost of mature competitive technologies.

  20. Percolation and Critical Phenomena of AN Attractive Micellar System

    Mallamace, F.; Chen, S. H.; Gambadauro, P.; Lombardo, D.; Faraone, A.; Tartaglia, P.

    In this work we study an attractive micellar system for which the percolation curve terminates near the critical point. We have studied such an intriguing situation by means of scattering (elastic and dynamical) and viscoelasticity experiments. Obtained data are accounted by considering in a proper way the fractal clustering processes typical of percolating systems and the related scaling concepts. We observe that the main role in the system structure and dynamics it is played by the cluster's partial screening of hydrodynamic interaction. This behaves on approaching the percolation threshold dramatic effects on the system rheological properties and on the density decay relaxations. The measured correlation functions assume a stretched exponential form and the system becomes strongly viscoelastic. The overall behavior of the measured dynamical and structural parameters indicates, that in the present micellar system, the clustering process originates dilute, poly-disperse and swelling structures. Finally, this originates an interesting situation observed in the present experiment. As it has been previously, proposed by A. Coniglio et al., percolation clusters can be considered to be "Ising clusters" with the same properties as the Fisher's critical droplets. Therefore at the critical point the percolation connectedness length (ξp) can be assumed as the diverging correlation length (ξp ≡ ξ) and the mean cluster size diverges as the susceptibility.

  1. The use of micellar solutions for novel separation techniques

    Roberts, B.L.


    Surfactant based separation techniques based on the solubilization of organic compounds into the nonpolar interior of a micelle or electrostatic attraction of ionized metals and metal complexes to the charged surface of a micelle were studied in this work. Micellar solutions were used to recover two model volatile organic compounds emitted by the printing and painting industries (toluene and amyl acetate) and to investigate the effect of the most important variables in the surfactant enhanced carbon regeneration (SECR) process. SECR for liquid phase applications was also investigated in which the equilibrium adsorption of cetyl pyridinium chloride (CPC) and sodium dodecyl sulfate (SDS) on activated carbon were measured. Micellar-enhanced ultrafiltration (MEUF) was investigated using spiral wound membranes for the simultaneous removal of organic compounds, metals and metal complexes dissolved in water, with emphasis on pollution control applications. Investigations of MEUF to remove 99+ per cent of trichloroethylene (TCE) from contaminated groundwater using criteria such as: membrane flux, solubilization equilibrium constant, surfactant molecular weight, and Krafft temperature led to the selection of an anionic disulfonate with a molecular weight of 642 (DOWFAX 8390). These data and results from supporting experiments were used to design a system which could clean-up water in a 100,000 gallon/day operation. A four stage process was found to be an effective design and estimated cost for such an operation were found to be in the range of the cost of mature competitive technologies.

  2. Stability of an ophthalmic micellar formulation of cyclosporine A in unopened multidose eyedroppers and in simulated use conditions.

    Chennell, P; Delaborde, L; Wasiak, M; Jouannet, M; Feschet-Chassot, E; Chiambaretta, F; Sautou, V


    Cyclosporine A eye drops are used at concentrations ranging from 0.5 to 20mg/mL to treat a variety of ophthalmic diseases. Cyclosporine A formulations at high concentrations are difficult to manufacture because of cyclosporine's lipophilicity, and generally require an oil based vector. In this study, we investigated the physicochemical and microbiological stability of two high concentrations (10mg/mL and 20mg/mL) of an ophthalmic cyclosporine A micellar solution in a low density polyethylene multidose eyedropper, at two conservation conditions (5°C and 25°C), before and with simulated use. Analyses used were the following: visual inspection, cyclosporine quantification by a stability-indicating liquid chromatography method, osmolality and pH measurements and turbidity. A complementary analysis by dynamic light scattering was implemented to evaluate potential particle formation or micelle size change. In the in-use study, cyclosporine quantification was also performed on the drops emitted from the multidose eyedroppers. Our results show that the cyclosporine micellar formulation retains good physicochemical and microbiological stability, as all parameters stayed within acceptable range limits, however a higher variability in cyclosporine concentrations was observed for 20mg/mL units stored at 25°C. The in-use study showed that cyclosporine concentrations in the emitted drops were also within acceptable range limits. The micellar formulation presented in this study can therefore be stored at 5°C or at ≤25°C for up to 6months. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Formation and properties of reverse micellar cubic liquid crystals and derived emulsions.

    Rodríguez-Abreu, Carlos; Shrestha, Lok Kumar; Varade, Dharmesh; Aramaki, Kenji; Maestro, Alicia; Quintela, Arturo López; Solans, Conxita


    The structure of the reverse micellar cubic (I2) liquid crystal and the adjacent micellar phase in amphiphilic block copolymer/water/oil systems has been studied by small-angle X-ray scattering (SAXS), rheometry, and differential scanning calorimetry (DSC). Upon addition of water to the copolymer/oil mixture, spherical micelles are formed and grow in size until a disorder-order transition takes place, which is related to a sudden increase in the viscosity and shear modulus. The transition is driven by the packing of the spherical micelles into a Fd3m cubic lattice. The single-phase I2 liquid crystals show gel-like behavior and elastic moduli higher than 104 Pa, as determined by oscillatory measurements. Further addition of water induces phase separation, and it is found that reverse water-in-oil emulsions with high internal phase ratio and stabilized by I2 liquid crystals can be prepared in the two-phase region. Contrary to liquid-liquid emulsions, both the elastic modulus and the viscosity decrease with the fraction of dispersed water, due to a decrease in the crystalline fraction in the sample, although the reverse emulsions remain gel-like even at high volume fractions of the dispersed phase. A temperature induced order-disorder transition can be detected by calorimetry and rheometry. Upon heating the I2 liquid crystals, two thermal events associated with small enthalpy values were detected: one endothermic, related to the "melting" of the liquid crystal, and the other exothermic, attributed to phase separation. The melting of the liquid crystal is associated with a sudden drop in viscosity and shear moduli. Results are relevant for understanding the formation of cubic-phase-based reverse emulsions and for their application as templates for the synthesis of structured materials.

  4. Utilization of micellar electrokinetic chromatography-tandem mass spectrometry employed volatile micellar phase in the analysis of cathinone designer drugs.

    Švidrnoch, Martin; Lněníčková, Ludmila; Válka, Ivo; Ondra, Peter; Maier, Vítězslav


    A micellar electrokinetic chromatography method with tandem mass spectrometry has been developed for the selective separation, identification and determination of twelve new designer drugs from the group of synthetic cathinones. Ammonium salt of perfluorooctanoic acid at various concentrations as a volatile background electrolyte (BGE) to create micellar phase was studied for separation of selected synthetic cathinones with direct tandem mass spectrometry without significant loss of detection sensitivity. The optimized BGE contained 100 mM perfluorooctanoic acid with 200 mM ammonium hydroxide providing acceptable resolution of studied drugs in the MEKC step. In order to minimize interferences with matrix components and to preconcentrate target analytes, solid phase extraction was introduced as a clean-up step. The method was linear in the concentration range of 10-5000 ng mL(-1) and the limits of detection were in the range of 10-78 ng mL(-1). The method was demonstrated to be specific, sensitive, and reliable for the systematic toxicological analysis of these derivatives in urine samples.

  5. Glycerol in micellar confinement with tunable rigidity

    Lannert, Michael; Müller, Allyn; Gouirand, Emmanuel; Talluto, Vincenzo; Rosenstihl, Markus; Walther, Thomas; Stühn, Bernd; Blochowicz, Thomas; Vogel, Michael


    We investigate the glassy dynamics of glycerol in the confinement of a microemulsion system, which is stable on cooling down to the glass transition of its components. By changing the composition, we vary the viscosity of the matrix, while keeping the confining geometry intact, as is demonstrated by small angle X-ray scattering. By means of 2H NMR, differential scanning calorimetry, and triplet solvation dynamics we, thus, probe the dynamics of glycerol in confinements of varying rigidity. 2H NMR results show that, at higher temperatures, the dynamics of confined glycerol is unchanged compared to bulk behavior, while the reorientation of glycerol molecules becomes significantly faster than in the bulk in the deeply supercooled regime. However, comparison of different 2H NMR findings with data from calorimetry and solvation dynamics reveals that this acceleration is not due to the changed structural relaxation of glycerol, but rather due to the rotational motion of essentially rigid glycerol droplets or of aggregates of such droplets in a more fluid matrix. Thus, independent of the matrix mobility, the glycerol dynamics remains unchanged except for the smallest droplets, where an increase of Tg and, thus, a slowdown of the structural relaxation is observed even in a fluid matrix.

  6. Effect of the interaction of heat-processing style and fat type on the micellarization of lipid-soluble pigments from green and red pungent peppers (Capsicum annuum).

    Victoria-Campos, Claudia I; Ornelas-Paz, José de Jesús; Yahia, Elhadi M; Failla, Mark L


    The high diversity of carotenoids and chlorophylls in foods contrasts with the reduced number of pigments that typically are investigated in micellarization studies. In this study, pepper samples (raw and heat-treated) contained 68 individual pigments, but only 38 of them were micellarized after in vitro digestion. The micellarization of pigments was majorly determined by the interaction effect of processing style (food matrix effect) and fat type (saturated and unsaturated). The highest micellarization was observed with raw peppers. Unsaturated fat increased the micellarization of carotenoid esters, while the impact of fat on the micellarization of free carotenoids seemed to be dependent on pigment structure. The micellarization efficiency was diminished as the esterification level of carotenoids increased. The type of fatty acid moiety and the polarity of the carotenoids modulated their micellarization. Chlorophylls were transformed into pheophytins by heat-processing and digestion, with the pheophytins being stable under gastrointestinal conditions. Micellarization of pheophytins was improved by fat.

  7. Effect of calcium chelators on physical changes in casein micelles in concentrated micellar casein solutions

    Kort, de E.J.P.; Minor, M.; Snoeren, T.H.M.; Hooijdonk, van A.C.M.; Linden, van der E.


    The effect of calcium chelators on physical changes of casein micelles in concentrated micellar casein solutions was investigated by measuring calcium-ion activity, viscosity and turbidity, and performing ultracentrifugation. The highest viscosities were measured on addition of sodium

  8. Application of micellar liquid chromatography for the determination of antitumoral and antiretroviral drugs in plasma.

    Peris-Vicente, Juan; Casas-Breva, Inmaculada; Roca-Genovés, Pasqual; Esteve-Romero, Josep


    In micellar liquid chromatography, the mobile phase is made of a surfactant and, eventually, an alcohol. This article describes several methods to measure the concentration of antitumoral and antiretroviral drugs in plasma, utilizing micellar liquid chromatography. Samples can be injected after dilution with a micellar solution and filtration, because proteins and other endogenous compounds are solubilized in micellar medium. We will discuss the following optimized parameters: dilution ratio, type of column, detection conditions and mobile phase composition. This article will also cover the validation performed following the International Conference on Harmonization guidelines and the results reported in the literature, indicating that the methods are useful for the routine analysis of plasma samples for clinical purposes.


    Although surfactants have received considerable attention as a potential means for enhancing the recovery of organic compounds from the subsurface, only limited information is available regarding the micellar solubilization of common groundwater contaminants by nonionic surfactan...

  10. Biopartitioning micellar chromatography with sodium dodecyl sulfate as a pseudo α(1)-acid glycoprotein to the prediction of protein-drug binding.

    Hadjmohammadi, Mohammadreza; Salary, Mina


    A simple and fast method is of urgent need to measure protein-drug binding affinity in order to meet the rapid development of new drugs. Biopartitioning micellar chromatography (BMC), a mode of micellar liquid chromatography (MLC) using micellar mobile phases in adequate experimental conditions, can be useful as an in vitro system in mimicking the drug-protein interactions. In this study, sodium dodecyl sulfate-micellar liquid chromatography (SDS-MLC) was used for the prediction of protein-drug binding based on the similar property of SDS micelles to α(1)-acid glycoprotein (AGP). The relationships between the BMC retention data of a heterogeneous set of 14 basic and neutral drugs and their plasma protein binding parameter were studied and the predictive ability of models was evaluated. Modeling of logk(BMC) of these compounds was established by multiple linear regression (MLR) and second-order polynomial models obtained in two different concentrations (0.07 and 0.09M) of SDS. The developed MLR models were characterized by both the descriptive and predictive ability (R(2)=0.882, R(CV)(2)=0.832 and R(2)=0.840, R(CV)(2)=0.765 for 0.07 and 0.09M SDS, respectively). The p values <0.01 also indicated that the relationships between the protein-drug binding and the logk(BMC) values were statistically significant at the 99% confidence level. The standard error of estimation showed the standard deviation of the regression to be 11.89 and 13.87 for 0.07 and 0.09M, respectively. The application of the developed model to a prediction set demonstrated that the model was also reliable with good predictive accuracy. The external and internal validation results showed that the predicted values were in good agreement with the experimental value.

  11. Removal of Pyrethrin from Aqueous Effluents by Adsorptive Micellar Flocculation

    Pardon K. Kuipa


    Full Text Available The equilibrium adsorption of pyrethrin onto aggregates formed by the flocculation of micelles of the surfactant sodium dodecyl sulphate (SDS with aluminium sulphate is reported. The experimental results were analysed using different adsorption isotherms (Langmuir, Freundlich, Redlich-Peterson, Sips, Radke-Prausnitz, Temkin, linear equilibrium, and the Dubin-Radushkevich isotherms. The Freundlich and linear equilibrium isotherms best describe the adsorption of pyrethrin onto SDS micellar flocs, with the Freundlich adsorption constant, KF, and the mass distribution coefficient, KD, of 64.266 ((mg/g(L/mg1/n and 119.65 L/g, respectively. Applicability of the Freundlich adsorption model suggests that heterogeneous surface adsorption affects the adsorption. The mean free energy value estimated using the Dubinin-Radushkevich isotherm was 0.136 kJ/mol indicating that physisorption may be predominant in the adsorption process.

  12. Influence of solvent on micellar morphologies of semifluorinated block copolymers.

    Lee, Min Young; Kim, Sang Jae; Jeong, Yeon Tae; Kim, Joo Hyun; Gal, Yeong-Soon; Lim, Kwon Taek


    The influence of solvents on micellar architectures of block copolymers composed of poly(1H,1H-dihydroperfluorooctyl methacrylate) and poly(ethylene oxide) was investigated. In this study, binary solvents with desired proportions were chosen, which had remarkable influence on the morphology of the resulting micelles. With simple adjusting the composition of the binary solvent of chloroform and trichlorofluoromethane, interesting shapes of micelle-like aggregates, such as core-shell, cylinder, worm-like and inverted micelles were formed with sizes of 15, 70, 30 and 250 nm, respectively. In the case of methanol/water system, core-shell spheres and vesicles were produced by varying the proportion of the contents. The morphologies were also tuned to honeycomb-like and bowl-shaped micelles as well as large planar lamellae with holes in DMF and water binary solvent.

  13. Micellar electrokinetic chromatography (MEKC) separation of furanonaphthoquinones from Tabebuia impetiginosa.

    Koyama, J; Morita, I; Kino, A; Tagahara, K


    The separation of nine furanonaphthoquinones by micellar electrokinetic chromatography (MEKC) is described. The running electrolytes used in this method were 0.03 M sodium dodecyl sulphate (SDS) in 0.09 M borate buffer (pH 9) containing 10% methanol, with an applied voltage of 20 kV. Application of this technique in the determination of the main furanonaphthoquinones, 5-hydroxy-2-(1-hydroxyethyl)naphtho[2,3-b]furan-4,9-dione, 8-hydroxy-2-(1-hydroxyethyl)naphtho[2,3-b]furan-4,9-dione, and 2-(1-hydroxyethyl)naphtho[2,3-b]furan-4,9-dione, of Tabebuia impetiginosa is demonstrated in this paper.

  14. Separation of bisbenzylisoquinoline alkaloids by micellar electrokinetic chromatography.

    Kuo, Ching-Hua; Sun, Shao-Wen


    The micellar electrokinetic chromatographic (MEKC) separation of seven bisbenzylisoquinoline alkaloids has been developed. The effects of various separating factors were studied. Optimum separation was achieved using a buffer (pH 9.2) of 20 mM sodium borate and 20 mM sodium dihydrogen phosphate buffer containing 55 mM sodium cholate; the optimum voltage and injection time were 21 kV and 0.05 min, respectively. Highest peak efficiency was obtained when the analytes were dissolved in 10 mM sodium dodecyl sulphate as sample matrix for injection. The elution order of the bisbenzylisoquinoline alkaloids was related to their lipophilicity. The resolution, run time and detection limits of the MEKC method were compared with those of an HPLC method developed previously.

  15. SANS study of three-layer micellar particles

    Plestil, J; Kuklin, A I; Cubitt, R


    Three-layer nanoparticles were prepared by polymerization of methyl methacrylate (MMA) in aqueous micellar solutions of poly(methyl methacrylate)-block-poly(methacrylic acid) (PMMA-b-PMA) and polystyrene-block-poly(methacrylic acid) (PS-b-PMA). The resulting polymer forms a layer on the core surface of the original micelles. SANS curves were fitted using an ellipsoidal (PMMA/PMMA/PMA) or spherical (PS/PMMA/PMA) model for the particle core. The particle size (for the presented series of the PMMA/PMMA/PMA particles, the core semiaxes ranged from 87 to 187 A and the axis ratio was about 6) can be finely tuned by variation of monomer concentration. Time-resolved SANS experiments were carried out to describe the growth of the PS/PMMA/PMA particles during polymerization. (orig.)

  16. Effect of Micelle Composition on Acidic Drugs Separation Behavior by Micellar Electrokinetic Capillary Chromatography


    Micellar electrokinetic capillary chromatography (MECC) separation of four acidic drugs similar in structure was studied. Both anionic surfactant sodium dodecyl sulfate (SDS) and nonionic surfactant Tween 20 were used to form single micelles and mixed micelles as pseudostationary phases. The effects of the composition of micellar solution on retention behaviors were studied. The results indicate that there is markedly different selectivity among SDS, Tween 20 and the mixed micelles systems.

  17. Separation of Six Pyridoncarboylxic Acid Derivatives by Micellar and Microemulsion Electrokinetic Chromatography


    Micellar and microemulsion electrokinetic chromatography (MEKC & MEEKC) separation of six closely structural pyridoncarboylxic acid derivatives were studied and compared. Both anionic surfactant sodium dodecyl sulfate (SDS) and cationic surfactant hexadecyl-trimethyl ammonium bromide (CTAB) were used to form micellar and microemulsion as pseudostation phases, respectively. The effects of the separation conditions on retention time and selectivity were studied. Good resolutions were obtained in selected systems, indicating that there is markably different selectivity between SDS and CTAB systems.

  18. Jet A fuel recovery using micellar flooding: Design and implementation.

    Kostarelos, Konstantinos; Lenschow, Søren R; Stylianou, Marinos A; de Blanc, Phillip C; Mygind, Mette Marie; Christensen, Anders G


    Surfactants offer two mechanisms for recovering NAPLs: 1) to mobilize NAPL by reducing NAPL/water interfacial tension, and; 2) to increase the NAPL's aqueous solubility-called solubilization-as an enhancement to pump & treat. The second approach has been well-studied and applied successfully in several pilot-scale and a few full-scale tests within the last 15years, known as Surfactant Enhanced Aquifer Remediation (SEAR). A useful source of information for this second approach is the "Surfactant-enhanced aquifer remediation (SEAR) design manual" from the U.S. Navy Facilities Engineering Command. Few attempts, however, have been made at recovering NAPLs using the mobilization approach presented in this paper. Now, a full-scale field implementation of the mobilization approach is planned to recover an LNAPL (Jet A fuel) from a surficial sand aquifer located in Denmark using a smaller amount of surfactant solution and fewer PVs of throughput compared with the SEAR approach. The approach will rely on mobilizing the LNAPL so that it is recovered ahead of the surfactant microemulsion, also known as a micellar flood. This paper will review the laboratory work performed as part of the design for a full-scale implementation of a micellar flood. Completed lab work includes screening of surfactants, phase behavior and detailed salinity scans of the most promising formulations, and generating a ternary diagram to be used for the numerical simulations of the field application. The site owners and regulators were able to make crucial decisions such as the anticipated field results based on this work.

  19. Bell Creek field micellar-polymer pilot demonstration. Third annual report, October 1978-September 1979

    Goldburg, A.


    Gary Energy Corporation is conducting a DOE Demonstration Pilot to determine if micellar-polymer flooding is an economically feasible technique to enhance oil recovery from the Bell Creek Field, Powder River County, southeastern Montana. The pilot is a contained 40-acre 5-spot located in a representative watered-out portion of Unit A Reservoir. The pay is sandstone with an average net pay of 6.4 feet, air permeability of 1050 md, and water TDS of 4000 ppM. The current average remaining oil saturation in the 40-acre pilot area is estimated to be 28%. The pilot has four injectors (Wells MPP-1, MPP-2, MPP-3, and MPP-4) and one producer (Well 12-1). The overall micellar-polymer oil recovery is estimated at 47% of the remaining oil at the initiation of the micellar-polymer flood. In the third contract year (October 1978 to September 1979), all tasks including the initiation of soluble oil/micellar injection were completed. Test site development included completion of: (1) radioactive tracer survey and analysis, (2) core analysis, (3) pressure pulse tests and analysis, (4) reservoir description, and (5) test site facilities. Based on test site development data, soluble oil/micellar formulation was finalized and mathematical simulation work by Intercomp completed. The preflush injection phase of the demonstration program was completed, and the soluble oil/micellar injection was initiated at the end of the contract year. The pilot demonstration project has progressed as scheduled.

  20. Aliphatic carboxylic acids as new modifiers for separation of 2,4-dinitrophenyl amino acids by micellar liquid chromatography.

    Boichenko, Alexander P; Kulikov, Artem U; Loginova, Lidia P; Iwashchenko, Anna L


    The possibilities of isocratic separation of 2,4-dinitrophenyl derivatives of 12 amino acids that considerably differ in hydrophobicity by micellar mobile phases with different organic modifiers have been discussed. For the first time aliphatic carboxylic acids have been used as modifiers of micellar eluent in micellar liquid chromatography with C18 columns. Elution strength of hybrid micellar phases on the basis of sodium dodecylsulfate and aliphatic carboxylic acids increases in sequence: aceticacid. The effect of sodium dodecylsulfate micelles on aliphatic carboxylic acids has been characterized by their micellar-induced shifts of ionization constants. The use of aliphatic carboxylic acids as modifiers of SDS micellar eluents provides better overall resolution of 2,4-dinitrophenyl-amino acids in comparison with aliphatic alcohols.

  1. Direct Injection of Seawater for the Analysis of Nitroaromatic Explosives and their Degradation Products by Micellar Electrokinetic Chromatography


    micellar electrokinetic chromatography Braden C. Giordanoa,∗, Dean S. Burgib, Greg E. Collinsa a Uanited States Naval Research Laboratory, Chemistry...threats to our coastal regions. Micellar electrokinetic chromatography (MEKC) has been demonstrated to be a useful analytical tool in the anal- ysis of...injection of seawater for the analysis of nitroaromatic explosives and their degradation products by micellar electrokinetic chromatography 5a. CONTRACT

  2. Profilin binding to sub-micellar concentrations of phosphatidylinositol (4,5) bisphosphate and phosphatidylinositol (3,4,5) trisphosphate

    Moens, Pierre D J; Bagatolli, Luis A


    its interaction with phosphatidylinositol 4,5-bisphosphate [PI(4,5)P(2)] and phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P(3)] (P.J. Lu, W.R. Shieh, S.G. Rhee, H.L. Yin, C.S. Chen, Lipid products of phosphoinositide 3-kinase bind human profilin with high affinity, Biochemistry 35 (1996) 14027......-14034). To date, profilin's interaction with polyphosphoinositides (PPI) has only been studied in micelles or small vesicles. Profilin binds with high affinity to small clusters of PI(4,5)P(2) molecules. In this work, we investigated the interactions of profilin with sub-micellar concentrations of PI(4,5)P(2......) and PI(3,4,5)P(3). Fluorescence anisotropy was used to determine the relevant dissociation constants for binding of sub-micellar concentrations of fluorescently labeled PPI lipids to profilin and we show that these are significantly different from those determined for profilin interaction with micelles...

  3. Prediction of retention in micellar electrokinetic chromatography based on molecular structural descriptors by using the heuristic method

    Liu Huanxiang [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Yao Xiaojun [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)]. E-mail:; Liu Mancang [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Hu Zhide [Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Fan Botao [Universite Paris 7-Denis Diderot, ITODYS 1, rue Guy de la Brosse, 75005 Paris (France)


    Based on calculated molecular descriptors from the solutes' structure alone, the micelle-water partition coefficients of 103 solutes in micellar electrokinetic chromatography (MEKC) were predicted using the heuristic method (HM). At the same time, in order to show the influence of different molecular descriptors on the micelle-water partition of solute and to well understand the retention mechanism in MEKC, HM was used to build several multivariable linear models using different numbers of molecular descriptors. The best 6-parameter model gave the following results: the square of correlation coefficient R {sup 2} was 0.958 and the mean relative error was 3.98%, which proved that the predictive values were in good agreement with the experimental results. From the built model, it can be concluded that the hydrophobic, H-bond, polar interactions of solutes with the micellar and aqueous phases are the main factors that determine their partitioning behavior. In addition, this paper provided a simple, fast and effective method for predicting the retention of the solutes in MEKC from their structures and gave some insight into structural features related to the retention of the solutes.

  4. A novel, rapid and automated conductometric method to evaluate surfactant-cells interactions by means of critical micellar concentration analysis.

    Tiecco, Matteo; Corte, Laura; Roscini, Luca; Colabella, Claudia; Germani, Raimondo; Cardinali, Gianluigi


    Conductometry is widely used to determine critical micellar concentration and micellar aggregates surface properties of amphiphiles. Current conductivity experiments of surfactant solutions are typically carried out by manual pipetting, yielding some tens reading points within a couple of hours. In order to study the properties of surfactant-cells interactions, each amphiphile must be tested in different conditions against several types of cells. This calls for complex experimental designs making the application of current methods seriously time consuming, especially because long experiments risk to determine alterations of cells, independently of the surfactant action. In this paper we present a novel, accurate and rapid automated procedure to obtain conductometric curves with several hundreds reading points within tens of minutes. The method was validated with surfactant solutions alone and in combination with Saccharomyces cerevisiae cells. An easy-to use R script, calculates conductometric parameters and their statistical significance with a graphic interface to visualize data and results. The validations showed that indeed the procedure works in the same manner with surfactant alone or in combination with cells, yielding around 1000 reading points within 20 min and with high accuracy, as determined by the regression analysis.

  5. Effects of ionic liquids on micellar microstructures and separation performance in micellar electrokinetic chromatography%离子液体对胶束电动色谱胶束微结构以及分离效果的影响

    余美娟; 杭栋; 曹玉华


    The effects of ionic liquids on micellar microstructures and separation performance in micellar electrokinetic chromatography ( MEKC ) were investigated. The experimental results showed that the addition of ionic liquids into micellar system would result in a decreased micellar surface charge density, an enlarged size of micelle and a slight enhancement of the polarity in the inner core of micelle. Prednisone , hydrocortisone and prednisolone were analyzed with MEKC to evaluate the separation performance. Hydrocortisone and prednisolone could not be separated in sodium lauryl sulfate ( SDS ) micellar system. However. the three analytes could be baseline separated in the mixed system of ionic liquids and SDS ( 20 mmol/L SDS-10 mmol/L 1-butyl-3-methyl imidazolium tetrafluoroborate-50 mmol/L borax , pH 8.4 ) within 17 min. Notably, the linearities of the three analytes ranged from 2 to 100 mg/L and the detection limits based on the ratio of signal to noise of 3 were 1.0, 1.1 and 1.0 mg/L for prednisone, hydrocortisone and prednisolone, respectively. The method has been used in the analysis of corticosteroids in cosmetic samples. The recoveries for the three analytes were between 95.1% and 117%. This method has the advantages of simple pretreatment, high accuracy, good reproducibility, and can be applied to the quality control of cosmetics.%考察了离子液体对胶束电动色谱胶柬微结构以及分离效果的影响.研究结果表明,离子液体使胶束的表面电荷密度变小、粒径变大及其内核极性增大.以泼尼松、氢化可的松和泼尼松龙为分析对象,氢化可的松与泼尼松龙在十二烷基硫酸钠(SDS)胶束体系中不能实现分离.而在SDS-离子液体混合介质(20 mmol/L SDS-10 mmol/L1-丁基-3-甲基咪唑四氟硼酸盐-50 mmol/L硼砂-硼酸缓冲液,pH 8.4)中,3种物质可在17 min内达到基线分离.各组分在2~100 mg/L范围内呈良好的线性关系,检出限(信噪比为3)分别为1.0、1.1和1

  6. Characterization and classification of pseudo-stationary phases in micellar electrokinetic chromatography using chemometric methods.

    Fu, Cexiong; Khaledi, Morteza G


    Two types of chemometric methods, principal component analysis (PCA) and cluster analysis, are employed to characterize and classify a total of 70 pseudostationary phases (54 distinct systems and 16 decoy systems) in micellar electrokinetic chromatography (MEKC). PCA excels at removing redundant information for micellar phase characterization and retaining principal determinants for phase classification. While PCA is useful in the characterization of micelle selectivities, it is ineffective in defining the grouping of micellar phases. Hierarchical clustering yields a complete dendrogram of cluster structures but provides only limited cluster characterizations. The combination of these two chemometric methods leads to a comprehensive interpretation of the micellar phase classification. Moreover, the k-means analysis can further discern subtle differences among those closely located micellar phases. All three chemometric methods result in similar classifications with respect to the similarities and differences of the 70 micelle systems investigated. These systems are categorized into 3 major clusters: fluoro-surfactants represent cluster I, identified as strong hydrogen bond donors and dipolar but weak hydrogen bond acceptors. Cluster II includes sulfonated acrylamide/acrylate copolymers and surfactants with trimethylammonium head groups, characterized by strong hydrophobicity (v) and weak hydrogen bond acidity (b). The last cluster consists of two subclusters: clusters III and IV. Cluster III includes siloxane-based polymeric micelles, exhibiting weak hydrophobicity and medium hydrogen bond acidity and basicity (a), and the cluster IV micellar systems are characterized by their strong hydrophobicity and medium hydrogen bond acidity and basicity but rather weak dipolarity. Cluster III differs from cluster IV by its slightly weaker hydrophobicity and hydrogen bond donating capability. The classification by chemometric methods is in good agreement with the

  7. Effect of calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein solutions: The role of calcium-ion activity and micellar integrity

    Kort, de E.J.P.; Minor, M.; Snoeren, T.A.L.; Hooijdonk, van A.C.M.; Linden, van der E.


    There is general consensus that calcium chelators enhance heat stability in milk. However, they increase the heat stability to considerably different extents. For this reason, the effect of various calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein

  8. Effect of calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein solutions: The role of calcium-ion activity and micellar integrity

    Kort, de E.J.P.; Minor, M.; Snoeren, T.A.L.; Hooijdonk, van A.C.M.; Linden, van der E.


    There is general consensus that calcium chelators enhance heat stability in milk. However, they increase the heat stability to considerably different extents. For this reason, the effect of various calcium chelators on heat coagulation and heat-induced changes of concentrated micellar casein solutio

  9. Drug-loaded pseudo-block copolymer micelles with a multi-armed star polymer as the micellar exterior

    Xie, Chen; Zhang, Peng; Zhang, Zhengkui; Yang, Chenchen; Zhang, Jialiang; Wu, Wei; Jiang, Xiqun


    Supramolecular constructed pseudo block copolymer micelles based on β-cyclodextrin terminated 4 and 7 armed star poly(N-vinylpyrrolidone) and adamantane terminated linear poly(ε-caprolactone) were prepared. The size, morphology, stability and protein adsorption were experimentally examined. The micelles with 7 armed PVP chains as the micellar exterior showed the lowest amount of protein adsorption and the best stability in media. When cabazitaxel, a new taxane, was loaded into the micelles, 14.4% drug loading content and 85% encapsulation efficacy were achieved. In vitro cytotoxicity studies demonstrated that the cabazitaxel-loaded micelles show significant cytotoxicity against drug-resistant A2780/T cell lines. Biodistribution studies showed that the micelles can almost double the content of cargo in tumor sites compared with the free cargo. In vivo antitumor activity examinations indicated that cabazitaxel-loaded micelles show superior antitumor activity over free paclitaxel and free cabazitaxel.Supramolecular constructed pseudo block copolymer micelles based on β-cyclodextrin terminated 4 and 7 armed star poly(N-vinylpyrrolidone) and adamantane terminated linear poly(ε-caprolactone) were prepared. The size, morphology, stability and protein adsorption were experimentally examined. The micelles with 7 armed PVP chains as the micellar exterior showed the lowest amount of protein adsorption and the best stability in media. When cabazitaxel, a new taxane, was loaded into the micelles, 14.4% drug loading content and 85% encapsulation efficacy were achieved. In vitro cytotoxicity studies demonstrated that the cabazitaxel-loaded micelles show significant cytotoxicity against drug-resistant A2780/T cell lines. Biodistribution studies showed that the micelles can almost double the content of cargo in tumor sites compared with the free cargo. In vivo antitumor activity examinations indicated that cabazitaxel-loaded micelles show superior antitumor activity over free

  10. Polymeric micelles based on poly(ethylene oxide) and α-carbon substituted poly(ɛ-caprolactone): An in vitro study on the effect of core forming block on polymeric micellar stability, biocompatibility, and immunogenicity.

    Garg, Shyam M; Vakili, Mohammad Reza; Lavasanifar, Afsaneh


    A series of block copolymers based on methoxy poly(ethylene oxide)-block-poly(ɛ-caprolactone) (PEO-b-PCL), PEO-b-PCL bearing side groups of benzyl carboxylate (PEO-b-PBCL), or free carboxyl (PEO-b-PCCL) on the PCL backbone with increasing degrees of polymerization of the PCL backbone were synthesized. Prepared block copolymers assembled to polymeric micelles by co-solvent evaporation. The physical stability of prepared micelles was assessed by measuring their tendency toward aggregation over time using dynamic light scattering (DLS). The resistance of micelles against dissociation in the presence of a micelle destabilizing agent, i.e., sodium dodecyl sulfate (SDS), was also investigated using DLS. The rate of micellar core degradation was determined using (1)H NMR for polymer molecular weight measurement upon incubation of micelles in PBS (pH=7.4) at 37°C followed by dialysis of the remaining polymer at different time intervals. The effect of pendent group chemistry in the micellar core on the adsorption of serum proteins to micellar structure was then evaluated using Bradford Protein assay kit. Finally, the effect of micellar core structure on the induction of bone marrow derived dendritic cell (BMDC) maturation and secretion of IL-12 was studied as a measure of micellar immunogenicity. The results showed micelle structures from polymers with higher degree of polymerization in the hydrophobic block and/or those with more hydrophobic substituents on the core-forming block, to be more stable. This was reflected by a decreased tendency for micellar aggregation, reduced dissociation of micelles in the presence of SDS, and diminished core degradation. All micelles were shown to have insignificant adsorption of serum protein suggesting that the hydrophilic PEO shell provided sufficient protection of the core. However, the protein adsorption increased with increase in the hydrophobicity and molecular weight of the core-forming block. Irrespective of the micellar core

  11. Preparation of PEO/Clay Nanocomposites Using Organoclay Produced via Micellar Adsorption of CTAB

    Ahmet Gürses


    Full Text Available The aim of this study was the preparation of polyethylene oxide (PEO/clay nanocomposites using organoclay produced via micellar adsorption of cethyltrimethyl ammonium bromide (CTAB and their characterisation by X-ray diffraction (XRD, and Fourier transform infrared (FT-IR spectra, and the investigation of certain mechanical properties of the composites. The results show that the basal distance between the layers increased with the increasing CTAB/clay ratio as parallel with the zeta potential values of particles. By considering the aggregation number of CTAB micelles and interlayer distances of organo-clay, it could be suggested that the predominant micelle geometry at lower CTAB/clay ratios is an ellipsoidal oblate, whereas, at higher CTAB/clay ratios, sphere-ellipsoid transition occurs. The increasing tendency of the exfoliation degree with an increase in clay content may be attributed to easier diffusion of PEO chains to interlayer regions. FT-IR spectra show that the intensity of Si-O stretching vibrations of the organoclays (1050 cm−1 increased, especially in the ratios of 1.0 g/g clay and 1.5 g/g clay with the increasing CTAB content. It was observed that the mechanical properties of the composites are dependent on both the CTAB/clay ratios and clay content of the composites.

  12. Selection of reservoirs amenable to micellar flooding. First annual report, October 1978-December 1979

    Goldburg, A.; Price, H.


    The overall project objective is to build a solid engineering base upon which the Department of Energy (DOE) can improve and accelerate the application of micellar-polymer recovery technology to Mid-Continent and California sandstone reservoirs. The purpose of the work carried out under these two contracts is to significantly aid, both DOE and the private sector, in gaining the following Project Objectives: to select the better micellar-polymer prospects in the Mid-Continent and California regions; to assess all of the available field and laboratory data which has a bearing on recovering oil by micellar-polymer projects in order to help identify and resolve both the technical and economic constraints relating thereto; and to design and analyze improved field pilots and tests and to develop a micellar-polymer applications matrix for use by the potential technology users; i.e., owner/operators. The report includes the following: executive summary and project objectives; development of a predictive model for economic evaluation of reservoirs; reservoir data bank for micellar-polymer recovery evaluation; PECON program for preliminary economic evaluation; ordering of candidate reservoirs for additional data acquisition; validation of predictive model by numerical simulation; and work forecast. Tables, figures and references are included.

  13. Chemometric Deconvolution of Continuous Electrokinetic Injection Micellar Electrokinetic Chromatography Data for the Quantitation of Trinitrotoluene in Mixtures of Other Nitroaromatic Compounds


    ABSTRACT Chemometric Deconvolution of Continuous Electrokinetic Injection Micellar Electrokinetic Chromatography Data for the Quantitation of...Unclassified Unlimited Unclassified Unlimited 13 Braden C. Giordano (202) 404-6320 Micellar electrokinetic chromatography Nitroaromatic explosives...Capillary electrophoresis DNT – Dinitrotoluene EOF – Electroosmotic flow MEKC – Micellar electrokinetic chromatography PLS – Partial least squares regression TNT – Trinitrotoluene 11

  14. Molecular thermodynamics for micellar branching in solutions of ionic surfactants.

    Andreev, Vasily A; Victorov, Alexey I


    We develop an analytical molecular-thermodynamic model for the aggregation free energy of branching portions of wormlike ionic micelles in 1:1 salt solution. The junction of three cylindrical aggregates is represented by a combination of pieces of the torus and bilayer. A geometry-dependent analytical solution is obtained for the linearized Poisson-Boltzmann equation. This analytical solution is applicable to saddle-like structures and reduces to the solutions known previously for planar, cylindrical, and spherical aggregates. For micellar junctions, our new analytical solution is in excellent agreement with numerical results over the range of parameters typical of ionic surfactant systems with branching micelles. Our model correctly predicts the sequence of stable aggregate morphologies, including a narrow bicontinuous zone, in dependence of hydrocarbon tail length, head size, and solution salinity. For predicting properties of a spatial network of wormlike micelles, our aggregation free energy is used in the Zilman-Safran theory. Our predictions are compared with experimental data for branching micelles of ionic surfactants.

  15. Glass and percolation transitions in dense attractive micellar system

    Mallamace, F.; Beneduci, R.; Gambadauro, P.; Lombardo, D.; Chen, S. H.


    In this work, we study a copolymer-micellar system characterized by clustering processes due to a short-range attractive interaction. This originates a percolation process and a new type of kinetic glass transition. We have studied these intriguing dynamical situations by means of an extensive set of light scattering and viscoelasticity experiments. Obtained data, in both the phenomena, are accounted for by considering in a proper way fractal clustering processes and the related scaling concepts. Near the percolation line the main role in the system structure and dynamics is played by the cluster's partial screening of hydrodynamic interaction, that behaves, on approaching the percolation threshold, dramatic effects on the rheological properties and on the density decay relaxations. The ergodic-nonergodic transition line (glass transition) is studied in terms of the intermediate scattering functions (ISF) in the frame of the mode coupling theory. The measured ISF gives evidence of a logarithmic decay on the density fluctuation followed by a power law behavior. This latter phenomenon is the signature of a high-order glass transition of the A3 type (cusp-like singularity).

  16. Micellar electrokinetic chromatography of organic and peroxide-based explosives.

    Johns, Cameron; Hutchinson, Joseph P; Guijt, Rosanne M; Hilder, Emily F; Haddad, Paul R; Macka, Mirek; Nesterenko, Pavel N; Gaudry, Adam J; Dicinoski, Greg W; Breadmore, Michael C


    CE methods have been developed for the analysis of organic and peroxide-based explosives. These methods have been developed for deployment on portable, in-field instrumentation for rapid screening. Both classes of compounds are neutral and were separated using micellar electrokinetic chromatography (MEKC). The effects of sample composition, separation temperature, and background electrolyte composition were investigated. The optimised separation conditions (25 mM sodium tetraborate, 75 mM sodium dodecyl sulfate at 25°C, detection at 200 nm) were applied to the separation of 25 organic explosives in 17 min, with very high efficiency (typically greater than 300,000 plates m(-1)) and high sensitivity (LOD typically less than 0.5 mg L(-1); around 1-1.5 μM). A MEKC method was also developed for peroxide-based explosives (10 mM sodium tetraborate, 100 mM sodium dodecyl sulfate at 25°C, detection at 200 nm). UV detection provided LODs between 5.5 and 45.0 mg L(-1) (or 31.2-304 μM), which is comparable to results achieved using liquid chromatography. Importantly, no sample pre-treatment or post-column reaction was necessary and the peroxide-based explosives were not decomposed to hydrogen peroxide. Both MEKC methods have been applied to pre-blast analysis and for the detection of post-blast residues recovered from controlled, small scale detonations of organic and peroxide-based explosive devices.

  17. Simultaneous micellar LC determination of lidocaine and tolperisone.

    Youngvises, Napaporn; Liawruangrath, Boonsom; Liawruangrath, Saisunee


    A micellar liquid chromatography (MLC) procedure was developed for the simultaneous separation and determination of lidocaine hydrochloride (LD HCl) and tolperisone hydrochloride (TP HCl) using a short-column C18 (12.5 mm x 4.6 mm, 5 microm), sodium dodecyl sulfate (SDS) with a small amount of isopropanol, and diode array detector. The optimum conditions for the simultaneous determination of both drugs were 0.075 mol l(-1) SDS-7.5% (v/v) isopropanol with a flow rate of 0.7 ml min(-1) and detection at 210 nm. The LOD (2S/N) of LD HCl was 0.73 ng 20 microl(-1), whereas that of TP HCl was 1.43 ng 20 microl(-1). The calibration curves for LD HCl and TP HCl were linear over the ranges 0.125-500 microg ml(-1) (r(2)=0.9999) and 1.00-500 microg ml(-1) (r(2)=0.9997), respectively. The %recoveries of both drugs were in the range 98-103% and the %RSD values were less than 2. The proposed method has been successfully applied to the simultaneous determination of TP HCl and LD HCl in various pharmaceutical preparations.

  18. PH-triggered micellar membrane for controlled release microchips

    Yang, Xiaoqiang


    A pH-responsive membrane based on polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) block copolymer was developed on a model glass microchip as a promising controlled polymer delivery system. The PS-b-P4VP copolymer assembles into spherical and/or worm-like micelles with styrene block cores and pyridine coronas in selective solvents. The self-assembled worm-like morphology exhibited pH-responsive behaviour due to the protonation of the P4VP block at low pH and it\\'s deprotonation at high pH and thus constituting a switchable "off/on" system. Doxorubicin (Dox) was used as cargo to test the PS-b-P4VP membrane. Luminescence experiments indicated that the membrane was able to store Dox molecules within its micellar structure at neutral pH and then release them as soon as the pH was raised to 8.0. The performance of the cast membrane was predictable and most importantly reproducible. The physiochemical and biological properties were also investigated carefully in terms of morphology, cell viability and cell uptake. This journal is © The Royal Society of Chemistry.

  19. Solvent blends can control cationic reversed micellar interdroplet interactions. The effect of n-heptane:benzene mixture on BHDC reversed micellar interfacial properties: droplet sizes and micropolarity.

    Agazzi, Federico M; Falcone, R Dario; Silber, Juana J; Correa, N Mariano


    We have investigated, for the first time, the effect of the composition of the nonpolar organic media on the benzyl-n-hexadecyl-dimethylammonium chloride (BHDC) reversed micelles (RMs) properties at fixed temperature. To achieve this goal we have used the solvatochromic behavior of 1-methyl-8-oxyquinolinium betaine (QB) as absorption probe and dynamic light scattering (DLS), to monitor droplet sizes, interfacial micropolarity, and sequestrated water structure of water/BHDC/n-heptane:benzene RMs. DLS results confirm the formation of the water/BHDC/n-heptane:benzene RMs at every n-heptane mole fraction (X(Hp)) investigated, that is, X(Hp) = 0.00, 0.13, 0.21, 0.30, and 0.38. Also, DLS was used to measure the RMs diffusion coefficient and to calculate the apparent droplet hydrodynamic diameter (d(App)) at different compositions of the nonpolar organic medium. The data suggest that as the n-heptane content increases, the interdroplet attractive interactions also increase with the consequent increment in the droplet size. Moreover, the interdroplet attractive interactions can be "switched on (increased)" or "switched off (decreased)" by formulation of appropriate n-heptane:benzene mixtures. Additionally, QB spectroscopy was used to obtain the "operational" critical micellar concentration (cmc) and to investigate both the RMs interfacial micropolarity and the sequestrated water structure in every RMs studied. The results show that BHDC RMs are formed at lower surfactant concentration when n-heptane or water content increases. When the interdroplet interaction "switches on", the RMs droplet sizes growth expelling benzene molecules from the RMs interface, favoring the water-BHDC interaction at the interface with the consequent increases in the interfacial micropolarity. Therefore, changing the solvent blend is possible to affect dramatically the interfacial micropolarity, the droplet sizes and the structure of the entrapped water.

  20. Fluid-Induced Propulsion of Rigid Particles in Wormlike Micellar Solutions

    Gagnon, David A; Shen, Xiaoning; Arratia, Paulo E


    In the absence of inertia, a reciprocal swimmer achieves no net motion in a viscous Newtonian fluid. Here, we investigate the ability of a reciprocally actuated particle to translate through a complex, "structured" fluid using tracking methods and birefringence imaging. A geometrically polar particle, a rod with a bead on one end, is reciprocally rotated using magnetic fields. The particle is immersed in a wormlike micellar solution that is known to be susceptible to shear banding and the formation of local anisotropic structures. Results show that the nonlinearities present in this structured fluid break time-reversal symmetry under certain conditions, and enable propulsion of an artificial "swimmer." We find three regimes dependent on the Deborah number (De): net motion towards the bead at low De, net motion towards the rod at intermediate De, and no propulsion at high De. At low De, we believe propulsion is caused by an imbalance in the first normal stress differences between the two ends of the particle (...

  1. Application of Sigmoidal Transformation Functions in Optimization of Micellar Liquid Chromatographic Separation of Six Quinolone Antibiotics.

    Hadjmohammadi, Mohammadreza; Salary, Mina


    A chemometrics approach has been used to optimize the separation of six quinolone compounds by micellar liquid chromatography (MLC). A Derringer's desirability function, a multicriteria decision-making (MCDM) method, was tested for evaluation of two different measures of chromatographic performance (resolution and analysis time). The effect of three experimental parameters on a chromatographic response function (CRF) expressed as a product of two sigmoidal desirability functions was investigated. The sigmoidal functions were used to transform the optimization criteria, resolution and analysis time into the desirability values. The factors studied were the concentration of sodium dodecyl sulfate, butanol content and pH of the mobile phase. The experiments were done according to the face-centered cube central composite design, and the calculated CRF values were fitted to a polynomial model to correlate the CRF values with the variables and their interactions. The developed regression model showed good descriptive and predictive ability (R(2) = 0.815, F = 6.919, SE = 0.038, [Formula: see text]) and used, by a grid search algorithm, to optimize the chromatographic conditions for the separation of the mixture. The efficiency of prediction of polynomial model was confirmed by performing the experiment under the optimal conditions.

  2. Iron(Ⅱ) tetrasulfophthalocyanine mimetic enzymatic synthesis of conducting polyaniline in micellar system

    HU Xing; LIU Hui; ZOU Guo-lin


    Iron(Ⅱ) tetrasulfophthalocyanine (FeTSPc), as a novel mimetic enzyme of peroxidase, was used in the synthesis of a conducting polyaniline (PANI)/sodium dodecylsulfate (SDS) complex in SDS aqueous micellar solutions. The effects of pH, concentrations of aniline, SDS and H_2O_2, and reaction time on polymerization of aniline were studied in this case as shown by UV-Vis absorption spectroscopy. The results show that a wide range of pH (0.5-4.0) is required to produce the conducting PANI, and the optimal pH is 1.0 in SDS micelle. The optimal concentrations of aniline, SDS and H_2O_2 in feed, and reaction time in this case for the production of conducting PANI are respectively 10 mmol/L, 10 mmol/L, 25 mmol/L, and 15 h. FT-IR spectrum, elemental analysis, conductivity, cyclic voltammetry and thermogravimetric analysis confirm the thermal stability and electroactive form of PANI.

  3. Micellar enhanced ultrafiltration process for the treatment of olive mill wastewater.

    El-Abbassi, Abdelilah; Khayet, Mohamed; Hafidi, Abdellatif


    Olive mill wastewater (OMW) is an important environmental pollution problem, especially in the Mediterranean, which is the main olive oil production region worldwide. Environmental impact of OMW is related to its high organic load and particularly to the phytotoxic and antibacterial action of its phenolic content. In fact, polyphenols are known as powerful antioxidants with interesting nutritional and pharmaceutical properties. In the present work, the efficiency of OMW Micellar Enhanced Ultrafiltration (MEUF) treatment for removal and concentration of polyphenols was investigated, using an anionic surfactant (Sodium Dodecyl Sulfate salt, SDS) and a hydrophobic poly(vinyldene fluoride) (PVDF) membrane. The effects of the process experimental conditions on the permeate flux were investigated, and the secondary membrane resistance created by SDS molecules was evaluated. The initial fluxes of OMW processing by MEUF using SDS were 25.7 and 44.5 l/m2 h under transmembrane pressures of 3.5 and 4.5 bar, respectively. The rejection rate of polyphenols without using any surfactant ranged from 5 to 28%, whereas, it reached 74% when SDS was used under optimum pH (pH 2). The MEUF provides a slightly colored permeate (about 88% less dark), which requires clearly less chemical oxygen demand (COD) for its oxidation (4.33% of the initial COD). These results showed that MEUF process can efficiently be applied to the treatment of OMW and for the concentration and recovery of polyphenols.

  4. Micellar Liquid Chromatographic Determination of Carbaryl and 1-Naphthol in Water, Soil, and Vegetables

    Mei-Liang Chin-Chen


    Full Text Available A liquid chromatographic procedure has been developed for the determination of carbaryl, a phenyl-N-methylcarbamate, and its main metabolite 1-naphthol, using a C18 column (250’mm’ × ’4.6’mm with a micellar mobile phase and fluorescence detection at maximum excitation/emission wavelengths of 225/333’nm, respectively. In the optimization step, surfactants sodium dodecyl sulphate (SDS, Brij-35 and N-cetylpyridinium chloride monohydrate, and organic solvents propanol, butanol, and pentanol were considered. The selected mobile phase was 0.15’M SDS-6% (v/v-pentanol-0.01’M NaH2PO4 buffered at pH 3. Validation studies, according to the ICH Tripartite Guideline, included linearity (r>0.999, limit of detection (5 and 18’ng mL-1, for carbaryl and 1-naphthol, resp., and limit of quantification (15 and 50’ng mL-1, for carbaryl and 1-naphthol, resp., with intra- and interday precisions below 1%, and robustness parameters below 3%. The results show that the procedure was adequate for the routine analysis of these two compounds in water, soil, and vegetables samples.

  5. Influence of ultrasound on chemically induced gelation of micellar casein systems.

    Chandrapala, Jayani; Zisu, Bogdan; Kentish, Sandra; Ashokkumar, Muthupandian


    Gelation is a significant operation in dairy processing. Protein gelation can be affected by several factors such as temperature, pH, or enzyme addition. Recently, the use of ultrasonication has been shown to have a significant impact on the formation of whey protein gels. In this work, the effect of ultrasonication on the gelation of casein systems was investigated. Gels were formed by the addition of 7.6 mm Tetra Sodium Pyro Phosphate (TSPP) to 5 wt% micellar casein (MC) solutions. Sonication at 20 KHz and 31 W for up to 30 min changed the surface hydrophobicity of the proteins, whereas surface charge was unaltered. Sonication before the addition of TSPP formed a firm gel with a fine protein network and low syneresis. Conversely, sonication after TSPP addition led to an inconsistent weak-gel-like structure with high syneresis. Gel strength in both cases increased significantly after short sonication times, while the viscoelastic properties were less affected. Overall, the results showed that ultrasonication can have a significant effect on the final gel properties of casein systems.

  6. Simple micellar electrokinetic chromatography method for the determination of hydrogen sulfide in hen tissues.

    Kubalczyk, Paweł; Borowczyk, Kamila; Chwatko, Grażyna; Głowacki, Rafał


    A new method for the determination of hydrogen sulfide in hen tissues has been developed and validated. For estimation of hydrogen sulfide content, a sample (0.1 g) of hen tissue was treated according to the procedure consisted of some essential steps: simultaneous homogenization of a tissue and derivatization of hydrogen sulfide to its S-quinolinium derivative with 2-chloro-1-methylquinolinium tetrafluoroborate, separation of so-formed derivative by micellar electrokinetic chromatography with sweeping, and detection and quantitation with the use of UV detector set to measure analytical signals at 375 nm. Effective electrophoretic separation was achieved using fused silica capillary (effective length 41.5 cm, 75 μm id) and 0.05 mol/L, pH 8 phosphate buffer with the addition of 0.04 mol/L SDS and 26% ACN. The lower limit of quantification was 0.12 μmol hydrogen sulfide in 1 g of tissue. The calibration curve prepared in tissue homogenate for hydrogen sulfide showed linearity in the range from 0.15 to 2.0 μmol/g, with the coefficient of correlation 0.9978. The relative standard deviation of the points of the calibration curve varied from 8.3 to 3.2% RSD.

  7. Simultaneous determination of ten preservatives in ten kinds of foods by micellar electrokinetic chromatography.

    Ding, Xiao-Jing; Xie, Na; Zhao, Shan; Wu, Yu-Chen; Li, Jiang; Wang, Zhi


    An improved micellar electrokinetic capillary chromatography method (MEKC) for the simultaneous determination of ten preservatives in ten different kinds of food samples was reported. An uncoated fused-silica capillary with 50 μm i.d. and 70 cm total length was used. Under the optimized conditions, the linear response was observed in the range of 1.2-200mg/L for the analytes. The limits of detection (LOD, S/N=3) and limits of quantitation (LOQ, S/N=10) ranging from 0.4 to 0.5mg/L and 1.2 to 1.5mg/L, respectively were obtained. The method was used for the determination of sorbic and benzoic acids in two FAPAS® (Food Analysis Performance Assessment Scheme) proficiency test samples (jam and chocolate cake). The results showed that the current method with simple sample pretreatment and small reagent consumption could meet the needs for routine analysis of the ten preservatives in ten types of food products.

  8. LPS-protein aggregation influences protein partitioning in aqueous two-phase micellar systems.

    Lopes, André Moreni; Santos-Ebinuma, Valéria de Carvalho; Novaes, Leticia Celia de Lencastre; Molino, João Vitor Dutra; Barbosa, Leandro Ramos Souza; Pessoa, Adalberto; Rangel-Yagui, Carlota de Oliveira


    Lipopolysaccharide endotoxins (LPS) are the most common pyrogenic substances in recombinant peptides and proteins purified from Gram-negative bacteria, such as Escherichia coli. In this respect, aqueous two-phase micellar systems (ATPMS) have already proven to be a good strategy to purify recombinant proteins of pharmaceutical interest and remove high LPS concentrations. In this paper, we review our recent experimental work in protein partitioning in Triton X-114 ATPMS altogether with some new results and show that LPS-protein aggregation can influence both protein and LPS partitioning. Green fluorescent protein (GFPuv) was employed as a model protein. The ATPMS technology proved to be effective for high loads of LPS removal into the micelle-rich phase (%REM(LPS) > 98 %) while GFPuv partitioned preferentially to the micelle-poor phase (K GFP(uv) system. Nonetheless, ATPMS can still be considered as an efficient strategy for high loads of LPS removal, but being aware that the excluded-volume partitioning theory available might overestimate partition coefficient values due to the presence of protein-LPS aggregation.

  9. Modulating Pluronics micellar rupture with cyclodextrins and drugs: effect of pH and temperature

    Valero, M.; Dreiss, C. A.


    Micelles of the triblock copolymer Pluronic F127 can encapsulate drugs with various chemical structures and their architecture has been studied by small-angle neutron scattering (SANS). Interaction with a derivative of β-cyclodextrin, namely, heptakis(2,6-di-O- methyl)-β-cyclodextrin (DIMEB), induces a complete break-up of the micelles, providing a mechanism for drug release. In the presence of drugs partitioned within the micelles, competitive interactions between polymer, drug and cyclodextrin lead to a modulation of the micellar rupture, depending on the nature of the drug and the exact composition of the ternary system. These interactions can be further adjusted by temperature and pH. While the most widely accepted mechanism for the interaction between Pluronics and cyclodextrins is through polypseudorotaxane (PR) formation, involving the threading of β-CD on the polymer backbone, time-resolved SANS experiments show that de-micellisation takes place in less than 100 ms, thus unambiguously ruling out an inclusion complex between the cyclodextrin and the polymer chains.

  10. Estimation of tea catechin levels using micellar electrokinetic chromatography: a quantitative approach.

    Liu, Chao-Ming; Chen, Chung-Yu; Lin, Yang-Wei


    A simple, inexpensive micellar electrokinetic chromatography (MEKC) method with UV detection was used to determine seven catechins and one xanthine (caffeine) in tea. All the compounds were successfully separated (15kV) within a 15-min migration period with a high number of theoretical plates (>8.0×10(4)) in a running buffer (pH 7) containing 10mmoll(-1) sodium tetraborate, 4mmoll(-1) sodium phosphate, and 25mmoll(-1) SDS. The regression lines of all standard catechins were linear within the range of 0.03-4μgml(-1). Green tea infused at 95°C for 10min showed higher levels of catechins (especially epigallocatechin galate, epicatechin gallate, and epicatechin) than tea infused at 80°C. In addition, major differences were observed in the levels of catechins in the first and second infusions (both brewed at 95°C for 10min). Finally, green tea leaves were infused separately with tap water, deionised water, spring water, reverse osmosis water, and distilled water at 95°C, and the catechin content of the infusions was investigated by the proposed method. In the infusion brewed with tap water, catechins appeared to be epimerisation from the epistructure to the nonepistructure. This epimerisation may take place more readily in tap water than in distilled water owing to the complexity of the ions present in tap water.

  11. Extraction of catechins and caffeine from different tealeaves and comparison with micellar electrokinetic chromatography

    SONG Guanqun; LIN Jinming; Qu Feng; C.W.Huie


    This work describes the simultaneous deter- mination of catechins and caffeine in green, black tealeaves and canned tea-drink using micellar electrokinetic chromatography. The catechins analyzed include (+)-catechin, (-)- epicatechin, (-)-epigallocatechin, (-)-epicatechin gallate and (-)-epigallocatechin gallate. Using UV absorption method at 280 nm, the limits of detections of catechins and caffeine are 10-6 mol/L, which is suitable for the real sample determination. Using this analytical method, the extraction of these compounds from the tealeaves with hot water is compared under different temperatures. The effects of temperature on the amount of catechins and caffeine extracted are evident, showing that (-)-epigallocatechin gallate is the most easiest to be extracted at 100℃. The stability of catechins and caffeine in stocking solution of tea-drink at 4℃ is also compared on five consecutive days. The contents of catechins and caffeine in green and black teas are discussed and the difference of the content between different tealeaves can provide a reference for the assessment of tea quality.

  12. Origin of shear thickening in semidilute wormlike micellar solutions and evidence of elastic turbulence

    Marín-Santibáñez, Benjamín M. [Escuela Superior de Ingeniería Química e Industrias Extractivas, Instituto Politécnico Nacional, U.P.A.L.M. C.P. 07738, Col. S. P. Zacatenco, Del. Gustavo A. Madero, Mexico D.F. (Mexico); Pérez-González, José, E-mail: [Laboratorio de Reología y Física de la Matería Blanda, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, U.P.A.L.M. C.P. 07730, Col. S. P. Zacatenco, Del. Gustavo A. Madero, Mexico D.F. (Mexico); Rodríguez-González, Francisco [Departamento de Biotecnología, Centro de Desarrollo de Productos Bióticos, Instituto Politécnico Nacional, C.P. 62731, Col. San Isidro, Yautepec, Morelos (Mexico)


    The origin of shear thickening in an equimolar semidilute wormlike micellar solution of cetylpyridinium chloride and sodium salicylate was investigated in this work by using Couette rheometry, flow visualization, and capillary Rheo-particle image velocimetry. The use of the combined methods allowed the discovery of gradient shear banding flow occurring from a critical shear stress and consisting of two main bands, one isotropic (transparent) of high viscosity and one structured (turbid) of low viscosity. Mechanical rheometry indicated macroscopic shear thinning behavior in the shear banding regime. However, local velocimetry showed that the turbid band increased its viscosity along with the shear stress, even though barely reached the value of the viscosity of the isotropic phase. This shear band is the precursor of shear induced structures that subsequently give rise to the average increase in viscosity or apparent shear thickening of the solution. Further increase in the shear stress promoted the growing of the turbid band across the flow region and led to destabilization of the shear banding flow independently of the type of rheometer used, as well as to vorticity banding in Couette flow. At last, vorticity banding disappeared and the flow developed elastic turbulence with chaotic dynamics.

  13. The magnetoviscous effect of micellar solutions doped with water based ferrofluids

    Arantes, Fabiana R., E-mail: [Institute of Physics, University of Sao Paulo (Brazil); Institute of Fluid Mechanics, Technische Universität Dresden (Germany); Odenbach, Stefan, E-mail: [Institute of Fluid Mechanics, Technische Universität Dresden (Germany)


    This work presents a magnetorheological study of micellar solutions of potassium laurate and water doped with magnetite nanoparticles, accompanied by auxiliary dynamic light scattering measurements. An increase in the viscosity of the samples under applied field was observed and, furthermore, a considerable magnetoviscous effect was revealed even at magnetic particles' concentrations as low as 0.005–0.01 vol%. This indicates that the rheological behavior of the micelles is changed by the interaction of the magnetic particles with the applied field, leading to different microscopic arrangements in the micellar solutions. - Highlights: • We study the magnetorheological behavior of micellar solutions doped with ferrofluids. • We observe an increase in the viscosity of the samples under an applied field. • We find a large magnetoviscous effect even at low magnetic particles' concentration. • Interaction of particles with the field changes the micelles' rheological behavior.

  14. Demonstrating Chemical and Analytical Concepts in the Undergraduate Laboratory Using Capillary Electrophoresis and Micellar Electrokinetic Chromatography

    Palmer, Christopher P.


    This paper describes instrumental analysis laboratory exercises that utilize capillary electrophoresis and micellar electrokinetic chromatography to demonstrate several analytical and chemical principles. Alkyl parabens (4-hydroxy alkyl benzoates), which are common ingredients in cosmetic formulations, are separated by capillary electrophoresis. The electrophoretic mobilities of the parabens can be explained on the basis of their relative size. 3-Hydroxy ethylbenzoate is also separated to demonstrate the effect of substituent position on the acid dissociation constant and the effect this has on electrophoretic mobility. Homologous series of alkyl benzoates and alkyl phthalates (common plasticizers) are separated by micellar electrokinetic chromatography at four surfactant concentrations. This exercise demonstrates the separation mechanism of micellar electrokinetic chromatography, the concept of chromatographic phase ratio, and the concepts of micelle formation. A photodiode array detector is used in both exercises to demonstrate the advantages and limitations of the detector and to demonstrate the effect of pH and substituent position on the spectra of the analytes.

  15. Effective solubilization of chalcones in micellar phase: Conductivity and voltammetric study

    Ahmed, Safeer; Khan, Gul Tiaz; Shah, Syed Sakhawat


    The solubilization of four chalcones, between aqueous and micellar phases of ionic surfactants (SDS and CTAB), was investigated by conductivity and cyclic voltammetry (CV) techniques. From conductivity data, a decrease in the critical micellar concentration (CMC) of the surfactants, in presence of the chalcones was ascribed to the decreased charge density over the surfactants. The results were seconded by thermodynamic parameters including degree of ionization (α), counter ion binding (β), and standard Gibbs free energy of micellization (Δ G {m/○}). The added surfactant decreased the peak current of the oxidized chalcone and shifted the peak potential either positively (in presence of SDS) or negatively (in presence of CTAB). The effect is rationalized as chalcone-surfactant interaction and quantitated as binding constant ( K b) assorting values from 8.78 to 552.97 M-1. The preferred solubilization of the chalcones in the micellar phase has been inferred.

  16. Protonation of 5, 10, 15, 20-Tetra(4-hydroxyphenyl)-porphyrin in SDS Micellar Solution

    Xiao Hong ZHAO; Yun Hong ZHANG


    An amphiphilic porphyrin, 5, 10, 15, 20-tetra(4-hydroxyphenyl)-porphyrin (P) was solubilized in SDS micellar solutions. By taking advantage of protonation property of pyridine groups of amphiphilic porphyrin and the UV-Vis spectral sensitivity of Soret band and Q bands to the microenvironment of the porphyrin moiety, two-step protonation was studied in detail by means of UV-Vis spectroscopy. The free base, monocation and dication were described in detail in SDS micellar solution. The possibility of microphase transition was proposed to relate to the observation of two isosbestic points.

  17. El Dorado Micellar-Polymer demonstration project. First annual report, January 1974-June 1975

    Coffman, C.L.; Rosenwald, G.W. (ed.); Miller, R.J. (ed.)


    Progress made in the implementation of a project designed to determine the economic feasibility of improved oil recovery using micellar-polymer processes and to determine the associated benefits and problems of each system tested is reported. The project allows a side-by-side comparison of two distinct micellar-polymer processes in the same abandoned field so that the reservoir conditions for the two floods are as nearly alike as possible. Results are reported for test wells drilled to obtain reservoir data, field injectivity and interference tests, and performance predictions. Engineering operations are summarized. (JSR)

  18. Determination of selected synthetic cannabinoids and their metabolites by micellar electrokinetic chromatography--mass spectrometry employing perfluoroheptanoic acid-based micellar phase.

    Švidrnoch, Martin; Přibylka, Adam; Maier, Vítězslav


    Perfluoroheptanoic acid was employed as a volatile micellar phase in background electrolyte for micellar electrokinetic chromatography-tandem mass spectrometry separation and determination of 15 selected naphthoyl- and phenylacetylindole- synthetic cannabinoids and main metabolites derived from JWH-018, JWH-019, JWH-073, JWH-200 and JWH-250. The influence of concentration of perfluoroheptanoic acid in background electrolytes on the separation was studied as well as the influence of perfluoroheptanoic acid on mass spectrometry detection. The background electrolyte consisted of 75 mM perfluoroheptanoic acid, 150 mM ammonium hydroxide pH 9.2 with 10% (v/v) propane-2-ol allowed micellar electrokinetic chromatography separation together with mass spectrometry identification of the studied parent synthetic cannabinoids and their metabolites. The limits of detection of studied synthetic cannabinoids and metabolites were in the range from 0.9 ng/mL for JWH-073 to 3.0 ng/mL for JWH-200 employing liquid-liquid extraction. The developed method was applied on the separation and identification of studied analytes after liquid-liquid extraction of spiked urine and serum samples to demonstrate the potential of the method applicability for forensic and toxicological purposes.

  19. Comparative study of multi walled carbon nanotubes-based electrodes in micellar media and their application to micellar electrokinetic capillary chromatography.

    Chicharro, Manuel; Arribas, Alberto Sánchez; Moreno, Mónica; Bermejo, Esperanza; Zapardiel, Antonio


    This work reports on a comparative study of the electrochemical performance of carbon nanotubes-based electrodes in micellar media and their application for amperometric detection in micellar electrokinetic capillary chromatography (MEKC) separations. These electrodes were prepared in two different ways: immobilization of a layer of carbon nanotubes dispersed in polyethylenimine (PEI), ethanol or Nafion onto glassy carbon electrodes or preparation of paste electrodes using mineral oil as binder. Scanning electron microscopy (SEM) was employed for surface morphology characterization while cyclic voltammetry of background electrolyte was used for capacitance estimation. The amperometric responses to hydrogen peroxide, amitrol, diuron and 2,3-dichlorophenol (2,3CP) in the presence and in the absence of sodium dodecylsulphate (SDS) were studied by flow injection analysis (FIA), demonstrating that the electrocatalytic activity, background current and electroanalytical performance were strongly dependent on the electrodes preparation procedure. Glassy carbon electrodes modified with carbon nanotubes dispersed in PEI (GC/(CNT/PEI)) displayed the most adequate performance in micellar media, maintaining good electrocatalytic properties combined with acceptable background currents and resistance to passivation. The advantages of using GC/(CNT/PEI) as detectors in capillary electrophoresis were illustrated for the MEKC separations of phenolic pollutants (phenol, 3-chlorophenol, 2,3-dichlorophenol and 4-nitrophenol) and herbicides (amitrol, asulam, diuron, fenuron, monuron and chlortoluron).

  20. Modified micellar electrokinetic chromatography in the analysis of catechins and xanthines in chocolate.

    Gotti, Roberto; Fiori, Jessica; Mancini, Francesca; Cavrini, Vanni


    Modified micellar electrokinetic chromatography (MEKC) analysis of monomeric flavanols (catechin and epicatechin) and methylxanthines (caffeine and theobromine) in chocolate and cocoa was performed by using sodium dodecyl sulfate (SDS) as a principal component of the running buffer. Because of the reported poor stability of catechins in alkaline solutions, acidic conditions (pH 2.5) were chosen and consequently the electroosmotic flow (EOF) was significantly suppressed; this resulted in a fast anodic migration of the analytes partitioned into the SDS micelles. Under these conditions, variations of either pH value in acidic range or SDS concentration, showed to be not suitable to modulate the selectivity. To overcome this limit, use of additives to the SDS-based running buffer was successfully applied and three different systems were optimized for the separation of (+)-catechin, (-)-epicatechin, caffeine, and theobromine in chocolate and cocoa powder samples. In particular, two mixed micelle systems were applied; the first consisted of a mixture of SDS and 3-[(3-cholamidopropyl)dimethylammonio]-1-propansulfonate (CHAPS) with a composition of 90 mM and 10 mM, respectively; the second was SDS and taurodeoxycholic acid sodium salt (TDC) with a composition of 70 mM and 30 mM, respectively. A further MEKC approach was developed by addition of 10 mM hydroxypropyl-beta-cyclodextrin (HP-beta-CD) to the SDS solution (90 mM); it provided a useful cyclodextrin(CD)-modified MEKC. By applying the optimized conditions, different separation profiles of the flavanols and methylxanthines were obtained showing interesting potential of these combined systems; their integrated application showed to be useful for the identification of the low level of (+)-catechin in certain real samples. The CD-MEKC approach was validated and applied to the determination of catechins and methylxanthines in aqueous extracts from four different commercial chocolate types (black and milk) and two cocoa

  1. Micellar electrokinetic chromatography for the analysis of D-amygdalin and its epimer in apricot kernel.

    Kang, S H; Jung, H; Kim, N; Shin, D H; Chung, D S


    We have developed a simple, rapid and reproducible method for the determination of D-amygdalin and its epimer by using micellar electrokinetic chromatography (MEKC). Separation of D-amygdalin was performed in a 20 mM sodium borate buffer (pH 8.5) containing 300 mM sodium dodecyl sulfate using a bare fused-silica capillary. The eluates were monitored by the absorbance at 210 nm. The applied electric field was 278 V/cm, and the time needed for the separation of D-amygdalin did not exceed 6 min. The calibration curve for D-amygdalin showed excellent linearity in the concentration range of 5-500 microg/ml. The migration time and the corrected peak area show relative standard deviations (n=6) of 0.86% and 1.48%, respectively. The limit of detection (S/N=3) for D-amygdalin was 2 microg/ml. Under acidic and neutral conditions, amygdalin exists only as the D-form; however, under basic conditions, it shows both the D- and L-forms with a concentration ratio of 1:1.3 (D-amygdalin/L-amygdalin). Results of HPLC, UV-Vis spectrophotometry, and mass spectrometry reconfirmed the identification of D-amygdalin and its epimer. The number of theoretical plates of D-amygdalin is about 100,000 in MEKC, which is significantly higher than approximately 8,000 of HPLC. This method has been successfully applied to the determination of amygdalin epimers in various apricot kernel extracts and pharmaceutical products.

  2. Radiation decomposition of alcohols and chloro phenols in micellar systems; Descomposicion por irradiacion de alcoholes y clorofenoles en sistemas micelares

    Moreno A, J


    The effect of surfactants on the radiation decomposition yield of alcohols and chloro phenols has been studied with gamma doses of 2, 3, and 5 KGy. These compounds were used as typical pollutants in waste water, and the effect of the water solubility, chemical structure, and the nature of the surfactant, anionic or cationic, was studied. The results show that anionic surfactant like sodium dodecylsulfate (SDS), improve the radiation decomposition yield of ortho-chloro phenol, while cationic surfactant like cetyl trimethylammonium chloride (CTAC), improve the radiation decomposition yield of butyl alcohol. A similar behavior is expected for those alcohols with water solubility close to the studied ones. Surfactant concentrations below critical micellar concentration (CMC), inhibited radiation decomposition for both types of alcohols. However radiation decomposition yield increased when surfactant concentrations were bigger than the CMC. Aromatic alcohols decomposition was more marked than for linear alcohols decomposition. On a mixture of alcohols and chloro phenols in aqueous solution the radiation decomposition yield decreased with increasing surfactant concentration. Nevertheless, there were competitive reactions between the alcohols, surfactants dimers, hydroxyl radical and other reactive species formed on water radiolysis, producing a catalytic positive effect in the decomposition of alcohols. Chemical structure and the number of carbons were not important factors in the radiation decomposition. When an alcohol like ortho-chloro phenol contained an additional chlorine atom, the decomposition of this compound was almost constant. In conclusion the micellar effect depend on both, the nature of the surfactant (anionic or cationic) and the chemical structure of the alcohols. The results of this study are useful for wastewater treatment plants based on the oxidant effect of the hydroxyl radical, like in advanced oxidation processes, or in combined treatment such as

  3. The Mobile Phase Motion in Ascending Micellar Thin-Layer Chromatography with Normal-Phase Plates

    Boichenko, Alexander P.; Makhno, Iryna V.; Renkevich, Anton Yu.; Loginova, Lidia P.


    The physical chemical characteristics (surface tension and viscosity) of micellar mobile phases based on the cationic surfactant cetylpiridinium chloride and additives of alcohols (ethanol, 1-propanol, 1-butanol, 1-pentanol) have been obtained in this work. The effect of mobile phase properties on t

  4. A new insight on the dynamics of sodium dodecyl sulfate aqueous micellar solutions by dielectric spectroscopy.

    Lanzi, Leandro; Carlà, Marcello; Lanzi, Leonardo; Gambi, Cecilia M C


    Aqueous sodium dodecyl sulfate micellar solutions were investigated by a recently developed double-differential dielectric spectroscopy technique in the frequency range 100 MHz-3 GHz at 22 degrees C, in the surfactant concentration range 29.8-524 mM, explored for the first time above 104 mM. The micellar contribution to dielectric spectra was analyzed according to three models containing, respectively, a single Debye relaxation, a Cole-Cole relaxation and a double Debye relaxation. The single Debye model is not accurate enough. Both Cole-Cole and double Debye models fit well the experimental dielectric spectra. With the double Debye model, two characteristic relaxation times were identified: the slower one, in the range 400-900 ps, is due to the motion of counterions bound to the micellar surface (lateral motion); the faster one, in the range 100-130 ps, is due to interfacial bound water. Time constants and amplitudes of both processes are in fair agreement with Grosse's theoretical model, except at the largest concentration values, where interactions between micelles increase. For each sample, the volume fraction of bulk water and the effect of bound water as well as the conductivity in the low frequency limit were computed. The bound water increases as the surfactant concentration increases, in quantitative agreement with the micellar properties. The number of water molecules per surfactant molecule was also computed. The conductivity values are in agreement with Kallay's model over the whole surfactant concentration range.

  5. Accelerating Strain-Promoted Azide-Alkyne Cycloaddition Using Micellar Catalysis.

    Anderton, Grant I; Bangerter, Alyssa S; Davis, Tyson C; Feng, Zhiyuan; Furtak, Aric J; Larsen, Jared O; Scroggin, Triniti L; Heemstra, Jennifer M


    Bioorthogonal conjugation reactions such as strain-promoted azide-alkyne cycloaddition (SPAAC) have become increasingly popular in recent years, as they enable site-specific labeling of complex biomolecules. However, despite a number of improvements to cyclooctyne design, reaction rates for SPAAC remain significantly lower than those of the related copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Here we explore micellar catalysis as a means to increase reaction rate between a cyclooctyne and hydrophobic azide. We find that anionic and cationic surfactants provide the most efficient catalysis, with rate enhancements of up to 179-fold for reaction of benzyl azide with DIBAC cyclooctyne. Additionally, we find that the presence of surfactant can provide up to 51-fold selectivity for reaction with a hydrophobic over hydrophilic azide. A more modest, but still substantial, 11-fold rate enhancement is observed for micellar catalysis of the reaction between benzyl azide and a DIBAC-functionalized DNA sequence, demonstrating that micellar catalysis can be successfully applied to hydrophilic biomolecules. Together, these results demonstrate that micellar catalysis can provide higher conjugation yields in reduced time when using hydrophobic SPAAC reagents.

  6. Phase Behavior and Micellar Packing of Impurity-Free Pluronic Block Copolymers in Water

    Ryu, Chang Yeol; Park, Hanjin

    We have investigated the impacts of the non-micellizable polymeric impurities on the micellar packing and solution phase behavior of Pluronic block copolymers in water. In particular, small angle x-ray scattering, rheology and dynamic light scattering techniques have been employed to elucidate how the low MW impurities affect the micellar packing and solution phase diagram in water, when ordered cubic structures of spherical micelles are formed. A silica slurry method has been developed using the competitive adsorption of the PEO-PPO-PEO triblock copolymers over the low MW polymeric impurities for a large scale purification of Pluronics and it purity of Pluronics has been assessed by interaction chromatography. Based on the comparative studies on micellar packing between As-Received (AR) and Purified (Pure) Pluronic F108 solutions, we found experimental evidence to support the hypothesis that the inter-micellar distance of Pluronic cubic structures in aqueous solution is governed by the effective polymer concentration in terms of PEO-PPO-PEO triblock copolymers. Removal of the impurities in AR F108 offers an important clue on window into the onset of BCC ordering via hydrodynamic contact between micelles in solution. NSF DMR Polymers.

  7. The Mobile Phase Motion in Ascending Micellar Thin-Layer Chromatography with Normal-Phase Plates

    Boichenko, Alexander P.; Makhno, Iryna V.; Renkevich, Anton Yu.; Loginova, Lidia P.


    The physical chemical characteristics (surface tension and viscosity) of micellar mobile phases based on the cationic surfactant cetylpiridinium chloride and additives of alcohols (ethanol, 1-propanol, 1-butanol, 1-pentanol) have been obtained in this work. The effect of mobile phase properties on

  8. Deracemization of bilirubin as the marker of the chirality of micellar aggregates.

    Sorrenti, Alessandro; Altieri, Barbara; Ceccacci, Francesca; Di Profio, Pietro; Germani, Raimondo; Giansanti, Luisa; Savelli, Gianfranco; Mancini, Giovanna


    The deracemization of bilirubin in micellar aggregates of structurally correlated chiral surfactants was studied by circular dichroism experiments and exploited as the marker of the expression of chirality of the aggregates. The obtained results suggest that the hydrophobic interactions control the transfer of chirality from the monomers to the aggregates, and that different regions of the same aggregate might feature opposite enantiorecognition capabilities.

  9. A kinetic study of 1,3-dipolar cycloadditions in micellar media

    Rispens, T; Engberts, JBFN


    The kinetics of the 1,3-dipolar cycloadditions (DC) of benzonitrile oxide with a series of N-substituted maleimides in micellar media have been investigated. Surfactants studied include anionic sodium dodecyl sulfate, cationic cetyltrimethylammonium bromide, and a series of nonionic alkyl poly(ethyl

  10. The Nature of the Micellar Stern Region As Studied by Reaction Kinetics. 2

    Buurma, Niklaas J.; Serena, Paola; Blandamer, Michael J.; Engberts, Jan B.F.N.


    The nature of rate-retarding effects of cationic micelles on the water-catalyzed hydrolyses of a series of para-substituted 1-benzoyl-1,2,4-triazoles (1a-f) and 1-benzoyl-3-phenyl-1,2,4-triazole (2) has been studied using kinetic methods. A comparison is drawn between medium effects in the micellar

  11. The Mobile Phase Motion in Ascending Micellar Thin-Layer Chromatography with Normal-Phase Plates

    Boichenko, Alexander P.; Makhno, Iryna V.; Renkevich, Anton Yu.; Loginova, Lidia P.


    The physical chemical characteristics (surface tension and viscosity) of micellar mobile phases based on the cationic surfactant cetylpiridinium chloride and additives of alcohols (ethanol, 1-propanol, 1-butanol, 1-pentanol) have been obtained in this work. The effect of mobile phase properties on t

  12. Formation of DNA Adducts by Ellipticine and Its Micellar Form in Rats — A Comparative Study

    Marie Stiborova


    Full Text Available The requirements for early diagnostics as well as effective treatment of cancer diseases have increased the pressure on development of efficient methods for targeted drug delivery as well as imaging of the treatment success. One of the most recent approaches covering the drug delivery aspects is benefitting from the unique properties of nanomaterials. Ellipticine and its derivatives are efficient anticancer compounds that function through multiple mechanisms. Formation of covalent DNA adducts after ellipticine enzymatic activation is one of the most important mechanisms of its pharmacological action. In this study, we investigated whether ellipticine might be released from its micellar (encapsulated form to generate covalent adducts analogous to those formed by free ellipticine. The 32P-postlabeling technique was used as a useful imaging method to detect and quantify covalent ellipticine-derived DNA adducts. We compared the efficiencies of free ellipticine and its micellar form (the poly(ethylene oxide-block-poly(allyl glycidyl ether (PAGE-PEO block copolymer, P 119 nanoparticles to form ellipticine-DNA adducts in rats in vivo. Here, we demonstrate for the first time that treatment of rats with ellipticine in micelles resulted in formation of ellipticine-derived DNA adducts in vivo and suggest that a gradual release of ellipticine from its micellar form might produce the enhanced permeation and retention effect of this ellipticine-micellar delivery system.

  13. First example of a lipophilic porphyrin-cardanol hybrid embedded in a cardanol-based micellar nanodispersion.

    Bloise, Ermelinda; Carbone, Luigi; Colafemmina, Giuseppe; D'Accolti, Lucia; Mazzetto, Selma Elaine; Vasapollo, Giuseppe; Mele, Giuseppe


    Cardanol is a natural and renewable organic raw material obtained as the major chemical component by vacuum distillation of cashew nut shell liquid. In this work a new sustainable procedure for producing cardanol-based micellar nanodispersions having an embedded lipophilic porphyrin itself peripherally functionalized with cardanol substituents (porphyrin-cardanol hybrid) has been described for the first time. In particular, cardanol acts as the solvent of the cardanol hybrid porphyrin and cholesterol as well as being the main component of the nanodispersions. In this way a "green" micellar nanodispersion, in which a high percentage of the micellar system is derived from renewable "functional" molecules, has been produced.

  14. Composition-insensitive highly viscous wormlike micellar solutions formed in anionic and cationic surfactant systems.

    Aramaki, Kenji; Iemoto, Suzuka; Ikeda, Naoaki; Saito, Keitaro


    We investigated phase behavior and rheological properties of aqueous micellar phase formed in water/cocoyl glutamate neutralized with triethanol amine (CGT-n)/hexadecyl trimethylammonium salt (CTAB or CTAC) systems, where n is a degree of neutralization. Micellar phase appears in wide composition range with respect to the surfactant mixing fraction in ternary phase diagrams at 25 degrees C. At high mixing fraction of cationic surfactant in the water/CGT-n/CTAB systems, one can observe a highly viscous micellar phase in which worm-like micelles are expected to form. Contrary to conventional systems in which worm-like micelles are formed, the zero-shear viscosity of the micellar solution in the water/CGT-n/CTAB system with n=1.2 increases with the addition of cationic cosurfactant and once decreases after a maximum, then increases again and decreases after the second maximum. At n=1.5 and 2, highly viscous solution is observed in the relatively wide range of surfactant mixing fraction instead of two maxima of the viscosity curve observed at n=1.2. In the case of CTAC instead of CTAB we can observe narrow composition range for the maximum viscosity. Frequency sweep measurements were performed on the highly viscous samples in the water/CGT-1.5/CTAB system. Typical viscoelastic behavior of worm-like micellar solutions is observed; i.e. the curves of storage (G') and loss (G") moduli make a crossover and the data points of G' and G" can be fitted to the Maxwell model. Relaxation time against the mixing fraction of two surfactants behaves similarly to the zero-shear viscosity change, whereas the plateau modulus continuously increases in the plateau region for the zero-shear viscosity curve.

  15. Folate Receptor-Targeted Polymeric Micellar Nanocarriers for Delivery of Orlistat as a Repurposed Drug against Triple-Negative Breast Cancer.

    Paulmurugan, Ramasamy; Bhethanabotla, Rohith; Mishra, Kaushik; Devulapally, Rammohan; Foygel, Kira; Sekar, Thillai V; Ananta, Jeyarama S; Massoud, Tarik F; Joy, Abraham


    Triple-negative breast cancer (TNBC) is a recalcitrant malignancy with no available targeted therapy. Off-target effects and poor bioavailability of the FDA-approved antiobesity drug orlistat hinder its clinical translation as a repurposed new drug against TNBC. Here, we demonstrate a newly engineered drug formulation for packaging orlistat tailored to TNBC treatment. We synthesized TNBC-specific folate receptor-targeted micellar nanoparticles (NP) carrying orlistat, which improved the solubility (70-80 μg/mL) of this water-insoluble drug. The targeted NPs also improved the delivery and bioavailability of orlistat to MDA-MB-231 cells in culture and to tumor xenografts in a nude mouse model. We prepared HEA-EHA copolymer micellar NPs by copolymerization of 2-hydroxyethylacrylate (HEA) and 2-ethylhexylacrylate (EHA), and functionalized them with folic acid and an imaging dye. Fluorescence-activated cell sorting (FACS) analysis of TNBC cells indicated a dose-dependent increase in apoptotic populations in cells treated with free orlistat, orlistat NPs, and folate-receptor-targeted Fol-HEA-EHA-orlistat NPs in which Fol-HEA-EHA-orlistat NPs showed significantly higher cytotoxicity than free orlistat. In vitro analysis data demonstrated significant apoptosis at nanomolar concentrations in cells activated through caspase-3 and PARP inhibition. In vivo analysis demonstrated significant antitumor effects in living mice after targeted treatment of tumors, and confirmed by fluorescence imaging. Moreover, folate receptor-targeted Fol-DyLight747-orlistat NP-treated mice exhibited significantly higher reduction in tumor volume compared to control group. Taken together, these results indicate that orlistat packaged in HEA-b-EHA micellar NPs is a highly promising new drug formulation for TNBC therapy. Mol Cancer Ther; 15(2); 221-31. ©2015 AACR.

  16. Micellar and sub-micellar ultra-high performance liquid chromatography of hydroxybenzoic acid and phthalic acid positional isomers.

    Fasciano, Jennifer M; Danielson, Neil D


    Micellar liquid chromatography (MLC) has been used primarily for the separation of neutral analytes of varying polarities, most commonly phenols and polyaromatic hydrocarbons, but does not seem to have been used to study aromatic hydroxy acids in detail. We have studied the separation of hydroxybenzoic acid mixtures, including monohydroxybenzoic and dihydroxybenzoic acid positional isomers by MLC. Sodium dodecylsulfate (SDS) is investigated as the modifying surfactant on a C18 ultra-high performance liquid chromatography (UHPLC) column (100 × 2.1mm, 1.8 μm). The addition of only SDS (no organic solvent) to the mobile phase reduced the influence of hydrophobic interactions while improving the retention times, resolution, and peak shapes, even at concentrations below the critical micellization concentration (CMC). The UHPLC separation of 7 hydroxybenzoic acids, including 6 dihydroxybenzoic acid positional isomers and one trihydroxybenzoic acid, is achieved with high efficiency using 0.1% SDS in 1.84 mM sulfuric acid (pH 2.43) mobile phase, in less than 6 min with a flow rate of 0.3 mL min(-1), and in less than four min with a flow rate of 0.7 mL min(-1). Six monohydroxybenzoic acid isomers are also effectively separated by MLC, using a 0.5% SDS mobile phase modifier, in less than 20 min with a flow rate of 0.3 mL min(-1), and in less than 14 min with a flow rate of 0.7 mL min(-1). The 3 phthalic acid isomers could be separated using a similar mobile phase and flow rates in less than 6 and 4 min. Solute-micelle equilibrium constants and partition coefficients are calculated for 6 monohydroxybenzoic acids based on a plot of MLC retention factor vs. mobile phase micelle concentration. All aromatic acid isomers studied can be classified as binding solutes in the MLC retention mechanism. Less effective separations are observed with shorter chain surfactants, leading to higher retention times and poor peak shapes. It is concluded that increasing chain length led to more

  17. Mesoscopic simulation of a micellar poly(N-isopropyl acrylamide)-b-(polyethylene oxide) copolymer system

    Bautista-Reyes, Rubén; Soto-Figueroa, César; Vicente, Luis


    In this article we studied the micellar formation of poly(N-isopropyl acrylamide)-b-polyethylene oxide (PNIPAM-b-PEO) copolymers in an aqueous system. From molecular simulations the dependence on temperature of the Flory-Huggins interaction parameter χ for PNIPAM and PEO in water is obtained and compared with available experimental results and values from other theoretical calculations. By means of dissipative particle dynamics (DPD) we then simulated the coil-globule transition for PNIPAM chains in water with a transition temperature of around 305 K. The simulations for PNIPAM-b-PEO copolymers showed that at room temperature the chains are miscible in an aqueous phase but with a temperature increase the system turns into micelles at T  =  305 K. The change in micelle anisotropy due to a different ratio PNIPAM/PEO of chains is also analyzed. What is observed is that for large PEO the large number of dissolved PEO chains gives a large corona size and the micelle is not spherical but obloide and as the number of PNIPAM is increased the micelle acquires a spherical shape. As an important application we considered the system micelle-water/anionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate [BMIM]+[PF6]-). By increasing the temperature of the system from 306 K it is shown that at T  =  345 K there is a transfer of the micelle from water to the ionic liquid phase and this was due to the change in the relative affinity of PEO to water and ionic liquid expressed by the change in χ. All the simulation outcomes are qualitatively consistent with experimental results and thus to our knowledge we give the first set of χ values for the interaction between PNIPAM and water in a wide range of temperature values.

  18. Micellar-enhanced ultrafiltration membrane (MEUF) of Batik wastewater using Cetylpyridinium chloride surfactant

    Aryanti, Nita; Pramudono, Bambang; Prawira, Christ Nadya P.; Renardi, Rheza; Fatikhatul K. Ika, S.


    In batik production, reactive dyes such as remazol, indigosol, naphtol and rapid are used in the dying process. Batik wastewater contains high level of reactive dyes, wax and sodium salts and is characterized with high Chemical Oxygen Demand (COD), Total Suspended Solids (TSS) as well as high concentration of phenol and Ammonia. Micellar-Enhanced Ultrafiltration Membrane (MEUF) is one of promising technology to separate low molecular weight substances such as dyes. The MEUF process involves combination of ultrafiltration membrane and surfactant at concentration higher than surfactant's Critical Micelle Concentration (CMC). This technique combines high selectivity of reverse osmosis membrane and high flux of ultrafiltration membrane but with lower pressure. Ultrafiltration of batik waste water without surfactant (UF) and with addition of surfactant (MEUF) were studied in order to compare the performance of both systems. The Batik wastewater were obtained from batik industry in Semarang and Surakarta, Central Java, Indonesia. Cetyl Pyridinium Chloride at concentration of 2 and 4 times of its CMC were used. Flatsheet ultrafiltration membrane was made from Polyethersulphone (12% w/w), N-methyl Pyrrolidone (83% w/w) and Polyethylene Glycol (5% w/w). The performance of the UF and MEUF were evaluated based on flux profiles and rejections (COD, TSS, concentration of Ammonia). The results showed that the MEUF had superior performance than the UF. Concentration of COD, TSS, phenol and ammonia were reduced significantly. The rejection of COD were 92.74% and 94.15%. Moreover, the MEUF was capable to reduce the TSS with the rejection of 86.26% and 65%. The concentration of ammonia in permeate were 0.43 ppm and below 0.01 ppm.


    Micellar electrokinetic chromatography (MEKC) with laser-induced fluorescence (LIF) detection was used for the trace analysis of phenoxy acid herbicides. Capillary electrophoresis (CE) with LIF detection, which has not previously been used for pesticide analysis, overcomes the po...

  20. Penn Grade Micellar Displacement Project. Third annual report, June 1977--June 1978. [Lawry project in Bradford field

    Danielson, H.H.; Paynter, W.T.; Ondrusek, P.S.; Finalle, L.L.


    During third year operations of the jointly funded Penn Grade Micellar Displacement Project, the plant facilities were completed for the 24-acre test designated Phase II. The transient testing program and the pre-flush brine and micellar slug injection stages were all completed. Biopolymer injection was initiated. This report details the development, testing, and operations of Phase II, as well as plans for continuing the test.

  1. Thermodynamic analysis of unimer-micelle and sphere-to-rod micellar transitions of aqueous solutions of sodium dodecylbenzenesulfonate


    Temperature dependence of specific conductivity of sodium dodecylbenzenesulfonate (NaDBS) aqueous solutions was analyzed. Two breaks on the plot appeared for all temperature, which suggest two micellar transitions. This has been corroborated by surface tension measurements. The first transition concentration occurs at the critical micelle concentration (CMC), whilst the second critical concentration (so-called transition micellar concentration, TMC) is due to a sphere-to-rod micelles transiti...

  2. Application of response function methodology for the simultaneous determination of potential fragrance allergens and preservatives in personal care products using micellar electrokinetic chromatography.

    Lopez-Gazpio, J; Garcia-Arrona, R; Millán, E


    A micellar electrokinetic chromatography method was developed for determination of 15 suspected fragrance allergens and preservatives. The target compounds are widely used as ingredients in many personal care products, and all of them are included in the European Regulation concerning cosmetic products. The method was optimized by using a central composite experimental design and response surface methodology. A modified chromatographic response function was defined to weigh the terms in the response function adequately. After optimization of experimental conditions, a background electrolyte of 100 mM sodium dodecyl sulphate and 24 mM sodium tetraborate and pH 9.0 was selected for the separation of the analytes. The developed methodology was evaluated in terms of linearity, limits of detection and quantification, precision and accuracy, showing appropriate values (i.e., R (2) = ≥0.99 and accuracy of 89-115 %). Finally, applicability of the micellar electrokinetic chromatography method was assessed by successfully quantifying fragrance allergens and preservatives in commercial personal care products. The most commonly found analyte was linalool (48.3 % of samples) followed by benzoic acid (37.6 %). All samples contained at least one of the target compounds, thus confirming the ubiquity of fragrance allergens and preservatives in personal care products.

  3. Paclitaxel-loaded PEG-PE-based micellar nanopreparations targeted with tumor specific landscape phage fusion protein enhance apoptosis and efficiently reduce tumors

    Wang, Tao; Yang, Shenghong; Mei, Leslie A.; Parmar, Chirag K.; Gillespie, James W.; Praveen, Kulkarni P.; Petrenko, Valery A.; Torchilin, Vladimir P.


    In an effort to improve the therapeutic index of cancer chemotherapy, we developed an advanced nanopreparation based on the combination of landscape phage display to obtain new targeting ligands with micellar nanoparticles for tumor targeting of water insoluble neoplastic agents. With paclitaxel as a drug, this self-assembled nanopreparation composed of MCF-7-specific phage protein and polyethylene glycol phosphatidyl ethanolamine (PEG- PE) micelles showed selective toxicity to target cancer cells rather than non-target, non- cancer cells in vitro. In vivo, the targeted phage-micelles triggered a dramatic tumor reduction and extensive necrosis as a result of improved tumor delivery of paclitaxel. The enhanced anticancer effect was also verified by an enhanced apoptosis and reduced tumor cell proliferation following the treatment with the targeted micellar paclitaxel both in vitro and in vivo. The absence of hepatotoxicity and pathological changes in tissue sections of vital organs, together with maintenance of overall health of mice following the treatment, further support its translational potential as an effective and safe chemotherapy for improved breast cancer treatment. PMID:25239936

  4. Magnetic isotope effect on kinetic parameters and quantum beats of radical pairs in micellar solution studied by optically detected esr using pulsed microwave.

    Kitahama, Yasutaka; Sakaguchi, Yoshio


    We investigated the quantum beats, the oscillation between singlet and triplet states of radical pairs induced by the microwave field resonant to one of the component radicals. They were observed as the alternation of the yields of the component radicals by a nanosecond time-resolved optical absorption with the X-band (9.15 GHz) resonant microwave pulse. This technique was applied to the photochemical reaction of benzophenone, benzophenone-d(10), and benzophenone-carbonyl-(13)C in a sodium dodecylsulfate micellar solution with a step-by-step increase of the resonant microwave pulse width. The yields of the component radicals showed alternation with an increase of the microwave pulse width. This indicates that the radical pair retains spin coherence in the micellar solution. The magnetic isotope effect on the amplitude of the quantum beat was observed. The MW effect on the quantum beat of BP-(13)C decreases from 80% to 60% of that of BP by irradiation of the pi-pulse MW due to spin-locking. The kinetic parameters were also determined using the X- or Ku-band (17.44 GHz) region. They are almost similar to each other except for the intersystem recombination rate in the system of BP-(13)C, which may be slightly higher than those in other systems.

  5. Study of Micellar-Enhanced Ultrafiltration. Progress report, March 1, 1985-February 28, 1986

    Scamehorn, J.F.; Christian, S.D.


    The feasibility of Micellar-Enhanced Ultrafiltration (MEUF) to remove dissolved organics from water has been established. One of the first tasks was to determine the best surfactant to use in MEUF for various situations. From a thorough analysis of the properties and characteristics of a variety of surfactants, combined with preliminary runs with several surfactants, cationic surfactants were determined to be the best surfactant for general use in MEUF. Further, cetylpyridinium chloride was identifid as a near-optimum surfactant in most applications. Therefore, all further studies reported used this surfactant. Elimination of surfactant type as a variable permits more detailed investigation of other important variables. A major effort has been made to develop techniques for measuring the extent of solubilization of organic solutes by aqueous micellar systems. An important accomplishment during the past year has been the development of the so-called semi-equilibrium dealysis (SED) technique for studying solubilization.

  6. Nanoparticles of complex metal oxides synthesized using the reverse-micellar and polymeric precursor routes

    Ashok K Ganguli; Tokeer Ahmad; Padam R Arya; Pika Jha


    Current interest in the properties of materials having grains in the nanometer regime has led to the investigation of the size-dependent properties of various dielectric and magnetic materials. We discuss two chemical methods, namely the reverse-micellar route and the polymeric citrate precursor route used to obtain homogeneous and monophasic nanoparticles of several dielectric oxides like BaTiO3, Ba2TiO4, SrTiO3, PbTiO3, PbZrO3 etc. In addition we also discuss the synthesis of some transition metal (Mn and Cu) oxalate nanorods using the reverse-micellar route. These nanorods on decomposition provide a facile route to the synthesis of transition metal oxide nanoparticles. We discuss the size dependence of the dielectric and magnetic properties in some of the above oxides.

  7. Structural micellar transition for fluorinated and hydrogenated sodium carboxylates induced by solubilization of benzyl alcohol.

    González-Pérez, Alfredo; Ruso, Juan M; Prieto, Gerardo; Sarmiento, Félix


    The solubility of benzyl alcohol in micellar solutions of sodium octanoate and sodium perfluorooctanoate was studied. From the isotherms of specific conductivity versus molality at different alcohol concentrations, the critical micelle concentration and the degree of ionization of the micelles were determined. The cmc linearly decreases upon increasing the amount of benzyl alcohol present in aqueous solutions with two distinct slopes. This phenomenon was interpreted as a clustering of alcohol molecules above a critical point, around 0.1 mol kg(-1). Attending to the equivalent conductivity versus square root of molality, the presence of a second micellar structure for the fluorinated compound was assumed. The thermodynamic parameters associated with the process of micellization were estimated by applying Motomura's model for binary surfactant mixtures, modified by Pérez-Villar et al. (Colloid Polym. Sci 1990, 268, 965) for the case of alcohol-surfactant solutions. A comparison of the hydrogenated and fluorinated compounds was carried out and discussed.

  8. Solubilization of benzene, toluene, and xylene (BTX) in aqueous micellar solutions of amphiphilic imidazolium ionic liquids.

    Łuczak, Justyna; Jungnickel, Christian; Markiewicz, Marta; Hupka, Jan


    Water-soluble ionic liquids may be considered analogues to cationic surfactants with a corresponding surface activity and ability to create organized structures in aqueous solutions. For the first time, the enhanced solubility of the aromatic hydrocarbons, benzene, toluene, and xylene, in aqueous micellar systems of 1-alkyl-3-methylimidazolium chlorides was investigated. Above a critical micelle concentration, a gradual increase in the concentration of aromatic hydrocarbons in the miceller solution was observed. This phenomenon was followed by means of the molar solubilization ratio, the micellar/water partition coefficient, and the number of solubilizate molecules per IL micelle. The molar solubilization ratio for ionic liquid micelles was found to be significantly higher when compared to that of ionic surfactants of similar chain length. The incorporation of the hydrocarbon into the micelle affects also an increase of the aggregation number.

  9. Penn Grade Micellar Displacement project. First annual report, June 1975--June 1976

    Danielson, H.H.; Paynter, W.T.; Midkiff, F.R.; Finalle, L.L.


    The main objective of the Penn Grade-ERDA Micellar Displacement Project is to assess and hopefully, demonstrate the feasibility of commercial application of the micellar-polymer process for tertiary oil recovery from a rather large, but relatively ''tight'' section of the Bradford Third Sand. The initial phase of this project involves pertinent core and field injectivity measurements from a freshly drilled well, as a basis for assessing the feasibility of a small demonstration test flood to be performed under Phase II. This report details the work done and results obtained under Phase I (Injectivity Test) completed during the first year of the project. These results, having indicated that the pattern test envisaged under Phase II is indeed feasible, work is now in progress to carry the project to the pattern test phase, in pursuit of project goals.

  10. Interfacial properties of nonionic micellar agregates as a function of temperatures and concentrations

    Falconi, L; Briganti, G; D'Arrigo, G; Falconi, Luca; Maccarini, Marco; Briganti, Giuseppe; Arrigo, Giovanni D'


    By means of density, dielectric spectroscopy and sound velocity measurements we perform a systematic study on the polyoxyethylene $C_{12}E_{6}$ nonionic surfactant solutions as a function of temperature and concentration. Both density and sound velocity data, at about $34^{\\circ}C$, coincide with the value obtained for pure water. Above this temperature the density is lower than the water density whereas below it is greater, the opposite happens for the compressibility. Combining results from these different techniques we tempt a very detailed description of the evolution of the micellar interfacial properties with temperature. It is well known that nonionic surfactant solutions dehydrate, growing temperature. Our results indicate that this process is associated with a continuous change in the polymer conformation and in the local density of the micellar interface.

  11. Interaction of antihypertensive drug amiloride with metal ions in micellar medium using fluorescence spectroscopy

    Gujar, Varsha; Pundge, Vijaykumar; Ottoor, Divya, E-mail:


    Steady state and life time fluorescence spectroscopy have been employed to study the interaction of antihypertensive drug amiloride with biologically important metal ions i.e. Cu{sup 2+}, Fe{sup 2+}, Ni{sup 2+} and Zn{sup 2+} in various micellar media (anionic SDS (sodium dodecyl sulfate), nonionic TX-100 (triton X-100) and cationic CTAB (cetyl trimethyl ammonium bromide)). It was observed that fluorescence properties of drug remain unaltered in the absence of micellar media with increasing concentration of metal ions. However, addition of Cu{sup 2+}, Fe{sup 2+} and Ni{sup 2+} caused fluorescence quenching of amiloride in the presence of anionic micelle, SDS. Binding of drug with metal ions at the charged micellar interface could be the possible reason for this pH-dependent metal-mediated fluorescence quenching. There were no remarkable changes observed due to metal ions addition when drug was present in cationic and nonionic micellar medium. The binding constant and bimolecular quenching constant were evaluated and compared for the drug–metal complexes using Stern–Volmer equation and fluorescence lifetime values. - Highlights: • Interaction of amiloride with biologically important metal ions, Fe{sup 2+}, Cu{sup 2+}, Ni{sup 2+} and Zn{sup 2+}. • Monitoring the interaction in various micelle at different pH by fluorescence spectroscopy. • Micelles acts as receptor, amiloride as transducer and metal ions as analyte in the present system. • Interaction study provides pH dependent quenching and binding mechanism of drug with metal ions.

  12. Micellar properties and surface activity of some bolaform drugs in aqueous solution.

    Attwood, D; Natarajan, R


    The micellar properties of a series of dicationic drugs with structures resembling those of the bolaform electrolytes have been examined using light scattering, surface tension and conductivity techniques. The compounds investigated included, demecarium bromide, ambenonium chloride, dequalinium acetate, distigmine bromide and chlorhexidine acetate. Demecarium and dequalinium formed micelles at critical concentrations of 9 x 10(-3) and 4 x 10(-3) mol kg-1 respectively. No significant association of chlorhexidine acetate could be detected, contrary to previous reports.

  13. Applying Theoretical Approach for Predicting the Selective Calcium Channel Blockers Pharmacological Parameter by Biopartitioning Micellar Chromatography

    WANG Su-Min; YANG Geng-Liang; LI Zhi-Wei; LIU Hai-Yan; GUO Hui-Juan


    The usefulness of biopartitioning micellar chromatography (BMC) for predicting oral drug acute toxicity and apparent bioavailability was demonstrated. A logarithmic model (an LD50 model) and the second order polynomial models (apparent bioavailability model) have been obtained using the retention data of the selective calcium channel blockers to predict pharmacological properties of compounds. The use of BMC is simple, reproducible and can provide key information about the acute toxicity and transport properties of new compounds during the drug discovery process.

  14. Studies of Micellar Electrokinetic Chromatography as an Analytical Technique in Pharmaceutical Analysis - an Industrial Perspective

    Stubberud, Karin


    Studies have been performed to evaluate the use of micellar electrokinetic chromatography (MEKC), one mode of capillary electrophoresis (CE), as an analytical technique in industrial pharmaceutical analysis. The potential for using chemometrics for the optimisation of MEKC methods has also been studied as well as the possibilities of coupling MEKC with mass spectrometry (MS). Two methods were developed, one for the determination of ibuprofen and codeine and another for pilocarpine, together ...

  15. Stratification of a Foam Film Formed from a Nonionic Micellar Solution: Experiments and Modeling.

    Lee, Jongju; Nikolov, Alex; Wasan, Darsh


    Thin liquid films containing surfactant micelles or other nanocolloidal particles are considered to be the key structural elements of foams containing gas and liquid. We report here the experimental results and theoretical modeling for the phenomenon of the stratification (stepwise thinning) of a foam film formed from a nonionic micellar solution. The film stratification phenomenon was experimentally observed by reflected light microinterferometry. We observed that the stepwise layer-by-layer decrease of the film thickness is due to the appearance and growth of a dark spot of one layer less than the film thickness in the film. The dark spot expansion is driven by the diffusion of the dislocation (or vacancy) in the micellar lattice. The vacancies from the meniscus diffuse and condense into the dark spot, leading to its expansion inside the film. We experimentally observed the expansion of the dark spot at various film thicknesses (i.e., the number of micellar layers) and at different film sizes. We also measured the contact angle between the film and the meniscus; we used the data to estimate the structural film interaction energy barrier and the apparent diffusion coefficient. We used the two-dimensional diffusion model to model the dynamics of the dark spot expansion with consideration to the apparent diffusion coefficient and the film size. The model predictions are in good agreement with the experimental observations. On the basis of this model, we carried out a parametric study depicting the effects of the film thickness (or the number of micellar layers) and film area on the rate of the dark spot expansion. We also generalized the model previously proposed by Kralchevsky et al. [ Langmuir 1990 , 6 , 1180 - 1189 ], incorporating the effects of the film size, film thickness, and apparent diffusion coefficient to predict the dark spot expansion rate.

  16. Conditions for and characteristics of nonaqueous micellar solutions and microemulsions with ionic liquids

    Zech, Oliver; Kunz, Werner


    Research on nonaqueous microemulsions containing ionic liquids as polar and/or apolar phase, respectively, is growing at a fast rate. One key property of ionic liquids that highlights their potential and their diversification compared to water is their wide liquid temperature range. In this emerging-area review article we survey recent developments in the field of nonaqueous micellar solutions and microemulsions containing ionic liquids in general with a strong emphasis on the effect of tempe...

  17. Isocratic and gradient elution in micellar liquid chromatography with Brij-35.

    Peris-García, Ester; Ortiz-Bolsico, Casandra; Baeza-Baeza, Juan José; García-Alvarez-Coque, María Celia


    Polyoxyethylene(23)lauryl ether (known as Brij-35) is a nonionic surfactant, which has been considered as an alternative to the extensively used in micellar liquid chromatography anionic surfactant sodium lauryl (dodecyl) sulfate, for the analysis of drugs and other types of compounds. Brij-35 is the most suitable nonionic surfactant for micellar liquid chromatography, owing to its commercial availability, low cost, low toxicity, high cloud temperature, and low background absorbance. However, it has had minor use. In this work, we gather and discuss some results obtained in our laboratory with several β-blockers, sulfonamides, and flavonoids, concerning the use of Brij-35 as mobile phase modifier in the isocratic and gradient modes. The chromatographic performance for purely micellar eluents (with only surfactant) and hybrid eluents (with surfactant and acetonitrile) is compared. Brij-35 increases the polarity of the alkyl-bonded stationary phase and its polyoxyethylene chain with the hydroxyl end group allows hydrogen-bond interactions, especially for phenolic compounds. This offers the possibility of using aqueous solutions of Brij-35 as mobile phases with sufficiently short retention times. The use of gradients of acetonitrile to keep the concentration of Brij-35 constant is another interesting strategy that yields a significant reduction in the peak widths, which guarantee high resolution.

  18. Can neutral analytes be concentrated by transient isotachophoresis in micellar electrokinetic chromatography and how much?

    Matczuk, Magdalena; Foteeva, Lidia S; Jarosz, Maciej; Galanski, Markus; Keppler, Bernhard K; Hirokawa, Takeshi; Timerbaev, Andrei R


    Transient isotachophoresis (tITP) is a versatile sample preconcentration technique that uses ITP to focus electrically charged analytes at the initial stage of CE analysis. However, according to the ruling principle of tITP, uncharged analytes are beyond its capacity while being separated and detected by micellar electrokinetic chromatography (MEKC). On the other hand, when these are charged micelles that undergo the tITP focusing, one can anticipate the concentration effect, resulting from the formation of transient micellar stack at moving sample/background electrolyte (BGE) boundary, which increasingly accumulates the analytes. This work expands the enrichment potential of tITP for MEKC by demonstrating the quantitative analysis of uncharged metal-based drugs from highly saline samples and introducing to the BGE solution anionic surfactants and buffer (terminating) co-ions of different mobility and concentration to optimize performance. Metallodrugs of assorted lipophilicity were chosen so as to explore whether their varying affinity toward micelles plays the role. In addition to altering the sample and BGE composition, optimization of the detection capability was achieved due to fine-tuning operational variables such as sample volume, separation voltage and pressure, etc. The results of optimization trials shed light on the mechanism of micellar tITP and render effective determination of selected drugs in human urine, with practical limits of detection using conventional UV detector.

  19. Micellar Packing in Aqueous Solutions of As-Received and Pure Pluronic Block Copolymers

    Ryu, Chang; Park, Han Jin


    Pluronic block copolymers (Pluronics) are produced on a commercial scale to enable wide range of novel applications from emulsification and colloidal stabilization as nonionic surfactants. While the Pluronic block copolymers offer the advantages of being readily available for such applications, it contains non-micellizable low molecular weight (MW) impurities that would interfere with the self-assembly and micellar packing of PEO-PPO-PEO triblock copolymers in aqueous solutions. The impacts of the low MW impurities will be discussed on the micellar packing of Pluronics F108 and F127 solutions, which form BCC and FCC. While as-received Pluronic samples typically contain about 20 wt.% low MW impurities, we were able to reduce the impurity level to less than 2 wt.% using our large scale purification technique. Comparative studies on small angle x-ray scattering (SAXS) experiments on as-received and purified Pluronics solutions revealed that the contents of triblock copolymers in solutions essentially governs the inter-micellar distance of Pluronic cubic structures. A universal relationship between triblock copolymer concentration and SAXS-based domain spacing has been finally discussed. Funding from Agency for Defense Development, Korea.

  20. Structural investigation of viscoelastic micellar water/CTAB/NaNO3 solutions

    K Kuperkar; L Abezgauz; D Danino; G Verma; P A Hassan; V K Aswal; D Varade; P Bahadur


    A highly viscoelastic worm-like micellar solution is formed in hexa-decyltrimethylammonium bromide (CTAB) in the presence of sodium nitrate (NaNO3). A gradual increase in micellar length with increasing NaNO3 was assumed from the rheological measurements where the zero-shear viscosity (0) versus NaNO3 concentration curve exhibits a maximum. However, upon increase in temperature, the viscosity decreases. Changes in the structural parameters of the micelles with addition of NaNO3 were inferred from small angle neutron scattering measurements (SANS). The intensity of scattered neutrons in the low region was found to increase with increasing NaNO3 concentration. This suggests an increase in the size of the micelles and/or decrease of intermicellar interaction with increasing salt concentration. Analysis of the SANS data using prolate ellipsoidal structure and Yukawa form of interaction potential between mi-celles indicate that addition of NaNO3 leads to a decrease in the surface charge of the ellipsoidal micelles which induces micellar growth. Cryo-TEM measurements support the presence of thread-like micelles in CTAB and NaNO3.

  1. Polymeric micellar nanocarriers of benzoyl peroxide as potential follicular targeting approach for acne treatment.

    Kahraman, Emine; Özhan, Gül; Özsoy, Yıldız; Güngör, Sevgi


    The aim of this work was to optimize polymeric nano-sized micellar carriers of the anti-acne compound benzoyl peroxide (BPO) and to examine the ability of these carriers to deposit into hair follicles with the objective of improving skin delivery of BPO. BPO loaded polymeric micelles composed of Pluronic(®) F127 were prepared by the thin film hydration method and characterized in terms of size, loading capacity, morphology and physical stability. The optimized micelle formulation was then selected for skin delivery studies. The penetration of BPO loaded micellar carriers into skin and skin appendages across full thickness porcine skin was examined in vitro. Confocal microscopy images confirmed the penetration of Nile Red into hair follicles, which was loaded into micellar carriers as a model fluorescent compound. The relative safety of the polymeric micelles was evaluated with the MTT viability test using mouse embryonic fibroblasts. The results indicated that nano-sized polymeric micelles of BPO composed of Pluronic(®) F127 offer a potential approach to enhance skin delivery of BPO and that targeting of micelles into hair follicles may be an effective and safe acne treatment.

  2. Bell Creek Field micellar-polymer pilot demonstration. Fourth annual report, October 1979-September 1980

    Goldburg, A.


    The pilot is a contained 40-acre 5-spot located in a representative watered-out portion of the Unit A Reservoir. The pay is sandstone with an average net pay of 6.4 feet, air permeability of 1050 md, and water TDS of 2500 ppM. The average remaining oil saturation in the 40-acre pilot area was estimated to be 28% at the start of chemical injection. The Pilot has four injectors (Wells MPP-1, MPP-2, MPP-3, and MPP-4) and one producer (Well 12-1). The overall micellar-polymer oil recovery is estimated at 47% of the remaining oil at the initiation of the micellar-polymer flood. In the fourth contract year, micellar slug injection was completed and injection of the graded mobility buffer began. A second radioactive/chemical tracer test was begun at the start of the polymer phase. A delay of approximately one year was experienced during the reservoir description phase. Otherwise, the project has remained on schedule.

  3. Bell Creek Fiel micellar-polymer pilot demonstration first annual report, July 1976--September 1977


    A Pilot Demonstration is being conducted to determine whether micellar-polymer flooding is an economically feasible technique for enhanced oil recovery from the Muddy Sand Unit ''A'' Reservoir of the Bell Creek Field, Powder River and Carter Counties, Montana. During the first year of this project extensive reservoir studies, site and pattern selection, design and selection of an optimal micellar-polymer system, water flood history matching and preliminary process simulations by numerical models, and development of pilot injection and production wells were completed. The major effort during the first contract year was the design for the Bell Creek pilot of two optimal micellar-polymer processes--one oil-external and one water-external; and the concomitant development of a Selection Methodology by which to decide upon the more suitable process by means of a standard set of laboratory experiments and numerical simulations. This effort was completed. The oil-external design was selected for Bell Creek application based upon its superior performance in the standard test series and simulations. The advantages of the Bell Creek oil-external design appear to be better recovery performance, mobility control, and protection against divalent ions. 30 tables, 41 figs.

  4. Microwave enhanced electroanalysis of formulations: processes in micellar media at glassy carbon and at platinum electrodes.

    Ghanem, Mohamed A; Compton, Richard G; Coles, Barry A; Canals, Antonio; Marken, Frank


    The direct electroanalysis of complex formulations containing alpha-tocopherol (vitamin E) is possible in micellar solution and employing microwave-enhanced voltammetry. In the presence of microwave radiation substantial heating and current enhancement effects have been observed at 330 microm diameter glassy carbon electrodes placed into a micellar aqueous solution and both hydrophilic and highly hydrophobic redox systems are detected. For the water soluble Fe(CN)(6)(3-/4-) redox system in micellar aqueous solutions of 0.1 M NaCl and 0.1 M sodium dodecylsulfate (SDS) at low to intermediate microwave power, thermal effects and convection effects are observed. At higher microwave power, thermal cavitation is induced and dominates the mass transport at the electrode surface. For the micelle-soluble redox systems tert-butylferrocene and 2,5-di-tert-butyl-1,4-benzoquinone, strong and concentration dependent current responses are observed only in the presence of microwave radiation. For the oxidation of micelle-soluble alpha-tocopherol current responses at glassy carbon electrodes are affected by adsorption and desorption processes whereas at platinum electrodes, analytical limiting currents are obtained over a wide range of alpha-tocopherol concentrations. However, for the determination of alpha-tocopherol in a commercial formulation interference from proteins is observed at platinum electrodes and direct measurements are possible only over a limited concentration range and at glassy carbon electrodes.

  5. Hydrophobically modified inulin as an amphiphilic carbohydrate polymer for micellar delivery of paclitaxel for intravenous route.

    Muley, Pratik; Kumar, Sunny; El Kourati, Fadoua; Kesharwani, Siddharth S; Tummala, Hemachand


    Micellization offers several advantages for the delivery of water insoluble drugs including a nanoparticulate 'core-shell' delivery system for drug targeting. Recently, hydrophobically modified polysaccharides (HMPs) are gaining recognition as micelle forming polymers to encapsulate hydrophobic drugs. In this manuscript, for the first time, we have evaluated the self-assembling properties of a lauryl carbamate derivative of the poly-fructose natural polymer inulin (Inutec SP1(®) (INT)) to form paclitaxel (PTX) loaded micelles. INT self-assembled into well-defined micellar structures in aqueous environment with a low critical micellar concentration of 27.8 μg/ml. INT micelles exhibited excellent hemocompatibility and low toxicity to cultured cells. PTX loaded INT micelles exhibited a mean size of 256.37 ± 10.45 nm with excellent drug encapsulation efficiency (95.66 ± 2.25%) and loading (8.69 ± 0.22%). PTX loaded micelles also displayed sustained release of PTX and enhanced anti-cancer efficacy in-vitro in mouse melanoma cells (B16F10) compared to Taxol formulation with Cremophor EL as solvent. In addition, PTX loaded INT micelles exhibited comparable in-vivo antitumor activity in B16F10 allograft mouse model at half the dose of Taxol. In conclusion, INT offers safe, inexpensive and natural alternative to widely used PEG-modified polymers for the formulation of micellar delivery systems for paclitaxel.

  6. Multiscale Modeling of the Effects of Salt and Perfume Raw Materials on the Rheological Properties of Commercial Threadlike Micellar Solutions.

    Tang, Xueming; Zou, Weizhong; Koenig, Peter H; McConaughy, Shawn D; Weaver, Mike R; Eike, David M; Schmidt, Michael J; Larson, Ronald G


    We link micellar structures to their rheological properties for two surfactant body-wash formulations at various concentrations of salts and perfume raw materials (PRMs) using molecular simulations and micellar-scale modeling, as well as traditional surfactant packing arguments. The two body washes, namely, BW-1EO and BW-3EO, are composed of sodium lauryl ethylene glycol ether sulfate (SLEnS, where n is the average number of ethylene glycol repeat units), cocamidopropyl betaine (CAPB), ACCORD (which is a mixture of six PRMs), and NaCl salt. BW-3EO is an SLE3S-based body wash, whereas BW-1EO is an SLE1S-based body wash. Additional PRMs are also added into the body washes. The effects of temperature, salt, and added PRMs on micellar lengths, breakage times, end-cap free energies, and other properties are obtained from fits of the rheological data to predictions of the "Pointer Algorithm" [ Zou , W. ; Larson , R.G. J. Rheol. 2014 , 58 , 1 - 41 ], which is a simulation method based on the Cates model of micellar dynamics. Changes in these micellar properties are interpreted using the Israelachvili surfactant packing argument. From coarse-grained molecular simulations, we infer how salt modifies the micellar properties by changing the packing between the surfactant head groups, with the micellar radius remaining nearly constant. PRMs do so by partitioning to different locations within the micelles according to their octanol/water partition coefficient POW and chemical structures, adjusting the packing of the head and/or tail groups, and by changing the micelle radius, in the case of a large hydrophobic PRM. We find that relatively hydrophilic PRMs with log POW 4, are isolated deep inside the micelle, separating from the tails and swelling the radius of the micelle, leading to shorter micelles and much lower viscosities, leading eventually to swollen-droplet micelles.

  7. Sequential optimization of methotrexate encapsulation in micellar nano-networks of polyethyleneimine ionomer containing redox-sensitive cross-links

    Abolmaali SS


    Full Text Available Samira Sadat Abolmaali,1 Ali Tamaddon,1,2 Gholamhossein Yousefi,1,2 Katayoun Javidnia,3 Rasoul Dinarvand41Department of Pharmaceutics, Shiraz School of Pharmacy, 2Center for Nanotechnology in Drug Delivery, 3Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; 4Nanotechnology Research Centre, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, IranAbstract: A functional polycation nanonetwork was developed for delivery of water soluble chemotherapeutic agents. The complexes of polyethyleneimine grafted methoxy polyethylene glycol (PEI-g-mPEG and Zn2+ were utilized as the micellar template for cross-linking with dithiodipropionic acid, followed by an acidic pH dialysis to remove the metal ion from the micellar template. The synthesis method was optimized according to pH, the molar ratio of Zn2+, and the cross-link ratio. The atomic force microscopy showed soft, discrete, and uniform nano-networks. They were sensitive to the simulated reductive environment as determined by Ellman's assay. They showed few positive ζ potential and an average hydrodynamic diameter of 162±10 nm, which decreased to 49±11 nm upon dehydration. The ionic character of the nano-networks allowed the achievement of a higher-loading capacity of methotrexate (MTX, approximately 57% weight per weight, depending on the cross-link and the drug feed ratios. The nano-networks actively loaded with MTX presented some suitable properties, such as the hydrodynamic size of 117±16 nm, polydispersity index of 0.22, and a prolonged swelling-controlled release profile over 24 hours that boosted following reductive activation of the nanonetwork biodegradation. Unlike the PEI ionomer, the nano-networks provided an acceptable cytotoxicity profile. The drug-loaded nano-networks exhibited more specific cytotoxicity against human hepatocellular carcinoma cells if compared to free MTX at concentrations above 1 µM. The

  8. On the appearance of vorticity and gradient shear bands in wormlike micellar solutions of different CPCl/salt systems

    Mütze, Annekathrin, E-mail:; Heunemann, Peggy; Fischer, Peter [ETH Zürich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 9, 8092 Zürich (Switzerland)


    Wormlike micellar salt/surfactant solutions (X-salicylate, cetylpyridinium chloride) are studied with respect to the applied shear stress, concentration, temperature, and composition of the counterions (X = lithium, sodium, potassium, magnesium, and calcium) of the salicylate salt solute to determine vorticity and gradient shear bands. A combination of rheological measurements, laser technique, video analysis, and rheo-small-angle neutron scattering allow for a detailed exploration of number and types of shear bands. Typical flow curves of the solutions show Newtonian, shear-thinning, and shear-thickening flow behavior. In the shear-thickening regime, the solutions show vorticity and gradient shear bands simultaneously, in which vorticity shear bands dominate the visual effect, while gradient shear bands always coexist and predominate the rheological response. It is shown that gradient shear bands change their phases (turbid, clear) with the same frequency as the shear rate oscillates, whereas vorticity shear bands change their phases with half the frequency of the shear rate. Furthermore, we show that with increasing molecular mass of the counterions the number of gradient shear bands increases, while the number of vorticity shear bands remains constant. The variation of temperature, shear stress, concentration, and counterions results in a predictable change in the rheological behavior and therefore allows adjustment of the number of vorticity shear bands in the shear band regime.

  9. Micellar liquid chromatographic determination of sertaconazole and terconazole in bulk, pharmaceutical dosage forms and spiked human plasma

    Mohamed Rizk


    Full Text Available A micellar liquid chromatographic method was developed for the determination of sertaconazole and terconazole in bulk, dosage forms and human plasma using intersil cyano column and mobile phase consisting of 0.1 M sodium dodecyl sulphate, 20% 1-propanol, and 0.3% triethylamine in 0.02 M ortho-phosphoric acid (pH 4 at 225 nm. Different chromatographic parameters were studied, e.g. types of columns, pH of mobile phase, concentration of sodium dodecyl sulphate, 1-propanol, triethylamine, etc. The method was validated over the concentration ranges 8–40 and 16–80 μg/ml, for sertaconazole and terconazole, respectively. The method was sensitive with limits of detection of 1.24 and 1.67 μg/ml for sertaconazole and terconazole in bulk, respectively. Inter and intra-day results showed % RSD < 0.9% and 1.55% for sertaconazole and terconazole, respectively. The result obtained by the proposed method was compared with that obtained by the reference HPLC technique. Furthermore, the proposed method was successfully applied as a stability-indicating method for the determination of drugs under different stressed conditions. The method showed good selectivity, repeatability, linearity and sensitivity according to the evaluation of the validation parameters.

  10. Influence of pH on heavy metal speciation and removal from wastewater using micellar-enhanced ultrafiltration.

    Huang, Jinhui; Yuan, Fang; Zeng, Guangming; Li, Xue; Gu, Yanling; Shi, Lixiu; Liu, Wenchu; Shi, Yahui


    pH plays an important role in heavy metal removal during micellar-enhanced ultrafiltration (MEUF). In the present work, the influence of pH on heavy metal speciation and removal from wastewater by MEUF was investigated using an anionic surfactant (sodium dodecyl sulfate, SDS) and a hydrophilic membrane (polyether sulfone). Experiments were performed with pH values in the range of 1-12. Metal ion removal efficiency (R) was used to assess the effects of the MEUF process. Results showed that better removal rate of copper and cadmium was achieved at high pH values (pH > 3) with SDS feed concentration of 8 mM, while the optimal pH range was 3-10 for zinc and lead. The corresponding efficiencies for heavy metal removal decreased with the increasing feed concentration of metal ions under the pH conditions of 1-12. Furthermore, the heavy metal ion removal rate (50 mg/L) followed the order of Pb(2+) > Cd(2+) > Zn(2+) > Cu(2+). These results showed that pH is a key parameter in metal ion speciation and removal during MEUF.

  11. Kinetics and Mechanism of Micellar Catalyzed Oxidation of Dextrose by N-Bromosuccinimide in H2SO4 Medium

    Minu Singh


    Full Text Available Kinetics and mechanism of micellar catalyzed N-bromosuccinimide oxidation of dextrose in H2SO4 medium was investigated under pseudo-first-order condition temperature of 40°C. The results of the reactions studied over a wide range of experimental conditions show that NBS shows a first order dependence, fractional order, on dextrose and negative fractional order dependence on sulfuric acid. The determined stoichiometric ratio was 1 : 1 (dextrose : N-bromosuccinimide. The variation of Hg(OAC2 and succinimide (reaction product has insignificant effect on reaction rate. Effects of surfactants, added acrylonitrile, added salts, and solvent composition variation have been studied. The Arrhenius activation energy and other thermodynamic activation parameters are evaluated. The rate law has been derived on the basis of obtained data. A plausible mechanism has been proposed from the results of kinetic studies, reaction stoichiometry, and product analysis. The role of anionic and nonionic micelle was best explained by the Berezin’s model.

  12. Study of monoprotic acid-base equilibria in aqueous micellar solutions of nonionic surfactants using spectrophotometry and chemometrics.

    Babamoradi, Hamid; Abdollahi, Hamid


    Many studies have shown the distribution of solutes between aqueous phase and micellar pseudo-phase in aqueous micellar solutions. However, spectrophotometric studies of acid-base equilibria in these media do not confirm such distribution because of the collinearity between concentrations of chemical species in the two phases. The collinearity causes the number of detected species to be equal to the number of species in a homogenous solution that automatically misinterpreted as homogeneity of micellar solutions, therefore the collinearity is often neglected. This interpretation is in contradiction to the distribution theory in micellar media that must be avoided. Acid-base equilibrium of an indicator was studied in aqueous micellar solutions of a nonionic surfactant to address the collinearity using UV/Visible spectrophotometry. Simultaneous analysis (matrix augmentation) of the equilibrium and solvation data was applied to eliminate the collinearity from the equilibrium data. A model was then suggested for the equilibrium that was fitted to the augmented data to estimate distribution coefficients of the species between the two phases. Moreover, complete resolution of concentration and spectral profiles of species in each phase was achieved.

  13. Fatty acids affect micellar properties and modulate vitamin D uptake and basolateral efflux in Caco-2 cells.

    Goncalves, Aurélie; Gleize, Béatrice; Roi, Stéphanie; Nowicki, Marion; Dhaussy, Amélie; Huertas, Alain; Amiot, Marie-Josèphe; Reboul, Emmanuelle


    We have recently shown that vitamin D3 (cholecalciferol) absorption is not a simple passive diffusion but involves cholesterol transporters. As free fatty acids (FAs) modulate cholesterol intestinal absorption and metabolism, we hypothesized that FAs may also interact with vitamin D absorption. Effects of FAs were evaluated at different levels of cholecalciferol intestinal absorption. First, the physicochemical properties of micelles formed with different FAs were analyzed. The micelles were then administered to human Caco-2 cells in culture to evaluate FA effects on (i) cholecalciferol uptake and basolateral efflux and (ii) the regulation of genes coding proteins involved in lipid absorption process. Micellar electric charge was correlated with both FA chain length and degree of unsaturation. Long-chain FAs at 500 μM in mixed micelles decreased cholecalciferol uptake in Caco-2 cells. This decrease was annihilated as soon as the long-chain FAs were mixed with other FAs. Oleic acid significantly improved cholecalciferol basolateral efflux compared to other FAs. These results were partly explained by a modulation of genes coding for lipid transport proteins such as Niemann-pick C1-like 1 and scavenger receptor class B type I. The data reported here show for the first time that FAs can interact with cholecalciferol intestinal absorption at different key steps of the absorption process. Cholecalciferol intestinal absorption may thus be optimized according to oil FA composition.

  14. Use of ligand-modified micellar-enhanced ultrafiltration to selectively separate copper ions from wastewater streams

    Shadizadeh, S.B.


    The selective removal of target ions from an aqueous solution containing ions of like charge by ligand-modified micellar-enhanced ultrafiltration (LM-MEUF), is presented. In LM-MEUF, surfactant and specially tailored ligand are added to the contaminated stream. The surfactant forms aggregates called micelles, the hydrocarbon core of which the ligand complexed with the target species will solubilize. The surfactant is chosen to have the same charge type as the target ion; therefore, other ions (with similar charge) will not associate with the micelle, which makes the separation of the target ion selective. The solution is then processed by ultrafiltration, using a membrane with pore size small enough to block the passage of the micelles. In this study the divalent copper is the target ion in the solution containing divalent calcium. The surfactant is cetylpyridinium chloride (CPC) and the ligand is 4-hexadecyloxybenzyliminodiacetic acid (C{sub 16}BIDA). Experiments were conducted with batch stirred cells and the results have been compared to separation that take place under a variety of conditions in the LM-MEUF process. Rejections of copper of up to 99.8% are observed, with almost no rejection of calcium, showing that LM-MEUF has excellent selectivity and separation efficiency.

  15. Field-Amplified Sample Injection-Micellar Electrokinetic Chromatography for the Determination of Benzophenones in Food Simulants

    Cristina Félez


    Full Text Available A field-amplified sample injection-micellar electrokinetic chromatography (FASI-MEKC method for the determination of 14 benzophenones (BPs in a food simulant used in migration studies of food packaging materials was developed, allowing almost baseline separation in less than 21 min. The use of a 10 mM sodium dodecyl sulfate (SDS solution as sample matrix was mandatory to achieve FASI enhancement of the analyzed BPs. A 21- to 784-fold sensitivity enhancement was achieved with FASI-MEKC, obtaining limits of detection down to 5.1–68.4 µg/L, with acceptable run-to-run precisions (RSD values lower than 22.3% and accuracy (relative errors lower than 21.0%. Method performance was evaluated by quantifying BPs in the food simulant spiked at 500 µg/L (bellow the established specific migration limit for BP (600 µg/L by EU legislation. For a 95% confidence level, no statistical differences were observed between found and spiked concentrations (probability at the confidence level, p value, of 0.55, showing that the proposed FASI-MEKC method is suitable for the analysis of BPs in food packaging migration studies at the levels established by EU legislation.

  16. Lipophilic properties of anti-Alzheimer's agents determined by micellar electrokinetic chromatography and reversed-phase thin-layer chromatography.

    Godyń, Justyna; Hebda, Michalina; Więckowska, Anna; Więckowski, Krzysztof; Malawska, Barbara; Bajda, Marek


    Lipophilicity as one of the most important physicochemical properties of the biologically active compounds is closely related to their pharmacokinetic parameters and therefore, it is taken into account at the design stage of new drugs. Among the novel, fast and reliable methods for determination of the lipophilicity of compounds micellar electrokinetic chromatography (MEKC) is considered to be an appropriate one for bioactive molecules, as it closely mimics the physiological conditions. In this paper MEKC was used for the estimation of log P values for 49 derivatives of phthalimide, tetrahydroisochinoline and indole, designed and synthesized as potential anti-Alzheimer's agents with cholinesterase inhibitory activity. RP-TLC method was applied for determination of another lipophilicity descriptor - RM0 . The results of both experimental methods were compared with each other giving satisfactory correlation (R = 0.784), and with computational methods (Marvin, ChemOffice Software) resulting in weaker correlation (R = 0.466 - 0.687). The lipophilicity-activity relationship was finally established, showing significant influence of lipophilicity on cholinesterase inhibition in some subgroups of phthalimide derivatives. This article is protected by copyright. All rights reserved.

  17. Simultaneous determination of amino acids in tea leaves by micellar electrokinetic chromatography with laser-induced fluorescence detection.

    Yan, Jin; Cai, Yuanli; Wang, Yufei; Lin, Xia; Li, Hui


    A rapid and effective method of micellar electrokinetic chromatography with laser-induced fluorescence detection was developed for the simultaneous determination of amino acids in tea leaves. Pre-column derivatization of the analytes used 4-chloro-7-nitrobenzofurazan (NDB-Cl). Optimal separation was achieved at +20kV using an uncoated fused silica capillary (40.0cm effective length, 50.2cm total length, 75μm internal diameter), as well as 20mM sodium borate (pH 8.5), 20mM Brij 35, and acetonitrile 10% (v/v) as running buffers. Within 11min, 15 amino acids were separated completely. The optimized method demonstrated good linearity (r(2)⩾0.9990), precision (⩽6.65%), accuracy (85.50-112.74%), and sensitivity (0.1ng/mL-100ng/mL). The method successfully determined the quantity of amino acids in five different tea leaves; furthermore, theanine was identified as the most abundant amino acid in teas. The proposed method showed great potential in further investigations on the biofunctions of different tea samples.

  18. Stability-indicating micellar electrokinetic chromatography technique for simultaneous measurement of delapril and manidipine from a combination drug formulation.

    Todeschini, Vítor; Sangoi, Maximiliano da Silva; Meira, Alianise da Silva; Miron, Diogo; Lange, Alini Dall Cortivo; Volpato, Nadia Maria


    A stability-indicating micellar electrokinetic chromatography (MEKC) method was developed and validated for simultaneous analysis of delapril (DEL) and manidipine (MAN) using salicylic acid as an internal standard. The MEKC method was performed using a fused-silica capillary (effective length of 72 cm) with 50 mM of borate buffer and 5 mM of anionic surfactant sodium dodecylsulfate at pH 9.0 as the background electrolyte. The separation was achieved at 25 kV applied voltage and 35 degrees C. The injection was performed at 50 mbar for 5 s, with detection at 208 nm. The method was linear in the range of 15-150 microg/mL (r2 = 0.9966) for DEL and 5-50 microg/mL (r2 = 0.9985) for MAN with adequate results for the precision (method and its stability-indicating capability was demonstrated through forced degradation studies, which showed that there was no interference from the excipients. The Plackett-Burman experimental design was used for robustness evaluation, giving results within the acceptable range. The method was successfully applied for analysis of the drugs, and the results were compared to an LC method, resulting in nonsignificant differences (P = 0.78 and 0.84 for DEL and MAN, respectively).

  19. Mixed micellar properties of sodium n-octanoate(SOC) with n-octylammonium chloride(OAC) in aqueous solution

    Lee, Byung Hwan [Korea University of Technology, Chonan (Korea, Republic of)


    The critical concentration(CMC) and the counterion binding constant(B) for the mixed micellization of sodium n-octanoate(SOC) with n-octylammonium chloride(OAC) were determined as a function of the overall mole fraction of SOC({alpha}{sub 1}). Various thermodynamic parameters(X{sub i}, {gamma}{sub i}, C{sub i}, a{sub i}{sup M}, and {delta}H{sub mix}) for the mixed micellization of the SOC/OAC systems have been calculated and analyzed by means of the equations derived from the nonideal mixed micellar model. The results show that there are great deviations from the ideal behavior for the mixed micellization of these systems. And other thermodynamic parameters({delta}G{sub m}{sup o}, {delta}H{sub m}{sup o}, and {delta}S{sub m}{sup o}) associated with the micellization of SOC, OAC, and their mixture({alpha}{sub 1}=0.5) have been also estimated from the temperature dependence of CMC and B values, and the significance of these parameters and their relation to the theory of the micelle formation have been considered and analyzed by comparing each other.

  20. Lecithin organogel: A unique micellar system for the delivery of bioactive agents in the treatment of skin aging

    Sushil Raut


    Full Text Available Skin aging is an unavoidable aspect of human life. Premature skin aging can result from poor care, environmental pollutants, and ultraviolet radiation exposure. Wrinkles, lines, spots, uneven skin tone, and pigmentation are often indicators of skin aging. One cannot avoid aging but cosmetics and pharmaceutical approaches can minimize and delay the damage. Topical applications of biocompatible and biodegradable vehicles have been explored for delivering anti-aging compounds. Lecithin organogel (LO is an effective vehicle for topical delivery of many bioactive agents used in aging treatment. Lecithin is cell component isolated from soya beans or eggs and purified to show excellent gelation in non-polar solvents when combined with water. LO can form a heat-stable, resistant to microbial growth, visco-elastic, optically transparent, and non-birefringent micellar system. It serves as an organic medium to enhance dermal permeation of poorly permeable drugs by effectively partitioning into the skin. Its ability to dissolve in hydrophilic as well as in lipophilic drugs makes it a dynamic vehicle, which can be explored as a carrier for anti-aging agents.

  1. Quantification of bio- and techno-functional peptides in tryptic bovine micellar casein and β-casein hydrolysates.

    Holder, Aline; Thienel, Katharina; Klaiber, Iris; Pfannstiel, Jens; Weiss, Jochen; Hinrichs, Jörg


    Numerous peptides generated by triptic hydrolysis of micellar casein and β-casein from bovine milk have been reported to exhibit bio-functional or techno-functional activities. In this study, the focus was placed on the quantification of eleven potential functional peptides generated by enzymatic hydrolysis with trypsin. The identity of the target peptides was verified by LC-ESI-MS/MS and a reverse phase high performance liquid chromatography method (RP-HPLC) was established to quantify the peptides. The quantification was based on calibration curves drawn using synthesised purified peptides. The regression analysis comparing >30 standard measurements of each peptide standard showed a regression coefficient R(2)>0.9958. The inter-day repeatability of the quantification method was always within a relative error of 0.2-6.5%, while the relative error of the accuracy for reproducibility was in the range of 0.1-2.4%. The established method was successfully applied for the quantitative analysis of the eleven functional peptides in different dairy fractions generated by cross-flow ultrafiltration.

  2. Kinetics and Mechanism of Electron Transfer to Heptavalent Manganese by DL-Aspartic Acid in Alkaline Aqueous and Micellar Media

    M. Sanjana


    Full Text Available The kinetics and mechanism of the electron transfer of dl-Aspartic acid (Asp by Mn (VII in alkaline medium has been studied spectrophotometrically over the range 2.0≤103[Asp] ≤5.0 mol dm−3; 0.01≤[OH-]≤0.05 mol dm−3; 298≤T≤318 K and I=0.05 mol dm−3 (KNO3. The reaction exhibits first-order dependence in [MnO4-]T but shows fractional-order dependence in both [Asp]T and [OH−]T. The reaction was studied in the presence of sodium dodecyl sulfate (SDS; an increase in the rate with the increase in the micellar concentration was observed. The products were characterized by spectral analysis. A mechanism involving free radicals is proposed. Asp binds MnO4- to form a complex that subsequently decomposes to products. Activation parameters ΔH° (kJ mol−1 and ΔS° (JK−1 mol−1 for the reaction are 5.62 ± 0.35 and −227.65 ± 1.1, respectively. The negative value of ΔS° indicates that oxidation occurs via inner sphere mechanism.

  3. Spectrophotometric determination of acidity constant of some indicators in various micellar media solutions by rank annihilation factor analysis.

    Niazi, Ali; Zolgharnein, Javad; Davoodabadi, Mohammad Reza


    Rank annihilation factor analysis (RAFA) was used to the spectrophotometric studies of the acidity constant of methyl orange, methyl red and methyl violet in water and different micellar solutions at 25 degrees C and an ionic strength of 0.1M. When the acidity constants (surfactant concentration dependent acidity constant) acts as an optimizing object, and simply combined with the pure spectrum of acidic and basic forms, the rank of original data matrix can be reduced. The residual standard deviation (R.S.D.) of the residual matrix after bi-linearization of the background matrix is regarded as the evaluation function. Results show that the acidity constant of these indicators are influenced as the percentages of neutral, cationic and anionic surfactant such as Triton X-100 (poly(oxyethylene)(9.5)p-(1,1,3,3-tetramethyl), sodiumdodecylsulfate (SDS) and cethyltrimethylammonium (CTAB), respectively, added to the solution of these reagents. Also, RAFA is an efficient chemometrics algorithm for completely analysis of acid-base equilibrium systems by spectrophotometric method. Effects of surfactant on acidity constant and absorption spectra are also discussed.

  4. Dielectric model and theoretical analysis of cationic reverse micellar solutions in CTAB/isooctane/n-hexanol/water systems.

    Yang, Likun; Zhao, Kongshuang


    Dielectric relaxation spectra of CTAB reverse micellar solutions, CTAB/isooctane/n-hexanol/water systems with different concentrations of CTAB and different water contents, were investigated in the frequency range from 40 Hz to 110 MHz. Two striking dielectric relaxations were observed at about 10(4) Hz and 10(5) Hz, respectively. Dielectric parameters were obtained by fitting the data using the Cole-Cole equation with two Cole-Cole dispersion terms and the electrode polarization term. These parameters show different variation with the increase of the concentration of CTAB or the water content. In order to explain the two relaxations systematically and obtain detailed information on the systems and the inner surface of the reverse micelles, an electrical model has been constituted. On the basis of this model, the low-frequency dielectric relaxation was interpreted by the radial diffusion of free counterions in the diffuse layer with Grosse model. For the high-frequency dielectric relaxation, Hanai theory and the corresponding analysis method were used to calculate the phase parameters of the constituent phases in these systems. The reasonable analysis results suggest that the high-frequency relaxation probably originated from the interfacial polarization. The structural and electrical information of the present systems were obtained from the phase parameters simultaneously.

  5. Application of principal component analysis-multivariate adaptive regression splines for the simultaneous spectrofluorimetric determination of dialkyltins in micellar media.

    Ghasemi, Jahan B; Zolfonoun, Ehsan


    A new multicomponent analysis method, based on principal component analysis-multivariate adaptive regression splines (PC-MARS) is proposed for the determination of dialkyltin compounds. In Tween-20 micellar media, dimethyl and dibutyltin react with morin to give fluorescent complexes with the maximum emission peaks at 527 and 520nm, respectively. The spectrofluorimetric matrix data, before building the MARS models, were subjected to principal component analysis and decomposed to PC scores as starting points for the MARS algorithm. The algorithm classifies the calibration data into several groups, in each a regression line or hyperplane is fitted. Performances of the proposed methods were tested in term of root mean square errors of prediction (RMSEP), using synthetic solutions. The results show the strong potential of PC-MARS, as a multivariate calibration method, to be applied to spectral data for multicomponent determinations. The effect of different experimental parameters on the performance of the method were studied and discussed. The prediction capability of the proposed method compared with GC-MS method for determination of dimethyltin and/or dibutyltin. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Small angle neutron scattering study of sodium dodecyl sulfate micellar growth driven by addition of a hydrotropic salt.

    Hassan, P A; Fritz, Gerhard; Kaler, Eric W


    The structures of aggregates formed in aqueous solutions of an anionic surfactant, sodium dodecyl sulfate (SDS), with the addition of a cationic hydrotropic salt, p-toluidine hydrochloride (PTHC), have been investigated by small angle neutron scattering (SANS). The SANS spectra exhibit a pronounced peak at low salt concentration, indicating the presence of repulsive intermicellar interactions. Model-independent real space information about the structure is obtained from a generalized indirect Fourier transformation (GIFT) technique in combination with a suitable model for the interparticle structure factor. The interparticle interaction is captured using the rescaled mean spherical approximation (RMSA) closure relation and a Yukawa form of the interaction potential. Further quantification of the geometrical parameters of the micelles was achieved by a complete fit of the SANS data using a prolate ellipsoidal form factor and the RMSA structure factor. The present study shows that PTHC induces a decrease in the fractional charge of the micelles due to adsorption at the micellar surface and consequent growth of the SDS micelles from nearly globular to rodlike as the concentration of PTHC increases.

  7. Micellar high performance liquid chromatographic determination of flunixin meglumine in bulk, pharmaceutical dosage forms, bovine liver and kidney

    Fathalla F. Belal


    Full Text Available A simple, sensitive and rapid liquid chromatographic method was developed and validated for the analysis of flunixin meglumine (flunixin-M in bulk, pharmaceutical dosage forms, bovine liver and kidney. Analytical separation was performed in less than 4 min using a C18 column with UV detection at 284 nm. A micellar solution composed of 0.15 M sodium dodecyl sulphate, 8% n-butanol and 0.3% triethylamine in 0.02 M phosphoric acid buffered at pH 7.0 was used as the mobile phase. The method was fully validated in accordance with the International Conference on Harmonization (ICH guidelines. The limit of detection and the limit of quantitation were 0.02 and 0.06 μg mL−1, respectively. The recoveries obtained were in range of 95.58–106.94% for bovine liver and kidney. High extraction efficiency was obtained without matrix interference in the extraction process and in the subsequent chromatographic determination. The method showed good repeatability, linearity and sensitivity according to the evaluation of the validation parameters.

  8. Removal of asphaltene and paraffin deposits using micellar solutions and fused reactions. Final report, 1995--1997

    Chang, C.L.; Nalwaya, V.; Singh, P.; Fogler, H.S.


    Chemical treatments of paraffin and asphaltene deposition by means of cleaning fluids were carried out in this research project. Research focused on the characterization of asphaltene and paraffin materials and dissolution of asphaltene and paraffin deposits using surfactant/micellar fluids developed early in the project. The key parameters controlling the dissolution rate were identified and the process of asphaltene/paraffin dissolution were examined using microscopic apparatus. Numerical modeling was also carried out to understand the dissolution of paraffin deposits. The results show that fused chemical reaction systems are a promising way of removing paraffin deposits in subsea pipelines. The fused system may be in the form of alternate pulses, emulsions systems or encapsulated catalyst systems. Fused reaction systems, in fact, are extremely cost-effective--less than 10% of the cost of replacing entire sections of the blocked pipeline. The results presented in this report can have a real impact on the petroleum industry and the National Oil Program, if it is realized that the remediation technologies developed here can substantially delay abandonment (due to asphaltene/paraffin plugging) of domestic petroleum resources. The report also sheds new light on the nature and properties of asphaltenes and paraffin deposits which will ultimately help the scientific and research community to develop effective methods in eliminating asphaltene/paraffin deposition problems. It must also be realized that asphaltene remediation technologies developed and presented in this report are a real alternative to aromatic cleaning fluids currently used by the petroleum industry.

  9. First Example of a Lipophilic Porphyrin-Cardanol Hybrid Embedded in a Cardanol-Based Micellar Nanodispersion

    Giuseppe Vasapollo


    Full Text Available Cardanol is a natural and renewable organic raw material obtained as the major chemical component by vacuum distillation of cashew nut shell liquid. In this work a new sustainable procedure for producing cardanol-based micellar nanodispersions having an embedded lipophilic porphyrin itself peripherally functionalized with cardanol substituents (porphyrin-cardanol hybrid has been described for the first time. In particular, cardanol acts as the solvent of the cardanol hybrid porphyrin and cholesterol as well as being the main component of the nanodispersions. In this way a “green” micellar nanodispersion, in which a high percentage of the micellar system is derived from renewable “functional” molecules, has been produced.

  10. Quantitation of antihistamines in pharmaceutical preparations by liquid chromatography with a micellar mobile phase of sodium dodecyl sulfate and pentanol.

    Gil-Agustí, M; Monferrer-Pons, L; Esteve-Romero, J; García-Alvarez-Coque, M C


    A reversed-phase liquid chromatographic procedure with a micellar mobile phase of sodium dodecyl sulfate (SDS), containing a small amount of pentanol, was developed for the control of 7 antihistamines of diverse action in pharmaceutical preparations (tablets, capsules, powders, solutions, and syrups): azatadine, carbinoxamine, cyclizine, cyproheptadine, diphenhydramine, doxylamine, and tripelennamine. The retention times of the drugs were <9 min with a mobile phase of 0.15M SDS-6% (v/v) pentanol. The recoveries with respect to the declared compositions were in the range of 93-110%, and the intra- and interday repeatabilities and interday reproducibility were <1.2%. The results were similar to those obtained with a conventional 60 + 40 (v/v) methanol-water mixture, with the advantage of reduced toxicity, flammability, environmental impact, and cost of the micellar-pentanol solutions. The lower risk of evaporation of the organic solvent dissolved in the micellar solutions also increased the stability of the mobile phase.

  11. Separation of cationic analytes by nonionic micellar electrokinetic chromatography using polyoxyethylene lauryl ether surfactants with different polyoxyethylene length.

    Quirino, Joselito P; Kato, Masaru


    Although nonionic micellar electrokinetic chromatography is used for the separation of charged compounds that are not easily separated by capillary zone electrophoresis, the effect of the hydrophilic moiety of the nonionic surfactant has not been studied well. In this study, the separation of ultraviolet-absorbing amino acids was studied in electrokinetic chromatography using neutral polyoxyethylene lauryl ether surfactants (Adekatol) in the separation solution. The effect of the polyethylene moiety (the number of repeating units was from 6.5 to 50) of the hydrophobic test amino acids (methionine, tryptophan, and tysorine) was studied using a 10 cm effective length capillary. The separation mechanism was based on hydrophobic as well as hydrogen bonding interactions at the micellar surface, which was made of the polyoxyethylene moiety. The length of the polyoxyethylene moiety of the surfactants was not important in nonionic micellar electrokinetic chromatography mode.

  12. Surface Attachment of Gold Nanoparticles Guided by Block Copolymer Micellar Films and Its Application in Silicon Etching

    Mingjie Wei


    Full Text Available Patterning metallic nanoparticles on substrate surfaces is important in a number of applications. However, it remains challenging to fabricate such patterned nanoparticles with easily controlled structural parameters, including particle sizes and densities, from simple methods. We report on a new route to directly pattern pre-formed gold nanoparticles with different diameters on block copolymer micellar monolayers coated on silicon substrates. Due to the synergetic effect of complexation and electrostatic interactions between the micellar cores and the gold particles, incubating the copolymer-coated silicon in a gold nanoparticles suspension leads to a monolayer of gold particles attached on the coated silicon. The intermediate micellar film was then removed using oxygen plasma treatment, allowing the direct contact of the gold particles with the Si substrate. We further demonstrate that the gold nanoparticles can serve as catalysts for the localized etching of the silicon substrate, resulting in nanoporous Si with a top layer of straight pores.

  13. Single step purification of lactoperoxidase from whey involving reverse micelles-assisted extraction and its comparison with reverse micellar extraction.

    Nandini, K E; Rastogi, Navin K


    The extraction of lactoperoxidase (EC from whey was studied using single step reverse micelles-assisted extraction and compared with reverse micellar extraction. The reverse micelles-assisted extraction resulted in extraction of contaminating proteins and recovery of lactoperoxidase in the aqueous phase leading to its purification. Reverse micellar extraction at the optimized condition after forward and backward steps resulted in activity recovery of lactoperoxidase and purification factor of the order of 86.60% and 3.25-fold, respectively. Whereas reverse micelles-assisted extraction resulted in higher activity recovery of lactoperoxidase (127.35%) and purification factor (3.39-fold). The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) profiles also evidenced that higher purification was obtained in reverse micelles-assisted extraction as compared of reverse micellar extracted lactoperoxidase.

  14. Optical properties and inclusion of an organic fluorophore in organized media of micellar solutions and beta-cyclodextrin

    El-Sayed, Yusif S.


    In this study, we prepared a new chalcone compound (3-(4'-diethylaminophenyl)-1-(2-pyridinyl) prop-2-en-1-one abbreviated as DEAPPP) and examined its characterization and photophysical properties such as singlet absorption, molar absorptivity, fluorescence spectra, and fluorescence quantum yield (ϕf). DEAPPP dye exhibited a large red shift in both absorption and emission spectra as solvent polarity increases, indicating a large change in dipole moment of molecule upon excitation. Also, the fluorescence quantum yield was solvent dependent. The absorption and fluorescence emission spectral properties of DEAPPP have been investigated in organized media of aqueous micellar and β-cyclodextrin (CD) solutions. While the absorption spectra were less sensitive to the nature of the added surfactant or CD, the characteristics of the intramolecular charge transfer (ICT) fluorescence were highly sensitive to the properties of the medium. The ICT maximum was strongly blue-shifted with a great enhancement in the fluorescence quantum yield on adding micellar or CD. This indicated that the solubilization of DEAPPP increased in the micellar core and an inclusion complex with β-CD was formed. The critical micelle concentration (CMC) as well as the polarity of the micellar core of sodium dodecyl sulfate (SDS), Cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX-100) have been determined. The CMC values were in good agreement with the reported values while the polarity was lower indicating that DEAPPP molecules were incorporated in the micellar core not at the micellar interface. The binding constants of DEAPPP: micelles or DEAPPP: CD complexes have been also determined.

  15. Analysis of catechins in Theobroma cacao beans by cyclodextrin-modified micellar electrokinetic chromatography.

    Gotti, Roberto; Furlanetto, Sandra; Pinzauti, Sergio; Cavrini, Vanni


    A micellar electrokinetic chromatography (MEKC) method was developed for the quantitation of polyphenols (+)-catechin and (-)-epicatechin (catechin monomers) and the methylxanthine theobromine in Theobroma cacao beans. Owing to the poor stability of catechin monomers in alkaline conditions, a 50 mM Britton-Robinson buffer at a pH 2.50 was preferred as the background electrolyte. Under these conditions, the addition of hydroxypropyl-beta-cyclodextrin (HP-beta-CD) at a concentration of 12 mM to the SDS micellar solution (90 mM), resulted in a cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) endowed with two peculiar advantages compare to the conventional MEKC: (i) strong improvement of separation of the most important phytomarkers of T. cacao and (ii) enantioselectivity toward (+/-)-catechin. In particular, separation of methylxanthines (theobromine and caffeine), procyanidin dimers B1 and B2, and catechins (epicatechin and catechin) was obtained simultaneously to the enantioseparation of racemic catechin within 10min. The enantioselectivity of the method makes it suitable in evaluation of possible epimerisation at the C-2 position of epicatechin monomer potentially occurring during heat processing and storage of T. cacao beans. The extraction procedure of the phytomarkers from the beans was approached using ultrasonic bath under mild conditions optimized by a multivariate strategy. The method was validated for robustness, selectivity, sensitivity, linearity, range, accuracy and precision and it was applied to T. cacao beans from different countries; interestingly, the native enantiomer (+)-catechin was found in the beans whereas, for the first time we reported that in chocolate, predominantly (-)-catechin is present, probably yielded by epimerisation of (-)-epicatechin occurred during the manufacture of chocolate.

  16. Micellar control of the photooxidation pathways of 10-methyl phenothiazine: electron versus energy transfer mechanisms.

    Manju, Thankamoniamma; Manoj, Narayanapillai; López Gejo, Juan; Braun, André M; Oliveros, Esther


    10-Methyl phenothiazine (MPS) was chosen as a model compound to investigate the effects of compartmentalisation and of charged interfaces on the primary mechanisms involved in the phototoxic reactions related to phenothiazine drugs. Two most important pathways resulting from the interaction of the triplet excited state of MPS ((3)MPS*) with molecular oxygen ((3)O2) have to be considered: (i) energy transfer producing singlet oxygen ((1)O2) and (ii) electron transfer generating the superoxide anion (O2˙(-)) and the radical cation (MPS˙(+)). The quantum yields of (1)O2 production by MPS solubilized in the dispersed pseudo-phase of aqueous micellar systems were found to be similar to those determined in solvents of various polarities, regardless of the anionic or cationic nature of the surfactant (SDS or CTAC). However, micellar compartmentalisation and surfactant charge affect considerably both the sensitized and the self-sensitized photooxidation of MPS. The formation of 10-methyl phenothiazine sulfoxide (MPSO), produced by the reaction of MPS with (1)O2, proceeds at a higher rate in SDS micelles than in neat polar solvents. This result may be explained by the protonation of the zwitterionic intermediate Z (MPS(+)OO(-)) at the micellar interface to yield the corresponding cation C (MPS(+)OOH) that is stabilized in the negatively charged micelles and reacts much faster with MPS than Z to yield MPSO. The electron transfer reaction from (3)MPS* to O2 yielding MPS˙(+) and O2˙(-) is also enhanced in SDS micelles, as back electron transfer (BET) is prevented by ejection of O2˙(-) to the aqueous bulk phase and stabilization of MPS˙(+) in the anionic micelles. The size of the SDS micelles modulates the relative contribution of each pathway (formation of MPSO or MPS˙(+)) to the overall conversion of MPS to its oxidation products. Photooxidation of MPS in cationic micelles is a very slow process, as the formation of neither C nor MPS˙(+) is favoured in positively

  17. Efficiency enhancements in micellar liquid chromatography through selection of stationary phase and alcohol modifier.

    Thomas, David P; Foley, Joe P


    Micellar liquid chromatography (MLC) remains hindered by reduced chromatographic efficiency compared to reversed phase liquid chromatography (RPLC) using hydro-organic mobile phases. The reduced efficiency has been partially explained by the adsorption of surfactant monomers onto the stationary phase, resulting in a slow mass transfer of the analyte within the interfacial region of the mobile phase and stationary phase. Using an array of 12 columns, the effects of various bonded stationary phases and silica pore sizes, including large-pore short alkyl chain, non-porous, superficially porous and perfluorinated, were evaluated to determine their impact on efficiency in MLC. Additionally, each stationary phase was evaluated using 1-propanol and 1-butanol as separate micellar mobile phase alcohol additives, with several columns also evaluated using 1-pentanol. A simplified equation for calculation of A' and C' terms from reduced plate height (h) versus reduced velocity (nu) plots was used to compare the efficiency data obtained with the different columns and mobile phases. Analyte diffusion coefficients needed for the h versus nu plots were determined by the Taylor-Aris dispersion technique. The use of a short alkyl chain, wide-pore silica column, specifically, Nucleosil C4, 1000A, was shown to have the most improved efficiency when using a micellar mobile phase compared to a hydro-organic mobile phase for all columns evaluated. The use of 1-propanol was also shown to provide improved efficiency over 1-butanol or 1-pentanol in most cases. In a second series of experiments, column temperatures were varied from 40 to 70 degrees C to determine the effect of temperature on efficiency for a subset of the stationary phases. Efficiency improvements ranging from 9% for a Chromegabond C8 column to 58% for a Zorbax ODS column were observed over the temperature range. Based on these observed improvements, higher column temperatures may often yield significant gains in column

  18. Removal of phenol from synthetic waste water using Gemini micellar-enhanced ultrafiltration (GMEUF)

    Zhang, Wenxiang [MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power University, Beijing 102206 (China); Huang, Guohe, E-mail: [MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power University, Beijing 102206 (China); Wei, Jia [Faculty of Engineering and Applied Science, University of Regina, Regina, Saskatchewan, Canada S4S 0A2 (Canada); Li, Huiqin; Zheng, Rubing; Zhou, Ya [MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power University, Beijing 102206 (China)


    Highlights: Black-Right-Pointing-Pointer Gemini surfactant micellar enhanced ultrafiltration was used to remove phenol. Black-Right-Pointing-Pointer The effect of different hydrophilic head groups of surfactant was analyzed. Black-Right-Pointing-Pointer SEM, ATR-FTIR and mercury porosimeter were applied to elucidate membrane fouling. Black-Right-Pointing-Pointer Gemini surfactant had superior performance in comparing with conventional surfactant. - Abstract: Comprehensive studies were conducted on the phenol wastewater ultrafiltration (UF) with the help of various concentrations of cationic Gemini surfactant (N1-dodecyl-N1,N1,N2,N2-tetramethyl-N2-octylethane-1,2-diaminium bromide, CG), conventional cationic surfactant (dodecyl trimethyl ammonium bromide, DTAB), anionic surfactant (sodium dodecyl sulfate, SDS) and nonionic surfactant ((dodecyloxy)polyethoxyethanol, Brij35). A flat sheet module with polyethersulfone (PES) membrane was employed in this investigation. The effects of feed concentration (phenol and surfactant) on the retention of phenol and surfactant, permeate flux and membrane fouling by micelles were evaluated. The distribution coefficient (D), the loading of the micelles (L{sub m}) and the equilibrium distribution constant (K) were also utilized to estimate the micellar-enhanced ultrafiltration ability for phenol. Scanning electron microscope (SEM), Fourier transform infrared spectrometer with attenuated total reflectance accessory (ATR-FTIR) and mercury porosimeter were applied to analyze membrane surface morphology, membrane material characteristics and membrane fouling for the original and fouled membranes. Based on the above analysis, the performance of the selected Gemini surfactant was proved superior in the following aspects: retention of phenol/surfactant (peak value is 95.8% for phenol retention), permeate flux and membrane fouling with respect to other conventional surfactants possessing equal alkyl chain length. These results demonstrated

  19. DNA packaging induced by micellar aggregates: a novel in vitro DNA condensation system.

    Ghirlando, R; Wachtel, E J; Arad, T; Minsky, A


    Evidence for a conceptually novel DNA packaging process is presented. X-ray scattering, electron microscopy, and circular dichroism measurements indicate that in the presence of positively charged micellar aggregates and flexible anionic polymers, such as negatively charged polypeptides or single-stranded RNA species, a complex is formed in which DNA molecules are partially embedded within a micellar scaffold and partially condensed into highly packed chiral structures. Based on studies of micelle-DNA and micelle-flexible anionic polymer systems, as well as on the known effects of a high charge density upon the micellar organization, a DNA packaging model is proposed. According to this model, the DNA induces the elongation of the micelles into rodlike aggregates, forming a closely packed matrix in which the DNA molecules are immobilized. In contrast, the flexible anionic polymers stabilize clusters of spherical micelles which are proposed to effect a capping of the rodlike micelles, thus arresting their elongation and creating surfactant-free segments of the DNA that are able to converge and collapse. Thus, unlike other in vitro DNA packaging systems, in which condensation follows encounters between charge-neutralized DNA molecules, a prepackaging phase where the DNA is immobilized within a matrix is proposed in this case. Cellular and nuclear membranes have been implicated in DNA packaging processes in vivo, and negatively charged polyelectrolytes were shown to be involved in the processes. These observations, combined with the basic tenets of the DNA condensation system described here, allow for the progression to the study of more elaborate model systems and thus might lead to insights into the nature and roles of the intricate in vivo DNA-membrane complexes.

  20. Micellar bolaform and omega-carboxylate phosphatidylcholines as substrates for phospholipases.

    Lewis, K A; Soltys, C E; Yu, K; Roberts, M F


    A series of mixed-chain diacyl-PCs which contain an omega-COOH on the sn-2 chain [1-Cx-2-Cy-(COOH)-PC] and bolaform (1-Cx-2,2'-Cy-1'-Cx-PC) phosphatidylcholines were synthesized and examined as substrates for phospholipase A2 (Naja naja naja) and C (Bacillus cereus). There is very little detectable phospholipase A2 activity toward pure micellar 1-acyl-2-acyl-(omega-COOH) species. In addition, when these same omega-COOH species are present at concentrations above their CMCs, they are potent inhibitors of phospholipase A2 hydrolysis of other micellar lipids. In contrast, phospholipase C hydrolysis of the same 1-acyl-2-acyl-omega-COOH)-PC species proceeds with rates comparable to that of diheptanoyl-PC. The bolaform lipids, which are tethered through a common sn-2 acyl chain, (e.g., 1-C8-2,2'-C12-1'-C8-PC) display quite different kinetic results. Under limiting Ca2+ conditions (100 microM) all the available sn-2 acyl bonds of the dimer are hydrolyzed. However, at high Ca2+ concentrations (1-10 mM) the reaction curves have a biphasic nature, characterized by an initial burst of activity followed by much slower rate. This is consistent with only the micellar 1-acyl-2-acyl-(omega-COOH)-PC produced in situ from phospholipase A2 hydrolysis of the dimer acting as an inhibitor of subsequent phospholipase A2 activity. Phospholipase C hydrolysis of the PC dimer and the sn-2 omega-COOH PC is rapid, with both available glycerophosphate groups cleaved at presumably the same rate. These results are discussed in terms of the unique physical properties (as measured by NMR and fluorescence experiments) of these phospholipids.

  1. Determination of oxolinic acid, danofloxacin, ciprofloxacin, and enrofloxacin in porcine and bovine meat by micellar liquid chromatography with fluorescence detection.

    Terrado-Campos, David; Tayeb-Cherif, Khaled; Peris-Vicente, Juan; Carda-Broch, Samuel; Esteve-Romero, Josep


    A method was developed for the determination of oxolinic acid, danofloxacin, ciprofloxacin and enrofloxacin by micellar liquid chromatography - fluorescence detection in commercial porcine and bovine meat. The samples were ultrasonicated in a micellar solution, free of organic solvent, to extract the analytes, and the supernatant was directly injected. The quinolones were resolved in 0.9998), trueness (89.3-105.1%), precision (<8.3%), decision limit (<12% over the maximum residue limit), detection capability (<21% over the maximum residue limit), ruggedness (<5.6%) and stability. The procedure was rapid, eco-friendly, safe and easy-to-handle.

  2. A mode coupling theory analysis of viscoelasticity near the kinetic glass transition of a copolymer micellar system

    Mallamace, Francesco [Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Tartaglia, Piero [Dipartimento di Fisica, INFM and Statistical Mechanics and Complexity Center, Universita di Roma La Sapienza, I-00185 Rome (Italy); Chen W R [Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Faraone, Antonio [Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Chen, S H [Department of Nuclear Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)


    We report a set of viscoelastic measurements in concentrated aqueous solutions of a copolymer micellar system with short-range inter-micellar attractive interactions, a colloidal system characterized, in different regions of the composition-temperature phase diagram, by the existence of a percolation line (PT) and a kinetic glass transition (KGT). Both these transitions cause dramatic changes in the system viscoelasticity. Whereas the observed variations of the shear moduli at the PT are described in terms of percolation models, for the structural arrest at the KGT we investigate the frequency-dependent shear modulus behaviours by using a mode coupling theory (MCT) approach.

  3. Viscoelastic processes in non-ergodic states (percolation and glass transitions) of attractive micellar systems

    Mallamace, F.; Broccio, M.; Tartaglia, P.; Chen, W. R.; Faraone, A.; Chen, S. H.


    We report a set of viscoelastic measurements in aqueous solutions of a copolymer micellar system with attractive interactions, a system characterized by a percolation line (PT), and a structural arrest (SA) in the particle diffusion motions of a kinetic glass transition (KGT). We observe, in both transitions, dramatic variations in both the elastic (or storage G‧( ω)) and loss components ( G″( ω)) of the shear moduli. At the PT, rheological data are characterized by a scaling behavior, whereas at the SA G‧ and G″ develop a plateau and a marked minimum, respectively. These behaviors are described in the frame of percolation models and mode coupling theory (MCT).

  4. Micellar-polymer joint demonstration project, Wilmington Field, California. Third annual report, June 1978-July 1979

    Staub, H.L.


    The micellar-polymer demonstration project to be conducted - through the design phase - in the HXa sand of Wilmington Field is proceeding satisfactorily but has fallen behind schedule. Results of some core floods were unsatisfactory. The recovery efficiencies were much lower than those achieved using the laboratory sample cosurfactant final design slug. Nearly six months of reformulating and additional core testing were required to finally achieve satisfactory laboratory results. Other laboratory tests were performed to optimize the polymer buffer for size and concentration. Other reservoir and reservoir fluid problems have been encountered in production and injection operations during the pre-flush period.

  5. An Asymptotic Theory for the Re-Equilibration of a Micellar Surfactant Solution

    Griffiths, I. M.


    Micellar surfactant solutions are characterized by a distribution of aggregates made up predominantly of premicellar aggregates (monomers, dimers, trimers, etc.) and a region of proper micelles close to the peak aggregation number, connected by an intermediate region containing a very low concentration of aggregates. Such a distribution gives rise to a distinct two-timescale reequilibration following a system dilution, known as the t1 and t2 processes, whose dynamics may be described by the Becker-Döring equations. We use a continuum version of these equations to develop a reduced asymptotic description that elucidates the behavior during each of these processes.© 2012 Society for Industrial and Applied Mathematics.

  6. Impact of Micellar Surfactant on Supersaturation and Insight into Solubilization Mechanisms in Supersaturated Solutions of Atazanavir.

    Indulkar, Anura S; Mo, Huaping; Gao, Yi; Raina, Shweta A; Zhang, Geoff G Z; Taylor, Lynne S


    The goals of this study were to determine: 1) the impact of surfactants on the "amorphous solubility"; 2) the thermodynamic supersaturation in the presence of surfactant micelles; 3) the mechanism of solute solubilization by surfactant micelles in supersaturated solutions. The crystalline and amorphous solubility of atazanavir was determined in the presence of varying concentrations of micellar sodium dodecyl sulfate (SDS). Flux measurements, using a side-by-side diffusion cell, were employed to determine the free and micellar-bound drug concentrations. The solubilization mechanism as a function of atazanavir concentration was probed using fluorescence spectroscopy. Pulsed gradient spin-echo proton nuclear magnetic resonance (PGSE-NMR) spectroscopy was used to determine the change in micelle size with a change in drug concentration. Changes in the micelle/water partition coefficient, K m/w , as a function of atazanavir concentration led to erroneous estimates of the supersaturation when using concentration ratios. In contrast, determining the free drug concentration using flux measurements enabled improved determination of the thermodynamic supersaturation in the presence of micelles. Fluorescence spectroscopic studies suggested that K m/w changed based on the location of atazanavir solubilization which in turn changed with concentration. Thus, at a concentration equivalent to the crystalline solubility, atazanavir is solubilized by adsorption at the micelle corona, whereas in highly supersaturated solutions it is also solubilized in the micellar core. This difference in solubilization mechanism can lead to a breakdown in the prediction of amorphous solubility in the presence of SDS as well as challenges with determining supersaturation. PGSE-NMR suggested that the size of the SDS micelle is not impacted at the crystalline solubility of the drug but increases when the drug concentration reaches the amorphous solubility, in agreement with the proposed changes in

  7. Application of micellar electrokinetic capillary chromatography for routine analysis of different materials

    Injac Rade


    Full Text Available Micellar electrokinetic capillary chromatography (MEKC has become a popular mode among the several capillary electro-migration techniques. Most drug analysis can be performed by using MEKC because of its wide applicability. Separation of very complex mixtures, determination of drugs in the biological materials, etc., can be successfully achieved by MEKC. This review surveys typical applications of MEKC analysis. Recent advances in MEKC, especially with solid-phase extraction and large-volume sample stacking, are described. Modes of electrokinetic chromatography including MEKC, a separation theory of MEKC, environmental friendly analysis, and selectivity manipulation in MEKC are also briefly mentioned.

  8. Features of the micellar solubility of metal-containing surfactants in hydrocarbons

    Fedorov, A.B.; Zdobnova, O.L.; Zaichenko, L.P.; Proskuryakov, V.A.


    Metal-containing surfactants (SF) are now widely used as different additives to oils and fuels. The micellar solubility of a series of individual metal-containing SF and widely used additives was investigated as a function of the structure and polarity of the additive, type of hydrocarbon solvent, and presence of water in this study. Individual decyl benzenesulfonates (DBS) of different metals and samples of surfactant additives for oils of the alkylphenolate (VNII NP-370), sulfonate (PMSA, PMSya, S-150, S-300, Lubrizol 58, SB-3, PMSya (bariated), alkylsalicylate (ASK, MASK), and dialkyldithiophosphate (DF-11, VNII NP-354) types were investigated.

  9. Quantitative determination of amygdalin epimers by cyclodextrin-modified micellar electrokinetic chromatography.

    Isoza, T; Matano, Y; Yamamoto, K; Kosaka, N; Tani, T


    A new capillary electrophoresis method was developed for the quantitative determination of the amygdalin epimers, amygdalin and neoamygdalin, which are biologically significant constituents in the crude drugs, namely Persicae Semen and Armeniacae Semen. The effects of surfactants, additives and other analytical parameters were studied. As a result, the resolution of two epimers was performed by cyclodextrin-modified micellar electrokinetic chromatography with a buffer containing alpha-cyclodextrin and sodium deoxycholate. By the application of this method, a simple, fast and simultaneous quantitative determinations of amygdalin epimers in the crude drugs (Persicae Semen and Armeniacae Semen) and the Chinese herbal prescriptions (Keishi-bukuryo-gan and Mao-to) were achieved.

  10. Vortex-assisted surfactant-enhanced emulsification liquid-liquid microextraction for the determination of carbamates in juices by micellar electrokinetic chromatography tandem mass spectrometry.

    Moreno-González, David; Huertas-Pérez, José F; García-Campaña, Ana M; Gámiz-Gracia, Laura


    A new method based on vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction has been developed for the extraction of carbamate pesticides in juice samples prior to their determination by micellar electrokinetic chromatography coupled to tandem mass spectrometry. This sample treatment allowed the satisfactory extraction and the extract clean-up of 25 carbamates from different fruit and vegetal juices (banana, tomato, and peach). In this study, the addition of ammonium perfluorooctanoate in the aqueous sample in combination with vortex agitation, provided very clean extracts with short extraction times. Under optimized conditions, recoveries of the proposed method for these pesticides from fortified juice samples ranged from 81% to 104%, with relative standard deviations lower than 15%. Limits of quantification were between 2.3µgkg(-)(1) and 4.7µgkg(-)(1), showing the high sensitivity of this fast and simple method.

  11. Electron transfer between excited states of some sulfonated phtha-locyanines and tyrosine as well as trptophan in homogeneous aqueous solution and aqueous micellar media

    张先付; 许慧君; 沈涛


    Rate constants for electron transfer between excited states of several tetrasulfonated phthalocyanines (MTSPC, M = H2, Zn, ClAl, ClGa) and tyrosine or trptophan have been measured in homogeneous aqueous and aqueous micellar media. Cationic micelles formed by surfactant cetyl trimethyl ammonium chloride (CTAC) promote the electron transfer reaction, whereas neutral micelles formed by Triton X-100 depress this process. The calculated free energy change shows that phthalocyanines act as electron donors in the electron transfer reaction of its excited singlet states with tyrosine or trptophan (Type Is), whereas they act as electron acceptors in the reaction of its excited triplet states with tyrosine or trptophan (type IT). The two different electron transfer processes involving singlet and triplet of sensitizer respectively compete with each other and form different intermediates which may induce the formation of different products. Factors that govern the importance of Type Is in the whole reaction includ

  12. Self-crosslinkable and intracellularly decrosslinkable biodegradable micellar nanoparticles: A robust, simple and multifunctional nanoplatform for high-efficiency targeted cancer chemotherapy.

    Zou, Yan; Fang, Ya; Meng, Hao; Meng, Fenghua; Deng, Chao; Zhang, Jian; Zhong, Zhiyuan


    Nanomedicines based on biodegradable micelles offer a most promising treatment for malignant tumors. Their clinical effectiveness, however, remains to be improved. Here, we report that self-crosslinkable and intracellularly decrosslinkable micellar nanoparticles (SCID-Ms) self-assembled from novel amphiphilic biodegradable poly(ethylene glycol)-b-poly(dithiolane trimethylene carbonate) block copolymer achieve high-efficiency targeted cancer chemotherapy in vivo. Interestingly, doxorubicin (DOX)-loaded SCID-Ms showed favorable features of superb stability, minimal drug leakage, long circulation time, triggered drug release inside the tumor cells, and an unprecedented maximum-tolerated dose (MTD) of over 100mg DOX equiv./kg in mice, which was at least 10 times higher than free drug. The in vivo studies in malignant B16 melanoma-bearing C57BL/6 mice revealed that DOX-SCID-Ms at a dosage of 30mg DOX equiv./kg could effectively suppress tumor growth and prolong mice survival time without causing obvious systemic toxicity. Moreover, DOX-SCID-Ms could be readily decorated with a targeting ligand like cRGD peptide. The biodistribution studies showed that cRGD20/DOX-SCID-Ms had a high tumor accumulation of 6.13% ID/g at 6h post injection, which was ca. 3-fold higher than that for clinically used pegylated liposomal doxorubicin (DOX-LPs). Accordingly, cRGD20/DOX-SCID-Ms exhibited significantly better therapeutic efficacy and lower side effects than DOX-LPs in B16 melanoma-bearing mice. These self-regulating biodegradable micellar nanoparticles offer a robust, multifunctional and viable nanoplatform for targeted cancer chemotherapy.

  13. Study of the micellization and micellar growth in pure alkanediyl-alpha-omega-bis(dodecyldimethylammonium) bromide and MEGA10 surfactant solutions and their mixtures. Influence of the spacer on the enthalpy change accompanying sphere-to-rod transitions.

    Martín, Victoria Isabel; Rodríguez, Amalia; Graciani, María del Mar; Robina, Inmaculada; Moyá, María Luisa


    The micellization and micellar growth in pure aqueous alkanediyl-alpha-omega-bis(dodecyldimethylammonium) bromide, 12-s-12,2Br(-) (with s = 2,5,6,8,10,12), and N-decanoyl-N-methylglucamide MEGA10 solutions and their mixtures are investigated at 303 K. Application of different theoretical approaches to the binary mixtures shows a nonideal behavior. It also shows that the spacer length does not play an important role in the attractive interactions shown by the mixed systems. The sphere-to-rod morphological transition in the pure dimeric micellar solutions is studied at 303 K. From comparison of these results with those at 298 K the key role played by the spacer in the micellar growth is shown. The spacer length controls not only the surfactant concentration at which the morphological transition happens but also the sign of the enthalpy change accompanying the sphere-to-rod equilibrium. Spacers with an even number of methylenes show smaller C* values than those with an odd number of -CH(2)- units. An endothermic enthalpy change is found for even spacers whereas an exothermic enthalpy change is found for odd spacers. To the authors knowledge, this is the first time this experimental trend has been shown. Addition of MEGA10 diminishes the tendency of the aggregates to grow. An increment in the solution mole fraction of MEGA10 makes the formation of elongated micelles difficult. Microviscosity measurements provide additional information about the influence of the MEGA10 content on the sphere-to-rod transition.

  14. A universal concept for stacking neutral analytes in micellar capillary electrophoresis.

    Palmer, J; Munro, N J; Landers, J P


    Unlike recent studies that have depended on manipulation of separation buffer parameters to facilitate stacking of neutral analytes in micellar capillary electrophoresis (MCE) mode, we have developed a method of stacking based simply on manipulation of the sample matrix. Many solutions for sample stacking in MCE are based on strict control of pH, micelle type, electroosmotic flow (EOF) rate, and separation-mode polarity. However, a universal solution to sample stacking in MCE should allow for free manipulation of separation buffer parameters without substantially affecting separation of analytes. Analogous to sample stacking in capillary zone electrophoresis by invoking field amplification of charged analytes in a low-conductivity sample matrix, the proposed method utilizes a high-conductivity sample matrix to transfer field amplification from the sample zone to the separation buffer. This causes the micellar carrier in the separation buffer to stack before it enters the sample zone. Neutral analytes moving out of the sample zone with EOF are efficiently concentrated at the micelle front. Micelle stacking is induced by simply adding salt to the sample matrix to increase the conductivity 2-3-fold higher than the separation buffer. This solution allows free optimization of separation buffer parameters such as micelle concentration, organic modifiers, and pH, providing a method that may complement virtually any existing MCE protocol without restricting the separation method.

  15. Micellarization and intestinal cell uptake of beta-carotene and lutein from drumstick (Moringa oleifera) leaves.

    Pullakhandam, Raghu; Failla, Mark L


    The leaves and pods of the drumstick tree are used as food and medicine in some Asian and African countries. Although relatively high concentrations of beta-carotene and lutein have been reported in the leaves, the bioavailability of these carotenoids from this source is unknown. We have analyzed the digestive stability and bioaccessibility of carotenoids in fresh and lyophilized drumstick leaves using the coupled in vitro digestion/Caco-2 cell model. Beta-carotene and lutein were stable during simulated gastric and small intestinal digestion. The efficiency of micellarization of lutein during the small intestinal phase of digestion exceeded that of beta-carotene. Addition of peanut oil (5% vol/wt) to the test food increased micellarization of both carotenoids, and particularly beta-carotene. Caco-2 cells accumulated beta-carotene and lutein from micelles generated during digestion of drumstick leaves in a time- and concentration-dependent manner. The relatively high bioaccessibility of beta-carotene and lutein from drumstick leaves ingested with oil supports the potential use of this plant food for improving vitamin A nutrition and perhaps delaying the onset of some degenerative diseases such as cataracts.

  16. Indirect detection by semiconductor laser-induced fluorometry in micellar electrokinetic chromatography

    Kaneta, Takashi; Imasaka, Totaro


    Indirect fluorescence detection of electrically neutral compounds separated by micellar electrokinetic chromatography is performed using a semiconductor laser as an exciting light source. Oxazine 750 is used as a visualizing agent of which absorption maximum is near 680 nm. A surfactant, tetradecyltrimethylammonium chloride, is used to form micelles and to prevent adsorption of oxazine 750 with a positive charge on the capillary wall negatively charged. This surfactant coats on the capillary wall so that oxazine 750 is repulsed electrically on the capillary wall. In this technique, some aromatic compounds with relatively polar functional groups, such as aniline and nitrobenzene, could be separated and detected, while nonpolar compounds such as benzene and toluene can not be detected. The range of the detection limit is from 4.2 X 10-4 to 1.6 X 10-3 M (S/N equals 3) for the aromatic compounds. The detection mechanism is based on enhancement of the fluorescence intensity in the micellar solution and on exclusion of the fluorophore attached at the hydrophilic moiety of the micelle by a hydrophilic sample.

  17. A micellar liquid chromatography method for the quantification of abacavir, lamivudine and raltegravir in plasma.

    Peris-Vicente, Juan; Villareal-Traver, Mónica; Casas-Breva, Inmaculada; Carda-Broch, Samuel; Esteve-Romero, Josep


    An analytical methodology based on micellar liquid chromatography has been developed to quantify abacavir, lamivudine and raltegravir in plasma. These three antiretroviral drugs are prescribed as a set in highly active antiretroviral therapy to acquired immunodeficiency syndrome patients. The experimental procedure consists in the dilution of the sample in micellar media, followed by filtration and, without cleanup step. The analytes were resolved in less than 30min using a mobile phase of 0.05M sodium dodecyl sulphate at pH 7, running at 1mLmin(-1) under isocratic mode at room temperature through a C18 column (125×4.6mm, 5μm particle size). The UV detection wavelength was set at 260nm. The method was successfully validated following the requirements of ICH guidelines in terms of: linear range (0.25-2.5μgmL(-1)), linearity (r(2)>0.990), intra- and interday precision (<6.8%) and accuracy (92.3-104.2%) and robustness (<7.1%). To the extent of our knowledge, this is the first published method to quantify these three drugs in plasma. Several blood samples from AIDS patients taking this HAART set provided by a local hospital were analyzed with satisfactory results.

  18. A concise review of applications of micellar liquid chromatography to study biologically active compounds.

    Stępnik, Katarzyna E


    The features of micellar systems are outstanding compared with conventional RP-LC ones. Therefore, the unique properties of micellar chromatography (MLC) are widely recognized. In this short review the applicability of MLC as an in vitro method for the determination of biological activity is discussed. For this purpose many specific examples of MLC applications supported by the theoretical backgrounds of the cited biological activity areas as well as the factors affecting them are presented. This study collects and organizes the most important references of bioactivity determination which were created both recently and in the past, using the MLC method. Although there are many papers on the MLC there is no literature review focused particularly on its applicability in the study of biological activity of various compounds. This work can be treated as a significant review of so far published papers which particularly emphasizes the importance of MLC as in vitro method for determination of bioactivity of different compounds. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Micellar LC Separation of Sesquiterpenic Acids and Their Determination in Valeriana officinalis L. Root and Extracts

    Artem U. Kulikov


    Full Text Available A simple micellar liquid chromatography (MLC method was developed and validated according to ICH Guidelines for the determination of sesquiterpenic acids (valerenic, hydroxyvalerenic, and acetoxyvalerenic acids in root and rhizome extract from Valeriana officinalis L. and valerian dry hydroalcoholic extract. Samples were analyzed on Nucleosil C18 column (150mm×4.6mm, 5 μm using an isocratic mobile phase which consisted of Brij 35 (5% (w/v aqueous solution; pH 2.3±0.1 by phosphoric acid and 1-butanol (6% (v/v; UV detection was at 220 nm. Micellar mobile phase using allows to fully separate valerenic acids within 25 minutes. Linearity for hydroxyvalerenic, acetoxyvalerenic, and valerenic acids was 1.9–27.9, 4.2–63.0, and 6.1–91·3 μg.mL−1, and limit of detection was 0.14, 0.037, and 0.09 μg·mL−1, respectively. Intraday and interday precisions were not less than 2% for all investigated compounds. The proposed method was found to be reproducible and convenient for quantitative analysis of sesquiterpenic acids in valerian root and related preparations.

  20. Removal of phenol from synthetic waste water using Gemini micellar-enhanced ultrafiltration (GMEUF).

    Zhang, Wenxiang; Huang, Guohe; Wei, Jia; Li, Huiqin; Zheng, Rubing; Zhou, Ya


    Comprehensive studies were conducted on the phenol wastewater ultrafiltration (UF) with the help of various concentrations of cationic Gemini surfactant (N1-dodecyl-N1,N1,N2,N2-tetramethyl-N2-octylethane-1,2-diaminium bromide, CG), conventional cationic surfactant (dodecyl trimethyl ammonium bromide, DTAB), anionic surfactant (sodium dodecyl sulfate, SDS) and nonionic surfactant ((dodecyloxy)polyethoxyethanol, Brij35). A flat sheet module with polyethersulfone (PES) membrane was employed in this investigation. The effects of feed concentration (phenol and surfactant) on the retention of phenol and surfactant, permeate flux and membrane fouling by micelles were evaluated. The distribution coefficient (D), the loading of the micelles (L(m)) and the equilibrium distribution constant (K) were also utilized to estimate the micellar-enhanced ultrafiltration ability for phenol. Scanning electron microscope (SEM), Fourier transform infrared spectrometer with attenuated total reflectance accessory (ATR-FTIR) and mercury porosimeter were applied to analyze membrane surface morphology, membrane material characteristics and membrane fouling for the original and fouled membranes. Based on the above analysis, the performance of the selected Gemini surfactant was proved superior in the following aspects: retention of phenol/surfactant (peak value is 95.8% for phenol retention), permeate flux and membrane fouling with respect to other conventional surfactants possessing equal alkyl chain length. These results demonstrated that CG surfactant with exceptional structure has favorable prospects in the treatment of phenol wastewater by the micellar-enhanced ultrafiltration. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Chromatographic performance of large-pore versus small-pore columns in micellar liquid chromatography.

    McCormick, Timothy J; Foley, Joe P; Lloyd, David K


    Micellar liquid chromatography (MLC) is useful in bioanalysis because proteinaceous biofluids can be directly injected onto the column. The technique has been limited in part because of the apparently weak eluting power of micellar mobile phases. It has recently been shown [Anal. Chem. 72 (2000) 294] that this may be overcome by the use of large pore size stationary phases. In this work, large-pore (1000 A) C(18) stationary phases were evaluated relative to conventional small-pore (100 A) C(18) stationary phases for the direct sample injection of drugs in plasma. Furthermore, the difference between the large and small pore phases in gradient elution separations of mixtures of widely varying hydrophobicities was investigated. Large-pore stationary phases were found to be very effective for eluting moderately to highly hydrophobic compounds such as ibuprofen, crotamiton, propranolol, and dodecanophenone, which were highly retained on the small-pore stationary phases typically used in MLC. The advantages of direct introduction of biological samples (drugs in plasma) and rapid column re-equilibration after gradient elution in MLC were maintained with large-pore phases. Finally, recoveries, precision, linearity, and detection limits for the determination of quinidine and DPC 961 in spiked bovine plasma were somewhat better using MLC with wide pore phases.

  2. Use of micellar mobile phases for the chromatographic determination of clorazepate, diazepam, and diltiazem in pharmaceuticals.

    Gil-Agustí, M; Carda-Broch, S; García-Alvarez-Coque, M C; Esteve-Romero, J


    An ODS-2 column, a micellar mobile phase of high elution strength containing 0.1M sodium dodecyl sulfate and 3% (v/v) butanol, and ultraviolet detection at 230 nm are used for the determination of either of two benzodiazepines (clorazepate and diazepam) and a benzothiazepine (diltiazem) in pharmaceuticals. The procedure is shown to be competitive against conventional chromatography with methanol-water mobile phases, especially for diltiazem. The composition of the micellar mobile phase is selected using a predictive strategy based on an accurate retention model and assisted by computer simulation. Calibration graphs are linear at least in the 2.5 to 20 microg/mL, 4 to 20 microg/mL, and 5 to 40 microg/mL ranges for clorazepate, diazepam, and diltiazem, respectively. The intra- and interday repeatabilities (%) are clorazepate (1.7, 5.2), diazepam (0.43, 3.7), and diltiazem (0.36, 3.1). Limits of detection are well below the concentrations of the drugs found in the commercial pharmaceutical preparations analyzed. The drug contents evaluated with the proposed procedure are compared with the declared contents given by the manufacturers. The achieved percentages of label claim are usually between 95 and 104%.

  3. Magnetic Properties of FePt Nanoparticles Prepared by a Micellar Method

    Gao Y


    Full Text Available Abstract FePt nanoparticles with average size of 9 nm were synthesized using a diblock polymer micellar method combined with plasma treatment. To prevent from oxidation under ambient conditions, immediately after plasma treatment, the FePt nanoparticle arrays were in situ transferred into the film-growth chamber where they were covered by an SiO2 overlayer. A nearly complete transformation of L10 FePt was achieved for samples annealed at temperatures above 700 °C. The well control on the FePt stoichiometry and avoidance from surface oxidation largely enhanced the coercivity, and a value as high as 10 kOe was obtained in this study. An evaluation of magnetic interactions was made using the so-called isothermal remanence (IRM and dc-demagnetization (DCD remanence curves and Kelly–Henkel plots (ΔM measurement. The ΔM measurement reveals that the resultant FePt nanoparticles exhibit a rather weak interparticle dipolar coupling, and the absence of interparticle exchange interaction suggests no significant particle agglomeration occurred during the post-annealing. Additionally, a slight parallel magnetic anisotropy was also observed. The results indicate the micellar method has a high potential in preparing FePt nanoparticle arrays used for ultrahigh density recording media.

  4. Bending energetics of tablet-shaped micelles: a novel approach to rationalize micellar systems.

    Bergström, L Magnus


    A novel approach to rationalize micellar systems is expounded in which the structural behavior of tablet-shaped micelles is theoretically investigated as a function of the three bending elasticity constants: spontaneous curvature (H0), bending rigidity (k(c)), and saddle-splay constant (k(c)). As a result, experimentally accessible micellar properties, such as aggregation number, length-to-width ratio, and polydispersity, may be related to the different bending elasticity constants. It is demonstrated that discrete micelles or connected cylinders form when H0 > 1/4xi, where xi is the thickness of a surfactant monolayer, whereas various bilayer structures are expected to predominate when H0 bending rigidity is lowered, approaching the critical point at k(c) = 0, whereas monodisperse globular micelles (small length-to-width ratio) are expected to be present at large k(c) values. The spontaneous curvature mainly determines the width of tablet-shaped or ribbonlike micelles, or the radius of disklike micelles, whereas the saddle-splay constant primarily influences the size but not the shape of the micelles.

  5. Capillaries modified by noncovalent anionic polymer adsorption for capillary zone electrophoresis, micellar electrokinetic capillary chromatography and capillary electrophoresis mass spectrometry

    Bendahl, L; Hansen, S H; Gammelgaard, Bente


    A simple coating procedure for generation of a high and pH-independent electroosmotic flow in capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) is described. The bilayer coating was formed by noncovalent adsorption of the ionic polymers Polybrene...

  6. Equipment for the Characterization of Synthetic Bio-hybrid Polymers and Micellar Nanoparticles for Stimuli Responsive Materials


    reactions. These materials couple together synthetic polymers with biopolymers including DNA, peptides and proteins. The project therefore requires a... Synthetic Bio-hybrid Polymers and Micellar Nanoparticles for Stimuli Responsive Materials. The views, opinions and/or findings contained in this...this instrument in terms of fully characterizing biomolecule interactions occurring at the interface of semi- synthetic biopolymer -based nano materials

  7. Multicompartment micellar aggregates of linear ABC amphiphiles in solvents selective for the C block: A Monte Carlo simulation

    Zhu, Yutian


    In the current study, we applied the Monte Carlo method to study the self-assembly of linear ABC amphiphiles composed of two solvophobic A and B blocks and a solvophilic C block. A great number of multicompartment micelles are discovered from the simulations and the detailed phase diagrams for the ABC amphiphiles with different block lengths are obtained. The simulation results reveal that the micellar structure is largely controlled by block length, solvent quality, and incompatibility between the different block types. When the B block is longer than or as same as the terminal A block, a rich variety of micellar structures can be formed from ABC amphiphiles. By adjusting the solvent quality or incompatibility between the different block types, multiple morphological transitions are observed. These morphological sequences are well explained and consistent with all the previous experimental and theoretical studies. Despite the complexity of the micellar structures and morphological transitions observed for the self-assembly of ABC amphiphiles, two important common features of the phase behavior are obtained. In general, the micellar structures obtained in the current study can be divided into zero-dimensional (sphere-like structures, including bumpy-surfaced spheres and sphere-on-sphere structures), one-dimensional (cylinder-like structures, including rod and ring structures), two-dimensional (layer-like structures, including disk, lamella and worm-like and hamburger structures) and three-dimensional (vesicle) structures. It is found that the micellar structures transform from low- to high- dimensional structures when the solvent quality for the solvophobic blocks is decreased. In contrast, the micellar structures transform from high- to low-dimensional structures as the incompatibility between different block types increases. Furthermore, several novel micellar structures, such as the CBABC five-layer vesicle, hamburger, CBA three-layer ring, wormlike shape with

  8. Influence of salts on the coexistence curve and protein partitioning in nonionic aqueous two-phase micellar systems

    A. M. Lopes


    Full Text Available Aqueous two-phase micellar systems (ATPMS can be exploited in separation science for the extraction/purification of desired biomolecules. Prior to phase separation the surfactant solution reaches a cloud point temperature, which is influenced by the presence of electrolytes. In this work, we provide an investigation on the cloud point behavior of the nonionic surfactant C10E4 in the presence of NaCl, Li2SO4 and KI. We also investigated the salts' influence on a model protein partitioning. NaCl and Li2SO4 promoted a depression of the cloud point. The order of salts and the concentration that decreased the cloud point was: Li2SO4 0.5 M > NaCl 0.5 M ≈ Li2SO4 0.2 M. On the other hand, 0.5 M KI dislocated the curve to higher cloud point values. For our model protein, glucose-6-phosphate dehydrogenase (G6PD, partitioning experiments with 0.5 M NaCl or 0.2 M Li2SO4 at 13.85 ºC showed similar results, with K G6PD ~ 0.46. The lowest partition coefficient was obtained in the presence of 0.5 M KI (K G6PD = 0.12, with major recovery of the enzyme in the micelle-dilute phase (%Recovery = 90%. Our results show that choosing the correct salt to add to ATPMS may be useful to attain the desired partitioning conditions at more extreme temperatures. Furthermore, this system can be effective to separate a target biomolecule from fermented broth contaminants.

  9. A new application of micellar liquid chromatography in the determination of free ampicillin concentration in the drug-human serum albumin standard solution in comparison with the adsorption method.

    Stępnik, Katarzyna E; Malinowska, Irena; Maciejewska, Małgorzata


    The determination of free drug concentration is a very important issue in the field of pharmacology because only the unbound drug fraction can achieve a pharmacological effect. Due to the ability to solubilize many different compounds in micellar aggregates, micellar liquid chromatography (MLC) can be used for direct determination of free drug concentration. Proteins are not retained on the stationary phase probably due to the formation of protein - surfactant complexes which are excluded from the pores of stationary phase. The micellar method is simple and fast. It does not require any pre-preparation of the tested samples for analysis. The main aim of this paper is to demonstrate a completely new applicability of the analytical use of MLC concerning the determination of free drug concentration in the standard solution of human serum albumin. The well-known adsorption method using RP-HPLC and the spectrophotometric technique was applied as the reference method. The results show that the free drug concentration value obtained in the MLC system (based on the RP-8 stationary phase and CTAB) is similar to that obtained by the adsorption method: both RP-HPLC (95.83μgmL(-1), 79.86% of free form) and spectrophotometry (95.71μgmL(-1), 79.76%). In the MLC the free drug concentration was 93.98μgmL(-1) (78.3%). This indicates that the obtained results are within the analytical range of % of free ampicillin fraction and the MLC with direct sample injection can be treated like a promising method for the determination of free drug concentration.

  10. 稳态荧光猝灭法确定胶束聚合合成条件%Determination of the synthesis condition of micellar polymerization by steady-state fluorescence quenching method

    钟金杭; 郭拥军; 柳建新; 杨雪杉; 杨红苹; 冯茹森; 祝仰文


    以芘(Py)为荧光探针,十六烷基氯化吡啶(CPC)为猝灭剂,用稳态荧光猝灭法研究十二烷基硫酸钠(SDS)浓度和溶液极性对其胶束聚集数的影响.结果表明,当SDS浓度在5~42倍cmc时,胶束聚集数Nagg随SDS的浓度增大而增大,并且趋势逐渐变缓.当SDS浓度为11.3倍cmc时,胶束聚集数随NaCl浓度增大而明显增大,I1/I3值逐渐减小.以上两种条件下聚集数的增大引起疏水微嵌段长度较大的变化,而微嵌段长度又是胶束聚合中最重要的参数之一.因此,胶束聚合合成微嵌段缔合聚合物中,SDS浓度和溶液极性对其胶束聚集数的影响不能忽略.%The micellar aggregation numbers of SDS with different concentrations of SDS or polarity were determined by steady-state fluorescence quenching method in which pyrene was used as a fluorescence probe and cetylpyridinium chloride as a quencher. The results showed that /Vagg increased with increasing the SDS concentration in a range of 5 -42 times cmc and the increased value became more and more slowly. When the concentration of SDS was 11.3 times cmc,the ./Vagg increased significantly with increasing the NaCl concentration and /,//3 decreased gradually. Under these two conditions, the increase numbers of aggregation caused a great change in hydrophobe micro-block length, and the micro-block length was one of the most important parameter in micellar polymerization. Therefore,in the synthesis of the micro-block' associative polymers by micellar polymerization, the effect of concentrations of SDS or polarity on micellar aggregation numbers can not be ignored.

  11. An in vivo mechanism for the reduced peripheral neurotoxicity of NK105: a paclitaxel-incorporating polymeric micellar nanoparticle formulation

    Nakamura, Iwao; Ichimura, Eiji; Goda, Rika; Hayashi, Hitomi; Mashiba, Hiroko; Nagai, Daichi; Yokoyama, Hirofumi; Onda, Takeshi; Masuda, Akira


    In our previous rodent studies, the paclitaxel (PTX)-incorporating polymeric micellar nanoparticle formulation NK105 had showed significantly stronger antitumor effects and reduced peripheral neurotoxicity than PTX dissolved in Cremophor® EL and ethanol (PTX/CRE). Thus, to elucidate the mechanisms underlying reduced peripheral neurotoxicity due to NK105, we performed pharmacokinetic analyses of NK105 and PTX/CRE in rats. Among neural tissues, the highest PTX concentrations were found in the dorsal root ganglion (DRG). Moreover, exposure of DRG to PTX (Cmax_PTX and AUC0-inf._PTX) in the NK105 group was almost half that in the PTX/CRE group, whereas exposure of sciatic and sural nerves was greater in the NK105 group than in the PTX/CRE group. In histopathological analyses, damage to DRG and both peripheral nerves was less in the NK105 group than in the PTX/CRE group. The consistency of these pharmacokinetic and histopathological data suggests that high levels of PTX in the DRG play an important role in the induction of peripheral neurotoxicity, and reduced distribution of PTX to the DRG of NK105-treated rats limits the ensuing peripheral neurotoxicity. In further analyses of PTX distribution to the DRG, Evans blue (Eb) was injected with BODIPY®-labeled NK105 into rats, and Eb fluorescence was observed only in the DRG. Following injection, most Eb dye bound to albumin particles of ~8 nm and had penetrated the DRG. In contrast, BODIPY®–NK105 particles of ~90 nm were not found in the DRG, suggesting differential penetration based on particle size. Because PTX also circulates as PTX–albumin particles of ~8 nm following injection of PTX/CRE, reduced peripheral neurotoxicity of NK105 may reflect exclusion from the DRG due to particle size, leading to reduced PTX levels in rat DRG (275). PMID:28243090

  12. Estrogenic compounds determination in water samples by dispersive liquid-liquid microextraction and micellar electrokinetic chromatography coupled to mass spectrometry.

    D'Orazio, Giovanni; Asensio-Ramos, María; Hernández-Borges, Javier; Fanali, Salvatore; Rodríguez-Delgado, Miguel Ángel


    In this work, a group of 12 estrogenic compounds, i.e., four natural sexual hormones (estrone, 17β-estradiol, 17α-estradiol and estriol), an exoestrogen (17α-ethynylestradiol), a synthetic stilbene (dienestrol), a mycotoxin (zearalenone) and some of their major metabolites (2-methoxyestradiol, α-zearalanol, β-zearalanol, α-zearalenol and β-zearalenol) have been separated and determined by micellar electrokinetic chromatography (MEKC) coupled to electrospray ion trap mass spectrometry. For this purpose, a background electrolyte containing an aqueous solution of 45 mM of perfluorooctanoic acid (PFOA) adjusted to pH 9.0 with an ammonia solution, as MS friendly surfactant, and methanol (10% (v/v)), as organic modifier, was used. To further increase the sensitivity, normal stacking mode was applied by injecting the sample dissolved in an aqueous solution of 11.5mM of ammonium PFO (APFO) at pH 9.0 containing 10% (v/v) of methanol for 25s. Dispersive liquid-liquid microextraction, using 110 μL of chloroform and 500 μL of acetonitrile as extraction and dispersion solvents, respectively, was employed to extract and preconcentrate the target analytes from different types of environmental water samples (mineral, run-off and wastewater) containing 30% (w/v) NaCl and adjusted to pH 3.0 with 1M HCl. The limits of detection achieved were in the range 0.04-1.10 μg/L. The whole method was validated in terms of linearity, precision, recovery and matrix effect for each type of water, showing determination coefficients higher than 0.992 for matrix-matched calibration and absolute recoveries in the range 43-91%.

  13. Use of micellar casein concentrate for Greek-style yogurt manufacturing: effects on processing and product properties.

    Bong, D D; Moraru, C I


    The objective of this work was to develop and optimize an alternative make process for Greek-style yogurt (GSY), in which the desired level of protein was reached by fortification with micellar casein concentrate (MCC) obtained from milk by microfiltration. Two MCC preparations with 58 and 88% total protein (MCC-58 and MCC-88) were used to fortify yogurt milk to 9.80% (wt/wt) protein. Strained GSY of similar protein content was used as the control. Yogurt milk bases were inoculated with 0.02% (wt/wt) or 0.04% (wt/wt) direct vat set starter culture and fermented until pH 4.5. The acidification rate was faster for the MCC-fortified GSY than for the control, regardless of the inoculation level, which was attributed to the higher nonprotein nitrogen content in the MCC-fortified milk. Steady shear rate rheological analysis indicated a shear-thinning behavior for all GSY samples, which fitted well with the power law model. Dynamic rheological analysis at 5°C showed a weak frequency dependency of the elastic modulus (G') and viscous modulus (G") for all GSY samples, with G' > G", indicating a weak gel structure. Differences in the magnitude of viscoelastic parameters between the 2 types of GSY were found, with G' of MCC-fortified GSY yogurt. Differences were also noticed in water-holding capacity, which was lower for the MCC-fortified GSY compared with the control, attributed to lower serum protein content in the former. Despite some differences in the physicochemical characteristics of the final product compared with GSY manufactured by straining, the alternative process developed here is a feasible alternative to the traditional GSY make process, with environmental and possibly financial benefits to the dairy industry.

  14. Differentiation between naproxen, naproxen-protein conjugates, and naproxen-lysine in plasma via micellar electrokinetic capillary chromatography : a new approach in the bioanalysis of drug targeting preparations

    Albrecht, C.; Reichen, J; Visser, Jan; Meijer, D.K F; Thormann, W


    Pharmacotherapy through the targeting of drugs is a promising new approach that requires adequate analytical methods capable of differentiating between the free drug the drug carrier, and metabolites. Using micellar electrokinetic capillary chromatography (MECC), we report the separation of naproxen

  15. Effect of tartarate and citrate based food additives on the micellar properties of sodium dodecylsulfate for prospective use as food emulsifier.

    Banipal, Tarlok S; Kaur, Harjinder; Kaur, Amanpreet; Banipal, Parampaul K


    Citrate and tartarate based food preservatives can be used to enhance the emulsifying properties of sodium dodecylsulfate (SDS) based micellar system and thus making it appropriate for food applications. Exploration of interactions between the two species is the key constraint for execution of such ideas. In this work various micellar and thermodynamic parameters of SDS like critical micellar concentration (CMC), standard Gibbs free energy of micellization (ΔG(0)mic.) etc. have been calculated in different concentrations of disodium tartarate (DST) and trisodium citrate (TSC) in the temperature range (288.15-318.15)K from the conductivity and surface tension measurements. The parameters obtained from these studies reveal the competitive nature of both the additives with SDS for available positions at the air/water interface. TSC is found to be more effective additive in order to make SDS micellar system better for its potential applications as food emulsifier.

  16. The Health Show

    Swann, David


    Dr David Swann interviewed on The Health Show, Series 1, Episode 5, 2011 for BBC World about the award-winning 21st Century Nursing Bag. BBC World News reaches 241million people every week, available in 296 million homes, 1.8 million hotel rooms and has the highest average viewership on a weekday of any international news channel. The Health Show is a new 26-part series for BBC World News covering the most important news stories from around the world.

  17. Biomedical Evaluation of Cortisol, Cortisone, and Corticosterone along with Testosterone and Epitestosterone Applying Micellar Electrokinetic Chromatography

    Bączek, Tomasz; Olędzka, Ilona; Konieczna, Lucyna; Kowalski, Piotr; Plenis, Alina


    The validated micellar electrokinetic chromatography (MEKC) was proposed for the determination of five steroid hormones in human urine samples. That technique allowed for the separation and quantification of cortisol, cortisone, corticosterone, testosterone, and epitestosterone and was sensitive enough to detect low concentrations of these searched steroids in urine samples at the range of 2–300 ng/mL. The proposed MEKC technique with solid-phase extraction (SPE) procedure was simple, rapid, and has been successfully applied as a routine procedure to analyze steroids in human urine samples. The MEKC method offered a potential in clinical routine practice because of the short analysis time (8 min), low costs, and simultaneous analysis of five endogenous hormones. Due to its simplicity, speed, accuracy, and high recovery, the proposed method could offer a tool to determine steroid hormones as potential biomarkers in biomedical investigations, what was additionally revealed with healthy volunteers. PMID:22536129

  18. Determination of adrenal steroids by microfluidic chip using micellar electrokinetic chromatography.

    Shen, Shuanglong; Li, Yan; Wakida, Shin-ichi; Takeda, Sahori


    This paper describes a sensitive and convenient method to separate progesterone, 17alpha-hydroxy progesterone, cortexolone, hydrocortisone and cortisone, all of which are steroids and have similar structures, using microfluidic chip-based technology with UV detection at 252 nm. We successfully obtained high-speed separation of the five steroids within 70 s in optimized microfluidic controls and micellar electrokinetic chromatography (MEKC) separation conditions. Fairly good linearity with correlation coefficient of over 0.98 from 10 or 20 to 100 mg/l steroid chemicals was obtained. The limits of detection obtained at a signal to noise ratio of 3 were from 3.89 to 7.80 mg/l. The values of the relative standard deviation (RSD) were 0.98-1.34% for repetitive injection (n = 12) and the intraday and interday RSDs were below 6%. The highly stable response reflected the feasibility of this method.

  19. Analysis of pharmaceutical preparations containing antihistamine drugs by micellar liquid chromatography.

    Martínez-Algaba, C; Bermúdez-Saldaña, J M; Villanueva-Camañas, R M; Sagrado, S; Medina-Hernández, M J


    Rapid chromatographic procedures for analytical quality control of pharmaceutical preparations containing antihistamine drugs, alone or together with other kind of compounds are proposed. The method uses C18 stationary phases and micellar mobile phases of cetyltrimethylammonium bromide (CTAB) with either 1-propanol or 1-butanol as organic modifier. The proposed procedures allow the determination of the antihistamines: brompheniramine, chlorcyclizine, chlorpheniramine, diphenhydramine, doxylamine, flunarizine, hydroxyzine, promethazine, terfenadine, tripelennamine and triprolidine, in addition to caffeine, dextromethorphan, guaifenesin, paracetamol and pyridoxine in different pharmaceutical presentations (tablets, capsules, suppositories, syrups and ointments). The methods require minimum handling sample and are rapid (between 3 and 12 min at 1 mLmin(-1) flow rate) and reproducible (R.S.D. values<5%). Limits of detection are lower than 1 microgmL(-1) and the recoveries of the analytes in the pharmaceutical preparations are in the range 100+/-10%.

  20. Separation of human, bovine, and porcine insulins, three very closely related proteins, by micellar electrokinetic chromatography.

    Lamalle, Caroline; Roland, Diane; Crommen, Jacques; Servais, Anne-Catherine; Fillet, Marianne


    Human, bovine, and porcine insulins are small proteins with very closely related amino acid sequences, which makes their separation challenging. In this study, we took advantage of the high-resolution power of CE, and more particularly of micellar electrokinetic chromatography, to separate those biomolecules. Among several surfactants, perfluorooctanoic acid ammonium salt was selected. Then, using a design of experiments approach, the optimal BGE composition was found to consist of 50 mM ammonium acetate pH 9.0, 65 mM perfluorooctanoic acid ammonium salt, and 4% MeOH. The three insulins could be separated within 12 min with a satisfactory resolution. This method could be useful to detect possible counterfeit pharmaceutical formulations. Indeed, it would be easy to determine if human insulin was replaced by bovine or porcine insulin.

  1. Predicting human intestinal absorption in the presence of bile salt with micellar liquid chromatography.

    Waters, Laura J; Shokry, Dina S; Parkes, Gareth M B


    Understanding intestinal absorption for pharmaceutical compounds is vital to estimate the bioavailability and therefore the in vivo potential of a drug. This study considers the application of micellar liquid chromatography (MLC) to predict passive intestinal absorption with a selection of model compounds. MLC is already known to aid prediction of absorption using simple surfactant systems; however, with this study the focus was on the presence of a more complex, bile salt surfactant, as would be encountered in the in vivo environment. As a result, MLC using a specific bile salt has been confirmed as an ideal in vitro system to predict the intestinal permeability for a wide range of drugs, through the development of a quantitative partition-absorption relationship. MLC offers many benefits including environmental, economic, time-saving and ethical advantages compared with the traditional techniques employed to obtain passive intestinal absorption values. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Biomedical Evaluation of Cortisol, Cortisone, and Corticosterone along with Testosterone and Epitestosterone Applying Micellar Electrokinetic Chromatography

    Tomasz Bączek


    Full Text Available The validated micellar electrokinetic chromatography (MEKC was proposed for the determination of five steroid hormones in human urine samples. That technique allowed for the separation and quantification of cortisol, cortisone, corticosterone, testosterone, and epitestosterone and was sensitive enough to detect low concentrations of these searched steroids in urine samples at the range of 2–300 ng/mL. The proposed MEKC technique with solid-phase extraction (SPE procedure was simple, rapid, and has been successfully applied as a routine procedure to analyze steroids in human urine samples. The MEKC method offered a potential in clinical routine practice because of the short analysis time (8 min, low costs, and simultaneous analysis of five endogenous hormones. Due to its simplicity, speed, accuracy, and high recovery, the proposed method could offer a tool to determine steroid hormones as potential biomarkers in biomedical investigations, what was additionally revealed with healthy volunteers.

  3. Silver and gold nanocluster catalyzed reduction of methylene blue by arsine in micellar medium

    Subrata Kundu; Sujit Kumar Ghosh; Madhuri Mandal; Tarasankar Pal


    Arsenic can be determined in parts-per-million (ppm) level by absorbance measurement. This method is based on the quantitative colour bleaching of the dye, methylene blue by arsine catalyzed by nanoparticles in micellar medium. The arsine has been generated in situ from sodium arsenate by NaBH4 reduction. The absorbance measurement was carried out at the max of the dye at 660 nm. The calibration graph set-up for three linear dynamic ranges (LDR) are 0–8.63 ppm, 0–1.11 ppm and 0–0.11 ppm and limit of detections (LODs) are 1.3, 0.53 and 0.03 ppm, respectively. This method is simple, sensitive and easy to carry out. It is free from phosphate and silicate interference and applicable to real sample analysis.

  4. Absorption, fluorescence, and acid-base equilibria of rhodamines in micellar media of sodium dodecyl sulfate

    Obukhova, Elena N.; Mchedlov-Petrossyan, Nikolay O.; Vodolazkaya, Natalya A.; Patsenker, Leonid D.; Doroshenko, Andrey O.; Marynin, Andriy I.; Krasovitskii, Boris M.


    Rhodamine dyes are widely used as molecular probes in different fields of science. The aim of this paper was to ascertain to what extent the structural peculiarities of the compounds influence their absorption, emission, and acid-base properties under unified conditions. The acid-base dissociation (HR+ ⇄ R + H+) of a series of rhodamine dyes was studied in sodium n-dodecylsulfate micellar solutions. In this media, the form R exists as a zwitterion R±. The indices of apparent ionization constants of fifteen rhodamine cations HR+ with different substituents in the xanthene moiety vary within the range of pKaapp = 5.04 to 5.53. The distinct dependence of emission of rhodamines bound to micelles on pH of bulk water opens the possibility of using them as fluorescent interfacial acid-base indicators.

  5. Amplification of Chirality through Self-Replication of Micellar Aggregates in Water

    Bukhriakov, Konstantin


    We describe a system in which the self-replication of micellar aggregates results in a spontaneous amplification of chirality in the reaction products. In this system, amphiphiles are synthesized from two "clickable" fragments: a water-soluble "head" and a hydrophobic "tail". Under biphasic conditions, the reaction is autocatalytic, as aggregates facilitate the transfer of hydrophobic molecules to the aqueous phase. When chiral, partially enantioenriched surfactant heads are used, a strong nonlinear induction of chirality in the reaction products is observed. Preseeding the reaction mixture with an amphiphile of one chirality results in the amplification of this product and therefore information transfer between generations of self-replicating aggregates. Because our amphiphiles are capable of catalysis, information transfer, and self-assembly into bounded structures, they present a plausible model for prenucleic acid "lipid world" entities. © 2015 American Chemical Society.

  6. Determination of catechins in matcha green tea by micellar electrokinetic chromatography.

    Weiss, David J; Anderton, Christopher R


    Catechins in green tea are known to have many beneficial health properties. Recently, it has been suggested that matcha has greater potential health benefits than other green teas. Matcha is a special powdered green tea used in the Japanese tea ceremony. However, there has been no investigation to quantitate the catechin intake from matcha compared to common green teas. We have developed a rapid method of analysis of five catechins and caffeine in matcha using micellar electrokinetic chromatography. Results are presented for water and methanol extractions of matcha compared with water extraction of a popular green tea. Using a mg catechin/g of dry leaf comparison, results indicate that the concentration of epigallocatechin gallate (EGCG) available from drinking matcha is 137 times greater than the amount of EGCG available from China Green Tips green tea, and at least three times higher than the largest literature value for other green teas.

  7. Study of Tea Digitized Chromatographic Fingerprint Spectra Using Micellar Electrokinetic Chromatography

    SONG, Guan-Qun; LIN, Jin-Ming; QU, Feng; DONG, Wen-Ju


    This paper described the principle of digitized chromatographic fingerprint spectrum and established digitized chromatographic fingerprint spectra of ten brands of Chinese famous tea by the micellar electrokinetic chromatography. This work was done using a 25 mmol. L- 1 sodium dodecylsulfate in a 20 mmol· L-1borate (pH 7.0) solution as running buffer, 20 kV applied potential and detection at 280 nm. The chromatographic fingerprint spectra were digitized by the relative retention value (α)and the relative area (Sr), and were analyzed to identify the tea samples. In the absence of the standard samples, the present method was easy setup and inexpensive, and provided the applicable information for the quality assessment of teas.

  8. Simultaneous determination of four bioactive constituents in Liuwei Dihuang Pills by micellar electrokinetic chromatography.

    Zhao, Xinfeng; Wang, Yue; Sun, Yuqing


    A micellar electrokinetic chromatography (MEKC) method for the simultaneous determination of four bioactive constituents (morroniside, loganin, paeoniflorin and paeonal) in the Chinese patent medicine Liuwei Dihuang Pills is established. A carrier composed of 0.2M boric acid, 0.02 M sodium dodecyl sulfate (SDS) and 5% acetonitrile (pH was adjusted to 10.5 with 0.1 M NaOH) is found to be the most suitable electrolyte for this separation. The four constituents in Liuwei Dihuang Pills can be easily determined within 16 min. Optimization of separation is realized with the univariate approach by studying the effects of four factors relevant to run buffer on migration times.

  9. Fluoride binding in water with the use of micellar nanodevices based on salophen complexes.

    Keymeulen, Flore; De Bernardin, Paolo; Giannicchi, Ilaria; Galantini, Luciano; Bartik, Kristin; Dalla Cort, Antonella


    The use of micelles to transpose lipophilic receptors, such as uranyl-salophen complexes, into an aqueous environment is a valuable and versatile tool. Receptor 1 incorporated into CTABr micelles forms a supramolecular system that exhibits excellent binding properties towards fluoride in water, despite the competition of the aqueous medium. To fully evaluate the potential of micellar nanodevices, we extended our previous study to other types of surfactants and to a uranyl-salophen receptor with a more extended aromatic surface. Paramagnetic relaxation enhancement experiments were used to obtain information on the location of the two receptors within the micelles and complementary information was obtained from dynamic light scattering experiments. With these data it is possible to account for the key factors necessary to obtain an efficient supramolecular device for anion binding in water.

  10. Optimization of the Separation of Quinolines in Micellar Liquid Chromatography by Experimental Design and Regression Models



    The chemometrics approach was applied to the optimization of separation of quinolines in micellar liquid tigated by means of multivariate analysis. The factors considered were the concentration of sodium dodecyl sulfate (SDS), the organic modifier concentration and the length of its alkyl chain, and pH of the mobile phase. The ex-periments were performed according to a face centered cube response surface experimental design. In order to op-timize the separation a Pareto-optimality method was employed. The models were verified, because a good agree-ment was observed between the predicted and experimental values of the chromatographic response function in the optimal condition. The obtained regression models were characterized by both descriptive and predictive ability (R2≥0.97 and R2cv≥0.92) and allowed the chromatographic separation of the quinolines with a good resolution and a total analysis time of 50 min.

  11. Analysis of epinephrine, norepinephrine, and dopamine in urine samples of hospital patients by micellar liquid chromatography.

    García Ferrer, Daniel; García García, Aurelio; Peris-Vicente, Juan; Gimeno-Adelantado, José Vicente; Esteve-Romero, Josep


    An analytical method based on micellar liquid chromatography was developed to determine the concentration of three catecholamines (epinephrine, norepinephrine, and dopamine) in urine. The detection of these compounds in urine can be useful to diagnose several diseases, related to stress and sympathoadrenal system dysfunction, using a non-invasive collection procedure. The sample pretreatment was a simple dilution in a micellar solution, filtration, and direct injection, thus avoiding time-consuming and tedious extraction steps. Therefore, there is no need to use an internal standard. The three catecholamines were eluted using a C18 column and a mobile phase of 0.055 M sodium dodecyl sulfate-1.5% methanol buffered at pH 3.8 running at 1.5 mL/min under isocratic mode in less than 25 min. The detection was performed by amperometry applying a constant potential of +0.5 V. The procedure was validated following the guidelines of the European Medicines Agency in terms of the following: calibration range (0.09-5 μg/mL), linearity (r(2) > 0.9995), limit of detection (0.02 μg/mL), within- and between-run accuracy (-6.5 to +8.4%) and precision (<10.2%), dilution integrity, matrix effect, robustness (<8.4), and stability. The obtained values were below those required by the guide. The method was rapid, easy-to-handle, eco-friendly, and safe and provides reliable quantitative data, and is thus useful for routine analysis. The procedure was applied to the analysis of epinephrine, norepinephrine, and dopamine in urine samples from patients of a local hospital.

  12. Electrophoretic concentration and sweeping-micellar electrokinetic chromatography analysis of cationic drugs in water samples.

    Wuethrich, Alain; Haddad, Paul R; Quirino, Joselito P


    Sample preparation by electrophoretic concentration, followed by analysis using sweeping-micellar electrokinetic chromatography, was studied as a green and simple analytical strategy for the trace analysis of cationic drugs in water samples. Electrophoretic concentration was conducted using 50 mmol/L ammonium acetate at pH 5 as acceptor electrolyte. Electrophoretic concentration was performed at 1.0 kV for 50 min and 0.5 kV and 15 min for purified and 10-fold diluted waste water samples, respectively. Sweeping-micellar electrokinetic chromatography was with 100 mmol/L sodium phosphate at pH 2, 100 mmol/L sodium dodecyl sulfate and 27.5%-v/v acetonitrile as separation electrolyte. The separation voltage was -20 kV, UV-detection was at 200 nm, and the acidified concentrate was injected for 36 s at 1 bar (or 72% of the total capillary length, 60 cm). Both purified water and 10-fold diluted waste water exhibited a linear range of two orders of concentration magnitude. The coefficient of determination, and intra- and interday repeatability were 0.991-0.997, 2.5-6.2, and 4.4-9.7%RSD (n=6), respectively, for purified water. The values were 0.991-0.997, 3.4-7.1, and 8.7-9.8%RSD (n=6), correspondingly, for 10-fold diluted waste water. The method detection limit was in the range from 0.04-0.09 to 1.20-6.97 ng/mL for purified and undiluted waste water, respectively.

  13. Invertible micellar polymer assemblies for delivery of poorly water-soluble drugs.

    Hevus, Ivan; Modgil, Amit; Daniels, Justin; Kohut, Ananiy; Sun, Chengwen; Stafslien, Shane; Voronov, Andriy


    Strategically designed amphiphilic invertible polymers (AIPs) are capable of (i) self-assembling into invertible micellar assemblies (IMAs) in response to changes in polarity of environment, polymer concentration, and structure, (ii) accommodating (solubilizing) substances that are otherwise insoluble in water, and (iii) inverting their molecular conformation in response to changes in the polarity of the local environment. The unique ability of AIPs to invert the molecular conformation depending on the polarity of the environment can be a decisive factor in establishing the novel stimuli-responsive mechanism of solubilized drug release that is induced just in response to a change in the polarity of the environment. The IMA capability to solubilize lipophilic drugs and deliver and release the cargo molecules by conformational inversion of polymer macromolecules in response to a change of the polarity of the environment was demonstrated by loading IMA with a phytochemical drug, curcumin. It was demonstrated that four sets of micellar vehicles based on different AIPs were capable of delivering the curcumin from water to an organic medium (1-octanol) by means of unique mechanism: AIP conformational inversion in response to changing polarity from polar to nonpolar. The IMAs are shown to be nontoxic against human cells up to a concentration of 10 mg/L. On the other hand, the curcumin-loaded IMAs are cytotoxic to breast carcinoma cells at this concentration, which confirms the potential of IMA-based vehicles in controlled delivery of poorly water-soluble drug candidates and release by means of this novel stimuli-responsive mechanism.

  14. Binding of chloroquine to ionic micelles: Effect of pH and micellar surface charge

    Souza Santos, Marcela de, E-mail: [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Perpétua Freire de Morais Del Lama, Maria, E-mail: [Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Avenida do Café, s/n, Ribeirão Preto, São Paulo 14040-903 (Brazil); Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Departamento de Química Analítica, Universidade Estadual de Campinas, Cidade Universitária Zeferino Vaz, s/n, Campinas, São Paulo 13083-970 (Brazil); Siuiti Ito, Amando, E-mail: [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo 14040-901 (Brazil); and others


    The pharmacological action of chloroquine relies on its ability to cross biological membranes in order to accumulate inside lysosomes. The present work aimed at understanding the basis for the interaction between different chloroquine species and ionic micelles of opposite charges, the latter used as a simple membrane model. The sensitivity of absorbance and fluorescence of chloroquine to changes in its local environment was used to probe its interaction with cetyltrimethylammonium micelles presenting bromide (CTAB) and sulfate (CTAS) as counterions, in addition to dodecyl sulfate micelles bearing sodium (SDS) and tetramethylammonium (TMADS) counterions. Counterion exchange was shown to have little effect on drug–micelle interaction. Chloroquine first dissociation constant (pKa{sub 1}) shifted to opposite directions when anionic and cationic micelles were compared. Chloroquine binding constants (K{sub b}) revealed that electrostatic forces mediate charged drug–micelle association, whereas hydrophobic interactions allowed neutral chloroquine to associate with anionic and cationic micelles. Fluorescence quenching studies indicated that monoprotonated chloroquine is inserted deeper into the micelle surface of anionic micelles than its neutral form, the latter being less exposed to the aqueous phase when associated with cationic over anionic assemblies. The findings provide further evidence that chloroquine–micelle interaction is driven by a tight interplay between the drug form and the micellar surface charge, which can have a major effect on the drug biological activity. -- Highlights: • Chloroquine (CQ) pKa{sub 1} increased for SDS micelles and decreased for CTAB micelles. • CQ is solubilized to the surface of both CTAB and SDS micelles. • Monoprotonated CQ is buried deeper into SDS micelles than neutral CQ. • Neutral CQ is less exposed to aqueous phase in CTAB over SDS micelles. • Local pH and micellar surface charge mediate interaction of CQ with

  15. A Fashion Show


    <正>Story: The yearly fashion show day.The children take turns to walk on the stage and show the class their favorite clothes.Now it’s Joe’s and Phoebe’s turn.Joe walks on the stage and says,“My shorts are blue.Do you like my blue shorts?”On the other side of the stage, Phoebe is wearing her favorite pink skirt.“My skirt is pink.Do you like my pink skirt?”asks

  16. The heat-chill method for preparation of self-assembled amphiphilic poly(ε-caprolactone)-poly(ethylene glycol) block copolymer based micellar nanoparticles for drug delivery.

    Payyappilly, Sanal Sebastian; Dhara, Santanu; Chattopadhyay, Santanu


    A new method is developed for preparation of amphiphilic block copolymer micellar nanoparticles and investigated as a delivery system for celecoxib, a hydrophobic model drug. Biodegradable block copolymers of poly(ethylene glycol) (PEG) and poly(ε-caprolactone) (PCL) were synthesized by ring opening copolymerization and characterized thoroughly using FTIR, (1)H NMR and GPC. The block copolymer was dispersed in distilled water at 60 °C and then it was chilled in an ice bath for the preparation of the micellar nanoparticles. Polymers self-assembled to form micellar nanoparticles (HR-TEM, DLS and DSC. The cytotoxicity of the polymer micellar nanoparticles was investigated against HaCaT cell lines. The study of celecoxib release from the micellar nanoparticles was carried out to assess their suitability as a drug delivery vehicle. Addition of the drug to the system at low temperature is an added advantage of this method compared to the other temperature assisted nanoparticle preparation techniques. In a nutshell, polymer micellar nanoparticles prepared using the heat-chill method are believed to be promising for the controlled drug release system of labile drugs, which degrade in toxic organic solvents and at higher temperatures.

  17. On not showing scalps

    Marselis, Randi Lorenz


    proposed by Janet Marstine, the editor of the Routledge Companion to Museum Ethics, I show how the museum succeeded in engaging users in questions of museum ethics. However, this specific debate on human remains in museums developed into an encounter between a global, museological discourse...

  18. Violence and TV Shows

    ÖZTÜRK, Yrd. Doç. Dr. Şinasi


    This study aims to discuss theories on theviolent effects of TV shows on viewers, especiallyon children. Therefore, this study includes a briefdiscussion of definitions of violence, discussionof violence theories, main results of researcheson televised violence, measuring TV violence,perception of televised violence, individualdifferences and reactions to TV violence,aggressiveness and preferences for TV violence.

  19. Honored Teacher Shows Commitment.

    Ratte, Kathy


    Part of the acceptance speech of the 1985 National Council for the Social Studies Teacher of the Year, this article describes the censorship experience of this honored social studies teacher. The incident involved the showing of a videotape version of the feature film entitled "The Seduction of Joe Tynan." (JDH)

  20. A Visionary Show


    Seduction. Distinction. Relax. Pulsation. These are the "style universes" on display at Première Vision, heralded as "The World’s Premiere Fabric Show." Started more than 35 years ago by 15 French weavers, Première Vision has expanded beyond its

  1. Honored Teacher Shows Commitment.

    Ratte, Kathy


    Part of the acceptance speech of the 1985 National Council for the Social Studies Teacher of the Year, this article describes the censorship experience of this honored social studies teacher. The incident involved the showing of a videotape version of the feature film entitled "The Seduction of Joe Tynan." (JDH)

  2. Shanghai Shows Its Heart


    The city known as China’s economic powerhouse showed a more caring face as host of the Special Olympic Games Between October 2 and 11,the Special Olympics Summer Games were hosted in Shanghai,the first time the 40-year-old athletic com- petition for people with intellectual disabilities came to a developing country. This Special Olympics was also larger than all previous games in temps of the number of athletes.

  3. Pilot scale production process of micellar casein concentrate powder%酪蛋白胶束粉的陶瓷膜分离生产工艺

    陈建行; 刘鹭; 孙颜君; 苏燕玲; 张书文; 孔凡丕; 蒋士龙; 吕加平


    manufacturing in China’s dairy plants. Preliminary studies involved the selection of a suitable hollow fiber ceramic membrane for the separation of casein micellar and serum protein between 100 nm and 40 nm pore size hollow fiber ceramic membranes (InoCep, Hyflux Ltd, Singapore). The 40nm pore size hollow fiber ceramic membrane, which had better separation performance, was chosen for further investigation on optimum operating parameters, mainly temperature and pressure. A four-stage diafiltration process was employed, in which chemical composition and flux changes were measured at the end of every stage in the production line. Finally, the micellar casein concentrate powder made after evaporation and spray drying process was compared with commercial MCC (Proteinco Inc., Quebec, Canada) in terms of their physical characteristics and chemical compositions. The yield rate and the production costs were also calculated. The results showed that:(1) the permeate of 100 nm pore size membrane was cloudy but the permeate of 40 nm pore size membrane was clear in appearance and the proportion of casein in the true protein of the permeate for the 100 and 40 nm pore size membrane were 40.03%and 17.48%, respectively. Therefore, the 40nm pore size membrane was found to be more suitable for the separation of casein micellar and serum protein and its average permeate flux during a 3×concentration at the optimal operating conditions (temperature 50℃, pressure 2×105 Pa) was above 60 L/(m2·h);(2) the best time for adding water during the whole diafiltration process was when the volume concentration factor was equal to 3, which reduced membrane fouling and enhanced average stage flux. After four stages of the continuous diafiltration process, the casein micellar purity and the pure protein content (on a dry basis) reached 93.34%and 88.15%, respectively;(3) at the end of the diafiltration process, the water flux declined by 39.98%, and when a biological-enzyme cleaning agent was used, water

  4. Not a "reality" show.

    Wrong, Terence; Baumgart, Erica


    The authors of the preceding articles raise legitimate questions about patient and staff rights and the unintended consequences of allowing ABC News to film inside teaching hospitals. We explain why we regard their fears as baseless and not supported by what we heard from individuals portrayed in the filming, our decade-long experience making medical documentaries, and the full un-aired context of the scenes shown in the broadcast. The authors don't and can't know what conversations we had, what documents we reviewed, and what protections we put in place in each televised scene. Finally, we hope to correct several misleading examples cited by the authors as well as their offhand mischaracterization of our program as a "reality" show.

  5. Spectroscopic Behavior of Some A3B Type Tetrapyrrolic Complexes in Several Organic Solvents and Micellar Media

    Radu Socoteanu


    Full Text Available The paper presents spectral studies of some unsymmetrical A3B tetrapyrrolic, porphyrin-type complexes with Cu(II and Zn(II in different solvents and micellar media aimed at estimating their properties in connection with the living cell. The results indicate that the position of the absorption and emission peaks is mostly influenced by the central metal ion and less by the environmental polarity or the peripheric substituents of the porphyrinic core. The comparison between the overall absorption and emission spectra of the compounds in methanol or cyclohexane vs. direct and reverse Triton X micellar systems, respectively, suggests for all compounds the localization at the interface between the polyethylene oxide chains and the tert-octyl-phenyl etheric residue of the Triton X-100 molecules. These findings could be important when testing the compounds embedded in liposomes or other delivery systems to the targeted cell.

  6. Enantiomeric Separation of Epinephrine and Salbutamol by Micellar Electrokinetic Chromatography Using β-Cyclodextrin as Chiral Additive

    ZHENG,Yan-Peng(郑妍鹏); MO,Jin-Yuan(莫金垣)


    Enantiomeric separations of epinephrine and salbutamol, by means of micellar electrokinetic chromatography (MEKC) employing β-cyclodextrin as chiral additive in ammonium chloride-ammonia solution were investigated.In this system, the analytes migrated with the micellar phase towards the anode and were detected by electrochemistry using gold microelectrode at +0.65 V vs. SCE. The success of the chiral separations is strongly dependent on the concentration of β-CD and SDS, and the optimal concentration is 8 mmol·L-1 and 15 mmol·L-1 respectively.The effects of detection potential, pH value of electrolyte and applied voltage were discussed also. Using the proposed method, baseline separation of the enantiomers could be accomplished in 6 min. Further, an attempt was made to elucidate the plausible mechanism of the chiral recognition.

  7. Can affinity interactions influence the partitioning of glucose-6-phosphate dehydrogenase in two-phase aqueous micellar systems?

    André M. Lopes


    Full Text Available In this work, we provide an investigation of the role and strength of affinity interactions on the partitioning of the glucose-6-phosphate dehydrogenase in aqueous two-phase micellar systems. These systems are constituted of micellar surfactant solutions and offer both hydrophobic and hydrophilic environments, providing selectivity to biomolecules. We studied G6PD partitioning in systems composed of the nonionic surfactants, separately, in the presence and absence of affinity ligands. We observed that G6PD partitions to the micelle-poor phase, owing to the strength of excluded-volume interactions in these systems that drive the protein to the micelle-poor phase, where there is more free volume available.

  8. Showing Value (Editorial

    Denise Koufogiannakis


    Full Text Available When Su Cleyle and I first decided to start Evidence Based Library and Information Practice, one of the things we agreed upon immediately was that the journal be open access. We knew that a major obstacle to librarians using the research literature was that they did not have access to the research literature. Although Su and I are both academic librarians who can access a wide variety of library and information literature from our institutions, we belong to a profession where not everyone has equal access to the research in our field. Without such access to our own body of literature, how can we ever hope for practitioners to use research evidence in their decision making? It would have been contradictory to the principles of evidence based library and information practice to do otherwise.One of the specific groups we thought could use such an open access venue for discovering research literature was school librarians. School librarians are often isolated and lacking access to the research literature that may help them prove to stakeholders the importance of their libraries and their role within schools. Certainly, school libraries have been in decline and the use of evidence to show value is needed. As Ken Haycock noted in his 2003 report, The Crisis in Canada’s School Libraries: The Case for Reform and Reinvestment, “Across the country, teacher-librarians are losing their jobs or being reassigned. Collections are becoming depleted owing to budget cuts. Some principals believe that in the age of the Internet and the classroom workstation, the school library is an artifact” (9. Within this context, school librarians are looking to our research literature for evidence of the impact that school library programs have on learning outcomes and student success. They are integrating that evidence into their practice, and reflecting upon what can be improved locally. They are focusing on students and showing the impact of school libraries and

  9. Enantiomeric Separation of Epinephrine and Salbutamol by Micellar Electrokinetic Chromatography Using β-Cyclodextrin as Chiral Additive

    Yan Peng ZHENG; Jin Yuan MO


    Enantiomeric separation of epinephrine and salbutamol was investigated by micellar electrokinetic chromatography employing β-cyclodextrin as chiral additive in ammonium chloride-ammonia solution. The analytes were detected by electrochemistry using gold microelectrode at +0.65 V versus SCE reference electrode. The effects of detection potential,concentration of β-cyclodextrin, concentration of sodium dodecyl sulfate, pH value of electrolyte and applied voltage were discussed.

  10. Public medical shows.

    Walusinski, Olivier


    In the second half of the 19th century, Jean-Martin Charcot (1825-1893) became famous for the quality of his teaching and his innovative neurological discoveries, bringing many French and foreign students to Paris. A hunger for recognition, together with progressive and anticlerical ideals, led Charcot to invite writers, journalists, and politicians to his lessons, during which he presented the results of his work on hysteria. These events became public performances, for which physicians and patients were transformed into actors. Major newspapers ran accounts of these consultations, more like theatrical shows in some respects. The resultant enthusiasm prompted other physicians in Paris and throughout France to try and imitate them. We will compare the form and substance of Charcot's lessons with those given by Jules-Bernard Luys (1828-1897), Victor Dumontpallier (1826-1899), Ambroise-Auguste Liébault (1823-1904), Hippolyte Bernheim (1840-1919), Joseph Grasset (1849-1918), and Albert Pitres (1848-1928). We will also note their impact on contemporary cinema and theatre.

  11. The Great Cometary Show


    its high spatial and spectral resolution, it was possible to zoom into the very heart of this very massive star. In this innermost region, the observations are dominated by the extremely dense stellar wind that totally obscures the underlying central star. The AMBER observations show that this dense stellar wind is not spherically symmetric, but exhibits a clearly elongated structure. Overall, the AMBER observations confirm that the extremely high mass loss of Eta Carinae's massive central star is non-spherical and much stronger along the poles than in the equatorial plane. This is in agreement with theoretical models that predict such an enhanced polar mass-loss in the case of rapidly rotating stars. ESO PR Photo 06c/07 ESO PR Photo 06c/07 RS Ophiuchi in Outburst Several papers from this special feature focus on the later stages in a star's life. One looks at the binary system Gamma 2 Velorum, which contains the closest example of a star known as a Wolf-Rayet. A single AMBER observation allowed the astronomers to separate the spectra of the two components, offering new insights in the modeling of Wolf-Rayet stars, but made it also possible to measure the separation between the two stars. This led to a new determination of the distance of the system, showing that previous estimates were incorrect. The observations also revealed information on the region where the winds from the two stars collide. The famous binary system RS Ophiuchi, an example of a recurrent nova, was observed just 5 days after it was discovered to be in outburst on 12 February 2006, an event that has been expected for 21 years. AMBER was able to detect the extension of the expanding nova emission. These observations show a complex geometry and kinematics, far from the simple interpretation of a spherical fireball in extension. AMBER has detected a high velocity jet probably perpendicular to the orbital plane of the binary system, and allowed a precise and careful study of the wind and the shockwave

  12. Thermodynamics of sodium dodecyl sulphate-salicylic acid based micellar systems and their potential use in fruits postharvest.

    Cid, A; Morales, J; Mejuto, J C; Briz-Cid, N; Rial-Otero, R; Simal-Gándara, J


    Micellar systems have excellent food applications due to their capability to solubilise a large range of hydrophilic and hydrophobic substances. In this work, the mixed micelle formation between the ionic surfactant sodium dodecyl sulphate (SDS) and the phenolic acid salicylic acid have been studied at several temperatures in aqueous solution. The critical micelle concentration and the micellization degree were determined by conductometric techniques and the experimental data used to calculate several useful thermodynamic parameters, like standard free energy, enthalpy and entropy of micelle formation. Salicylic acid helps the micellization of SDS, both by increasing the additive concentration at a constant temperature and by increasing temperature at a constant concentration of additive. The formation of micelles of SDS in the presence of salicylic acid was a thermodynamically spontaneous process, and is also entropically controlled. Salicylic acid plays the role of a stabilizer, and gives a pathway to control the three-dimensional water matrix structure. The driving force of the micellization process is provided by the hydrophobic interactions. The isostructural temperature was found to be 307.5 K for the mixed micellar system. This article explores the use of SDS-salicylic acid based micellar systems for their potential use in fruits postharvest.

  13. Impact of selected wastewater constituents on the removal of sulfonamide antibiotics via ultrafiltration and micellar enhanced ultrafiltration.

    Exall, Kirsten; Balakrishnan, Vimal K; Toito, John; McFadyen, Renée


    To better understand the environmental mobility of sulfonamide antibiotics and develop improved processes for their removal during wastewater treatment, stirred cell ultrafiltration (UF) experiments were conducted using both synthetic and real wastewater effluent. The interactions between selected sulfonamides (sulfaguanidine, sulfathiazole and sulfamerazine), solids and dissolved organic matter were systematically explored. The further impact of micellar enhanced ultrafiltration (MEUF), a process in which surfactants are added at micellar concentrations to enhance removal of various trace contaminants from aqueous streams, was then explored by using a cationic surfactant, cetyltrimethylammonium bromide (CTAB). Ultrafiltration of sulfonamides in the absence of other materials generally removed only 15-20% of the antibiotics. The presence of micellar solutions of CTAB generally improved removal of sulfonamides over UF alone, with rejections ranging from 20 to 74%. Environmental solids (sediment) further increased retention of sulfonamides using both UF and MEUF, but the presence of DOM did not influence rejection. Similar trends were observed on UF and MEUF of real effluent samples that had been spiked with the sulfonamides, confirming the environmental relevance of the observed interactions between sulfonamides, surfactant, and wastewater constituents. The results demonstrate that MEUF processes can be designed for the selective removal of such trace contaminants as sulfonamide antibiotics.

  14. Separation and analysis of cis-diol-containing compounds by boronate affinity-assisted micellar electrokinetic chromatography.

    Wang, Heye; Lü, Chenchen; Li, Hengye; Chen, Yang; Zhou, Min; Ouyang, Jian; Liu, Zhen


    Cis-diol-containing compounds (CDCCs) are usually highly hydrophilic compounds and are therefore difficult to separate by conventional reversed-phase-based micellar electrokinetic chromatography (MEKC) due to poor selectivity. Here, we report a new method, called boronate affinity-assisted micellar electrokinetic chromatography (BAA-MEKC), to solve this issue. A boronic acid with a hydrophobic alkyl chain was added to the background electrolyte, which acted as a modifier to adjust the selectivity. CDCCs can covalently react with the boronic acid to form negatively charged surfactant-like complexes, which can partition into micelles formed with a cationic surfactant. Thus, CDCCs can be separated according to the differential partition constants of their boronic acid complexes between the micellar phase and the surrounding aqueous phase. To verify this method, eight nucleosides were employed as the test compounds and their separation confirmed that the combination of boronate affinity interaction with MEKC can effectively enhance the separation of CDCCs. The effects of experimental conditions on the separation were investigated. Finally, the BAA-MEKC method was applied to the separation and analysis of nucleosides extracted from human urine. BAA-MEKC exhibited better selectivity and improved separation as compared with conventional MEKC and CZE. Successful quantitative analysis of urinary nucleosides by BAA-MEKC was demonstrated.

  15. Rapid ultrasonic and microwave-assisted micellar extraction of zingiberone, shogaol and gingerols from gingers using biosurfactants.

    Peng, Li-Qing; Cao, Jun; Du, Li-Jing; Zhang, Qi-Dong; Xu, Jing-Jing; Chen, Yu-Bo; Shi, Yu-Ting; Li, Rong-Rong


    Two kinds of extraction methods ultrasonic-assisted micellar extraction (UAME) and microwave-assisted micellar extraction (MAME) coupled with ultra-high performance liquid chromatography with ultraviolet detector (UHPLC-UV) were developed and evaluated for extraction and determination of zingerone, 6-gingerol, 8-gingerol, 6-shogaol and 10-gingerol in Rhizoma Zingiberis and Rhizoma Zingiberis Preparata. A biosurfactant, hyodeoxycholic acid sodium salt, was used in micellar extraction. Several experimental parameters were studied separately by a univariate method. The result indicated that the MAME was more efficient than UAME. The optimal conditions of MAME were as follows: 100mM of hyodeoxycholic acid sodium salt was used as surfactant, the irradiation time was set at 10s and the extraction temperature was set at 60°C. The validation results indicated that the limits of detection were in the range of 3.80-8.11ng/mL. The average recoveries were in the range of 87.32-103.12% for the two samples at two spiking levels. Compared with other reported methods, the proposed MAME-UHPLC-UV method was more effective, quicker (10s) and more eco-friendly. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Determination of the hydrolysis kinetics of alpha-naphthyl acetate in micellar systems and the effect of HPMC (catalyst present).

    Werawatganone, Pornpen; Wurster, Dale Eric


    The change in the hexadecyltrimethylammonium bromide (CTAB) critical aggregation concentration (CAC) was studied in the presence of various concentrations and grades of hydroxypropylmethyl cellulose (HPMC) using surface tension measurement (duNoüy ring and Wilhelmy plate) and oil red O solubilization. According to the surface tension methods, the CAC was higher than the CTAB critical micelle concentration (CMC). CAC and CMC were not different when the solubilization method was used. Micellar solutions of CTAB have been found to accelerate the hydrolysis of alpha-naphthyl acetate (alpha-NA) by o-iodosobenzoic acid (IBA), a strong nucleophile. Pseudo-first-order kinetics were utilized for rate constant determination. The observed rate constants for the degradation of alpha-NA in the presence of varying CTAB concentrations with and without HPMC were analyzed according to the pseudophase model. The micellar rate constants and the micellar binding constants for the substrates were obtained. The presence of HPMC retarded the reaction rate, and the rate constant decreased as the polymer concentration increased. However, there was no obvious difference in the observed rate constants among the different grades of HPMC (Methocel E5, Methocel E15, Methocel E50). The decrease in the rate constant was likely due to the polymer-micelle interaction interfering with substrate binding to the CTAB micelles.

  17. Production efficiency of micellar casein concentrate using polymeric spiral-wound microfiltration membranes.

    Beckman, S L; Zulewska, J; Newbold, M; Barbano, D M


    Most current research has focused on using ceramic microfiltration (MF) membranes for micellar casein concentrate production, but little research has focused on the use of polymeric spiral-wound (SW) MF membranes. A method for the production of a serum protein (SP)-reduced micellar casein concentrate using SW MF was compared with a ceramic MF membrane. Pasteurized (79°C, 18s) skim milk (1,100 kg) was microfiltered at 50°C [about 3 × concentration] using a 0.3-μm polyvinylidene fluoride spiral-wound membrane, bleed-and-feed, 3-stage process, using 2 diafiltration stages, where the retentate was diluted 1:2 with reverse osmosis water. Skim milk, permeate, and retentate were analyzed for SP content, and the reduction of SP from skim milk was determined. Theoretically, 68% of the SP content of skim milk can be removed using a single-stage 3× MF. If 2 subsequent water diafiltration stages are used, an additional 22% and 7% of the SP can be removed, respectively, giving a total SP removal of 97%. Removal of SP greater than 95% has been achieved using a 0.1-μm pore size ceramic uniform transmembrane pressure (UTP) MF membrane after a 3-stage MF with diafiltration process. One stage of MF plus 2 stages of diafiltration of 50°C skim milk using a polyvinylidene fluoride polymeric SW 0.3-μm membrane yielded a total SP reduction of only 70.3% (stages 1, 2, and 3: 38.6, 20.8, and 10.9%, respectively). The SP removal rate for the polymeric SW MF membrane was lower in all 3 stages of processing (stages 1, 2, and 3: 0.05, 0.04, and 0.03 kg/m(2) per hour, respectively) than that of the comparable ceramic UTP MF membrane (stages 1, 2, and 3: 0.30, 0.11, and 0.06 kg/m(2) per hour, respectively), indicating that SW MF is less efficient at removing SP from 50°C skim milk than the ceramic UTP system. To estimate the number of steps required for the SW system to reach 95% SP removal, the third-stage SP removal rate (27.4% of the starting material SP content) was used to

  18. Imidazolium-based ionic liquid-type surfactant as pseudostationary phase in micellar electrokinetic chromatography of highly hydrophilic urinary nucleosides.

    Rageh, Azza H; Pyell, Ute


    Ionic liquid (IL)-type surfactants have been shown to interact more strongly with polar compounds than traditionally used quaternary ammonium cationic surfactants. The aim of this study is to provide an alternative micellar electrokinetic chromatographic method (MEKC) for the analysis of urinary nucleosides in their ionic form at low surfactant concentration. This approach could overcome the use of high surfactant concentrations typically associated with the analysis of these highly hydrophilic metabolites as neutral species, which is frequently accompanied by high electric current, Joule heating and long analysis time. The investigated IL-type surfactant; 1-tetradecyl-3-methylimidazolium bromide (C14MImBr) is similar to the commonly employed cationic surfactant; tetradecyltrimethylammonium bromide (TTAB) but it provides a different separation selectivity. We employed C14MImBr micelles for the MEKC analysis of seven urinary nucleosides. The studied analytes possess a negative charge at pH 9.38 (exceptions are adenosine and cytidine which are neutral at this pH value). Borate imparts an additional negative charge to these compounds after complexation with the cis-diol functionality of the ribose unit, which in turn enables them to interact with the oppositely charged C14MImBr micelles via electrostatic (Coulomb) forces. The effect of the concentration of borate (the complexing, competing and buffering ion) on the effective electrophoretic mobilities and on the retention factors was investigated. The effective electrophoretic mobility data show that complexation between these nucleosides and borate occurs with high degree of complexation even at very low borate concentration (2.5 mmol L(-1) disodium tetraborate). In addition, we found that the retention factors are strongly dependent on the borate concentration being the highest when using the lowest borate concentration and they can be regulated by variation of either tetraborate concentration or the pH of the

  19. Micellar electrokinetic capillary chromatography determination of alginic acid in pharmaceutical formulations after treatment with alginate lyase and UV detection.

    Volpi, Nicola


    A new highly specific and sensitive capillary electrophoresis method (electrokinetic chromatography with SDS) for the determination of the total alginic acid (AA) content in pharmaceutical formulations is described by means of capillary electrophoresis at 230 nm after treatment with alginate lyase [] and separation of unsaturated products, Delta-oligomers (DeltaHexA-[HexA](n)), in particular, DP3 (DeltaHexA-HexA-HexA) and DP4 (DeltaHexA-HexA-HexA-HexA). Using a buffer constituted with 10 mM sodium borate and 50 mM SDS at pH 9.0, micellar electrokinetic capillary chromatography was able to determine with very high resolution the AA Delta-oligomers produced by the action of the lyase (mainly DP3 and DP4) as one single species. The intra- and inter-day variations (CV%) were between 6.3 and 9.1 for migration time and between 2.5 and 5.7 for peak area, respectively. The calibration curve showed good linearity for the examined concentration range (60-360 ng) with an average correlation coefficient greater than 0.980. The lowest detection limit and the lowest quantitation limit of the method were 15 ng (0.25 mg/mL) and 40 ng (0.67 mg/mL), respectively. The intra- and inter-day variations in terms of CV% were 5.5 and 8.6%, respectively, and the intra- and inter-day accuracy was estimated to range from 4.1 to 8.9%, while the percent recoveries of AA were calculated to be 102, 97 and 93% for different AA amounts. Variations in temperatures, voltage and buffer composition in comparison with adopted conditions within a 10% limit do not modify the electrophoresis results. The evaluation of AA was performed in both solid and liquid pharmaceutical formulations also in the presence of other ingredients, in particular, aluminium, sodium and potassium bicarbonate, and emulsifying and flavouring agents. The quantitative results obtained were 101.2+/-3.4% of AA content in tablets and 98.4+/-2.8% in liquid formulation, in total conformity with the label claims.

  20. Structural and phase transition changes of sodium dodecyl sulfate micellar solution in alcohols probed by small-angle neutron scattering (SANS)

    Putra, Edy Giri Rachman [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Patriati, Arum [Neutron Scattering Laboratory, National Nuclear Energy Agency of Indonesia (BATAN), Gedung 40 BATAN, Kawasan Puspiptek Serpong, Tangerang 15314 (Indonesia); Department of Chemistry, Faculty of Mathematics and Natural Sciences, University of Gadjah Mada, Bulaksumur, Yogyakarta 55281, Indonesia (Indonesia)


    Small-angle neutron scattering (SANS) measurements on 0.3M sodium dodecyl sulfate (SDS) micellar solutions have been performed in the presence of n-alcohols, from ethanol to decanol at different alcohol concentrations, 2–10 wt%. The ellipsoid micellar structure which occurred in the 0.3M SDS in aqueous solution with the size range of 30–50 Å has different behavior at various hydrocarbon chain length and concentration of alcohols. At low concentration and short chain-length of alcohols, such as ethanol, propanol, and butanol, the size of micelles reduced and had a spherical-like structure. The opposite effect occurred as medium to long chain alcohols, such as hexanol, octanol and decanol was added into the 0.3M SDS micellar solutions. The micelles structure changed to be more elongated in major axis and then crossed the critical phase transition from micellar solution into liquid crystal phase as lamellar structure emerged by further addition of alcohols. The inter-lamellar distances were also depending on the hydrocarbon chain length and concentration of alcohols. In the meantime, the persistent micellar structures occurred in addition of medium chain of n-alcohol, pentanol at all concentrations.

  1. Separation and determination of nimesulide related substances for quality control purposes by micellar electrokinetic chromatography.

    Zacharis, Constantinos K; Tzanavaras, Paraskevas D; Notou, Maria; Zotou, Anastasia; Themelis, Demetrius G


    A micellar electrokinetic chromatography (MEKC) method has been developed and validated for the determination of nimesulide related compounds in pharmaceutical formulations. Electrophoretic separation of six European Pharmacopoeia (EP) impurities (A-F) was performed using a fused silica capillary (L(eff.)=50 cm, L(tot.)=57 cm, 50 microm i.d.) with a background electrolyte (BGE) containing 25 mM borate buffer (pH 9.5), 30 mM sodium dodecyl sulphate and phi=3% (v/v) acetonitrile. The influence of several factors (surfactant and buffer concentration, pH, organic modifier, applied voltage, capillary temperature and injection time) was studied. The method was suitably validated with respect to linearity, limit of detection and quantification, accuracy, precision and selectivity. The calibration curves obtained for the six compounds were linear over the range 5-12 microgml(-1) (0.05-0.12%). The relative standard deviations (s(r)) of intra- and inter-day experiments were less than 5.0%. The detection limits ranged between 0.7 and 1.6 microgml(-1) depending on the impurity. The proposed method was applied successfully to the quantification of nimesulide impurities in its pharmaceutical formulation.

  2. Environmental monitoring of phenolic pollutants in water by cloud point extraction prior to micellar electrokinetic chromatography

    Stege, Patricia W.; Sombra, Lorena L.; Messina, German A.; Martinez, Luis D. [National University of San Luis, CONICET, INQUISAL, Department of Chemistry, San Luis (Argentina); Silva, Maria F. [Universidad Nacional de Cuyo, Departamento de Biomatematica y Fisicoquimica, Facultad de Ciencias Agrarias, Mendoza (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnologicas (CONICET), Buenos Aires (Argentina)


    Many aromatic compounds can be found in the environment as a result of anthropogenic activities and some of them are highly toxic. The need to determine low concentrations of pollutants requires analytical methods with high sensitivity, selectivity, and resolution for application to soil, sediment, water, and other environmental samples. Complex sample preparation involving analyte isolation and enrichment is generally necessary before the final analysis. The present paper outlines a novel, simple, low-cost, and environmentally friendly method for the simultaneous determination of p-nitrophenol (PNP), p-aminophenol (PAP), and hydroquinone (HQ) by micellar electrokinetic capillary chromatography after preconcentration by cloud point extraction. Enrichment factors of 180 to 200 were achieved. The limits of detection of the analytes for the preconcentration of 50-ml sample volume were 0.10{mu}g L{sup -1} for PNP, 0.20 {mu}g L{sup -1} for PAP, and 0.16{mu}g L{sup -1} for HQ. The optimized procedure was applied to the determination of phenolic pollutants in natural waters from San Luis, Argentina. (orig.)

  3. Determination of polymer log D distributions by micellar and microemulsion electrokinetic chromatography.

    Jin, Xiaoyun; Leclercq, Laurent; Cottet, Hervé


    The characterization of the hydrophobicity of polymer compounds in solution remains a challenging issue of importance, especially for biomedical or pharmaceutical applications. To our knowledge, there is no data of polymer hydrophobicity (log D) in the literature. In this work, for the first time, the log D distributions of cationic polymers were characterized using micellar or microemulsion electrokinetic chromatography at physiological pH. The log D distributions of the polymer samples were obtained from the electrophoretic/chromatographic retardation of the polymer derivatives in presence of neutral micelles (or neutral microemulsion), using small cationic molecules for calibration. Separating electrolytes were based on a TRIS–chloride buffer containing a neutral surfactant (polyoxyethyleneglycoldodecyl ether) for the formation of micelles (in water) or microemulsion (in water/n-pentanol mixture).The log D distributions obtained at pH 7.4 using this method were in good agreement with the chemical structures of cationic polypeptides: poly(lys, phe) 1:1 > poly(lys, tyr) 1:1 > poly(lys, trp) 4:1 > poly(lys, ser)3:1 > poly(l-lysine), where x:y represents the molar ratio of each amino acid in the copolymer. Weight average octanol–water log D values and the dispersion of the log D distribution were also defined and determined for each polymer sample.

  4. Micellar nanotubes dispersed electrokinetic chromatography for the simultaneous determination of antibiotics in bovine milk.

    Springer, Valeria H; Lista, Adriana G


    A method to determine four antibiotics for veterinary use (ciprofloxacin, enrofloxacin, florfenicol, and chloramphenicol) of different families (fluoroquinolones and amphenicols) in bovine milk was developed. The determination of the analytes was carried out using micellar electrokinetic capillary chromatography (MEKC) with a common sodium borate-SDS buffer solution containing single-walled carbon nanotubes (SWCNTs). In this way, a great improvement in the electrophoretic resolution and the separation efficiency was achieved compared to MEKC. An online reverse electrode polarity-stacking mode (REPSM) was carried out to enhance sensitivity. This step was performed in only 2 min and it allowed a stacked percentage of 103. That means that all the amount of injected analytes is effectively stacked. When this stacking procedure was combined with an off-line preconcentration step, based on SPE, analytes could be detected in lower concentration than the established maximum residue limits (MRLs). The LODs for the four compounds were between 6.8 and 13.8 μg L(-1) and the RSD values were between 1.1% and 6.6%. The whole method was applied to spiked real samples with acceptable precision and satisfactory recoveries.

  5. On the role of a coumarin derivative for sensing applications: Nucleotide identification using a micellar system.

    Bettoschi, Alexandre; Ceglie, Andrea; Lopez, Francesco; Meli, Valeria; Murgia, Sergio; Tamburro, Manuela; Caltagirone, Claudia; Cuomo, Francesca


    The recognition of nucleotides is of crucial importance because they are the basic constituents of nucleic acids. The present study is focused on the selective interaction between a novel amphiphilic fluorophore containing coumarin and imidazole, CI (1-methyl-3-(12-((2-oxo-2H-chromen-7-yl)oxy)dodecyl)-1H-imidazol-3-ium bromide), and different nucleotide-monophosphates (NMPs). It was supposed that the solubilization of the low water soluble CI in a micelle system of hexadecyltrimethylammonium chloride (CTAC) would make the coumarin moiety of CI available to the interaction with the water-soluble NMPs. Changes in CTAC critical micelle concentration suggested that CI strongly interacted with the host cationic surfactant, thus forming a positively charged interface enriched with coumarin able to interact with the anionic NMPs. Steady-state fluorescence quenching revealed that CI/CTAC system was capable of distinguish between purine- and pyrimidine-based nucleotides. A modified Stern-Volmer equation permitted the use of a quenching model that accounted for the possible interactions between the micelles and the nucleotides. The data analysis allowed calculating selective parameters that differentiated according to the type of nucleotide either at 25 or 50°C. Our results established the utility of the novel coumarin derivative fluorophore, supported by the simple and suitable micellar systems, as a tool for DNA sensing applications.


    Noor Rehman; Abbas Khan; Iram Bibi; Mohammad Siddiq


    The interactions of non-ionic amphiphilic diblock copolymer poly(oxyethylene/oxybutylene) (E39B18) with anionic surfactant sodium dodecyl sulphate (SDS) and cationic surfactant hexadecyltrimethylammonium bromide (CTAB) were studied by using various techniques such as surface tension,conductivity,steady-state fluorescence and dynamic light scattering.Surface tension measurements were used to determine the critical micelle concentration (CMC) and thereby the free energy of micellization (AGmic),free energy of adsorption (AGads),surface excess concentration (F) and minimum area per molecule (A).Conductivity measurements were used to determine the critical micelle concentration (CMC),critical aggregation concentration (CAC),polymer saturation point (PSP),degree of ionization (α) and counter ion binding (β).Dynamic light scattering experiments were performed to check the changes in physiochemical properties of the block copolymer micelles taken place due to the interactions of diblock copolymers with ionic surfactants.The ratio of the first and third vibronic peaks (I1/I13) indicated the polarity of the pyrene micro environment and was used for the detection of micelle as well as polymer-surfactant interactions.Aggregation number (N),number of binding sites (n) and free energy of binding (AGb) for pure surfactants as well as for polymer-surfactant mixed micellar systems were determined by the fluorescence quenching method.

  7. The usage of micellar extraction for analysis of fluvastatin in water and wastewater samples.

    Hryniewicka, Marta; Starczewska, Barbara


    This work illustrates the development of new procedures for the isolation and preconcentration of fluvastatin (FLU) from aqueous solutions. Micellar extraction (ME) combined with high performance liquid chromatography (HPLC-UV) has been successfully applied for this purpose. It was found that the analyte created micelle with anionic sodium dodecylsulfate (SDS) and/or with the binary mixture of surfactants nonionic triton X114 (TX114) and cationic tetra-n-butyloammonium bromide (TBAB). The optimal analytical conditions for the proposed extraction procedures (solution pH, concentration of surfactants, centrifugation time and electrolyte type) were ascertained. The calibration curves were recorded. The linearity ranges for FLU, isolated by SDS and the mixture of TX114/TBAB, were 0.21-28.79 μg mL(-1) and 0.21-16.45 μg mL(-1) with limit of detection (LOD) 0.19 μg mL(-1) and 0.14 μg mL(-1), respectively. The recoveries afforded by the proposed methods were high, approximately 97%. These preconcentration procedures were applied for the isolation of the statin from water and wastewater samples taken from the local rivers and wastewater treatment plants.

  8. Modeling transport effects of perfluorinated and hydrocarbon surfactants in groundwater by using micellar liquid chromatography

    Simmons, Rashad N. [Department of Chemistry and Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1322 (United States); McGuffin, Victoria L. [Department of Chemistry and Center for Integrative Toxicology, Michigan State University, East Lansing, MI 48824-1322 (United States)], E-mail:


    The effects of hydrocarbon and perfluorinated surfactants, above their critical micelle concentration (CMC), on the transport of neutral environmental pollutants are compared. Reversed-phase micellar liquid chromatography is used to model the groundwater system. The octadecylsilica stationary phase serves to simulate soil particles containing organic matter, whereas the aqueous surfactant mobile phases serve to simulate groundwater containing a surfactant at varying concentrations. Sodium dodecyl sulfate and lithium perfluorooctane sulfonate are used as representatives of the hydrocarbon and perfluorinated surfactants, respectively. Benzene, mono- and perhalogenated benzenes, and polycyclic aromatic hydrocarbons are used as models for environmental pollutants. Transport effects were elucidated from the retention factor, k, and the equilibrium constant per micelle, K{sub eq}, of the model pollutants in the individual surfactants. Based on k values, the transport of the model pollutants increased in both surfactant solutions in comparison to pure water. As the concentration of the surfactants increased, the transport of the pollutants increased as well. Notably, the K{sub eq} values of the pollutants in the perfluorinated surfactant were at least an order of magnitude less than those in the hydrocarbon surfactant. Overall, these results suggest that the presence of a perfluorinated surfactant, above its CMC, increases the transport of pollutants in a groundwater system. However, the perfluorinated surfactant exhibits a lesser transport effect than the hydrocarbon surfactant.

  9. Micellar electrokinetic chromatography method development for simultaneous determination of thiabendazole, carbendazim, and fuberidazole.

    Soliman, Laiel C; Donkor, Kingsley K


    Thiabendazole (TBz), carbendazim (CBz), and fuberidazole (FBz) are systemic benzimidazole-type fungicides used for pre- and post-harvest treatment to control various types of fungal diseases on a variety of crops. Significant levels of these fungicides could alter the composition or flavour of crops, and being possible carcinogens, they could also pose risks for humans and the environment. A mode of capillary electrophoresis called micellar electrokinetic chromatography (MEKC) was investigated for the determination of these three benzimidazole fungicides. The study involved two kinds of surfactants in which several experimental conditions were optimized, i.e., buffer concentration, pH, micelle concentration, and percent organic modifier (methanol). Using the optimum experimental conditions, the fungicides were successfully separated by MEKC. The limits of detection and quantification were in the range of 0.6-0.7 and 2.1-2.5 mg L(-1), respectively, and the calibration curves were linear over the range of 5-60 mg L(-1) for the three fungicides. The potential of the proposed MEKC method was demonstrated by analyzing water samples which were fortified with the fungicides. The proposed method enabled simultaneous determination of the three benzimidazole fungicides and method validation with spiked water samples yielded satisfactory quantitative recoveries for all the three fungicides.

  10. Determination of seven preservatives in cosmetic products by micellar electrokinetic chromatography.

    Huang, Jun-Qiang; Hu, Cho-Chun; Chiu, Tai-Chia


    A micellar electrokinetic chromatography method using cetyltrimethylammonium bromide (CTAB) as a cationic surfactant, coupled with UV-Vis detection, was developed for the simultaneous determination of seven preservatives, including methyl-, ethyl-, propyl- and butyl-paraben and phenol, phenoxyethanol and resorcinol. The method involved optimizing the pH of the phosphate buffer and concentrations of CTAB, ethanol and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD). The preservatives were well separated using optimum conditions and separated within 10 min at a separation voltage of -12.5 kV with the 1.0 mM phosphate buffer (pH 7.0) containing 90 mM CTAB, 25 mM HP-β-CD and 10% (v/v) ethanol. Satisfactory recoveries (84.1-103.0%), migration time (RSD < 3.1%) and peak area (RSD < 4.5%) repeatabilities were achieved. Detection limits of the preservatives were between 0.31 and 1.52 μg mL(-1) (S/N = 3, n = 5). The optimized method was successfully applied to the simultaneous determination of these preservatives in 10 commercial cosmetic products.

  11. Use of micellar liquid chromatography for rapid monitoring of fungicides post harvest applied to citrus wastewater.

    Peris-Vicente, Juan; Marzo-Mas, Ana; Roca-Genovés, Pasqual; Carda-Broch, Samuel; Esteve-Romero, Josep


    A method based on micellar liquid chromatography has been developed to simultaneously monitor four pesticides largely post-harvest applied to citrus: thiabendazole, pyrimethanil, o-phenylphenol and imazalil. Water samples were filtered and directly injected without other treatment, thus avoiding extraction steps. The composition of the mobile phase was optimized using a chemometrical approach to achieve and excellent resolution to 0.07 mol/L SDS/5%, V/V 1-pentanol buffered at pH3. Mobile phase run through a C18 column at 1 mL/min at room temperature. The detection was performing by UV-Visible absorbance using a wavelength program: 0-10 min, 305 nm (for thiabendazole); 10-12; 265 nm (for pyrimethanil) and 12-18, 220 nm (o-phenylphenol and imazalil). The developed method was validated following the guidelines of the US Environmental Protection Agency in terms of: quantitation range, (0.5-4 to 15 μg/mL), linearity (r(2)>0.9995), sensitivity (LOD, 0.18-1.4 μg/mL), precision (<9.2%), trueness (93.9%-103.7%), and ruggedness (<9.9%). It was found that the fungicides remain up to eight days in surface water at outdoor conditions. The method was used to screen the presence of the analytes in several waste water samples, and was proved to be useful in routine analysis.

  12. Sequential micellar electrokinetic chromatography analysis of racemization reaction of alanine enantiomers.

    Fu, Rao; Liu, Lina; Guo, Yingna; Guo, Liping; Yang, Li


    A novel method for online monitoring racemization reaction of alanine (Ala) enantiomers was developed, by combining sequential sample injection and micellar electrokinetic chromatography (MEKC) technique. Various conditions were investigated to optimize the sequential injection, Ala derivatization and MEKC chiral separation of d-/l-Ala. High reproducibility of the sequential MEKC analysis was demonstrated by analyzing the standard Ala samples, with relative standard deviation values (n=20) of 1.35%, 1.98%, and 1.09% for peak height, peak area and migration time, respectively. Ala racemization was automatically monitored every 40s from the beginning to the end of the reaction, by simultaneous detection of the consumption of the substrate enantiomer and the formation of the product enantiomer. The Michaelis constants of the racemization reaction were obtained by the sequential MEKC method, and were in good agreement with those obtained by traditional off-line enzyme assay. Our study indicated that the present sequential MEKC method can perform fast, efficient, accurate and reproducible analysis of racemization reaction of amino acids, which is of great importance for the determination of the activity of racemase and thus understanding its metabolic functions.

  13. Comparison of monolithic capillary electrochromatography and micellar electrokinetic chromatography for the separation of polycyclic aromatic hydrocarbons.

    Salwiński, Aleksander; Delépée, Raphaël


    Atmospheric pollution of anthropic origin is recognized as a major risk factor for health, in particular for respiratory and cardio-vascular systems. Among these pollutants, polycyclic aromatic hydrocarbons (PAHs) are placed on the list of US Environmental Protection Agency (EPA) as 'priority' pollutants and four of them are assigned as potential carcinogens by The International Agency for Research on Cancer (IARC). In the present work two capillary techniques-micellar electrokinetic chromatography (MEKC) and monolithic capillary electrochromatography (CEC)-were compared for the separation of eleven PAHs. Both techniques compared in the present work are fully compatible with every standard apparatus of capillary electrophoresis. For MEKC, enhancement of selectivity and decrease of the separation window of eleven PAHs were obtained with methanol:borate 25 mM (20/80, v/v) running buffer containing 10 mM of hydroxypropylated γ-cyclodextrins with low SDS content (25 mM). In case of CEC, two acrylate-based monolithic stationary phases (MSPs) were evaluated for their application in the separation of eleven PAHs. The best MSP based on butyl acrylate was compared with MEKC in terms of sample capacity, PAHs elution order, LOQ, efficiency and effect of pH. Influence of the hydrophobicity of mobile phase on the PAHs elution order was also studied.

  14. Headspace in-tube microextraction coupled with micellar electrokinetic chromatography of neutral aromatic compounds.

    Cho, Sung Min; Park, Bum Su; Jung, Woo Sung; Lee, Sang Won; Jung, Yunhwan; Chung, Doo Soo


    Headspace (HS) extraction can be carried out easily and aptly via single drop microextraction coupled with capillary electrophoresis (CE). However, one drawback is the difficulty of keeping the single drop stably at the capillary tip. To solve this problem, we have recently demonstrated HS in-tube microextraction (ITME) of acidic compounds such as chlrophenols in an acidic sample using a basic run buffer plug in the separation capillary for CE as an acceptor phase. In this report, an organic acceptor plug in a capillary was used to extract neutral organic volatile pollutants such as BTEX (benzene, toluene, ethylbenzene, and m-xylene). After extraction, the analytes enriched in the organic acceptor plug were analyzed with micellar electrokinetic chromatography (MEKC). The enrichment factors for BTEX in a standard solution were up to 350 under an optimal condition of 25°C for 20 min. As an application, BTEX spiked into bottled water were analyzed with HS-ITME-MEKC, and the enrichment factors for BTEX were up to 320. The limits of detections were 1-4 ppb, which are at least 200 times lower than the US Environmental Protection Agency guidelines for drinking water, except benzene. The entire procedure of HS-ITME-MEKC was carried out automatically using a commercial CE instrument.

  15. A Novel Micellar Electrokinetic Chromatographic Method for Separation of Metal-DDTC Complexes

    Arfana Mallah


    Full Text Available Micellar electrokinetic chromatography (MEKC was examined for the separation and determination of Mo(VI, Cr(VI, Ni(II, Pd(II, and Co(III as diethyl dithiocarbamate (DDTC chelates. The separation was achieved from fused silica capillary (52 cm × 75 m id with effective length 40 cm, background electrolyte (BGE borate buffer pH 9.1 (25 mM, CTAB 30% (100 mM, and 1% butanol in methanol (70 : 30 : 5 v/v/v with applied voltage of −10 kV using reverse polarity. The photodiode array detection was achieved at 225 nm. The linear calibration for each of the element was obtained within 0.16–10 g/mL with a limit of detection (LOD 0.005–0.0167 g/mL. The separation and determination was repeatable with relative standard deviation (RSD within 2.4–3.3% (=4 in terms of migration time and peak height/peak area. The method was applied for the determination of Mo(VI from potatoes and almond, Ni(II from hydrogenated vegetable oil, and Co(III from pharmaceutical preparations with RSD within 3.9%. The results obtained were checked by standard addition and rechecked by atomic absorption spectrometry.

  16. Stereospecific micellar electrokinetic chromatography assay of methionine sulfoxide reductase activity employing a multiple layer coated capillary.

    Zhu, Qingfu; El-Mergawy, Rabab G; Heinemann, Stefan H; Schönherr, Roland; Jáč, Pavel; Scriba, Gerhard K E


    A micellar electrokinetic chromatography method for the analysis of the l-methionine sulfoxide diastereomers employing a successive multiple ionic-polymer layer coated fused-silica capillary was developed and validated in order to investigate the stereospecificity of methionine sulfoxide reductases. The capillary coating consisted of a first layer of hexadimethrine and a second layer of dextran sulfate providing a stable strong cathodic EOF and consequently highly repeatable analyte migration times. The methionine sulfoxide diastereomers, methionine as product as well as β-alanine as internal standard were derivatized by dabsyl chloride and separated using a 35 mM sodium phosphate buffer, pH 8.0, containing 25 mM SDS as BGE and a separation voltage of 25 kV. The method was validated in the range of 0.15-2.0 mM with respect to linearity and precision. The LODs of the analytes ranged between 0.04 and 0.10 mM. The assay was subsequently applied to determine the stereospecificity of methionine sulfoxide reductases as well as the enzyme kinetics of human methionine sulfoxide reductase A. Monitoring the decrease of the l-methionine-(S)-sulfoxide Km = 411.8 ± 33.8 μM and Vmax = 307.5 ± 10.8 μM/min were determined.

  17. Micellar electrokinetic chromatography: a review of methodological and instrumental innovations focusing on practical aspects.

    Silva, Manuel


    This review article addresses recent methodological and instrumental innovations in MEKC with emphasis on practical aspects. Like its predecessors, this review is intended to provide an updated overview covering work on the most salient methodological contributions to enhancing sensitivity and resolution in MEKC-based determinations published over the past two years. The most widespread approaches to enhancing sensitivity, which include improving "classical" online sample concentration techniques, combinations of on- and off-line sample concentration protocols and recent developments are discussed, and so are modifications of existing MEKC systems with various micellar phases, the use of BGE additives (organic modifiers, chiral selectors, gold nanoparticles) and coated capillaries, and the implementation of 2D separations and chemometric methods to enhance resolution. Instrumental approaches such as MS and LIF are also discussed, and proposals for overcoming the problems typically encountered in directly coupling MEKC with MS, and the recent inception of quantum dots with a great potential for LIF detection in MEKC, are also dealt with. Finally, foreseeable developments on potential future directions are also expressed.

  18. Micellar and structural stability of nanoscale amphiphilic polymers: Implications for anti-atherosclerotic bioactivity.

    Zhang, Yingyue; Li, Qi; Welsh, William J; Moghe, Prabhas V; Uhrich, Kathryn E


    Atherosclerosis, a leading cause of mortality in developed countries, is characterized by the buildup of oxidized low-density lipoprotein (oxLDL) within the vascular intima, unregulated oxLDL uptake by macrophages, and ensuing formation of arterial plaque. Amphiphilic polymers (AMPs) comprised of a branched hydrophobic domain and a hydrophilic poly(ethylene glycol) (PEG) tail have shown promising anti-atherogenic effects through direct inhibition of oxLDL uptake by macrophages. In this study, five AMPs with controlled variations were evaluated for their micellar and structural stability in the presence of serum and lipase, respectively, to develop underlying structure-atheroprotective activity relations. In parallel, molecular dynamics simulations were performed to explore the AMP conformational preferences within an aqueous environment. Notably, AMPs with ether linkages between the hydrophobic arms and sugar backbones demonstrated enhanced degradation stability and storage stability, and also elicited enhanced anti-atherogenic bioactivity. Additionally, AMPs with increased hydrophobicity elicited increased atheroprotective bioactivity in the presence of serum. These studies provide key insights for designing more serum-stable polymeric micelles as prospective cardiovascular nanotherapies.

  19. Development and validation of micellar liquid chromatographic methods for the determination of antibiotics in different matrixes.

    Rambla-Alegre, Maria; Esteve-Romero, Josep; Carda-Broch, Samuel


    Antibiotics are the most important bioactive and chemotherapeutic compounds to be produced by microbiological synthesis, and they have proved their worth in a variety of fields, such as medicinal chemistry, agriculture, and the food industry. Interest in antibiotics has grown in parallel with an increasingly high degree of productivity in the field of analytical applications. Therefore, it is necessary to develop chromatographic procedures capable of determining various drugs simultaneously in the shortest possible time. Micellar liquid chromatography (MLC) is an RP-HPLC technique that offers advantages over conventional HPLC as far as sample preparation, selectivity, and versatility are concerned. Its main advantage is that samples can be injected directly into the chromatographic system with no previous preparation step. This paper mainly focuses on the results of the authors' own recent research and reports the chromatographic conditions for determination of various antibiotics (penicillins, quinolones, and sulfonamides) in different matrixes (pharmaceuticals, biological fluids, and food). The work of other authors on MLC-based antibiotic determination has been included.

  20. LPS removal from an E. coli fermentation broth using aqueous two-phase micellar system.

    Lopes, André M; Magalhães, Pérola O; Mazzola, Priscila G; Rangel-Yagui, Carlota O; de Carvalho, João C M; Penna, Thereza C V; Pessoa, Adalberto


    In biotechnology, endotoxin (LPS) removal from recombinant proteins is a critical and challenging step in the preparation of injectable therapeutics, as endotoxin is a natural component of bacterial expression systems widely used to manufacture therapeutic proteins. The viability of large-scale industrial production of recombinant biomolecules of pharmaceutical interest significantly depends on the separation and purification techniques used. The aim of this work was to evaluate the use of aqueous two-phase micellar system (ATPMS) for endotoxin removal from preparations containing recombinant proteins of pharmaceutical interest, such as green fluorescent protein (GFPuv). Partition assays were carried out initially using pure LPS, and afterwards in the presence of E. coli cell lysate. The ATPMS technology proved to be effective in GFPuv recovery, preferentially into the micelle-poor phase (K(GFPuv) 98.00%). Therefore, this system can be exploited as the first step for purification in biotechnology processes for removal of higher LPS concentrations. Copyright © 2010 American Institute of Chemical Engineers (AIChE).

  1. Analysis of carbofuran, carbosulfan, isoprocarb, 3-hydroxycarbofuran, and 3-ketocarbofuran by micellar electrokinetic chromatography.

    Hsu, Chien-Hua; Hu, Cho-Chun; Chiu, Tai-Chia


    We developed an analytical method for the detection and quantitation of five pesticides and some of their metabolites - 3-hydroxycarbofuran, 3-ketocarbofuran, carbofuran, carbosulfan, and isoprocarb - using micellar electrokinetic chromatography coupled with a UV-Vis detector. The optimum separation conditions were 20 mM phosphate buffer (pH 8.0) containing 15 mM sodium dodecyl sulfate. The detection wavelength was set at 200 nm and the applied voltage was 12.5 kV. Under these conditions, baseline separation of five pesticides was achieved in 15 min, and the detection limits (S/N = 3) of 3-hydroxycarbofuran, 3-ketocarbofuran, carbofuran, carbosulfan, and isoprocarb were 0.3, 0.3, 0.3, 4.0, and 0.3 μM, respectively. The linear ranges for 3-hydroxycarbofuran, 3-ketocarbofuran, carbofuran, and isoprocarb were between 1.0 and 50.0 μM and that for carbosulfan was between 10.0 and 100.0 μM, with R(2) larger than 0.995. When applied to the analysis of a carbofuran-spiked rice sample, this approach yielded results with excellent repeatability (3.3%, n = 5), reproducibility (4.5%, n = 5), separation efficiency (>2.1 × 10(4) theoretical plates), and recovery (95.5 ± 1.4%, n = 5).

  2. Analysis of reducing carbohydrates by reductive tryptamine derivatization prior to micellar electrokinetic capillary chromatography.

    Andersen, Keld E; Bjergegaard, Charlotte; Sørensen, Hilmer


    A micellar electrokinetic capillary chromatography method for determination of low molecular weight carbohydrates (dp 1-2) with an unbound carbonyl group as in aldoses or other reducing carbohydrates has been developed. Reductive amination of aldoses on the carbonyl group using tryptamine introduced a chromophor system to the carbohydrates enabling their sensitive UV detection at 220 nm and identification based on the indole group using diode array detection. Twelve carbohydrates including pentoses (d-ribose, l-arabinose, and d-xylose), hexoses (d-glucose, d-mannose, and d-galactose), deoxy sugars (l-rhamnose and l-fucose), uronic acids (d-glucuronic acid and d-galacturonic acid), and disaccharides (cellobiose and melibiose) are included in the study, using d-thyminose (2-deoxy-d-ribose) as the internal standard. Detection of all 12 carbohydrates is performed within 30 min. Linearity with correlation coefficients from 0.9864 to 0.9992 was found in the concentration range of 25-2500 micromol/L for all carbohydrates; the relative standard deviation on the migration times was between 0.27 and 0.80 min, and limits of quantification and limits of determination were in the picomole range.

  3. Quantitative analysis of synthetic dyes in lipstick by micellar electrokinetic capillary chromatography.

    Desiderio, C; Marra, C; Fanali, S


    The separation of synthetic dyes, used as color additives in cosmetics, by micellar electrokinetic capillary chromatography (MEKC) is described in this study. The separation of seven dyes, namely eosine, erythrosine, cyanosine, rhodamine B, orange II, chromotrope FB and tartrazine has been achieved in about 3 min in an untreated fused silica capillary containing as background electrolyte a 25 mM tetraborate/phosphate buffer, pH 8.0, and 30 mM sodium dodecyl sulfate. The electrophoretic method exhibits precision and relatively high sensitivity. A detection limit (LOD, signal/noise = 3) in the range of 5-7.5 X 10(-7) M of standard compounds was recorded. Intra-day repeatability of all the studied dye determinations (8 runs) gave the following results (limit values), % standard deviation: 0.24-1.54% for migration time, 0.99-1.24% for corrected peak areas, 0.99-1.24% for corrected peak area ratio (analyte/internal standard) and 1.56-2.74% for peak areas. The optimized method was successfully applied to the analysis of a lipstick sample where eosine and cyanosine were present.

  4. Micellar-enhanced ultrafiltration process (MEUF) for removing copper from synthetic wastewater containing ligands.

    Liu, Chuan-Kun; Li, Chi-Wang; Lin, Ching-Yu


    The effects of the type and concentration of ligands on the removal of Cu by micellar-enhanced ultrafiltration (MEUF) with the help of either anionic or cationic surfactants were investigated. The removal efficiency of copper by anionic surfactant-(SDS-) MEUF depends on the ligand-to-Cu ratio and the ligand-to-Cu complexation constant. At fixed ligand-to-Cu ratio, the Cu removal efficiency decreases in the order of citric acid>NTA>EDTA, which is the reverse order of Cu-ligand complexation constants for these ligands. Increasing SDS-ligand ratios from 12 to 60 at fixed ligand concentration did not improve copper removal efficiency. The cationic surfactant, CPC, enhances Cu removal efficiency in systems with condition of ligand-copper ratios higher than 1.0, where Cu removal is not very efficient using SDS-MEUF process. The Cu removal efficiency with CPC-MEUF depends on both the ligand-to-Cu ratio and the type of ligands.

  5. Kinetics and mechanism of the cutinase-catalyzed transesterification of oils in AOT reversed micellar system.

    Badenes, Sara M; Lemos, Francisco; Cabral, Joaquim M S


    The kinetics of the enzymatic transesterification between a mixture of triglycerides (oils) and methanol for biodiesel production in a bis(2-ethylhexyl) sodium sulfosuccinate (AOT)/isooctane reversed micellar system, using recombinant cutinase from Fusarium solani pisi as a catalyst, was investigated. In order to describe the results that were obtained, a mechanistic scheme was proposed, based on the literature and on the experimental data. This scheme includes the following reaction steps: the formation of the active enzyme-substrate complex, the addition of an alcohol molecule to the complex followed by the separation of a molecule of the fatty acid alkyl ester and a glycerol moiety, and release of the active enzyme. Enzyme inhibition and deactivation effects due to methanol and glycerol were incorporated in the model. This kinetic model was fitted to the concentration profiles of the fatty acid methyl esters (the components of biodiesel), tri-, di- and monoglycerides, obtained for a 24 h transesterification reaction performed in a stirred batch reactor under different reaction conditions of enzyme and initial substrates concentration.

  6. Quantitative analysis of flavonoids and phenolic acids in Arnica montana L. by micellar electrokinetic capillary chromatography.

    Ganzera, Markus; Egger, Christoph; Zidorn, Christian; Stuppner, Hermann


    Arnica montana preparations have been used in Europe for centuries to treat skin disorders. Among the biologically active ingredients in the flower heads of the plant are sequiterpenes, flavonoids and phenolic acids. For the simultaneous determination of compounds belonging to the latter two groups a micellar electrokinetic capillary chromatography (MEKC) method was developed and validated. By using an electrolyte solution containing 50 mM borax, 25 mM sodium dodecyl sulfate and 30% of acetonitrile the separation of seven flavonoids and four caffeic acid derivatives was feasible in less than 20 min. The optimized system was validated for repeatability (sigma(rel) or = 0.9996), and then successfully applied to assay several plant samples. In all of them the most dominant flavonoid was found to be quercetin 3-O-glucuronic acid, whereas 3,5-dicaffeoylquinic acid was the major phenolic acid; the total content of flavonoids and phenolic acids varied in the samples from 0.60 to 1.70%, and 1.03 to 2.24%, respectively.

  7. Holistic analysis of seven active ingredients by micellar electrokinetic chromatography from three medicinal herbs composing Shuanghuanglian.

    Zhou, Xian-Jing; Chen, Juan; Li, Ying-Dong; Jin, Ling; Shi, Yan-Ping


    A simple and reliable method has been developed with a new strategy named holistic analysis of multiple constituents to evaluate the quality of the well-known traditional Chinese medicine (TCM) Shuanghuanglian (SHL) oral liquid and soft capsule. Seven main constituents of the medicine, i.e., baicalein, baicalin, chlorogenic acid, wogonin, scutellarin, forsythin and hyperin, were selected as the evaluation markers and analyzed by micellar electrokinetic chromatography. The effects of buffer pH, concentration of electrolyte, organic modifier and applied voltage on migration behavior were studied systematically. The optimum conditions for the separation were achieved in a 12.5 mM borate-10 mM sodium dihydrogen phosphate-10 mM sodium dodecyl sulfate buffer at pH 9.1 containing 10% (v/v) acetonitrile under 15 kV. The analytes were identified by their relative time with regard to para-hydroxybenzoic acid migration time used as an internal standard. The method was validated in terms of linearity, limit of detection and quantification, precision, accuracy and recoveries. The correlation coefficient ranged from 0.9962 to 0.9992. The limits of detection (S/N = 3) were from 0.15 to 3.95 μg mL(-1). Recoveries of seven analytes in the SHL samples ranged from 89.00 to 103.04%. The proposed method was successfully applied for the quality control of complicated TCM SHL.

  8. Micellar-polymer for enhanced oil recovery for Upper Assam Basin

    B.M. Das


    Full Text Available One of the major enhanced oil recovery (EOR processes is chemical flooding especially for the depleted reservoirs. Chemical flooding involves injection of various chemicals like surfactant, alkali, polymer etc. to the aqueous media. Bhogpara and Nahorkatiya are two depleted reservoirs of upper Assam basin where chemical flooding can be done to recover the trapped oil that cannot be recovered by conventional flooding process. Micellar-polymer (MP flooding involves injection of micelle and polymer to the aqueous phase to reduce interfacial tension and polymer is added to control the mobility of the solution, which helps in increasing both displacement and volumetric sweep efficiency and thereby leads to enhanced oil recovery. This work represents the use of black liquor as micelle or surfactant that is a waste product of Nowgong Paper Mills, Jagiroad, Assam, which is more efficient than the synthetic surfactants. The present study examines the effect of MP flooding through the porous media of two depleted oil fields of upper Assam basin i.e. Bhogpara and Nahorkatiya for MP EOR. This work also compares the present MP flood with the earlier work done on surfactant (S flooding. It was experimentally determined that the MP flood is more efficient EOR process for Bhogpara and Nahorkatiya reservoirs. The study will pertain to the comprehensive interfacial tension (IFT study and the displacement mechanism in conventional core samples.

  9. Role of spacer lengths of gemini surfactants in the synthesis of silver nanorods in micellar media.

    Bhattacharya, Santanu; Biswas, Joydeep


    In this work, we have prepared Ag-nanorods using biscationic gemini surfactant micelles as the media by a seed-mediated wet synthesis method. Towards this end, we first synthesized Ag-nanoseeds of diameter ~7 nm stabilized by trisodium citrate (as the capping agent). Then these Ag-nanoseeds were used to synthesize Ag-nanorods of different aspect ratios. With decreasing Ag-nanoseed concentration, the aspect ratios of the Ag-nanorods stabilized by these gemini surfactants increased gradually. Various Ag-nanoseeds and Ag-nanospecies were characterized using UV-Vis spectroscopy (to know the surface plasmon bands), transmission electron microscopy (to find out their particle sizes and distribution), energy-dispersive X-ray spectroscopy and X-ray diffraction. When we used micelles derived from gemini surfactants of shorter spacer -(CH(2))(n)- (n = 2 or 4) to stabilize the Ag-nanorods, the λ(max) of the longitudinal band shifted more towards the blue region compared to that of the gemini surfactant micelles with a longer spacer -(CH(2))(n)- (n = 5, 12) at a given amount of the Ag-nanoseed solution. So, the growth of Ag-nanorods in the gemini micellar solutions depends on the spacer-chain length of gemini surfactants employed.

  10. Prostaglandin H synthase kinetics in the two-phase aqueous-micellar system.

    Ponomareva, Olga A; Trushkin, Nikita A; Filimonov, Ivan S; Krivoshey, Alexandr V; Barkhatov, Vladimir I; Mitrofanov, Sergey I; Vrzheshch, Petr V


    Reaction mixture for PGHS (prostaglandin-H-synthase) is a two-phase system including micellar hydrophobic phase and hydrophilic aqueous phase. Reagents added to the mixture are distributed between phases, thus concentrations of reagents dissolved in phases can differ significantly from their overall contents. Using dynamic light scattering we found that the hydrophobic phase produced by tween-20 consists of micelles, which radius (4-5nm) does not depend on either tween-20 overall content (0.1%-1% v/v) or arachidonic acid (AA) addition (10-1000μM) or PGHS addition (1μM). Tween-20 overall content changing from 0.1% to 2% v/v dramatically affected COX kinetic, but accounting AA distribution between phases allowed us to estimate "true" parameters, independent of the tween-20 overall content and the concentration of another substrate: KM(Ox) equals 9.8μM O2 in the aqueous phase or 0.0074bar in the gaseous phase, KM(AA) equals 5400μM AA in the phase of tween-20 micelles and 5400/PμM AA in the aqueous phase (P is the distribution ratio for the AA between the aqueous phase and the hydrophobic phase (P≫1000)). This approach allowed to evaluate PS, the distribution ratio for the AA between the hydrophobic phase and the PGHS active center (PS ~310). This coefficient indicates the AA selectivity toward the cyclooxygenase active center.

  11. Simultaneous determination of eleven preservatives in cosmetics by micellar electrokinetic chromatography.

    Wang, Ping; Ding, Xiaojing; Li, Yun; Yang, Yuanyuan


    A new method for the simultaneous quantitation of 11 preservatives-imidazolidinyl urea, benzyl alcohol, dehydroacetic acid, sorbic acid, phenoxyethanol, benzoic acid, salicylic acid, and four parabens (methyl, ethyl, propyl, and butyl)-in cosmetics by micellar electrokinetic capillary chromatography was established and validated. The separation was performed using an uncoated fused-silica capillary (50 pm id x 60.2 cm, effective length 50 cm) with a running buffer consisting of 15 mmol/L sodium tetraborate, 60 mmol/L boric acid, and 100 mmol/L sodium dodecyl sulfate. A 1:10 dilution of the running buffer was used as the sample buffer to extract the cosmetic samples. The key factors, such as the concentration and pH of the running and sample buffers, which influence quantitative analysis of the above 11 preservatives in cosmetic samples, were investigated in detail. The linear ranges of the calibration curves for imidazolidinyl urea and the other 10 preservatives were 50-1000 and 10-200 mg/L, respectively. The correlation coefficients of the standard curves were all higher than 0.999. The recoveries at the concentrations studied ranged from 93.0 to 102.7%. RSDs were all less than 5%. The new method with simple sample pretreatment met the needs for routine analysis of the 11 preservatives in cosmetics.

  12. Optimization of Micellar Electrokinetic Chromatography Method for the Simultaneous Determination of Seven Hydrophilic and Four Lipophilic Bioactive Components in Three Salvia Species.

    Cao, Jiliang; Hu, Ji; Wei, Jinchao; Li, Baocai; Zhang, Mi; Xiang, Cheng; Li, Peng


    A micellar electrokinetic chromatography (MEKC) method was developed for the simultaneous determination of seven hydrophilic phenolic acids and four lipophilic tanshinones in three Salvia species. In normal MEKC mode using SDS as surfactant, the investigated 11 compounds could not be well separated. Therefore, several buffer modifiers including β-cyclodextrins (β-CD), ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) and organic solvents have been added to the buffer solution to improve the separation selectivity. Under the optimized conditions (BGE, 15 mM sodium tetraborate with 10 mM SDS, 5 mM β-CD, 10 mM [bmim]BF4 and 15% ACN (v/v) as additives; buffer pH, 9.8; voltage, 20 kV; temperature, 25 °C), the 11 investigated analytes could achieve baseline separation in 34 min. The proposed MEKC was additionally validated by evaluating the linearity (R(2) ≥ 0.9965), LODs (0.27-1.39 μg·mL(-1)), and recovery (94.26%-105.17%), demonstrating this method was reproducible, accurate and reliable. Moreover, the contents of the 11 compounds in three Salvia species, including S. miltiorrhiza, S. przewalskii and S. castanea were analyzed. The result showed that the established MEKC method was simple and practical for the simultaneous determination of the hydrophilic and lipophilic bioactive components in Salvia species, which could be used to effectively evaluate the quality of these valued medicinal plants.

  13. Evaluation of the oxidative deoxyribonucleic acid damage biomarker 8-hydroxy-2'-deoxyguanosine in the urine of leukemic children by micellar electrokinetic capillary chromatography.

    Zhang, Pingping; Lian, Kaoqi; Wu, Xiaoli; Yao, Min; Lu, Xin; Kang, Weijun; Jiang, Lingling


    Determining the level of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), an oxidative DNA damage biomarker, is vital to the study of clinical pathogenesis and drug toxicity. The principal limitation of capillary electrophoresis (CE) with UV detection is its low sensitivity. To overcome this shortcoming, we developed a micellar electrokinetic capillary chromatography (MEKC) with solid-phase extraction (SPE) for urinary 8-OHdG analysis. The sensitivity of MEKC-UV was improved using a reasonable UV system, injection mode, and SPE. The parameters affecting MEKC and SPE were also optimized. The calibration curve was linear within the range from 1 to 500 μg L(-1). The limits of detection and quantification were 0.27 μg L(-1) and 0.82 μg L(-1), respectively. Interday and intraday precision were both <5.6%. The recovery of 8-OHdG in urine ranged from 94.5% to 103.2%. This method was used to measure urinary 8-OHdG from eight normal children, eight newly diagnosed leukemic children, and eight leukemic children undergoing chemotherapy. The results show that the proposed method can be used to assess oxidative stress in patients and the side effects of chemotherapeutic drugs by measuring urinary 8-OHdG.

  14. A micellar electrokinetic chromatography-mass spectrometry approach using in-capillary diastereomeric derivatization for fully automatized chiral analysis of amino acids.

    Moldovan, Radu-Cristian; Bodoki, Ede; Kacsó, Timea; Servais, Anne-Catherine; Crommen, Jacques; Oprean, Radu; Fillet, Marianne


    In the context of bioanalytical method development, process automatization is nowadays a necessity in order to save time, improve method reliability and reduce costs. For the first time, a fully automatized micellar electrokinetic chromatography-mass spectrometry (MEKC-MS) method with in-capillary derivatization was developed for the chiral analysis of d- and l-amino acids using (-)-1-(9-fluorenyl) ethyl chloroformate (FLEC) as labeling reagent. The derivatization procedure was optimized using an experimental design approach leading to the following conditions: sample and FLEC plugs in a 2:1 ratio (15s, 30mbar: 7.5s, 30mbar) followed by 15min of mixing using a voltage of 0.1kV. The formed diastereomers were then separated using a background electrolyte (BGE) consisting of 150mM ammonium perfluorooctanoate (APFO) (pH=9.5) and detected by mass spectrometry (MS). Complete chiral resolution was obtained for 8 amino acids, while partial separation was achieved for 6 other amino acid pairs. The method showed good reproducibility and linearity in the low micromolar concentration range. The applicability of the method to biological samples was tested by analyzing artificial cerebrospinal fluid (aCSF) samples.

  15. Monitoring the quality consistency of Fufang Danshen Pills using micellar electrokinetic chromatography fingerprint coupled with prediction of antioxidant activity and chemometrics.

    Ji, Zhengchao; Sun, Wanyang; Sun, Guoxiang; Zhang, Jin


    A fast micellar electrokinetic chromatography fingerprint method combined with quantification was developed and validated to evaluate the quality of Fufang Danshen Pills, a traditional Chinese Medicine, which has been used in the treatment of cardiovascular system diseases, in which the tetrahedron optimization method was first used to optimize the background electrolyte solution. Subsequently, the index of the fingerprint information amount of I was performed as an excellent objective indictor to investigate the experimental conditions. In addition, a systematical quantified fingerprint method was constructed for evaluating the quality consistency of 20 batches of test samples obtained from the same drug manufacturer. The fingerprint analysis combined with quantitative determination of two components showed that the quality consistency of the test samples was quite good within the same commercial brand. Furthermore, the partial least squares model analysis was used to explore the fingerprint-efficacy relationship between active components and antioxidant activity in vitro, which can be applied for the assessment of anti-oxidant activity of Fufang Danshen pills and provide valuable medicinal information for quality control. The result illustrated that the present study provided a reliable and reasonable method for monitoring the quality consistency of Fufang Danshen pills.

  16. Development and validation of a micellar high-performance liquid chromatographic method for determination of risedronate in raw material and in a pharmaceutical formulation: application to stability studies.

    Walash, Mohamed; Metwally, Mohamed; Eid, Manal; El-Shaheny, Rania


    A micellar HPLC method was developed for analysis of the antiosteoporosis drug risedronate. The analysis was carried out using a 250 x 4.6 mm id, 5 microm particle size C18 Waters Symmetry column. The mobile phase consisted of 0.02 M sodium dodecyl sulfate + 0.3% triethylamine + 10% n-propanol, prepared in 0.02 M orthophosphoric acid. The pH of the mobile phase was adjusted to pH 6.0, and it was pumped at a flow rate of 0.7 mL/min with UV detection at 262 nm. The method showed good linearity in the range of 2-80 microg/mL, with an LOD of 0.40 microg/mL (1.31 x 10(-6) M) and an LOQ of 1.21 microg/mL. The suggested method was successfully applied for the analysis of risedronate in raw material and a tablet formulation, with average recoveries of 99.91 +/- 1.30 and 101.52 +/- 0.30%, respectively. The stability-indicating capability of the proposed method was proved using forced degradation. By changing the pH of the mobile phase to 4.0, the oxidative degradation product could be separated from risedronate.

  17. Application of Surfactant Micellar Solutions as Extractants and Mobile Phases for TLC-Determination of Purine Bases and Doping Agents in Biological Liquids

    Daria Victorovna Yedamenko


    Full Text Available Separation of caffeine and its metabolites (theophylline and theobromine and doping agents (spironolactone, propranolol, and ephedrine and determination of caffeine in serum sample and propranolol and ephedrine in urine were studied on normal-phase thin layers (“Sorbfil-UV-254”. Aqueous organic solvents and aqueous micellar surfactant solutions were compared as the mobile phases for separation. The acceptable separation of purine bases and doping agents was achieved by micellar Thin Layer Chromatography and normal-phase Thin Layer Chromatography. Anionic surfactant solution with added 1-propanol was the best eluent as for caffeine, theophylline, and theobromine separation, as for doping agents. The best characteristics of caffeine extraction from serum, and propranolol and ephedrine from urine were achieved when micellar eluent based on non-ionic Tween-80 surfactant was used. DOI:

  18. Factors that influence the membrane area of a multistage microfiltration process required to produce a micellar casein concentrate.

    Hurt, Emily E; Barbano, David M


    The objective of the work reported in this paper was to develop a theoretical model to determine the effect of type of microfiltration (MF)-process feed, number of stages, and flux on the minimization of the MF membrane area required to produce a 95% serum protein-reduced micellar casein concentrate. The MF feed, number of stages, and flux were all factors that had an effect on the MF membrane area and should be taken into consideration when designing a MF system to produce a 95% serum protein-reduced micellar casein concentrate. Feeding the MF process with a diluted ultrafiltration retentate (DUR) diluted to the protein concentration of skim milk, as opposed to skim milk, reduced the required membrane area by 36% for a 5-stage process. When DUR was the MF feed, feed protein concentration, which depended on the number of MF stages, was optimized. The DUR protein concentration that minimized the required MF membrane area was 2.47, 3.85, 4.77, and 5.41% for a 2-, 3-, 4-, or 5-stage MF process, respectively. For a 5-stage process, increasing the protein concentration of the feed from 3.2 to 5.4% decreased the required MF membrane area by 10%. It was also found that as the number of stages increased from 2 to 5, the required MF membrane area decreased by 39%, when the MF feed was DUR at the optimal feed protein concentration. Finally, increasing the flux from 50 to 60 kg/m(2) per hour decreased the required MF membrane area by 17% when the MF feed was DUR at the optimal MF feed protein concentration. Overall, using DUR as a feed for MF could reduce the amount of MF membrane area required to make a 95% serum protein-reduced micellar casein concentrate.

  19. A simple spectrophotometric method for the determination of trace level lead in biological samples in the presence of aqueous micellar solutions

    Khan, Humaira; Ahmed, M. Jamaluddin; Bhanger, M. Iqbal


    A very simple, ultra-sensitive and fairly selective new spectrophotometric method has been developed for the rapid determination of lead(II) at ultra-trace level using 1,5-diphenylthiocarbazone (dithizone) in presence of aqueous micellar solutions. The proposed method enabled the determination of lead down to µg l−1 in human blood and urine in aqueous media without resource of any “clean-up” step. The most remarkable point of this method is that the presence of micellar system avoids the prev...

  20. Fast relaxation of a hexagonal Poiseuille shear-induced near-surface phase in a threadlike micellar solution.

    Hamilton, W A; Butler, P D; Magid, L J; Han, Z; Slawecki, T M


    The dynamics of near-surface conformations in complex fluids under flow should dramatically affect their rheological properties. We have made the first measurements resolving the decay kinetics of a hexagonal phase induced in a threadlike polyionic micellar system under Poiseuille shear near a quartz surface. Upon cessation of shearing flow, this minimum interference crystalline phase formed within approximately 20 microm of the surface "melts" to a metastable two-dimensional liquid of aligned micelles in approximately 0.7 s. This is some three orders of magnitude shorter than the time required for bulk (Couette) shear-aligned micelles in this system to reach a fully entangled state.

  1. Determination of ephedrine and codeine in human urine by cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography

    Li Jun Li; Si Guang Li; Hai Yan Li; Zhuo Cai; Hao Cheng


    A sensitive method for the determination of ephedrine and codeine in human urine by capillary electrophoresis (CE) was described. In order to improve the sensitivity, two online concentration techniques including cation-selective exhaustive injection (CSEI) and sweeping micellar electrokinetic chromatography (sweeping-MEKC) were used. Under the optimum conditions, the detection limits (S/N = 3) were 0.10 μg/L for ephedrine and 0.80 μg/L for codeine. This method was successfully applied to real urine sample analysis.

  2. 微波辅助胶团提取甘草中的甘草酸和甘草甙%Microwave-assisted Micellar Extraction and Determination of Glycyrrhizic Acid and Liquiritin in Licorice Root by HPLC

    孙晨; 谢渝春; 刘会洲


    The feasibility of employing non-ionic surfactant (Triton X-100) as an alternative and effective solvent for the microwave-assisted extraction of glycyrrhizic acid (GA) and liquiritin (LQ) from licorice root was studied.The optimal extraction parameters based on the microwave-assisted micellar extraction technique were determined.Under the optimal conditions, i.e. 5% (by volume) Triton X-100, microwave-assisted extraction for 3-5min at 373K, the percentage extraction of active ingredients reached the highest value. The preconcentration factor for GA and LQ (about 13.5) and the extraction efficiency for these two ingredients approached 100% showed the coupling of microwave-assisted extraction and cloud-point extraction could be employed as a new and effective technique for the rapid extraction and preconcentration of pharmacologically active ingredients from medicinal plants such as licorice root without disturbing chromatographic analysis.

  3. Stability-indicating micellar electrokinetic chromatography method for the analysis of sumatriptan succinate in pharmaceutical formulations.

    Al Azzam, Khaldun M; Saad, Bahruddin; Tat, Chai Yuan; Mat, Ishak; Aboul-Enein, Hassan Y


    A micellar electrokinetic chromatography method for the determination of sumatriptan succinate in pharmaceutical formulations was developed. The effects of several factors such as pH, surfactant and buffer concentration, applied voltage, capillary temperature, and injection time were investigated. Separation took about 5 min using phenobarbital as internal standard. The separation was carried out in reversed polarity mode at 20 °C, 26 kV and using hydrodynamic injection for 10s. Separation was achieved using a bare fused-silica capillary 50 μm×40 cm and background electrolyte of 25 mM sodium dihydrogen phosphate-adjusted with concentrated phosphoric acid to pH 2.2, containing 125 mM sodium dodecyl sulfate and detection was at 226 nm. The method was validated with respect to linearity, limits of detection and quantification, accuracy, precision and selectivity. The calibration curve was linear over the range of 100-2000 μg mL(-1). The relative standard deviations of intra-day and inter-day precision for migration time, peak area, corrected peak area, ratio of corrected peak area and ratio of peak area were less than 0.68, 3.48, 3.28, 2.97 and 2.83% and 2.01, 5.50, 4.46, 4.92 and 4.07%, respectively. The proposed method was successfully applied to the determinations of the analyte in tablet. Forced degradation studies were conducted by introducing a sample of sumatriptan succinate standard solution to different forced degradation conditions using neutral (water), basic (0.1 M NaOH), acidic (0.1 M HCl), oxidative (10% H(2)O(2)) and photolytic (exposure to UV light at 254 nm for 2 h). It is concluded that the stability-indicating method for sumatriptan succinate can be used for the analysis of the drug in various samples.

  4. Determination of diuron, terbuthylazine, and terbutryn in wastewater and soil by micellar liquid chromatography.

    Pitarch-Andrés, Susana; Roca-Genovés, Pasqual; Peris-Vicente, Juan; Esteve-Romero, Josep


    An analytical method for the quantification of the herbicides and algaecides diuron, terbuthylazine, and terbutryn in wastewater and soil by micellar liquid chromatography was developed. The sample preparation was expedited to reduce the number of intermediate steps and the use of chemicals. The analytes in soils were recovered by ultrasonication in the mobile phase. The obtained supernatant and the water samples were directly injected, thus avoiding intermediate steps. The chromatographic behavior of the analytes, depending on the surfactant and alcohol was studied, in order to optimize the chromatographic run, by a chemometrical approach. The herbicides were resolved in <16 min using a C18 column and a mobile phase of 0.07 M sodium dodecyl sulfate/6% 1-pentanol phosphate buffered at pH 3, running under isocratic mode at 1 mL/min. The detection absorbance wavelength was set to 240 nm. The method was successfully validated in terms of selectivity, detection limit (0.06 mg/L in water and 0.3 mg/kg in soil), quantitation range (0.2-2 mg/L in water and 1-10 mg/kg in soil), trueness (-6.1 to +5.0%), precision (<9.4%), and ruggedness (<8.3%). The procedure was reliable, practical, easy-to-handle, available, short-time and ecofriendly and useful for routine analysis. Its applicability to real samples was evaluated by analyzing several wastewater, decorative reservoir, and soil samples from agricultural and urban sources.

  5. On structural transitions in a discontinuous micellar cubic phase loaded with sodium diclofenac.

    Efrat, R; Aserin, A; Garti, N


    An intermediate mesophase of lyotropic liquid crystalline structure from the ternary mixtures of glycerol monooleate, water, and ethanol was recently characterized in our lab. This mesophase, termed Q(L), consists of discrete discontinuous micelles arranged in a cubic array. The Q(L) phase can solubilize very significant loads of water-insoluble anti-inflamatory drug sodium diclofenac (Na-DFC). Close examination of the internal structures of the lyotropic liquid structure upon increasing the solubilization loads reveals the existence of three structural transitions controlled by the Na-DFC levels. Up to 0.4 wt% Na-DFC, the Q(L) structure remains intact with some influence on the hydration of the headgroups and on the intermicellar forces. However, at 0.8 to 1.2 wt% Na-DFC, the discontinuous micellar cubic phase is transformed into a more condensed mesophase of a bicontinuous cubic phase. At > or =1.2 wt% Na-DFC, the cubic phase is converted into a lamellar phase (L(alpha)). Within 5.5 to 7.3 wt% Na-DFC the mesophase is progressively transformed into a less ordered lamellar structure. At 12 wt% Na-DFC crystals tend to precipitate out. At low Na-DFC concentrations the drug behaves like a lyotropic or kosmotropic salt and can salt-out the surfactant from its water layer, but at higher levels it behaves like a hydrotropic, chaotropic salt and can salt-in the surfactant. The Na-DFC location and position within the interface as well as its polarization and partial ionization are strongly affected by its solubilization contents and the structure that it is inducing. In the cubic phase the drug is located less close to the hydration layer while once transition occurs it is exposed more to the water layer and the surfactant headgroups.

  6. Separation of selected imidazole enantiomers using dual cyclodextrin system in micellar electrokinetic chromatography.

    Wan Ibrahim, Wan Aini; Abd Wahib, Siti Munirah; Hermawan, Dadan; Sanagi, Mohd Marsin; Aboul-Enein, Hassan Y


    Cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC) method was developed for simultaneous enantioseparation of three imidazole drugs namely tioconazole, isoconazole and fenticonazole. Three easily available and inexpensive cyclodextrins namely 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), 2-hydroxypropyl-γ-cyclodextrin (HP-γ-CD) and heptakis(2,6-di-O-methyl)-β-cyclodextrin (DM-β-CD) were evaluated to discriminate the six stereoisomers of the drugs. However, none of the three CDs gave a complete enantioseparation of the drugs. Effective enantioseparation of tioconazole, isoconazole and fenticonazole was achieved using a combination of 35 mM HP-γ-CD and 10 mM DM-β-CD as chiral selectors. The best separation using both HP-γ-CD and DM-β-CD (35 mM:10 mM) as chiral selectors were accomplished in background electrolyte (BGE) containing 35 mM phosphate buffer (pH 7.0), 50 mM sodium dodecyl sulfate (SDS) and 15% (v/v) acetonitrile at 27 kV and 30 °C with all peaks resolved in less than 15 min with resolutions, Rs 1.90-27.22 and peak efficiencies, N > 180 000. The developed method was linear over the concentration range of 25-200 mg l(-1) (r(2) > 0.998) and the detection limits (S/N = 3) of the three imidazole drugs were found to be 2.7-7.7 mg l(-1). The CD-MEKC method was successfully applied to the determination of the three imidazole drugs in spiked human urine sample and commercial cream formulation of tioconazole and isoconazole with good recovery (93.6-106.2%) and good RSDs ranging from 2.30-6.8%.

  7. Enthalpy of interaction and binding isotherms of non-ionic surfactants onto micellar amphiphilic polymers (amphipols).

    Diab, C; Winnik, F M; Tribet, C


    The interactions in water between short amphiphilic macromomolecules, known as amphipols, and three neutral surfactants (detergents), dodecylmaltoside (DM), n-octylthioglucoside (OTG), and n-octyltetraethyleneoxide (C8E4), have been assessed by static and dynamic light-scattering (SLS and DLS), capillary electrophoresis (CE), and isothermal titration calorimetry (ITC). The amphipols selected are random copolymers of the hydrophobic n-octylacrylamide (25-30 mol %), a charged hydrophilic monomer, either acrylic acid ( approximately 35 mol %) or a phosphorylcholine-modified acrylamide (40-70 mol %), and, optionally, N-isopropylacrylamide (30-40 mol %). In water, the copolymers form micelles of small size (hydrodynamic radius: approximately 5 nm). Neutral surfactants, below their critical micellar concentration (cmc), form mixed micelles with the amphipols irrespective of the chemical structure of the detergent or the polymer. The fraction of detergent in the surfactant/polymer complexes increases significantly (cooperatively) as the surfactant concentration nears the cmc. The ITC data, together with data gathered by CE, were fitted via a regular mixing model, which allowed us to predict the detergent concentration in equilibrium with complexes and the heat evolved upon transfer of detergent from water into a mixed surfactant/polymer complex. The enthalpy of transfer was found to be almost equal to the enthalpy of micellization, and the regular mixing model points to a near-ideal mixing behavior for all systems. Amphipols are promising tools in biochemistry where they are used, together with neutral surfactants, for the stabilization and handling of proteins. This study provides guidelines for the optimization of current protein purification protocols and for the formulations of surfactant/polymer systems used in pharmaceutics, cosmetics, and foodstuffs.

  8. Micellar liquid chromatographic determination of arbutin and hydroquinone in medicinal plant extracts and commercial cosmetic products.

    Thogchai, W; Liawruangrath, B


    A simple micellar liquid chromatographic (MLC) procedure for simultaneous determination of arbutin and hydroquinone in medicinal plant extracts and commercial cosmetic products was proposed. This method was developed and validated. The chromatographic conditions were also optimized. All analyses were performed at room temperature in an isocratic mode, using a mixture of 1% (v/v) acetonitrile and 0.006 mol L⁻¹ Brij 35 (pH 6.0) as a mobile phase. The flow rate was set at 1.0 mL min⁻¹. The analytical column was a 150 × 3.9 mm Nova-Pak C-18 column. The effluent from the analytical column was monitored by UV detection at 280 nm. Under the optimum conditions, arbutin and hydroquinone could be determined within a concentration range of 2-50 μg mL⁻¹ of arbutin, and hydroquinone was obtained with the regression equations; y = 0.045x + 0.042 (r² = 0.9923) and y = 0.091x + 0.050 (r² = 0.9930) respectively. The limits of detection were found to be 0.51 μg mL⁻¹ and 0.37 μg mL⁻¹ for arbutin and hydroquinone respectively. The proposed MLC method was applied for the determination of arbutin and hydroquinone contents in medicinal plant extracts and commercial cosmetic products. This proposed MLC method is thus suitable for routine analysis of arbutin and hydroquinone in the pharmaceutical formulations, cosmetic products and raw medicinal plant extracts.

  9. Micellar aggregates of saponins from Chenopodium quinoa: characterization by dynamic light scattering and transmission electron microscopy.

    Verza, S G; de Resende, P E; Kaiser, S; Quirici, L; Teixeira, H F; Gosmann, G; Ferreira, F; Ortega, G G


    Entire seeds of Chenopodium quinoa Willd are a rich protein source and are also well-known for their high saponin content. Due to their amphiphily quinoa saponins are able to form intricate micellar aggregates in aqueous media. In this paper we study the aggregates formed by self-association of these compounds from two quinoa saponin fractions (FQ70 and FQ90) as well as several distinctive nanostructures obtained after their complexation with different ratios of cholesterol (CHOL) and phosphatidylcholine (PC). The FQ70 and FQ90 fractions were obtained by reversed-phase preparative chromatography. The structural features of their resulting aggregates were determined by Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Novel nanosized spherical vesicles formed by self-association with mean diameter about 100-200 nm were observed in FQ70 aqueous solutions whereas worm-like micelles an approximate width of 20 nm were detected in FQ90 aqueous solutions. Under experimental conditions similar to those reported for the preparation of Quillaja saponaria ISCOM matrices, tubular and ring-like micelles arose from FQ70:CHOL:PC and FQ90:CHOL:PC formulations, respectively. However, under these conditions no cage-like ISCOM matrices were observed. The saponin composition of FQ70 and FQ90 seems to determine the nanosized structures viewed by TEM. Phytolaccagenic acid, predominant in FQ70 and FQ90 fractions, is accountable for the formation of the nanosized vesicles and tubular structures observed by TEM in the aqueous solutions of both samples. Conversely, ring-like micelles observed in FQ90:CHOL:PC complexes can be attributed to the presence of less polar saponins present in FQ90, in particular those derived from oleanolic acid.

  10. Simultaneous determination of paracetamol, caffeine and propyphenazone in ternary mixtures by micellar electrokinetic capillary chromatography.

    Emre, Deniz; Ozaltin, Nuran


    A new micellar electrokinetic capillary chromatographic method has been developed to analyze the pharmaceutical preparations containing ternary combination of paracetamol (PAR), caffeine (CAF) and propyphenazone (PRO). Best results were obtained by using 20mM pH 9.0 borate buffer containing 30mM sodiumdodecylsulphate as the background electrolyte. Diflunisal (DIF) was used as internal standard (IS). The separation was performed through a fused silica capillary (50microm internal diameter, 44cm total length, 35.5cm effective length) at 25 degrees C with the application of 3s of hydrodynamic injection at 50mbar pressure and a potential of 29kV. Detection wavelength was 200nm. Under these conditions, the migration times were found to be 5.174min for PAR, 5.513min for CAF, 7.195min for DIF, and 9.366min for PRO. Linearity ranges for the method were determined as 2-200microgmL(-1) for PAR and CAF and 3-200microgmL(-1) for PRO. Limit of detections were found as 0.6microgmL(-1) for PAR and CAF and 0.8microgmL(-1) for PRO. According to the validation study, the developed method was proved to be accurate, precise, sensitive, specific, rugged and robust. Three pharmaceutical preparations, which are produced by different drug companies in Turkey, were analyzed by the developed method. One of the same preparations was also analyzed by the derivative ratio spectro zero-crossing spectrophotometric method reported in literature. No significant differences were found statistically.

  11. Predicting drug penetration across the blood-brain barrier: comparison of micellar liquid chromatography and immobilized artificial membrane liquid chromatography.

    De Vrieze, Mike; Lynen, Frédéric; Chen, Kai; Szucs, Roman; Sandra, Pat


    Several in vitro methods have been tested for their ability to predict drug penetration across the blood-brain barrier (BBB) into the central nervous system (CNS). In this article, the performance of a variety of micellar liquid chromatographic (MLC) methods and immobilized artificial membrane (IAM) liquid chromatographic approaches were compared for a set of 45 solutes. MLC measurements were performed on a C18 column with sodium dodecyl sulfate (SDS), polyoxyethylene (23) lauryl ether (Brij35), or sodium deoxycholate (SDC) as surfactant in the micellar mobile phase. IAM liquid chromatography measurements were performed with Dulbecco's phosphate-buffered saline (DPBS) and methanol as organic modifier in the mobile phase. The corresponding retention and computed descriptor data for each solute were used for construction of models to predict transport across the blood-brain barrier (log BB). All data were correlated with experimental log BB values and the relative performance of the models was studied. SDS-based models proved most suitable for prediction of log BB values, followed closely by a simplified IAM method, in which it could be observed that extrapolation of retention data to 0% modifier in the mobile phase was unnecessary.

  12. [Separation of cefoperazone and its S-isomer and other related substances by micellar electrokinetic capillary chromatography].

    Zhang, Huiwen; Hu, Changqin; Xu, Mingzhe; Li, Yaping; Hang, Taijun


    The separation of cefoperazone, its S-isomer, impurity A and other unknown related substances by micellar electrokinetic capillary chromatography (MECC) using sodium dodecyl sulphate (SDS) as the micellar phase was investigated. The effects of pH, concentration of phosphate buffer solution, SDS micelle concentration, methanol volume fraction, applied voltage and temperature on the separation were studied. It was found that the migration of these compounds was affected by these factors, especially by pH of the solution. The elution, as well as the migration time and separation efficiency of cefoperazone, its S-isomer, impurity A and other related substances changed with the acidity of the solution. The optimized separation conditions consisted of a running buffer of 70 mmol/L sodium phosphate buffer, at pH 6.5, containing 100 mmol/L SDS, with an applied voltage of 15 kV and a temperature of 25 degrees C. An uncoated fused-silica capillary of 51.0 cm x 75 microm (42.5 cm of effective length) was used. The sample was injected into the column by pressure (5 kPa) for 5 s. The detection wavelength was set at 254 nm. Twenty-eight impurities in cefoperazone sodium could be detected. Cefoperazone sodium and the degradation products could be separated well. The method was applied to separate and determine cefoperazone and its related substances successfully.

  13. Effect of high pressure--low temperature treatments on structural characteristics of whey proteins and micellar caseins.

    Baier, Daniel; Purschke, Benedict; Schmitt, Christophe; Rawel, Harshadrai M; Knorr, Dietrich


    In this study, structural changes in micellar caseins and whey proteins due to high pressure--low temperature treatments (HPLT) were investigated and compared to changes caused by high pressure treatments at room temperature. Whey protein isolate (WPI) solutions as well as micellar casein (MC) dispersions and mixtures were treated at 500 MPa (pH 7.0 and 5.8) at room temperature, -15 °C and -35 °C. Surface hydrophobicity and accessible thiol groups remained nearly unchanged after HPLT treatments whereas HP treatments at room temperature caused an unfolding of the WPI, resulting in an increase in surface hydrophobicity and exposure of the thiol groups. For HPLT treatments, distinct changes in the secondary structure (increase in the amount of β-sheets) were observed while the tertiary structure remained unchanged. Large flocs, stabilized by hydrophobic interactions and hydrogen bonds, were formed in casein containing samples due to HPLT treatments. Depending on the pH and the applied HPLT treatment parameters, these interactions differed significantly from the interactions determined in native micelles.

  14. Micellar effect on the kinetics of oxidation of methyl blue by Ce(IV in sulfuric acid medium

    Mohammed Hassan


    Full Text Available The kinetics of oxidation of methyl blue (MB by Ce(IV in aqueous and surfactant media has been carried out to explore the micellar effect on the rate and kinetic parameters of the reaction. The reaction was found to be first order with respect to both oxidant and substrate and fractional order with respect to H+. The active kinetic species of the oxidant was found to be Ce(SO4+2 based on the effect of ionic strength and sulfate ion on the rate of the reaction. The presence of micelles was found to inhibit the reaction and this effect has been explained by the association of one of the reactants with the micelles leaving the other reactant in the bulk solution. The binding constant and first order rate constant in micellar medium has been obtained by the application of pseudo-phase model to the experimental data. Interestingly, the temperature dependence of the reaction reveals that the reaction has negative activation energy in the absence of micelles, which turns to a positive value in the presence of micelles.

  15. Complexation of Cu(II) by original tartaric acid-based ligands in nonionic micellar media: thermodynamic study and applications.

    Dupont-Leclercq, Laurence; Giroux, Sébastien; Parant, Stéphane; Khoudour, Leïla; Henry, Bernard; Rubini, Patrice


    The complexation of Cu(II) with original alkylamidotartaric acids (C(x)T) is investigated in homogeneous aqueous medium and in the presence of nonionic micelles of Brij 58 (C16EO20), thanks to various analytical techniques such as NMR self-diffusion experiments, CD and UV-vis spectroscopy, ESI mass spectrometry, pHmetry and micellar-enhanced ultrafiltration (MEUF). First, a complete speciation study proves the formation of dimeric complexes in water and provides their formation constants. Second, a similar study is led in the presence of nonionic micelles. It underlines a modification of the apparent equilibrium constants in micellar medium and demonstrates that the structure of the complexes is slightly modified in the presence of micelles. This thermodynamic and structural study is applied to modelize the evolution of the extraction yields of Cu(II) by the micelles as a function of pH and to identify the complexes extracted in the micelles. The effects of the chain length of the ligand (C3T vs C8T) on the solubilization properties are put into relief and discussed. Anionic species are proved to be more incorporated in the nonionic micelles than the cationic species. The extracting system constituted of octylamidotartaric acid (CsT) solubilized in nonionic micelles of Brij 58 is demonstrated to be very efficient for the extraction of Cu(II) by MEUF, this technique being an interesting green alternative to traditional solvent extraction.

  16. Commercial scale demonstration enhanced oil recovery by micellar-polymer flood. Annual report, October 1979-September 1980

    Howell, J.C.; Snyder, W.O.


    This commercial scale test, known as the M-1 Project, is located in Crawford County, Illinois. It encompasses 407 acres of Robinson sand reservoir and covers portions of several waterflood projects that were approaching economic limit. The project includes 248 acres developed on a 2.4-acre five-spot pattern and 159 acres developed on a 5.0-acre five-spot pattern. Development work commenced in late 1974 and has previously been reported. Micellar solution (slug) injection was initiated on February 10, 1977, and is now completed. After 10% of a pore volume of micellar slug was injected, injection of 11% pore volume of Dow 700 Pusher polymer was conducted at a concentration of 1156 ppM. At the end of this reporting period, 625 ppM polymer was being injected into the 2.5-acre pattern and 800 ppM polymer was being injected into the 5.0-acre pattern. The oil cut of the 2.5 and 5.0-acre patterns increased from 8.6% and 5.2%, respectively in September 1979, to 11.0% and 5.9% in September 1980. The oil cut performance has consistently exceeded that predicted for the project. This Fourth Annual Report is organized under the following three Work Breakdown Structures: fluid injection; production; and performance monitoring.

  17. Supramolecular micellar nanoaggregates based on a novel chitosan/vitamin E succinate copolymer for paclitaxel selective delivery

    Lian H


    experiments, conducted by confocal laser scanning microscopy, showed an enhanced cellular uptake efficiency of the CS-VES micelles in MCF-7 cells compared with Taxol. The PTX-micelles exhibited a comparable but delayed cytotoxic effect compared with Taxol against MCF-7 cells, due to the sustained-release characteristics of the nanomicelles. More interestingly, blank nanomicelles based on CS-VES copolymer demonstrated significant cytotoxicity against MCF-7 cells.Conclusion: The supramolecular micellar aggregates based on CS-VES copolymer is a promising nanocarrier and efficacy enhancer when used as an anticancer drug-delivery system.Keywords: nanomicelles, cellular uptake, cytotoxicity

  18. Rheological Properties of Hydrophobically Associative Copolymers Prepared in a Mixed Micellar Method Based on Methacryloxyethyl-dimethyl Cetyl Ammonium Chloride as Surfmer

    Rui Liu


    Full Text Available A novel cationic surfmer, methacryloxyethyl-dimethyl cetyl ammonium chloride (DMDCC, is synthesized. The micellar properties, including critical micelle concentration and aggregation number, of DMDCC-SDS mixed micelle system are studied using conductivity measurement and a steady-state fluorescence technique. A series of water-soluble associative copolymers with acrylamide and DMDCC are prepared using the mixed micellar polymerization. Compared to conventional micellar polymerization, this new method could not only reasonably adjust the length of the hydrophobic microblock, that is, NH, but also sharply reduce the amount of surfactant. Their rheological properties related to hydrophobic microblock and stickers are studied by the combination of steady flow and linear viscoelasticity experiments. The results indicate that both the hydrophobic content and, especially the length of the hydrophobic microblock are the dominating factors effecting the intermolecular hydrophobic association. The presence of salt influences the dynamics of copolymers, resulting in the variation of solution characters. Viscosity measurement indicates that mixed micelles between the copolymer chain and SDS molecules serving as junction bridges for transitional network remarkably enhance the viscosity. Moreover, the microscopic structures of copolymers at different experimental conditions are conducted by ESEM. This method gives us an insight into the preparation of hydrophobically associative water-soluble copolymers by cationic surfmer-anionic surfactant mixed micellar polymerization with good performance.

  19. Protolytic properties and complexation of DL-alpha-alanine and DL-alpha-valine and their dipeptides in aqueous and micellar solutions of surfactants

    Chernyshova, O. S.; Boychenko, Oleksandr; Abdulrahman, H.; Loginova, L. P.


    In this work we investigated the effect of the micellar media of anionic (sodium dodecylsulfate, SDS), cationic (cetylpiridinium chloride, CPC) and non-ionic (Brij-35) surfactants on the protolytic properties of amino acids DL-alpha-alanine, DL-alpha-valine and dipeptides L-alpha-alanyl-L-alpha-alan

  20. Monitoring of cefepime in human serum and plasma by micellar electrokinetic capillary chromatography: Improvement of sample preparation and validation by liquid chromatography coupled to mass spectrometry.

    Šestáková, Nela; Theurillat, Regula; Sendi, Parham; Thormann, Wolfgang


    Cefepime monitoring in deproteinized human serum and plasma by micellar electrokinetic capillary chromatography and liquid chromatography coupled to mass spectrometry in presence of other drugs is reported. For micellar electrokinetic capillary chromatography, sample preparation comprised dodecylsulfate protein precipitation at pH 4.5 using an increased buffer concentration compared to that of a previous assay and removal of hydrophobic compounds with dichloromethane. This provided robust conditions for cefepime analysis in the presence of sulfamethoxazole and thus enabled its determination in samples of patients that receive co-trimoxazole. The liquid chromatography assay is based upon use of a column with a pentafluorophenyl-propyl modified and multi-endcapped stationary phase and the coupling to electrospray ionization with a single quadrupole detector. The performances of both assays with multi-level internal calibration were assessed with calibration and control samples and both assays were determined to be robust. Cefepime levels monitored by micellar electrokinetic capillary chromatography in samples from patients that were treated with cefepime only and with cefepime and co-trimoxazole were found to compare well with those obtained by liquid chromatography coupled to mass spectrometry. Cefepime drug levels determined by micellar electrokinetic capillary chromatography could thereby be validated. This article is protected by copyright. All rights reserved.

  1. On-line Sweeping Sample Concentration in Micellar Electrokinetic Chromatography with Enhanced Sensitivity for the Determination of Carbamazepine in Human Serum

    Dan Dan HAN; Chun WANG; Zhi WANG; Qiu Hua WU; Xiao Huan ZANG


    A sensitive and simple micellar electrokinetic chromatography (MEKC) method was developed for the determination of antiepileptic drug, carbamazepine (CBZ), using sweeping on-line concentration method with photodiode array detection. Under the optimal conditions, the method has been successfully applied to the analysis of CBZ in human serum.

  2. Suitable combination of promoter and micellar catalyst for kilo fold rate acceleration on benzaldehyde to benzoic acid conversion in aqueous media at room temperature: a kinetic approach.

    Ghosh, Aniruddha; Saha, Rumpa; Ghosh, Sumanta K; Mukherjee, Kakali; Saha, Bidyut


    The kinetics of oxidation of benzaldehyde by chromic acid in aqueous and aqueous surfactant (sodium dodecyl sulfate, SDS, alkyl phenyl polyethylene glycol, Triton X-100 and N-cetylpyridinium chloride, CPC) media have been investigated in the presence of promoter at 303 K. The pseudo-first-order rate constants (kobs) were determined from a logarithmic plot of absorbance as a function time. The rate constants were found to increase with introduction of heteroaromatic nitrogen base promoters such as Picolinic acid (PA), 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen). The product benzoic acid has been characterized by conventional melting point experiment, NMR, HRMS and FTIR spectral analysis. The mechanism of both unpromoted and promoted reaction path has been proposed for the reaction. In presence of the anionic surfactant SDS, cationic surfactant CPC and neutral surfactant TX-100 the reaction can undergo simultaneously in both aqueous and micellar phase with an enhanced rate of oxidation in the micellar phase. Both SDS and TX-100 produce normal micellar effect whereas CPC produce reverse micellar effect in the presence of benzaldehyde. The observed net enhancement of rate effects has been explained by considering the hydrophobic and electrostatic interaction between the surfactants and reactants. SDS and bipy combination is the suitable one for benzaldehyde oxidation.

  3. Evaluation of angiotensin-converting enzyme inhibitor's absorption with retention data of micellar thin-layer chromatography and suitable molecular descriptor.

    Odovic, Jadranka; Markovic, Bojan; Vladimirov, Sote; Karljikovic-Rajic, Katarina


    Twelve angiotensin-converting enzyme (ACE) inhibitors were studied to evaluate correlation between their absorption (ABS) data available in the literature (22-96%) and hydrophobicity parameters (km and Pm/w) obtained in micellar thin-layer chromatography (MTLC) using Brij 35. The theoretical considerations showed that the geometric molecular descriptor-volume value (Vol) should be considered as an independent variable simultaneously with calculated hydrophobicity parameters in multiple linear regression analysis to obtain reliable correlation between ACE inhibitor's absorption and lipophilicity (calculated KOWWINlog P) and that captopril should be excluded from further correlations. The results of MTLC confirmed that between the two hydrophobicity parameters km and Pm/w, for absorption prediction of 11 ACE inhibitors, the micelle-water partition coefficient Pm/w provided higher correlation (R(2) = 0.756), while for the km parameter R(2) = 0.612 was obtained. The micelle-water partition coefficient Pm/w could be considered as analogous to hydrophobicity parameter C0 from reversed-phase thin-layer chromatography. Dissimilar retention behavior of lisinopril indicated its lowest non-polar interaction with micelle, because of its di-acid form. The proposed model which included ACE inhibitors on the opposite site of lipophilicity-lisinopril and fosinopril (KOWWINlog P = -0.96 and KOWWINlog P = 6.61, respectively), both with similar absorption values (25 and 36%, respectively), could indicate that absorption of investigated compounds occurs via two different mechanisms: active and passive transport. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email:

  4. Optimization of Micellar Electrokinetic Chromatography Method for the Simultaneous Determination of Seven Hydrophilic and Four Lipophilic Bioactive Components in Three Salvia Species

    Jiliang Cao


    Full Text Available A micellar electrokinetic chromatography (MEKC method was developed for the simultaneous determination of seven hydrophilic phenolic acids and four lipophilic tanshinones in three Salvia species. In normal MEKC mode using SDS as surfactant, the investigated 11 compounds could not be well separated. Therefore, several buffer modifiers including β-cyclodextrins (β-CD, ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4 and organic solvents have been added to the buffer solution to improve the separation selectivity. Under the optimized conditions (BGE, 15 mM sodium tetraborate with 10 mM SDS, 5 mM β-CD, 10 mM [bmim]BF4 and 15% ACN (v/v as additives; buffer pH, 9.8; voltage, 20 kV; temperature, 25 °C, the 11 investigated analytes could achieve baseline separation in 34 min. The proposed MEKC was additionally validated by evaluating the linearity (R2 ≥ 0.9965, LODs (0.27–1.39 μg·mL–1, and recovery (94.26%–105.17%, demonstrating this method was reproducible, accurate and reliable. Moreover, the contents of the 11 compounds in three Salvia species, including S. miltiorrhiza, S. przewalskii and S. castanea were analyzed. The result showed that the established MEKC method was simple and practical for the simultaneous determination of the hydrophilic and lipophilic bioactive components in Salvia species, which could be used to effectively evaluate the quality of these valued medicinal plants.

  5. Use of spectroscopic technique to develop a reagent for Mo(VI) utilizing micellar effects on complex formation

    Taşcioğlu, Sülin; Kaki, E.; Taşcioğlu, Senay


    Ultraviolet and visible spectral properties of aqueous solutions of molybdenum(VI) (Mo), gallic acid (GA), Lalanine (Ala), and L-Phenylalanine (Phe), and of their binary and ternary solutions were investigated in the absence and presence of anionic, cationic, and nonionic surfactant micelles. Evaluation of the spectra in a comparative way revealed that both Ala and Phe form ternary complexes with Mo and GA. The formation of a quaternary complex between Mo, GA, Phe, and cetyltrimethylammonium bromide at pH 4.5 provided a reagent system with a strikingly high sensitivity (1.2•106 l/(mol•cm)) for use in the spectrophotometric determination of Mo. A mechanism of micellar effects was discussed in terms of the substrate molecular charge and hydrophobicity, and rationalized on the basis of the spectral data obtained above and below the isoelectric pH of the amino acids.

  6. Fast relaxation of a hexagonal Poiseuille shear-induced near-surface phase in a threadlike micellar solution

    Hamilton, W.A. [Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6393 (United States); Butler, P.D.; Slawecki, T.M. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Magid, L.J.; Han, Z. [Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37996 (United States)


    The dynamics of near-surface conformations in complex fluids under flow should dramatically affect their rheological properties. We have made the first measurements resolving the decay kinetics of a hexagonal phase induced in a threadlike polyionic micellar system under Poiseuille shear near a quartz surface. Upon cessation of shearing flow, this minimum interference crystalline phase formed within {approximately}20 {mu}m of the surface {open_quotes}melts{close_quotes} to a metastable two-dimensional liquid of aligned micelles in {approximately}0.7 s. This is some three orders of magnitude shorter than the time required for bulk (Couette) shear-aligned micelles in this system to reach a fully entangled state. {copyright} {ital 1999} {ital The American Physical Society}

  7. Modification of the murakami retention model in reversed-phase high-performance liquid chromatography for micellar chromatographic separations

    Loginova, L. P.; Boichenko, A. P.; Kulikov, A. Yu.


    A retention model for micellar liquid chromatography was tested based on the data of separation of three benzodiazepins and six β-blockers. The model was obtained by analyzing changes in the microenvironment of a sorbate in transferring from the mobile to stationary phase. It can be used to describe the retention of benzodiazepins, which are neutral under the separation conditions, and the positively charged β-blockers. The calculated model coefficients are indicative of an increase in the number of 1-pentanol molecules and sodium dodecyl sulfate monomers in the microenvironment of the sorbates in transferring from the mobile to stationary phase. The solvation of the positive β-blockers by anionic surfactant monomers was higher than that of neutral benzodiazepins.

  8. Monitoring subcellular biotransformation of N-L-leucyldoxorubicin by micellar electrokinetic capillary chromatography coupled to laser-induced fluorescence detection.

    Satori, Chad P; Meyer, Brandon; Arriaga, Edgar A


    Development of prodrugs is a promising alternative to address cytotoxicity and nonspecificity of common anticancer agents. N-L-leucyldoxorubicin (LeuDox) is a prodrug that is biotransformed to the anticancer drug doxorubicin (Dox) in the extracellular space; however, its biotransformation may also occur intracellularly in endocytic organelles. Such organelle-specific biotransformation is yet to be determined. In this study, magnetically enriched endocytic organelle fractions from human uterine sarcoma cells were treated with LeuDox. Micellar electrokinetic chromatography with laser-induced fluorescence detection (MEKC-LIF) was used to determine that 10% of LeuDox was biotransformed to Dox, accounting for ~43% of the biotransformation occurring in the post-nuclear fraction. This finding suggests that endocytic organelles also participate in the intracellular biotransformation of LeuDox to Dox.

  9. Determination of triazine herbicide residues in water samples by on-line sweeping concentration in micellar electrokinetic chromatography


    A new method for the determination of atrazine, simazine and prometryn in water samples by on-line sweeping concentration technique in micellar electrokinetic chromatography (MEKC) was developed. Various parameters affecting sample enrichment and separation efficiency were systematically studied. Compared with the conventional MEKC method, up to 60-200-fold improve-merit in concentration sensitivity was achieved in terms of peak height by using this sweeping injection technique. The compound strychnine was used as the internal standard for the improvement of the experimental reproducibility. The limits of detection (S/ N = 3:1) for atrazine, simazine and prometryn were 9, 10 and 0.5 ng mL-1, respectively. This method has been successfully applied to the analysis of atrazine, simazine and prometryn in lake, steam and ground water.

  10. Effect of micellar species on photoinduced hydrogen production with Mg chlorophyll-a from spirulina and colloidal platinum

    Tomonou, Yumiko; Amao, Yutaka [Oita Univ., Dept. of Applied Chemistry, Oita (Japan)


    Effect of micellar species on the photostability of Mg chlorophyll-a and the photoinduced hydrogen production with Mg chlorophyll-a by use of three component system consisting of NADPH, methylviologen and colloidal platinum was investigated. Triton X-100 and CTAB solubilized Mg chlorophyll-a solution were rapidly bleached by irradiation and 50% of Mg chlorophyll-a was degraded in 90 min irradiation. On the other hand, the decay rate of Mg chlorophyll-a concentration in the presence of NADPH was suppressed and the degradation rate was 15% in 90 min irradiation. The effective hydrogen production system was developed using CTAB solubilized Mg chlorophyll-a (2.7 {mu}mol in 4 h), compared with that using Triton X-100 solubilized Mg chlorophyll-a (0.1 {mu}mol in 4 h). (Author)

  11. Highly ordered and highly aligned two-dimensional binary superlattice of a SWNT/cylindrical-micellar system.

    Lim, Sung-Hwan; Jang, Hyung-Sik; Ha, Jae-Min; Kim, Tae-Hwan; Kwasniewski, Pawel; Narayanan, Theyencheri; Jin, Kyeong Sik; Choi, Sung-Min


    We report a highly ordered intercalated hexagonal binary superlattice of hydrophilically functionalized single-walled carbon nanotubes (p-SWNTs) and surfactant (C12 E5 ) cylindrical micelles. When p-SWNTs (with a diameter slightly larger than that of the C12 E5 cylinders) were added to the hexagonally packed C12 E5 cylindrical-micellar system, p-SWNTs positioned themselves in such a way that the free-volume entropies for both p-SWNTs and C12 E5 cylinders were maximized, thus resulting in the intercalated hexagonal binary superlattice. In this binary superlattice, a hexagonal array of p-SWNTs is embedded in a honeycomb lattice of C12 E5 cylinders. The intercalated hexagonal binary superlattice can be highly aligned in one direction by an oscillatory shear field and remains aligned after the shear is removed.

  12. Determination of the macromolecular dimensions of hydrophobically modified polymers by micellar size exclusion chromatography coupled with multiangle light scattering.

    Dupuis, Guillaume; Rigolini, Julien; Clisson, Gérald; Rousseau, David; Tabary, René; Grassl, Bruno


    The present work demonstrates that the use of a nonionic surfactant in the mobile phase together with light scattering coupled to size exclusion chromatography (SEC) provides an accurate determination of macromolecular dimensions of hydrophobically modified water-soluble polymer and polyelectrolyte, i.e., weight-average molar mass M(w) and polydispersity I(p). This method, called micellar SEC, is based on the dissociation of the aggregates in aqueous solution and the formation of mixed micelles between the surfactant and the polymer hydrophobic groups. The methodology and its application are presented for synthetic sulfonated polyacrylamides (5 and 20 mol %) modified with three hydrophobic alkyl side groups (C8, C12, and C18) and with Triton X-100 as a nonionic surfactant and are discussed according to the associativity of polymers. The results are compared to those obtained by classical SEC in 0.1 M NaNO(3) and by static light scattering in formamide solution.

  13. On the predictions and limitations of the Becker–Döring model for reaction kinetics in micellar surfactant solutions

    Griffiths, I.M.


    We investigate the breakdown of a system of micellar aggregates in a surfactant solution following an order-one dilution. We derive a mathematical model based on the Becker-Döring system of equations, using realistic expressions for the reaction constants fit to results from Molecular Dynamics simulations. We exploit the largeness of typical aggregation numbers to derive a continuum model, substituting a large system of ordinary differential equations for a partial differential equation in two independent variables: time and aggregate size. Numerical solutions demonstrate that re-equilibration occurs in two distinct stages over well-separated timescales, in agreement with experiment and with previous theories. We conclude by exposing a limitation in the Becker-Döring theory for re-equilibration of surfactant solutions. © 2011 Elsevier Inc.

  14. Determination of caffeine and associated compounds in food, beverages, natural products, pharmaceuticals, and cosmetics by micellar electrokinetic capillary chromatography.

    Injac, Rade; Srdjenovic, Branislava; Prijatelj, Matevz; Boskovic, Marija; Karljikovic-Rajic, Katarina; Strukelj, Borut


    A method is described for quantitating caffeine, theobromine, theophylline, paracetamol, propyphenazone, acetylsalicylic acid, salicylic acid, and codeine phosphate in corresponding real samples of food, beverages, natural products, pharmaceuticals, and cosmetic preparations by micellar electrokinetic capillary chromatography. The separation is carried out at 25 degrees C and 25 kV, using a 20 mM phosphate buffer (pH 9.0), 80 mM sodium dodecyl sulfate, and 7.5% (v/v) acetonitrile. UV detection is at 210 nm. The method is shown to be specific, accurate (recoveries over the range 98.9-101.2%), linear over the tested range (correlation coefficients>or=0.9993), and precise (relative standard deviation below 2.1%). The method is applied for the quantitative analysis of these compounds in different foods, beverages, natural products, pharmaceuticals, and cosmetic products.

  15. Solubilization of rehydrated frozen highly concentrated micellar casein for use in liquid food applications.

    Lu, Y; McMahon, D J; Metzger, L E; Kommineni, A; Vollmer, A H


    Highly concentrated micellar casein concentrate (HC-MCC), a potential ingredient of protein-fortified food, is a gel at cold temperature. It contains ~17 to 21% casein, with most serum proteins and lactose removed by microfiltration and diafiltration, and it is then further concentrated using vacuum evaporation. The HC-MCC can be stored frozen, and our objective was to determine the conditions needed to obtain complete solubility of thawed HC-MCC in water and to understand its gelation upon cooling. Dispersibility (ability to pass through a 250-µm mesh sieve), suspendability (percentage of protein not sedimented at 80 × g within 5min), and solubility (percentage of protein not sedimented at 20,000 × g within 5min) were measured at 4, 12, or 20°C after various mixing conditions. Gelation upon cooling from 50 to 5°C was monitored based on storage (G') and loss (G'') moduli. The gelled HC-MCC was also examined by transmission electron microscopy. Thawed HC-MCC was added to water to reach a protein concentration of 3% and mixed using high shear (7,500rpm) for 1min or low shear (800rpm) for 30min at 4, 12, 20, or 50°C and at pH 6.4 to 7.2. The HC-MCC completely dispersed at 50°C, or at ≤20°C followed by overnight storage at 4°C. Suspendability at 50°C was ~90% whereas mixing at ≤20°C followed by overnight storage resulted in only ~57% suspendability. Solubility followed a similar trend with ~83% at 50°C and only ~29% at ≤20°C. Mixing HC-MCC with 60mM trisodium citrate increased dispersibility to 99% and suspendability and solubility to 81% at 20°C. Cold-gelling temperature, defined as the temperature at which G'=G'' when cooling from 50 to 5°C, was positively correlated with protein level in HC-MCC. Gelation occurred at 38, 28, and 7°C with 23, 20, and 17% of protein, respectively. Gelation was reversible upon heating, although after a second cooling cycle the HC-MCC gel had lower G'. In micrographs of gelled HC-MCC, the casein micelles were

  16. Determination of selective serotonin reuptake inhibitors in plasma and urine by micellar liquid chromatography coupled to fluorescence detection.

    Agrawal, Nitasha; Esteve-Romero, Josep; Bose, Devasish; Dubey, Neeti Prakesh; Peris-Vicente, Juan; Carda-Broch, Samuel


    Citalopram, paroxetine and fluoxetine are selective serotonin reuptake inhibitor (SSRIs) currently used in the treatment of psychiatric disorders. We present an analytical method using micellar liquid chromatography to quantify these three drugs in pharmaceutical formulations, plasma and urine. The resolution was performed using a mobile phase of 0.075 M SDS - 6% (v/v) butanol buffered at pH 7 running through a C18 column under isocratic mode at 1 mL/min at 25°C. The analytes were eluted in less than 20 min. The fluorescence detection was programmed at the maximum excitation (236, 295 and 230 nm) and emission (310, 350 and 305 nm) wavelengths for citalopram, paroxetine and fluoxetine, respectively. The experimental procedure was expedited to 1/5 dilution of the sample in the micellar mobile phase and filtration, thus avoiding clean-up and extraction steps. An aliquot of 20 μL was injected after 80 min of preparation, to obtain maximum sensitivity. The method was validated according to the guidelines of the Food and Drug Administration (FDA) in terms of calibration range (20-500 ng/mL; r(2)>0.999), sensitivity, accuracy (91.3-103.2%), precision (<9.3%), and robustness (<6.1%). The suitability of the method was successfully evaluated by analyzing plasma and urine samples from patients treated with SSRIs and checking the content of the active principle in tablets. Thus, the method can be applied to pharmacokinetics studies and in forensic cases, as well as in quality control of commercial pharmaceutical formulations.

  17. Biopartitioning micellar chromatography as a predictive tool for skin and corneal permeability of newly synthesized 17β-carboxamide steroids.

    Dobričić, Vladimir; Nikolic, Katarina; Vladimirov, Sote; Čudina, Olivera


    In this paper, human skin and corneal permeability of twenty-two newly synthesized 17β-carboxamide steroids was predicted using biopartitioning micellar chromatography (BMC). These compounds are potential soft glucocorticoids with local anti-inflammatory activity when applied to the skin or eye. BMC systems are used to simulate physicochemical properties of human skin (BMC-skin) and cornea (BMC-cornea). Micellar mobile phase, consisted of 0.04 M solution of polyoxyethylene (23) lauryl ether (Brij 35), was prepared at different pH values - 5.50 (BMC-skin) and 7.50 (BMC-cornea). Retention factors (k), obtained by use of BMC, were calculated for all newly synthesized 17β-carboxamide steroids as well as for parent glucocorticoids (hydrocortisone, prednisolone, methylprednisolone, dexamethasone and betamethasone). Good correlation was obtained between BMC-skin retention factors and permeability coefficients calculated by use of the artificial membrane that simulates stratum corneum of the human skin. Quantitative structure-retention relationship (QSRR) study was performed in order to explain retention factors of these compounds in the tested BMC systems. ANN-QSRR(k), PLS-QSRR(k) and MLR-QSRR(k) models, created by use of BMC-skin retention data, were compared and optimal model (PLS-QSRR(k)) was selected. Molecular descriptors of the selected model indicate that lipophilicity and number of short C-C fragments of tested compounds have the strongest influence on the retention in the BMC-skin system and presumably on their in vivo permeability through human skin. The same model can be applied to the BMC-cornea system and the same conclusion can be drawn for corneal permeability. This model could be used as a predictive tool for the synthesis of novel 17β-carboxamide steroids with desirable permeability through human skin or cornea, depending on their potential pharmacological application.

  18. A rapid spectrophotometric method for the determination of trace level lead using 1,5-diphenylthiocarbazone in aqueous micellar solutions.

    Khan, Humaira; Ahmed, M Jamaluddin; Bhanger, M Iqbal


    A very simple, ultra-sensitive and fairly selective direct spectrophotmetric method is presented for the rapid determination of lead(II) at ultra-trace level using 1,5-diphenylthiocarbazone (dithizone) in micellar media. The presence of the micellar system avoids the previous steps of solvent extraction and reduces the cost and toxicity while enhancing the sensitivity, selectivity and the molar absorptivity. The molar absorptivities of the lead-dithizone complex formed in the presence of the cationic cetyltrimethylammonium bromide (CTAB) surfactants are almost ten times the value observed in the standard method, resulting in an increase in the sensitivity of the method. The reaction is instantaneous and the absorbance remains stable for over 24 h. The average molar absorption coefficient was found to be 3.99 x 10(5) L mol(-1) cm(-1) and Sandell's sensitivity was 30 ng cm(-2) of Pb. Linear calibration graphs were obtained for 0.06-60 mg L(-1) of Pb(II); the stoichiometric composition of the chelate is 1:2 (Pb:dithizone). The interference from over 50 cations, anions and complexing agents has been studied at 1 mg L(-1) of Pb(II). The method was successfully used in the determination of lead in several standard reference materials (alloys and steels), environmental water samples (potable and polluted), biological samples (human blood and urine), soil samples and solutions containing both lead(II) and lead(IV) and complex synthetic mixtures. The method has high precision and accuracy (sigma = +/-0.01 for 0.5 mg L(-1)).

  19. Commercial scale demonstration: enhanced oil recovery by micellar-polymer flood. Annual report, October 1980-September 1981

    Howell, J.C.


    This commercial scale test, known as the M-1 Project, is located in Crawford County, Illinois. It encompasses 407 acres of Robinson sand reservoir and covers portions of several waterflood projects that were approaching economic limit. The project includes 248 acres developed on a 2.5-acre five-spot pattern and 159 acres developed on a 5.0-acre five-spot pattern. Development work commenced in late 1974 and has previously been reported. Micellar solution (slug) injection was initiated on February 10, 1977, and is now completed. After 10% of a pore volume of micellar slug was injected, injection of 11% pore volume of Dow 700 Pusher polymer was conducted at a concentration of 1156 ppM. At the end of this reporting period, 625 ppM polymer was being injected into the 2.5-acre pattern and 800 ppM polymer was being injected into the 5.0-acre pattern. The oil cut of the 2.5-acre pattern has decreased from 11.0% in September 1980, to 7.9% in September 1981. The 2.5-acre pattern had been on a plateau since May 1980, and as of May 1981 appears to be on a decline. The oil cut of the 5.0-acre pattern has increased from 5.9% in September 1980, to 10.9% in September 1981. The 5.0-acre pattern experienced a sharp increase in oil cut after 34% of a pore volume of total fluid had been injected and appears to be continuing its incline. This fifth annual report is organized under the following three work breakdown structures: fluid injection; production; and performance monitoring.

  20. Alkyl imidazolium ionic liquid based sweeping-micellar electrokinetic chromatography for simultaneous determination of seven tea catechins in human plasma.

    El-Hady, Deia Abd; Albishri, Hassan M


    Determination of tea catechins in human plasma might provide a means of better evaluation of their benefits. The main difficulty in their analysis is the low catechins concentrations in plasma and their susceptible to oxidation during sample pretreatment. In the current work, a sweeping-micellar electrokinetic chromatography (sweeping-MEKC) by long alkyl chain ionic liquid was investigated for the simultaneous determination of seven principal naturally-occurring tea catechins in human plasma under acidic conditions after the intake of green tea beverage. The effects of type and concentration of three 1-tetradecyl-3-methylimidazolium ionic liquids, namely bromide, acetate and hydrogen sulfate salts were studied. The seven catechins were successfully separated within 5min by micellar running buffer of 5mmolL(-1) 1-tetradecyl-3-methylimidazolium bromide and 15mmolL(-1) phosphate buffer at pH 4.5 under optimal parameters of 50mbar injection for 150s, 10kV, 25°C and 200nm. To prevent the possibility of IL adsorption, an appropriate rinsing protocol was established. The method has analytical ranges from 0.5, 1, 0.5, 1, 2, 1 and 1 to 500ngmL(-1) for GC, C, EC, EGCG, GCG, ECG and EGC, respectively (r ranged from 0.995 to 0.999). The intraday precision and accuracy were 0.1-0.9% RSD (n=10) and 97-106% recovery, respectively. Limits of detections of analytes were ranged from 0.2 to 1.2ngmL(-1). The current sweeping-MEKC achieved sensitivity enhancement factor (SEF) up to 183-fold of analytes concentrations compared to other hitherto published CE reports that is suitable to find out the trace amounts of catechins in plasma.

  1. Solubility limits and phase diagrams for fatty alcohols in anionic (SLES) and zwitterionic (CAPB) micellar surfactant solutions.

    Tzocheva, Sylvia S; Danov, Krassimir D; Kralchevsky, Peter A; Georgieva, Gergana S; Post, Albert J; Ananthapadmanabhan, Kavssery P


    By analysis of experimental data, a quantitative theoretical interpretation of the solubility limit of medium- and long-chain fatty alcohols in micellar solutions of water-soluble surfactants is presented. A general picture of the phase behavior of the investigated systems is given in the form of phase diagrams. The limited solubility of the fatty alcohols in the micelles of conventional surfactants is explained with the precipitation of their monomers in the bulk, rather than with micelle phase separation. The long chain fatty alcohols (with n=14, 16 and 18 carbon atoms) exhibit an ideal mixing in the micelles of the anionic surfactant sodium laurylethersulfate (SLES) and the zwitterionic surfactant cocamidopropyl betaine (CAPB) at temperatures of 25, 30, 35 and 40 °C. Deviations from ideality are observed for the alcohols of shorter chain (n=10 and 12), which can be explained by a mismatch with the longer chains of the surfactant molecules. Using the determined thermodynamic parameters of the systems, their phase diagrams are constructed. Such a diagram consists of four domains, viz. mixed micelles; coexistent micelles and precipitate (dispersed crystallites or droplets); precipitate without micelles, and molecular solution. The four boundary lines intersect in a quadruple point, Q. For ionic surfactants (like SLES), a detailed theory for calculating the boundary lines of the phase diagrams is developed and verified against data for the positions of the kinks in surface tension isotherms. The theory takes into account the electrostatic interactions in the micellar solutions and the effect of counterion binding. The results can be useful for a quantitative interpretation and prediction of the phase behavior of mixed solutions of two (or more) surfactants, one of them being water soluble and forming micelles, whereas the other one has a limited water solubility, but readily forms mixed micelles with the former surfactant.

  2. Effects of depleting ionic strength on (31)P nuclear magnetic resonance spectra of micellar casein during membrane separation and diafiltration of skim milk.

    Boiani, Mattia; McLoughlin, Padraig; Auty, Mark A E; FitzGerald, Richard J; Kelly, Phil M


    Membrane separation processes used in the concentration and isolation of micellar casein-based milk proteins from skim milk rely on extensive permeation of its soluble serum constituents, especially lactose and minerals. Whereas extensive literature exists on how these processes influence the gross composition of milk proteins, we have little understanding of the effects of such ionic depletion on the core structural unit of micellar casein [i.e., the casein phosphate nanocluster (CPN)]. The (31)P nuclear magnetic resonance (NMR) is an analytical technique that is capable of identifying soluble and organic forms of phosphate in milk. Thus, our objective was to investigate changes to the (31)P NMR spectra of skim milk during microfiltration (MF) and diafiltration (DF) by tracking movements in different species of phosphate. In particular, we examined the peak at 1.11 ppm corresponding to inorganic phosphate in the serum, as well as the low-intensity broad signal between 1.5 and 3.0 ppm attributed to casein-associated phosphate in the retentate. The MF concentration and DF using water caused a shift in the relevant (31)P NMR peak that could be minimized if orthophosphate was added to the DF water. However, this did not resolve the simultaneous change in retentate pH and increased solubilization of micellar casein protein. The addition of calcium in combination with orthophosphate prevented micellar casein solubilization and simultaneously contributed to preservation of the CPN structure, except for overcorrection of retentate pH in the acidic direction. A more complex DF solution, involving a combination of phosphate, calcium, and citrate, succeeded in both CPN and micellar casein structure preservation while maintaining retentate pH in the region of the original milk pH. The combination of (31)P NMR as an analytical technique and experimental probe during MF/DF processes provided useful insights into changes occurring to CPN while retaining the micellar state of

  3. Planning a Successful Tech Show

    Nikirk, Martin


    Tech shows are a great way to introduce prospective students, parents, and local business and industry to a technology and engineering or career and technical education program. In addition to showcasing instructional programs, a tech show allows students to demonstrate their professionalism and skills, practice public presentations, and interact…

  4. A new wastewater treatment technology—micellar-enhanced ultrafiltration%废水处理新技术—胶团强化超滤

    彭跃莲; 纪树兰; 姚仕仲; 高以烜


    80年代,国外开始研究一种新的水处理技术,以去除废水中的微量有机污染物和金属离子,即胶团强化超滤法(Micellar-enhancedUltrafiltration,简称MEUF).这是一种将表面活性剂和超滤膜结合起来的新技术,国内还没有深入的研究报道,国外也还处于研究阶段.%Micellar-enhanced ultrafiltration is a new purification techniquecombining surfactants and ultrafiltration membranes, and can be used to remove trace organic matter and metal ions from wastewater.

  5. A method to quantify several tyrosine kinase inhibitors in plasma by micellar liquid chromatography and validation according to the European Medicines Agency guidelines.

    Garrido-Cano, Iris; García-García, Aurelio; Peris-Vicente, Juan; Ochoa-Aranda, Enrique; Esteve-Romero, Josep


    A procedure based on micellar liquid chromatography has been developed to monitor five tyrosine kinase inhibitors in plasma, prescribed against several kinds of cancer: erlotinib, imatinib, sunitinib, sorafenib and lapatinib. The sample was diluted in a micellar solution and directly injected, thus clean-up steps were not required. The analytes were resolved without interferences in 0.990), limit of detection (15-35 ng/mL), carry-over effect, accuracy (-10.4 to +11.0%), precision (<9.2%), matrix effect, robustness (<8.4%) and stability. The procedure is rapid, easy-to-handle, uses a low amount of toxic chemical provide reliable results. Finally, the method was successfully used to analyze the studied tyrosine kinase inhibitors in plasma from cancer patients.

  6. Determination of lysergic acid diethylamide (LSD) in mouse blood by capillary electrophoresis/ fluorescence spectroscopy with sweeping techniques in micellar electrokinetic chromatography.

    Fang, Ching; Liu, Ju-Tsung; Chou, Shiu-Huey; Lin, Cheng-Huang


    The separation and on-line concentration of lysergic acid diethylamide (LSD) in mouse blood was achieved by means of capillary electrophoresis/fluorescence spectroscopy using sodium dodecyl sulfate (SDS) as the surfactant. Techniques involving on-line sample concentration, including sweeping micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were applied; the optimum on-line concentration and separation conditions were determined. In the analysis of an actual sample, LSD was found in a blood sample from a test mouse (0.1 mg LSD fed to a 20 g mouse; approximately 1/10 to the value of LD(50)). As a result, 120 and 30 ng/mL of LSD was detected at 20 and 60 min, respectively, after ingestion of the doses.

  7. A reliable and reproducible method for the lipase assay in an AOT/isooctane reversed micellar system: modification of the copper-soap colorimetric method.

    Kwon, Chang Woo; Park, Kyung-Min; Choi, Seung Jun; Chang, Pahn-Shick


    The copper-soap method, which is based on the absorbance of a fatty acid-copper complex at 715 nm, is a widely used colorimetric assay to determine the lipase activity in reversed micellar system. However, the absorbance of the bis(2-ethylhexyl) sodium sulfosuccinate (AOT)-copper complex prevents the use of an AOT/isooctane reversed micellar system. An extraction step was added to the original procedure to remove AOT and eliminate interference from the AOT-copper complex. Among the solvents tested, acetonitrile was determined to be the most suitable because it allows for the generation of a reproducible calibration curve with oleic acid that is independent of the AOT concentrations. Based on the validation data, the modified method, which does not experience interference from the AOT-copper complex, could be a useful method with enhanced accuracy and reproducibility for the lipase assay.

  8. Determination of lysergic acid diethylamide (LSD) by application of online 77 K fluorescence spectroscopy and a sweeping technique in micellar electrokinetic chromatography.

    Fang, Ching; Liu, Ju-Tsung; Lin, Cheng-Huang


    The principal advantage of the use of Shopl'skii effect (low temperature spectrum) is that spectral sharpening occurs both in absorption and emission. However, thus far using the technique of capillary electrophoresis/low temperature fluorescence spectroscopy (CE/LTFS) either at 77 or 4.2 K remains difficult to obtain an on-line spectrum, if the analyte is present at low concentration. This paper examines the feasibility of combining the techniques of online concentration and CE/LTFS to identify LSD and related compounds in urine at 77 K. To improve sensitivity, sweeping-micellar electrokinetic chromatography (sweeping-MEKC) and cation-selective exhaustive injection-sweep-micellar electrokinetic chromatography (CSEI-sweep-MEKC) were used for on-line concentration which resulted in detection limits of approximately 20 approximately 60 ppt, respectively.

  9. Comparative study of Palladium (II using 4-Hydroxy 3, 5 dimethoxy benzaldehyde 4-hydroxy benzoyl hydrazone and Cinnamaldehyde 4-hydroxy benzoylhydrazone in presence of micellar medium by Spectrophotometry

    D.Gopala Krishna,


    Full Text Available Two simple, sensitive, rapid and selective spectrophotometric methods have been developed for the determination of Palladium (II using newly synthesized reagents 4-Hdroxy3,5dimethoxy benzaldehyde-4-hydroxybenzoylhydrazone (HDMBHBH and Cinnamaldehyde 4-hydroxy benzoylhydrazone (CMHBH in presence of neutral surfactant TritonX-100-5% (micellar medium. Palladium (II forms a brown coluored water-soluble complex with HDMBHBH and CMHBH-in the pH range 1.0-6.0. The Pd (II-HDMBHBH complex shows maximum absorbance at max 373 nm in the pH range 3.0-4.0 and Pd (II-CMHBH shows at max 375 nm in thepH range 4.0-5.0. At these wavelengths (max, the complex shows maximum absorbance while the reagent blanks shows negligible absorbance. Hence, analytical studies were carried out at max 373 nm at pH 3.0 for HDMBHBH and 375 nm at pH 4.0 for CMHBH against reagent blanks. Beer's law is obeyed in the range 0.106-1.064 μg ml-1 and the optimum concentration range from ringbom plot is 0.212-0.957 g/ml of Palladium (II for both reagents. The molar absorptivity and Sandell's sensitivity for the coloured solution were found to be 7.5 x 104 L mol-1 cm-1 and 0.0015-μg. cm-2 for HDMBHBH, 6.0x104L mol-1 cm-1 , and 0.0017 -μg. cm-2 for CMHBH respectively. The interference effects of various diverse ions have been studied. Palladium (II forms 1:1 complex with HDMBHBH and CMHBH stoichiometry with stability constant 7.29 x 106 for HDMBHBH and 3.55 x 106 for CMHBH. The standard deviation in the determination of 0.638-μg ml-1 of Palladium (II is 0.003 for HDMBHBH and 0.008 for CMHBH. The Relative standard deviation is 0.71% for HDMBHBH and 2.5% for CMHBH. First and second order derivative spectroscopic methods were developed at max 422 nm and 444 nm for HDMBHBH and at 402 nm and438 nm for CMHBH respectively, for the determination of Palladium (II, which is more sensitive than the zero order method. The developed method has been employed for the determination of

  10. Risk Aversion in Game Shows


    We review the use of behavior from television game shows to infer risk attitudes. These shows provide evidence when contestants are making decisions over very large stakes, and in a replicated, structured way. Inferences are generally confounded by the subjective assessment of skill in some games......, and the dynamic nature of the task in most games. We consider the game shows Card Sharks, Jeopardy!, Lingo, and finally Deal Or No Deal. We provide a detailed case study of the analyses of Deal Or No Deal, since it is suitable for inference about risk attitudes and has attracted considerable attention....

  11. Measuring performance at trade shows

    Hansen, Kåre


    Trade shows is an increasingly important marketing activity to many companies, but current measures of trade show performance do not adequately capture dimensions important to exhibitors. Based on the marketing literature's outcome and behavior-based control system taxonomy, a model is built...... that captures a outcome-based sales dimension and four behavior-based dimensions (i.e. information-gathering, relationship building, image building, and motivation activities). A 16-item instrument is developed for assessing exhibitors perceptions of their trade show performance. The paper presents evidence...

  12. Performance of different C18 columns in reversed-phase liquid chromatography with hydro-organic and micellar-organic mobile phases.

    Ruiz-Angel, M J; Pous-Torres, S; Carda-Broch, S; García-Alvarez-Coque, M C


    Column selection in reversed-phase liquid chromatography (RPLC) can become a challenge if the target compounds interact with the silica-based packing. One of such interactions is the attraction of cationic solutes to the free silanols in silica-based columns, which is a slow sorption-desorption interaction process that gives rise to tailed and broad peaks. The effect of silanols is minimised by the addition of a competing agent in the mobile phase, such as the anionic surfactant sodium dodecyl sulphate (SDS). In micellar-organic RPLC, the adsorption of an approximately fixed amount of SDS monomers gives rise to a stable modified stationary phase, with properties remarkably different from those of the underlying bonded phase. The chromatographic behaviour (in terms of selectivity, analysis time and peak shape) of eight C18 columns in the analysis of weakly acidic phenols and basic β-blockers was examined with hydro-organic and micellar-organic mobile phases. The behaviour of the columns differed significantly when the cationic basic drugs were eluted with hydro-organic mobile phases. With micellar-organic mobile phases, the adsorption of surfactant, instead of making the columns similar, gave rise to a greater diversity of behaviours (especially in terms of selectivity and analysis time), for both groups of phenols and β-blockers, which should be explained by the residual effect of the underlying bonded stationary phase and the different amount of surfactant covering the packing. Therefore, the implementation of a micellar-organic procedure in RPLC will depend significantly on the selected type of C18 column.

  13. in vitro and in silico determination of oral, jejunum and Caco-2 human absorption of fatty acids and polyphenols. Micellar liquid chromatography.

    Stępnik, Katarzyna E; Malinowska, Irena; Rój, Edward


    In this investigation chosen saturated, mono- and polyunsaturated fatty acids as well as polyphenols have been analyzed. The main aim of this study was to determine oral, jejunum and Caco-2 human absorption of chosen fatty acids and polyphenols using in vitro and in silico methods. For in vitro determination of human drug absorption, the usefulness of Micellar Liquid Chromatography (MLC) with mobile phases containing different surfactants (including Brij35-Biopartitioning Micellar Chromatography (BMC)) has been confirmed. On the basis of Foley's equation, 1/k vs. CM correlations for the tested compounds have been done. Satisfactory linearity of the relationships was found over the whole eluents composition range studied with R(2) approximately 0.99 in each case. Moreover, the analyte-micelle association constants (Kma) from Foley's equation have been compared for different micellar environments, containing Brij35, SDS and CTAB as a main component of micellar mobile phases. Completely new models describing human oral as well as Caco-2 and jejunum absorption have been constructed and compared with the cited models. These models are based on the Abraham descriptors and lipophilicity parameters as well as steric descriptors. Furthermore, many different correlations between physicochemical parameters and human intestinal absorption have been done, e.g. the correlation between human jejunum permeability estimated in silico and received using LSER parameters was excellent (R(2) nearly 0.99). Chromatographic parameters have been collated with steric, electronic and physicochemical ones using QRAR (Quantitative Retention - Activity Relationships) and QSAR (Quantitative Structure - Activity Relationships) models. Moreover, retention BMC data have been compared with lipophilicity parameter logPo/w (n-octanol-water partition coefficient). The influence of lipophilicity on oral absorption (%) has been checked. The correlation between predicted oral absorption (%) and log

  14. First- and Second-Derivative Spectrophotometry for Simultaneous Determination of Copper and Cobalt by 1-(2-Pyridylazo)-2-naphthol in Tween 80 Micellar Solutions

    Eskandari, Habibollah; SAGHSELOO, Ali Ghanbari


    1-(2-Pyridylazo)-2-naphthol (PAN) has been used for the simultaneous determination of copper and cobalt at trace levels. PAN at pH 1.89 forms red and green complexes with copper and cobalt, respectively, which are soluble in aqueous Tween 80 micellar media and are stable for at least 3 days. Under optimum conditions, calibration graphs were obtained for individual determination of copper and cobalt by zero- and first-derivative spectrophotometry and for simultaneous determination by ...

  15. First- and Second-Derivative Spectrophotometry for Simultaneous Determination of Copper and Cobalt by 1-(2-Pyridylazo)-2-naphthol in Tween 80 Micellar Solutions

    Eskandari, Habibollah; SAGHSELOO, Ali Ghanbari


    1-(2-Pyridylazo)-2-naphthol (PAN) has been used for the simultaneous determination of copper and cobalt at trace levels. PAN at pH 1.89 forms red and green complexes with copper and cobalt, respectively, which are soluble in aqueous Tween 80 micellar media and are stable for at least 3 days. Under optimum conditions, calibration graphs were obtained for individual determination of copper and cobalt by zero- and first-derivative spectrophotometry and for simultaneous determination by ...

  16. Approaching over 10 000-fold sensitivity increase in chiral capillary electrophoresis: Cation-selective exhaustive injection and sweeping cyclodextrin-modified micellar electrokinetic chromatography.

    Mikuma, Toshiyasu; Iwata, Yuko T; Miyaguchi, Hajime; Kuwayama, Kenji; Tsujikawa, Kenji; Kanamori, Tatsuyuki; Kanazawa, Hideko; Inoue, Hiroyuki


    A novel and simple method that combines an online concentration technique with an enantioseparation technique for capillary electrophoresis-namely, cation-selective exhaustive injection and sweeping cyclodextrin-modified micellar electrokinetic chromatography (CSEI-sweeping CD-modified MEKC)-realizes the effective enantioseparation of cationic analytes while keeping a significant increase of detection sensitivity. This technique consists of a slight modification of the basic CSEI-sweeping MEKC. The main idea is to simply add an anionic CD as a chiral selector into the micellar buffer including sodium dodecyl sulfate, but not to change any other buffers in order to preserve the online concentration mechanism. When applied to analysis of the street drug, methamphetamine, the method achieved not only a baseline enantioseparation but also limits of detection (LODs; S/N = 3) of 70-90 pg/mL (ppt) for each isomer. This translates to a more than 10 000-fold improvement compared to the LODs by the usual injection method. The present technique, which was made from a slight modification of CSEI-sweeping MEKC, would give an attractive approach that is applicable to almost any analytes for which CSEI-sweeping MEKC is applicable; all that is required is the selection of an appropriate anionic CD to be added to the micellar buffer.

  17. Development and validation of a stability-indicating micellar liquid chromatographic method for the determination of timolol maleate in the presence of its degradation products.

    Rizk, Mohamed S; Merey, Hanan A; Tawakkol, Shereen M; Sweilam, Mona N


    A stability-indicating micellar liquid chromatographic (MLC) method was developed and validated for the quantitative determination of timolol maleate (TM) in the presence of its degradation products resulting from accelerated degradation in a run time not more than 8 min. TM was subjected to stress conditions of hydrolysis (including alkaline, acidic and thermal hydrolysis) and oxidation. An isocratic, rapid and mobile phase saving the micellar LC method was developed with a BioBasic phenyl column (150 × 1.0 mm, 5 µm particle size) and a micellar mobile phase composed of 0.1 M sodium dodecyl sulfate, 10% of 1-propanol and 0.1% of triethylamine in 0.035 M ortho-phosphoric acid. The flow rate of the mobile phase was 0.1 mL/min. UV detection was adjusted at 298 nm and performed at room temperature. The method has been validated according to the International Conference on Harmonisation guidelines. The method is successfully applied for the determination of TM in bulk powder and pharmaceutical dosage form.

  18. Tokyo Motor Show 2003; Tokyo Motor Show 2003

    Joly, E.


    The text which follows present the different techniques exposed during the 37. Tokyo Motor Show. The report points out the great tendencies of developments of the Japanese automobile industry. The hybrid electric-powered vehicles or those equipped with fuel cells have been highlighted by the Japanese manufacturers which allow considerable budgets in the research of less polluting vehicles. The exposed models, although being all different according to the manufacturer, use always a hybrid system: fuel cell/battery. The manufacturers have stressed too on the intelligent systems for navigation and safety as well as on the design and comfort. (O.M.)

  19. Risk Aversion in Game Shows

    Andersen, Steffen; Lau, Morten I.; Rutström, E. Elisabet


    , and the dynamic nature of the task in most games. We consider the game shows Card Sharks, Jeopardy!, Lingo, and finally Deal Or No Deal. We provide a detailed case study of the analyses of Deal Or No Deal, since it is suitable for inference about risk attitudes and has attracted considerable attention....

  20. Phyllodes tumor showing intraductal growth.

    Makidono, Akari; Tsunoda, Hiroko; Mori, Miki; Yagata, Hiroshi; Onoda, Yui; Kikuchi, Mari; Nozaki, Taiki; Saida, Yukihisa; Nakamura, Seigo; Suzuki, Koyu


    Phyllodes tumor of the breast is a rare fibroepithelial lesion and particularly uncommon in adolescent girls. It is thought to arise from the periductal rather than intralobular stroma. Usually, it is seen as a well-defined mass. Phyllodes tumor showing intraductal growth is extremely rare. Here we report a girl who has a phyllodes tumor with intraductal growth.

  1. Pembrolizumab Shows Promise for NSCLC.


    Data from the KEYNOTE-001 trial show that pembrolizumab improves clinical outcomes for patients with advanced non-small cell lung cancer, and is well tolerated. PD-L1 expression in at least 50% of tumor cells correlated with improved efficacy.

  2. Create a Polarized Light Show.

    Conrad, William H.


    Presents a lesson that introduces students to polarized light using a problem-solving approach. After illustrating the concept using a slinky and poster board with a vertical slot, students solve the problem of creating a polarized light show using Polya's problem-solving methods. (MDH)

  3. Reality show: um paradoxo nietzschiano

    Ilana Feldman


    Full Text Available

    O fenômeno dos reality shows - e a subseqüente relação entre imagem e verdade - assenta-se sobre uma série de paradoxos. Tais paradoxos podem ser compreendidos à luz do pensamento do filósofo alemão Friedrich Nietzsche, que, através dos usos de formulações paradoxais, concebia a realidade como um mundo de pura aparência e a verdade como um acréscimo ficcional, como um efeito. A ficção é então tomada, na filosofia de Nietzsche, não em seu aspecto falsificante e desrealizador - como sempre pleiteou nossa tradição metafísica -, mas como condição necessária para que certa espécie de invenção possa operar como verdade. Sendo assim, a própria expressão reality show, através de sua formulação paradoxal, engendra explicitamente um mundo de pura aparência, em que a verdade, a parte reality da proposição, é da ordem do suplemento, daquilo que se acrescenta ficcionalmente - como um adjetivo - a show. O ornamento, nesse caso, passa a ocupar o lugar central, apontando para o efeito produzido: o efeito-de-verdade. Seguindo, então, o pensamento nietzschiano e sua atualização na contemporaneidade, investigaremos de que forma os televisivos “shows de realidade” operam paradoxalmente, em consonância com nossas paradoxais práticas culturais.

  4. Impactfactors and optimization method on the separation of active components in licorice by micellar thin layer chromatography%胶束薄层色谱分离甘草活性成分的影响因素及优化方法

    崔淑芬; 林焕冰; 王小如


    目的:为甘草的胶束薄层色谱指纹图谱寻找最优胶束流动相.方法:首先采用单因子法,寻找影响甘草胶束薄层色谱的影响因素,在此基础上,采用控制加权可变步长单纯形优化法进行甘草胶束薄层色谱指纹图谱的流动相优化.结果:对甘草的胶束薄层色谱分离条件(表面活性剂的种类和含量、醇和酸改性剂的影响等)进行了实验,表明纯胶束薄层色谱的柱效较低,加入醇和酸类改性剂后柱效有明显提高.通过对改性胶束的进一步优化(控制加权可变步长单纯形优化法),得到优化的甘草改性胶束展开剂组成为:0.23 mol·L-1的SDS+ 16%(v/v)正丁醇+11%(v/v)甲酸.本研究对胶束薄层色谱的一些分离机理亦进行了探讨.结论:胶束薄层色谱的表面活性剂和各添加剂间存在交互作用,需采用合适的优化方法,才能达到分离中药材复杂活性成分群的目的.%Objective: To seek the best mobile phase of micellar thin - layer chromatography ( MTLC) of licorice fingerprint. Method: Single impact factor of mobile phase in licorice MTLC fingerprint was tested individually and controlled weighted centroid simplex method was used finally to optimize the mobile phase of licorice MTLC fingerprint. Results: The selectivity of micellar TLC was studied for the separation of active components in licorice under various operation variables including concentrations of surfactant and co - surfactant, surfactant type, addition of acid modifier,et al. The results show that the low chromatography efficiency of micellar TLC could be improved by the addition of alcohol and acid modifier. Using controlled weighted centroid simplex method,optimization micellar TLC developing system of licorice was achieved which consists of 0. 23 mol · L-1 SDS,16% (v/v)n -butanol and 11% (v/v)methyl acid. In addition,the separation mechanism of micellar TLC was also discussed. Conclusion: he appropriate optimization method should

  5. Micellar HPLC Method for Simultaneous Determination of Ethamsylate and Mefenamic Acid in Presence of Their Main Impurities and Degradation Products.

    Ibrahim, Fawzia; Sharaf El-Din, Mohie K; El-Deen, Asmaa Kamal; Shimizu, Kuniyoshi


    An eco-friendly sensitive, rapid and less hazardous micellar liquid chromatographic method was developed and validated for the simultaneous analysis of ethamsylate (ETM) and mefenamic acid (MFA) in the presence of hydroquinone (HQ) and 2,3-dimethylaniline (DMA) the main impurities of ETM and MFA, respectively. Good chromatographic separation was attained using Eclipse XDB-C8 column (150 mm × 4.6 mm, 5 μm particle size) adopting UV detection at 300 nm with micellar mobile phase consisting of 0.12 M sodium dodecyl sulfate, 0.3% triethylamine and 15% 2-propanol in 0.02 M orthophosphoric acid (pH 7.0) at 1.0 mL/min. The analytes were well resolved in <6.0 min, ETM (tR = 1.55 min), HQ (tR = 1.95 min), MFA (tR = 4.55 min) and DMA (tR = 5.80 min). Different validation parameters were examined as recommended by international conference on harmonization (ICH) guidelines. The method was linear over the concentration ranges of 0.5-18.0, 0.5-20.0, 0.01-0.5 and 0.02-0.2 µg/mL with limits of detection of 0.118, 0.159, 0.005 and 0.005 µg/mL and limits of quantification of 0.358, 0.482, 0.014 and 0.015 µg/mL for ETM, MFA, HQ and DMA, respectively. The suggested method was successfully applied for the determination of the two drugs in their bulk powder, laboratory-prepared mixtures, single-ingredient and co-formulated tablets. The obtained results were in accordance with those of the comparison method. The method can also detect trace amounts of HQ and DMA as the main impurities of ETM and MFA, respectively, within the BP limit (0.1%) for both impurities. Furthermore, it is a stability-indicating one for the determination of ETM in its pure form, single-component tablet and co-formulated tablets with other drugs. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email:

  6. Co-delivery of doxorubicin and (131)I by thermosensitive micellar-hydrogel for enhanced in situ synergetic chemoradiotherapy.

    Huang, Pingsheng; Zhang, Yumin; Wang, Weiwei; Zhou, Junhui; Sun, Yu; Liu, Jinjian; Kong, Deling; Liu, Jianfeng; Dong, Anjie


    Combined chemoradiotherapy is potent to defeat malignant tumor. Concurrent delivery of radioisotope with chemotherapeutic drugs, which also act as the radiosensitizer, to tumor tissues by a single vehicle is essential to achieve this objective. To this end, a macroscale injectable and thermosensitive micellar-hydrogel (MHg) depot was constructed by thermo-induced self-aggregation of poly(ε-caprolactone-co-1,4,8-trioxa[4.6]spiro-9-undecanone)-poly(ethyleneglycol)-poly(ε-caprolactone-co-1,4,8-trioxa[4.6]spiro-9-undecanone) (PECT) triblock copolymer micelles (Ms), which could not only serve as a micellar drug reservoir to locally deliver concentrated nano chemotherapeutic drugs, but also immobilize radioisotopes at the internal irradiation hot focus. Doxorubicin (DOX) and iodine-131 labeled hyaluronic acid ((131)I-HA) were used as the model therapeutic agents. The aqueous mixture of drug-loaded PECT micelles and (131)I-HA exhibited sol-to-gel transition around body temperature. In vitro drug release study indicated that PECT/DOX Ms were sustainedly shed from the native PECT/DOX MHg formulation, which could be internalized by tumor cells with rapid intracellular DOX release. This hydrogel formulation demonstrated considerable in vitro antitumor effect as well as remarkable radiosensitization. In vivo subcutaneous injection of PECT MHg demonstrated that (131)I isotope was immobilized stably at the injection location and no obvious indication of damage to major organs were observed as indicated by the histopathological analysis. Furthermore, the peritumoral injection of chemo-radiation therapeutic agents-encapsulated MHg formulation on tumor-bearing nude mice resulted in the desired combined treatment effect, which significantly improved the tumor growth inhibition efficiency with minimized drug-associated side effects to major organs. Consequently, such a thermosensitive MHg formulation, which enabled the precise control over the dosage and ratio of combination

  7. Micellar solubilization of ibuprofen: influence of surfactant head groups on the extent of solubilization Solubilização micelar do ibuprofeno: influência do grupo polar dos tensoativos no grau de solubilização

    Carlota O. Rangel-Yagui


    Full Text Available An important property of micelles with particular significance in pharmacy is their ability to increase the solubility of poorly soluble drugs in water, thus increasing their bioavailability. In this work, the solubilization of ibuprofen (IBU was studied in micellar solutions of three surfactants possessing the same hydrocarbon tail but different hydrophilic head groups, namely sodium dodecyl sulphate (SDS, dodecyltrimethylammonium bromide (DTAB, and n-dodecyl octa(ethylene oxide (C12EO8. The results showed that, irrespective of the surfactant type, the solubility of IBU increased linearly with increasing surfactant concentration, as a consequence of the association between the drug and the micelles. The 80 mM DTAB and the 80 mM C12EO8 micellar solutions resulted in a 16-fold increase in solubility of IBU when compared to the buffer solution, whereas the 80 mM SDS micellar solution resulted in a 5.5-fold increase in IBU solubility. The highest value of molar solubilization capacity (chi was obtained with DTAB, chi = 0.97, followed by C12EO8 ,chi = 0.72, and finally SDS, chi = 0.23. However, due to the stronger tendency of the nonionic surfactant in forming micelles in solution, at the same surfactant concentration, we obtained the same solubility of IBU in both DTAB and C12EO8.Uma propriedade importante das micelas, do ponto de vista farmacêutico, refere-se ao potencial destas em solubilizar fármacos pouco solúveis em água, aumentando sua biodisponibilidade. No presente trabalho, estudou-se a solubilização de ibuprofeno (IBU em soluções micelares constituídas de três tensoativos apresentando a mesma cauda apolar, porém diferentes grupos hidrofílicos. Os tensoativos estudados foram dodecil sulfato de sódio (SDS, brometo de dodeciltrimetilamônio (DTAB e óxido de n-dodecil octaetileno (C12EO8. De acordo com os resultados obtidos, a solubilidade do IBU aumentou linearmente com o aumento da concentração de todos os tensoativos

  8. Picasso on Show in Shanghai


    A staff member of the National Picasso Museum of France checks one of the great Spanish artist Pablo Picasso’s works at the China Pavilion inside the site of the 2010 World Expo in Shanghai on October 12.Sixty-two priceless paintings and statues selected from the works of the renowned artist have been brought to the pavilion for an upcoming exhibition to premiere on October 18.Besides these representative masterpieces,50 valuable photographs showing the artist’s whole life will also be presented.The exhibition’s estimated value is 678 million euros ($934 million).It will be held until January 10,2012.

  9. Reality shows: uma abordagem psicossocial

    Marília Pereira Bueno Millan

    Full Text Available Desde os primórdios da civilização, o ser humano mostra necessidade de representar cenicamente seus dramas pessoais e vicissitudes existenciais. O "reality show" é uma das versões pós-modernas da encenação da vida humana. Este artigo, por meio de uma pesquisa bibliográfica, analisa criticamente as relações existentes entre o "reality show" e aspectos psicossociais do comportamento humano. Conclui-se que tais programas televisivos são o retrato da contemporaneidade, ou seja, revelam a morte do sujeito, a fugacidade das experiências vividas, a desvalorização da história e o culto à imagem e à superficialidade. Por meio da sedução do espectador, mobilizam-se aspectos primitivos de seu psiquismo, fazendo com que ele se sinta narcisicamente poderoso e onipotente e se acredite dono do destino dos participantes do programa. Sugerem-se novos estudos que contribuam para a reflexão crítica e maior conscientização.

  10. "Medicine show." Alice in Doctorland.


    This is an excerpt from the script of a 1939 play provided to the Institute of Social Medicine and Community Health by the Library of Congress Federal Theater Project Collection at George Mason University Library, Fairfax, Virginia, pages 2-1-8 thru 2-1-14. The Federal Theatre Project (FTP) was part of the New Deal program for the arts 1935-1939. Funded by the Works Progress Administration (WPA) its goal was to employ theater professionals from the relief rolls. A number of FTP plays deal with aspects of medicine and public health. Pageants, puppet shows and documentary plays celebrated progress in medical science while examining social controversies in medical services and the public health movement. "Medicine Show" sharply contrasts technological wonders with social backwardness. The play was rehearsed by the FTP but never opened because funding ended. A revised version ran on Broadway in 1940. The preceding comments are adapted from an excellent, well-illustrated review of five of these plays by Barabara Melosh: "The New Deal's Federal Theatre Project," Medical Heritage, Vol. 2, No. 1 (Jan/Feb 1986), pp. 36-47.

  11. Casimir experiments showing saturation effects

    Sernelius, Bo E


    We address several different Casimir experiments where theory and experiment disagree. First out is the classical Casimir force measurement between two metal half spaces; here both in the form of the torsion pendulum experiment by Lamoreaux and in the form of the Casimir pressure measurement between a gold sphere and a gold plate as performed by Decca et al.; theory predicts a large negative thermal correction, absent in the high precision experiments. The third experiment is the measurement of the Casimir force between a metal plate and a laser irradiated semiconductor membrane as performed by Chen et al.; the change in force with laser intensity is larger than predicted by theory. The fourth experiment is the measurement of the Casimir force between an atom and a wall in the form of the measurement by Obrecht et al. of the change in oscillation frequency of a 87 Rb Bose-Einstein condensate trapped to a fused silica wall; the change is smaller than predicted by theory. We show that saturation effects can exp...

  12. The forward and backward transport processes in the AOT/hexane reversed micellar extraction of soybean protein.

    Chen, Jun; Chen, Fengliang; Wang, Xianchang; Zhao, Xiaoyan; Ao, Qiang


    Soybean protein was taken as a model protein to investigate two aspects of the protein extraction by sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelles: (1) the forward protein extraction from the solid state, and the effect of pH, AOT concentration, alcohol and water content (W0) on the transfer efficiency; (2) the back-transfer, the capability of the protein to be recovered from the micellar solution. The experimental results led to the conclusion that the highest forward extraction efficiency of soybean protein was reached at AOT concentration 180 mmol l(-1), aqueous pH 7.0, KCl concentration 0.05 mol l(-1), 0.5 % (v/v) alcohol, W0 18. Under these conditions, the forward extraction efficiency of soybean protein achieved 70.1 %. It was noted that the percentage of protein back extraction depended on the salt concentration and pH value. Around 92 % of protein recovery was obtained after back extraction.

  13. A fast and efficient method for the study of caffeine levels in energy drinks using micellar electrokinetic chromatography (MEKC

    Cristiano Augusto Ballus


    Full Text Available Energy drinks are becoming popular in Brazil and in the world due to their stimulant properties. Caffeine is present in energy drinks with the aim of stimulating the central nervous system and intensifying brain activity. On the other hand, the ingestion of high doses of caffeine can cause undesirable symptoms such as anxiety and tachycardia. Therefore, it is necessary to monitor the caffeine content added to energy drinks to guarantee that the levels in the final product are in accordance with the labeling and within the legislation limits. The goal of this work was to validate a fast, efficient, and low-cost method for the determination of caffeine in energy drinks by micellar electrokinetic chromatography (MEKC. A total of seven brands were analyzed, each in three lots. The electrolyte was prepared with 50 mmol.L-1 of sodium dodecyl sulfate (SDS and 10 mmol.L-1 of sodium carbonate (pH 11.0. The mean concentration of caffeine ranged from 122.8 to 318.6 mg.L-1. None of the brands had caffeine levels above the maximum limit. Considering the interval of confidence (95%, 72% of the samples had less caffeine than the amount informed on the product label.

  14. Micellar electrokinetic chromatographic determination of rosuvastatin in rabbit plasma and evaluation of its pharmacokinetics and interaction with niacin.

    El-Kommos, Michael E; Mohamed, Niveen A; Ali, Hassan R H; Abdel Hakiem, Ahmed F


    A specific, accurate, precise and reproducible micellar electrokinetic chromatographic method was developed for in vitro and in vivo estimation of rosuvastatin, a synthetic and potent HMG-CoA inhibitor, in rabbit plasma. Further, its pharmacokinetics in the presence of niacin, which could be co-administered for monitoring of severe hypercholestremia, was investigated. The assay procedures involved simple liquid-liquid extraction of rosuvastatin and internal standard, atorvastatin, from a small plasma volume directly into acetonitrile. The organic layer was separated and evaporated under a gentle stream of nitrogen. The residue was reconstituted in the mobile phase and injected electrokinetically into electropherosis system. The background electrolyte consisted of borate buffer (25.0 mm, pH 9.5), 10.0% organic modifier (5.0% methanol + 5.0% acetonitrile) and 25.0 mm sodium dodecyl sulfate at 20.0 kV applied voltage and 215.0 nm detection wavelength for the effective separation of rosuvastatin, niacin and atorvastatin.

  15. Micellar Electrokinetic Chromatography with Laser-Induced Fluorescence Detection for Separation of Red and Yellow Historical Dyes

    Shokoufeh Ahmadi


    Full Text Available In this study, the separation parameters in micellar electrokinetic chromatography (MEKC-laser-induced fluorescence (LIF were optimized for the separation of red and yellow historical dyes in 20 mM borate buffer with 20 mM sodium dodecyl sulfate (SDS. Separation conditions were optimized by changing pH, organic modifier (methanol and acetonitrile concentrations and applied voltage. The mixtures of dyes used in this study included four anthraquinone dyes (alizarin, purpurin, emodin and carmine and six flavonoid dyes (luteolin, apigenin, kaempferol, quercetin, morin and myricetin. For this work, dyes were introduced electro-kinetically (10 kV for 5 s into a 50 cm capillary (10 µm id and separated using a running potential of 18, 20, 22 and 25 kV. Absolute limits of detection for most of these dyes was less than 1 pg. For dyes such as alizarin, improved detection limits were achieved at pH = 9.24; however dyes such as purpurin had significantly improved detection limits at pH = 8.0. The successful extraction and identification of a number of dyes in plants and textiles samples is also described.

  16. Optimization of micellar electrokinetic capillary chromatography method using central composite design for the analysis of components in Yangwei granule

    Shu-fang WANG; Hai-yan FANG; Hai-bin QU


    Central composite design (CCD), together with multiple linear regression, was successfully used to optimize the electrophoretic buffer system of micellar electrokinetic capillary chromatography (MEKC) for the determination of albiflorin, paeoniflorin, liquiritin, and glycyrrhizic acid in the traditional Chinese medicine (TCM) prescription,Yangwei granule. Concentrations of sodium deoxycholate (SDC) and borate, and proportions of ammonia, acetonitrile,and methanol were optimized. The total resolutions of peaks between the analytes and their adjacent peaks in real samples were integrated into the evaluation index of separation efficiency. The optimum electrophoretic buffer contained 80 mmol/L SDC, 20 mmol/L borate, 5% (v/v) methanol, 0.5% (v/v) ammonia, and 5% (v/v) acetonitrile. The correlation coefficients (R2) between the peak areas and the corresponding concentrations of analytes were greater than 0.9956. The limits of detection (LODs) (S/N=3) of the analytes were 0.97-4.00 μg/mi. The results indicate the superiority of CCD in optimizing the separation conditions of complex samples such as TCM prescriptions.

  17. Simultaneous and Rapid Determination of Main Lignans in Different Parts of Schisandra Sphenanthera by Micellar Electrokinetic Capillary Chromatography

    Ming Guan


    Full Text Available Lignans are imporant active ingredients of Schisandra sphenanthera. A micellar electrokinetic chromatography method was developed for the simultaneous determination of eight lignans – schizandrin, schisandrol B, schisantherin A, schisanhenol, anwulignan, deoxyschizandrin, schizandrin B and schizandrin C – in different parts of S. sphenanthera. The key factors for separation and determination were studied and the best analysis conditions were obtained using a background electrolyte of 10 mM phosphate-37.5 mM SDS-35% v/v acetonitrile (pH 8.0 at the separation voltage of 28 kV and detection at 214 nm, whereby the plant samples could be analyzed within 9.0 min. Analysis yielded good reproducibility (RSD between 1.19-2.28% and good recovery (between 92.2-103.8%. The detection limits (LOD and limit of quantification (LOQ were within 0.4-1.2 mg/L and 1.5-4.0 mg/L. This method is promising to improve the quality control of different parts of S. sphenanthera.

  18. Sensitive determination of pyrrolizidine alkaloids in Tussilago farfara L. by field-amplified, sample-stacking, sweeping micellar electrokinetic chromatography.

    Cao, Kun; Xu, Yi; Mu, Xiuni; Zhang, Qing; Wang, Renjie; Lv, Junjiang


    Pyrrolizidine alkaloids are the toxic components in Tussilago farfara L. Due to the lack of standard substances for quantitative analysis and traces of pyrrolizidine alkaloids in total alkaloids, the full quality control of Tussilago farfara L has been limited. In this study, we aimed to solve the difficulty of determination of pyrrolizidine alkaloids and identify more components in the total alkaloids. An on-line preconcentration method has been applied to improve determining sensitivity of pyrrolizidine alkaloids in Tussilago farfara L. in which included field-amplified sample stacking and sweeping in micellar electrokinetic capillary chromatography. The main parameters that affected separation and stacking efficiency were investigated in details. Under the optimal conditions, the sensitivity enhancement factors obtained by the developed method for the analytes were from 15- to 12-fold, the limits of detection of senkirkine and senecionine were 2∼5 μg/L. Senkirkine and senecionine have been detected in alkaloids (c) of Tussilago farfara L, along ferulic acid methyl ester and methyl caffeate. The developed method was also applied to the analysis of acid extraction (a) of Tussilago farfara L, and senkirkine could be detected directly. The results indicated that the developed method is feasible for the analysis of pyrrolizidine alkaloids in Tussilago farfara L with good recoveries.

  19. Direct determination of lignin peroxidase released from Phanerochaete chrysosporium by in-capillary enzyme assay using micellar electrokinetic chromatography.

    Harada, Airi; Sasaki, Keiko; Kaneta, Takashi


    Here we describe the application of an in-capillary enzyme assay using micellar electrokinetic chromatography (MEKC) in the determination of enzyme activity in a crude culture medium containing lignin peroxidase released from Phanerochaete chrysosporium (P. chrysosporium). The method consists of a plug-plug reaction between lignin peroxidase and its substrate, veratryl alcohol, the separation of the product, veratraldehyde, from the other components including the enzyme and the culture medium, and the determination of the enzyme activity from the peak area of veratraldehyde produced by the plug-plug reaction. This method is more sensitive than conventional spectrophotometry since the background originates from the enzyme and the culture medium can be removed via MEKC separation. Veratraldehyde was separated at -10kV in a background electrolyte containing 50mM tartrate buffer (pH 2.5) and 50mM sodium dodecyl sulfate (SDS) after a plug-plug reaction in the capillary for 5min. The calibration curve of veratraldehyde was linear up to 4pmol (500μM) with a limit to quantification of 0.026pmol (3.2μM) (SN=10). The activity of lignin peroxidase was directly measured from the peak area of veratraldehyde. The activity of lignin peroxidase released from P. chrysosporium into the medium for 7 days was successfully determined to be 3.40UL(-1).

  20. Micellar Liquid Chromatography Determination of Spermine in Fish Sauce after Derivatization with 3,5-Dinitrobenzoyl Chloride

    Mei-Liang Chin-Chen


    Full Text Available A practical liquid chromatographic method has been developed for the selective determination of the levels of spermine in anchovy sauce after derivatization with 3,5 dinitrobenzoyl chloride. The micellar liquid chromatographic separation proposed here uses a C18 column (125×4.6 mm, followed by detection of spermine derivative at 260 nm. Elution of the analyte was performed using a mobile phase of 0.15 M SDS-4% (v/v 1-pentanol-pH 7 running under isocratic mode at 25°C. Validation parameters were linearity (2–100 μg/mL, R2>0.999, detection and quantification limits (0.4 and 1.2 μg/mL, resp., precision (less than 3.6%, accuracy (93.3–101.1%, and robustness (less than 4.8%. These results are in agreement with the requirements of the FDA guidelines. The proposed method was successfully applied to the monitorization of spermine formation in unsalted and salted fish sauce samples. The suggested methodology was found useful in routine analysis of spermine in fish sauce samples.

  1. Micellar Electrokinetic Chromatographic Study of the Separation of an Aromatase Inhibitor and a Tryciclic Antidepressant in the Breast Cancer Treatment

    J. Rodríguez Flores


    Full Text Available Micellar electrokinetic chromatography (MEKC was investigated for the simultaneous determination of letrozole, imipramine and their metabolites in human urine samples over a concentration range of therapeutic interest. Experimental parameters such as pH of the running electrolyte, sodium dodecylsulphate (SDS concentration, borate concentration, voltage, etc were investigated. Under optimal conditions of 25 mM SDS, 15 mM borate buffer (pH 9.2, 15% 2-propanol, as back- ground electrolyte; 28 kV and 40 ºC, as voltage and cartridge temperature, respectively; resolution between the peaks was greater than 1.7. Before the determination, a solid phase extraction (SPE procedure with a C18 cartridge was optimized. Good linearity, accuracy, precision, robustness and ruggedness were achieved and detection limits of 12.5 ng/mL for letrozole and its metabolite and 37.5 ng/mL, were obtained for imipramine and their metabolites. Real determinations of these analytes in two patient urines were carried out. Sensitivity achieved in this method is sufficient to perform kinetic studies in humans.

  2. Determination of eight triazine herbicide residues in cereal and vegetable by micellar electrokinetic capillary chromatography with on-line sweeping.

    Fang, Rou; Chen, Guan-hua; Yi, Ling-xiao; Shao, Yu-xiu; Zhang, Li; Cai, Qing-hong; Xiao, Jing


    A new method was developed for the determination of eight triazine herbicide residues in cereal and vegetable samples by on-line sweeping technique in micellar electrokinetic capillary chromatography (MEKC). Some factors affecting analyte enrichment and separation efficiency were examined. The optimum buffer was composed of 25 mM borate, 15 mM phosphate, 40 mM sodium dodecylsulfate (SDS) and 3% (v/v) of 1-propanol at pH 6.5. The separation voltage was 20 kV and the sample was injected at 0.5 psi for 240 s. The detection wavelength was set at 220 nm with the capillary temperature being at 25 °C. Under the optimized conditions, the enrichment factors were achieved from 479 to 610. The limits of detection (LODs, S/N = 3) ranged from 0.02 to 0.04 ng/g and the limits of quantification (LOQs) of eight triazine herbicides were all 0.1 ng/g. The average recoveries of spiked samples were 82.8-96.8%. This method has been successfully applied to the determination of the triazine herbicide residues in cereal and vegetable samples.

  3. Retention-property relationships of 1,2,4-triazoles by micellar and reversed-phase liquid chromatography.

    Janicka, Małgorzata; Pachuta-Stec, Anna


    The properties of 21 1,2,4-triazoles, relevant to their pharmacokinetics, were investigated using experimental methods and in silico calculations. The lipophilicities of the compounds were determined experimentally using reversed-phase chromatography and liquid chromatography with micellar mobile phases, or they were calculated in silico from their molecular structures. In the reversed-phase technique, an octadecylsilyl, immobilized artificial membrane and immobilized cholesterol were used as the stationary phases. Biological descriptors of compounds, i.e. log BB, log KHSA, Caco-2, and fu,brain, were determined in silico by using ACD/Percepta software. Principal component analysis was used to indicate similarities between chromatographic, partitioning, and biological variables. Highly significant relationships were determined to exist between the chromatographic parameters and the biological descriptors, especially for log BB and log KHSA. The chromatographic parameters measured on the cholesterol column were recommended for use in predicting the lipophilic and biological properties of the 1,2,4-triazoles that were tested.

  4. Effect of low concentration sodium dodecyl sulfate on the electromigration of palonosetron hydrochloride stereoisomers in micellar electrokinetic chromatography.

    Hu, Shao-Qiang; Wang, Gui-Xia; Guo, Wen-Bo; Guo, Xu-Ming; Zhao, Min


    The effect of low concentrations of sodium dodecyl sulfate (SDS) on the separation of palonosetron hydrochloride (PALO) stereoisomers by micellar electrokinetic chromatography (MEKC) has been investigated. It was found that the addition of SDS prolongs the migration time and the migration order of four stereoisomers changes regularly with the SDS concentration. Good separations for all the four stereoisomers were achieved at appropriate SDS concentration. The effect of SDS on the electromigration (mobilities) of PALO stereoisomers has been studied, in order to explain its effect on the separation by MEKC. It was found that low concentrations of SDS added into the separation media forms negatively charged complexes with PALO stereoisomers and hence reverses their electromigration direction. Furthermore, the migration order between two enantiomeric pairs is also reversed because the enantiomeric pair with a bigger positive mobility than that of another pair turns to have a bigger negative mobility when bound with SDS. Based on these results, the effect of SDS on the MEKC separation of PALO stereoisomers was elucidated reasonably. The performance of the developed chiral MEKC method was validated by the analysis of a real sample.

  5. Determination of tamoxifen and its main metabolites in plasma samples from breast cancer patients by micellar liquid chromatography.

    Peris-Vicente, Juan; Ochoa-Aranda, Enrique; Bose, Devasish; Esteve-Romero, Josep


    A method was developed for the analysis of tamoxifen and its main derivatives (4-hydroxytamoxifen, N-desmethyl-tamoxifen, tamoxifen-N-oxide and endoxifen) in human plasma, using micellar liquid chromatography coupled with fluorescence detection. Analytes were off-line derivatized by sample UV-irradiation for 20 min to form the photocycled fluorescent derivatives. Then samples were diluted, filtered and directly injected, thus avoiding extraction steps. The analytes were resolved using a mobile phase containing 0.08 M SDS-4.5% butanol at pH 3 running at 1.5 mL/min through a C18 column at 40°C, without interferences from endogenous compounds in plasma. Excitation and emission wavelengths were 260 and 380 nm, respectively. The chromatographic analysis time was less than 40 min. The analytical methodology was validated following the International Conference on Harmonization of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) guidelines in terms of: selectivity, linear range (0.3-15 μg/mL), linearity (r(2)>0.999), sensitivity (LOD, 65-80 ng/mL; LOQ, 165-200 ng/mL), intra- and interday accuracy (-12.2-11.5%) and precision (<9.2%) and robustness (<6.3%). The method was used to quantify the tamoxifen and tamoxifen derivatives in several breast cancer patients from a local hospital, in order to study the correlation between the genotype of the patient and the ability to metabolize tamoxifen.

  6. Quantification of main bioactive metabolites from saffron (Crocus sativus) stigmas by a micellar electrokinetic chromatographic (MEKC) method.

    Gonda, Sándor; Parizsa, Péter; Surányi, Gyula; Gyémánt, Gyöngyi; Vasas, Gábor


    Saffron is an expensive spice, cultivated in many regions of the world. Its chief metabolites include crocins, which are responsible for the coloring ability, safranal, which is the main essential oil constituent, and picrocrocin which is the main bitter constituent of the spice. A simple micellar capillary electrochromatographic (MEKC) method capable of quantifying all three types of main constituents was established. The pH, sodium dodecyl sulphate (SDS) content and electrolyte concentration of the background electrolyte was optimized. A simple extraction protocol was developed which can extract all metabolites of different polarity from the saffron stigmas. Optimal background electrolyte composed of 20 mM disodium phosphate, 5mM sodium tetraborate, 100 mM SDS, pH was set 9.5. Optimal extracting solvent was the background electrolyte, incubated with the sample for 60 min. The proposed method allows quantification of picrocrocin, safranal, crocetin- Di-(β-D-gentiobiosyl) ester and crocetin (β-D-glycosyl)-(β-D-gentiobiosyl) ester within 17.5 min, with limit of detection values ranging from 0.006 to 0.04 mg/ml, from a single stigma.

  7. Simultaneous optimization of variables influencing selectivity and elution strength in micellar liquid chromatography. Effect of organic modifier and micelle concentration.

    Strasters, J K; Breyer, E D; Rodgers, A H; Khaledi, M G


    Previously, the simultaneous enhancement of separation selectivity with elution strength was reported in micellar liquid chromatography (MLC) using the hybrid eluents of water-organic solvent-micelles. The practical implication of this phenomenon is that better separations can be achieved in shorter analysis times by using the hybrid eluents. Since both micelle concentration and volume fraction of organic modifier influence selectivity and solvent strength, only an investigation of the effects of a simultaneous variation of these parameters will disclose the full separation capability of the method, i.e. the commonly used sequential solvent optimization approach of adjusting the solvent strength first and then improving selectivity in reversed-phase liquid chromatography is inefficient for the case of MLC with the hybrid eluents. This is illustrated in this paper with two examples: the optimization of the selectivity in the separation of a mixture of phenols and the optimization of a resolution-based criterion determined for the separation of a number of amino acids and small peptides. The large number of variables involved in the separation process in MLC necessitates a structured approach in the development of practical applications of this technique. A regular change in retention behavior is observed with the variation of the surfactant concentration and the concentration of organic modifier, which enables a successful prediction of retention times. Consequently interpretive optimization strategies such as the interative regression method are applicable.

  8. Features of mixing micellar muds with oil and water in their influence on efficiency of oil displacement

    Jiang, Y.; Lu, G.


    An experimental study was made of the process of mixing micellar muds (MM) and different composition with oil and water (a total of 150 samples), and also the influence of this mixing on the efficient displacement of oil with the use of MM to increase oil output. It has been indicated that the process of mixing MM with oil and water can be examined as a process of diffusion. It is described by the second law of Fick. In this case the coefficient of diffusion depends on the concentration of salt in water: with an increase in concentration of salt in water, the coefficient of diffusion of MM in water is diminished, and in oil increases. In addition, the coefficient of diffusion depends on the viscosity of MM, and is higher if the initial concentration of the diffused substance is high. It was found that in the process of mixing MM with oil in water, emulsification of dilution and selected emulsification and MM of different compositions can be divided into four types: does not emulsify in oil and water; does not emulsify in oil, but emulsifies in water; emulsifies in oil but does not emulsify in water, and emulsifies in oil and water. It was established that of the aforementioned four types of MM, type one has the highest effective displacement of oil. Injection initially of MM of type two, and then type 3 results in even higher efficiency of oil displacement.

  9. A validated micellar electrokinetic chromatography method for the quantitation of dexamethasone, ondansetron and aprepitant, antiemetic drugs, in organogel.

    Bourdon, Florence; Lecoeur, Marie; Duhaut, Marion; Odou, Pascal; Vaccher, Claude; Foulon, Catherine


    A micellar electrokinetic chromatography (MEKC) method was developed for the determination of three anti-vomiting drugs (aprepitant, dexamethasone and ondansetron) in pharmaceutical formulations. The method was optimized using a central composite design (CCD). Four main factors (borate buffer concentration, pH, methanol content and sodium dodecyl sulfate concentration) were optimized in order to obtain best resolutions and peak efficiencies in a minimum runtime. The separation was performed in a fused-silica capillary. After optimization, the background electrolyte consisted of a borate buffer (62.5mM, pH 8.75) containing sodium dodecyl sulfate (77.5mM) and methanol (3.75%). Under these conditions, a complete separation of each antiemetic drug and its respective internal standards was achieved in 38min. The method was validated with trueness values from 94.9 to 107.2% and precision results (repeatability and intermediate precision) lower than 5.9%. MEKC-UV was the first method allowing the separation of aprepitant, dexamethasone and ondansetron and was suitable for the quantitation of these three antiemetic drugs in organogel formulations. The rapid sample preparation coupled with an automated separation technique make this method convenient for quality control of extemporaneous magistral ready-to-use formulation.

  10. Examining the Roles of Emulsion Droplet Size and Surfactant in the Interfacial Instability-Based Fabrication Process of Micellar Nanocrystals

    Sun, Yuxiang; Mei, Ling; Han, Ning; Ding, Xinyi; Yu, Caihao; Yang, Wenjuan; Ruan, Gang


    The interfacial instability process is an emerging general method to fabricate nanocrystal-encapsulated micelles (also called micellar nanocrystals) for biological detection, imaging, and therapy. The present work utilized fluorescent semiconductor nanocrystals (quantum dots or QDs) as the model nanocrystals to investigate the interfacial instability-based fabrication process of nanocrystal-encapsulated micelles. Our experimental results suggest intricate and intertwined roles of the emulsion droplet size and the surfactant poly (vinyl alcohol) (PVA) used in the fabrication process of QD-encapsulated poly (styrene-b-ethylene glycol) (PS-PEG) micelles. When no PVA is used, no emulsion droplet and thus no micelle is successfully formed; Emulsion droplets with large sizes ( 25 μm) result in two types of QD-encapsulated micelles, one of which is colloidally stable QD-encapsulated PS-PEG micelles while the other of which is colloidally unstable QD-encapsulated PVA micelles; In contrast, emulsion droplets with small sizes ( 3 μm or smaller) result in only colloidally stable QD-encapsulated PS-PEG micelles. The results obtained in this work not only help to optimize the quality of nanocrystal-encapsulated micelles prepared by the interfacial instability method for biological applications but also offer helpful new knowledge on the interfacial instability process in particular and self-assembly in general.

  11. Excimer formation and singlet-singlet energy transfer of organoluminophores in the premicellar and micellar-polyelectrolytes solutions

    Bisenbaev, Adel K.; Levshin, L. V.; Saletsky, A. M.


    Recently the investigation of photoprocesses in organized synthetical structures (ionic micelles, vesicles, linear polyelectrolytes, polymer gels etc.), intermolecular interactions of which are formed by hydrophobic and electric forces, have been of great interest.12 These systems are of particular interest due to the possibility of using luminescent data, which reflected the peculiarities of photoprocesses in organized assemblies. This can be used to establishing the mechanism of photobiological processes. Due to the very complex nature of biostructures our approximation can be considered phenomenological, however it gives the possibility of revealing the energy dissipation path in biosystems. Such model approach is based on a principal resemblance between a living matter and synthetical polymolecular structures with a certain degree of organization. This resemblance is displayed in theoretical models of synthetic polymers,3 which are the foundation of modern ideas on biomolecule conformation. Organized synthetical structures like ionic micelles, polymer gel, bilayer and strong polyelectrolytes could be made to represent biosystems like cell, protoplasm, membrane and NADH, respectively. In this paper we report some new results on the complex formation of dyes and detergents in premicellar region and singlet-singlet energy transfer from pyrene (Py) excimer to dye monomers in ionic micellar-polyion-water system.

  12. Lignin chemistry: biosynthetic study and structural characterisation of coniferyl alcohol oligomers formed in vitro in a micellar environment.

    Reale, Samantha; Attanasio, Francesca; Spreti, Nicoletta; De Angelis, Francesco


    Model coniferyl alcohol lignin (the so-called dehydrogenative polymerisate, DHP) was produced in water under homogeneous conditions guaranteed by the presence of a micellised cationic surfactant. A complete study of the activity of the enzymatic system peroxidase/H(2)O(2) under our reaction conditions was reported and all the reaction products up to the pentamer were characterised by (1)H NMR spectroscopy and ESI mass spectrometry. Our system, and the molecules that have been generated in it, represent a closer mimicry of the natural microenvironment since an enzyme, under micellar conditions, reproduces the cell system better than in buffer alone. On the basis of the oligomers structures a new biosynthetic perspective was proposed that focused attention on a coniferyl alcohol dimeric quinone methide as the key intermediate of the reaction. A formal, strictly alternate sequence of a radical and an ionic step underlines the reaction, thus generating ordered oligolignols structures. Alternatively to other model lignins, our olignols present a lower degree of radical coupling between oligomeric units. This offers a closer biosynthetic situation to the observation of a low rate of radical generation in the cell wall.

  13. Micellar electrokinetic chromatography for separation of a mixture of coptis alkaloids, scute flavonoids, and rhubarb anthraquinones and bianthrones.

    Chang, Lin-Chau; Sun, Shao-Wen


    Coptidis Rhizoma, Scutellariae Radix, and Rhei Rhizoma are three common Chinese herbs. There are many herbal formulas which contain either two or all three of the herbs mentioned above. Their bioactive components have already been identified, respectively. However, there is no report about separation of the 13 bioactive constituents of the three herbs at the same time. In order to assess these constituents of related Chinese herbal preparations, a micellar electrokinetic chromatography method was developed. While buffer pH and surfactant concentration affected the resolution of separation, acetonitrile percentage was found to significantly influence the resolution, peak shape, and elution window. Optimum separation of 13 compounds was achieved at pH 7.3 using a buffer mixture of 70% (v/v) 3 mM di-sodium tetraborate, 10 mM sodium dihydrogen phosphate, and 50 mM sodium deoxycholate with 30% (v/v) acetonitrile. When applying the developed method to analyze a model preparation, San-huang-xie-xin-tang, which contains all three herbs, 8 of the 13 bioactive constituents, could be determined. The present study proposed a method to assess San-huang-xie-xin-tang within short analysis time and also provided a possible starting point to evaluate related herbal preparations containing Coptidis Rhizoma, Scutellariae Radix, and Rhei Rhizoma.

  14. Triblock polyphiles through click chemistry: self-assembled thermotropic cubic phases formed by micellar and monolayer vesicular aggregates.

    Tan, Xiaoping; Kong, Leiyang; Dai, Heng; Cheng, Xiaohong; Liu, Feng; Tschierske, Carsten


    Three series of triblock polyphiles consisting of a rigid 4-phenyl-1,2,3-triazole or 1,4-diphenyl-1,2,3-triazole core with three lipophilic and flexible alkoxyl chains at one end and a polar glycerol group at the opposite end were synthesized by copper-catalyzed azide-alkyne click reactions. Their mesophase behavior was studied by polarizing optical microscopy, differential scanning calorimetry, and XRD. Depending on alkyl chain length and core length, a transition from hexagonal columnar to Pm3n-type cubic phases was observed. In the cubic phases, the molecules are organized as spherical objects. Remarkably, compounds with a longer core unit have a higher tendency to form these cubic phases, and their stability is strongly enhanced over those of the compounds with a shorter core, despite longer cores having a smaller cone angle and therefore being expected to disfavor the formation of spherical objects. There is a large difference in the number of molecules involved in the spherical aggregates formed by compounds with long and short cores. Whereas the aggregates in the cubic phases of the compounds with short rod units are small and could be regarded as micellar, the long-core compounds form much larger aggregates which are regarded as a kind of monolayer vesicular aggregate.

  15. Micellar electrokinetic chromatography method for the determination of several natural red dyestuff and lake pigments used in art work.

    Maguregui, M I; Alonso, R M; Barandiaran, M; Jimenez, R M; García, N


    The identification of organic colorants used in artistic paintings is an important information source for reconstructing the working techniques found in a particular work and for defining a programme for the restoration and conservation of the painting. In this work, sodium dodecyl sulfate (SDS) was used as a surfactant in micellar electrokinetic chromatography (MEKC) for separating a broad range of red organic pigments, based on their colouring matters: madder (colouring matters: alizarin, quinizarin and purpurin), cochineal (colouring matter: carminic acid), red sandalwood (colouring matter: santalin), brazilwood (colouring matter: brazilin), lac dye (colouring matter: laccaic acid) and dragon's blood (colouring matter: dracorhodin). The running electrolyte used was 20 mM borax (pH 9), containing 20 mM SDS and 10% acetonitrile as organic modifier. Separation was carried out by applying a +20 kV voltage at the injection end, 25 degrees C and 214 nm/254 nm as detection wavelengths. All colorants were separated within less than 13 min with a good baseline resolution. The method was applied to the analysis of paint samples obtained from the Diocesan Museum of Holy Art of Bilbao.

  16. Validation and divergence of the activation energy barrier crossing transition at the AOT/lecithin reverse micellar interface.

    Narayanan, S Shankara; Sinha, Sudarson Sekhar; Sarkar, Rupa; Pal, Samir Kumar


    In this report, the validity and divergence of the activation energy barrier crossing model for the bound to free type water transition at the interface of the AOT/lecithin mixed reverse micelle (RM) has been investigated for the first time in a wide range of temperatures by time-resolved solvation of fluorophores. Here, picosecond-resolved solvation dynamics of two fluorescent probes, ANS (1-anilino-8-naphthalenesulfonic acid, ammonium salt) and Coumarin 500 (C-500), in the mixed RM have been carefully examined at 293, 313, 328, and 343 K. Using the dynamic light scattering (DLS) technique, the size of the mixed RMs at different temperatures was found to have an insignificant change. The solvation process at the reverse micellar interface has been found to be the activation energy barrier crossing type, in which interface-bound type water molecules get converted into free type water molecules. The activation energies, Ea, calculated for ANS and C-500 are 7.4 and 3.9 kcal mol(-1), respectively, which are in good agreement with that obtained by molecular dynamics simulation studies. However, deviation from the regular Arrhenius type behavior was observed for ANS around 343 K, which has been attributed to the spatial heterogeneity of the probe environments. Time-resolved fluorescence anisotropy decay of the probes has indicated the existence of the dyes in a range of locations in RM. With the increase in temperature, the overall anisotropy decay becomes faster revealing the lability of the microenvironment at elevated temperatures.

  17. Rapid determination of piracetam in human plasma and cerebrospinal fluid by micellar electrokinetic chromatography with sample direct injection.

    Yeh, Hsin-Hua; Yang, Yuan-Han; Ko, Ju-Yun; Chen, Su-Hwei


    A simple micellar electrokinetic chromatography (MEKC) method with UV detection at 200 nm for analysis of piracetam in plasma and in cerebrospinal fluid (CSF) by direct injection without any sample pretreatment is described. The separation of piracetam from biological matrix was performed at 25 degrees C using a background electrolyte consisting of Tris buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Several parameters affecting the separation of the drug from biological matrix were studied, including the pH and concentrations of the Tris buffer and SDS. Under optimal MEKC condition, good separation with high efficiency and short analyses time is achieved. Using imidazole as an internal standard (IS), the linear ranges of the method for the determination of piracetam in plasma and in CSF were all between 5 and 500 microg/mL; the detection limit of the drug in plasma and in CSF (signal-to-noise ratio=3; injection 0.5 psi, 5s) was 1.0 microg/mL. The applicability of the proposed method for determination of piracetam in plasma and CSF collected after intravenous administration of 3g piracetam every 6h and oral administration 1.2g every 6h in encephalopathy patients with aphasia was demonstrated.

  18. Determination of three phthalate esters in environmental samples by coal cinder extraction and cyclodextrin modified micellar electrokinetic chromatography.

    Sun, Hongli; Jiang, Feng; Chen, Lin; Zheng, Jing; Wu, Yiwei; Liu, Meilin


    A new micellar electrokinetic chromatography (MEKC) method using beta-cyclodextrin (ß-CD) as the electrophoresis additive has been developed for the simultaneous determination of dimethyl phthalate (DMP), diethyl phthalate (DEP) and di(2-ethylhexyl) phthalate (DEHP) in environmental samples. To improve the sensitivity of cyclodextrin-modified MEKC (CD-MEKC), a flow injection procedure using a microcolumn packed with coal cinder as the solid-phase extractant was also investigated for the preconcentration and separation of DMP, DEP and DEHP in environmental samples. Parameters affecting CD-MEKC separation and coal cinder flow injection solid-phase extraction were systematically researched. In the presence of the running buffer [5 mmol/L of borax, 5% (v/v) methanol and 25 mmol/L of sodium dodecyl sulfate at pH 9.5], the addition of 14 mmol/L ß-CD greatly improved the separation efficiency. The analytes were quantitatively adsorbed by coal cinders and readily desorbed quantitatively with 0.2 mL of 10% (v/v) methanol-10 mmol/L disodium hydrogen phosphate. Under the optimum conditions, the enrichment factor of coal cinder was 60, and the determination limits of DMP, DEP and DEHP were 3.07, 2.07 and 4.06 ng/mL, respectively. The presented procedure was successfully applied to determine DMP, DEP and DEHP in landfill leachate and water samples with satisfactory results.

  19. Solubilisation des hydrocarbures dans les solutions micellaires Influence de la structure et de la masse moléculaire Solubilization of Hydrocarbons in Micellar Solutions Influence of Structure and Molecular Weight

    Baviere M.


    oil. Such research must result in the adapting of procedures, in searching for solutions and in setting limits to the process from this standpoint. This article describes the methodology and preliminary results leading to the comparing of the phase behavior of mixtures containing model hydrocarbons having different structures, normal alkanes and alkylbenzenes or stock-tank crudes. The methodology is based on the correlations worked out by Reed and Healy [1] between the, existence of low interfacial tensions and the obtaining of a phase diagram having a specific configuration said to be of the Winsor Type III [7]. In this configuration, the multiphase zone contains, in particular, a three-phase domain in which an intermediate micellar phase is in equilibrium with an aqueous phase and a hydrocarbon phase. When the affinity of the surfactant for the water and the hydrocarbon is the same, the micellar phase contains equal amounts of water and hydrocarbon. The system is then considered, by convention to be an optimal one. In mixtures of water, amphiphilic compounds (surfactant and alcohol and hydrocarbons having different molecular weights and structures, the solubilizing power is measured at the reference point obtained by adjusting the molecular weight of the surfactant. However, all optimal systems are not equivalent. Solubilization is all the greater and hence the lowering of the interfacial tension is all the more marked as the energies of cohesion between the surfactant and the water and hydrocarbon are strong. This approach is fruitful for interpreting performance variations when some parameters of the system are modified, such as the molecular weight and structure of the hydrocarbon or the salinity of the water. During this study, we show that the optimal molecular weight of the surfactant varies linearly with that of the pure hydrocarbon (alkane or alkylbenzene, at least within the range of molecular weights examined here. Solubilization also varies linearly. This

  20. Study on Treatment of Radioactive Wastewater Containing Activated Products by Micellar-Enhanced Ultrafiltration Process%含活化产物放射性废水的胶束强化超滤处理研究

    孔劲松; 王晓伟; 姚青旭


    Experiments of removing nickel from simulated radioactive wastewater containing activated products by micellar-enhanced ultrafiltration which using odecylbenzene sulfonate(SDBS) and polyoxyethylene octyl phenyl ether (TritonX-100) as surfactants were carried out. Results showed that rejection efficiency of nickel was affected by the mole ratio of TritonX-100/SDBS, surfactants concentration and pH. Nickel rejection ratio could reach 95% when the mole ratio of TritonX-100/SDBS was 0.1 and feedwater pH was adjusted above 9.0.%以含活化腐蚀产物废水中镍(Ni)为去除对象,采用十二烷基苯磺酸钠( SDBS)和辛基酚聚氧乙烯醚( TritonX-100)复配形成胶束,研究胶束强化超滤(MEUF)处理含活化腐蚀产物废水的效果.结果表明:TritonX-1 00和SDBS复配的MEUF过程对含活化腐蚀产物废水中Ni2+的截留效果受到复配比、表面活性剂用量和pH的影响.保持复配比为0.1,在pH大于9.0时,MEUF对Ni2+的截留率可达95%.

  1. Vortex-assisted liquid-liquid extraction combined with field-amplified sample injection and sweeping micellar electrokinetic chromatography for improved determination of β-blockers in human urine.

    Jouyban, Abolghasem; Sorouraddin, Mohammad Hossein; Farajzadeh, Mir Ali; Somi, Mohammad Hossein; Fazeli-Bakhtiyari, Rana


    A new micellar electrokinetic chromatography (MEKC) method was developed and validated for the analysis of carvedilol and propranolol in human urine samples. In this study, vortex-assisted liquid-liquid extraction (VALLE) coupled with field-amplified sample injection and sweeping was employed for biological sample clean-up and sensitivity enhancement in MEKC. After VALLE, the urine samples were analyzed by MEKC. Tris-phosphate buffer (60mmolL(-1), pH 2.0) containing 40% (v/v) methanol was first filled into an uncoated fused-silica capillary (56cm, 50µm i.d.). The pretreated urine sample was loaded by electrokinetic injection (10kV, 250s). The stacking and separation were performed using Tris-phosphate buffer (30mmolL(-1), pH 3.0) containing 30% (v/v) methanol and 50mmolL(-1) sodium dodecyl sulfate (SDS) at -25kV. Detection was carried out at 195 and 214nm for carvedilol and propranolol, respectively. The suggested method is linear (r(2)≥0.997) over a dynamic range of 0.005-1µgmL(-1) in urine. The intra- and inter-day relative standard deviation and relative error values of the method were below 20%, which shows good precision and accuracy. Finally, this method was successfully applied to the analysis of real urine samples.

  2. Integration of vanadium-mixed addenda Dawson heteropolytungstate within poly(3,4-ethylenedioxythiophene) and poly(2,2'-bithiophene) films by electrodeposition from the nonionic micellar aqueous medium

    Goral, Monika [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Jouini, Mohamed, E-mail: jouini@univ-paris-diderot.f [Laboratory Interfaces, Traitements, Organisation et DYnamique des Systemes (ITODYS) UMR 7086, Universite Paris Diderot Paris 7 Batiment Lavoisier, 15 Rue Jean Antoine de Baif, 75205 Paris Cedex 13 (France); Perruchot, Christian [Laboratory Interfaces, Traitements, Organisation et DYnamique des Systemes (ITODYS) UMR 7086, Universite Paris Diderot Paris 7 Batiment Lavoisier, 15 Rue Jean Antoine de Baif, 75205 Paris Cedex 13 (France); Miecznikowski, Krzysztof; Rutkowska, Iwona A. [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland); Kulesza, Pawel J., E-mail: [Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)


    A comparative study describing immobilization of the Dawson type mixed addenda heteropolyanion, [P{sub 2}W{sub 17}VO{sub 62}]{sup 8-} into conducting polymer films of poly(3,4-ethylenedioxythiophene), PEDOT, and poly(2,2'-bithiophene), PBT, is reported. Electrosynthesis of these hybrid films was performed using a micellar aqueous solution of the nonionic surfactant, polyethylene glycol tert-octylphenyl ether (Triton X-100). Deposited composite films were characterised electrochemically and, on the whole, they exhibited fast electron transfer (ET) properties and relatively high stability towards continuous potential cycling in acidic media. In particular, PEDOT composite showed relatively faster ET properties in comparison to PBT composite. Their permeability was investigated in the presence of cationic and anionic redox probes. Our results implied good mediating capabilities of the [P{sub 2}W{sub 17}V{sup 4+}O{sub 62}]{sup 8-} anion (within the [P{sub 2}W{sub 17}V{sup 4+}O{sub 62}]{sup 8-}-PEDOT hybrid film) towards the iron (III) reduction. The specific electrocatalytic (reductive) capabilities of hybrid films were also studied by probing the reduction of bromate. The films were further characterised by X-ray photoelectron spectroscopy to establish their interfacial elemental composition. Moreover, their surface morphology was imaged by atomic force microscopy and scanning electron microscopy. Results have shown that physicochemical properties of the investigated hybrid films were affected by polymer hydrophobicity.

  3. Thermoresponsive supramolecular micellar drug delivery system based on star-linear pseudo-block polymer consisting of β-cyclodextrin-poly(N-isopropylacrylamide) and adamantyl-poly(ethylene glycol).

    Song, Xia; Zhu, Jing-Ling; Wen, Yuting; Zhao, Feng; Zhang, Zhong-Xing; Li, Jun


    Chemotherapy is facing several limitations such as low water solubility of anticancer drugs and multidrug resistance (MDR) in cancer cells. To overcome these limitations, a thermoresponsive micellar drug delivery system formed by a non-covalently connected supramolecular block polymer was developed. The system is based on the host-guest interaction between a well-defined β-cyclodextrin (β-CD) based poly(N-isopropylacrylamide) star host polymer and an adamantyl-containing poly(ethylene glycol) (Ad-PEG) guest polymer. The structures of the host and guest polymers were characterized by (1)H and (13)C NMR, GPC and FTIR. Subsequently, they formed a pseudo-block copolymer via inclusion complexation between β-CD core and adamantyl-moiety, which was confirmed by 2D NMR. The thermoresponsive micellization of the copolymer was investigated by UV-vis spectroscopy, DLS and TEM. At 37°C, the copolymer at a concentration of 0.2mg/mL in PBS formed micelles with a hydrodynamic diameter of ca. 282nm. The anticancer drug, doxorubicin (DOX), was successfully loaded into the core of the micelles with a loading level of 6% and loading efficiency of 17%. The blank polymer micelles showed good biocompatibility in cell cytotoxicity studies. Moreover, the DOX-loaded micelles demonstrated superior therapeutic effects in AT3B-1-N (MDR-) and AT3B-1 (MDR+) cell lines as compared to free DOX control, overcoming MDR in cancer cells.

  4. Combination of capillary micellar liquid chromatography with on-chip microfluidic chemiluminescence detection for direct analysis of buspirone in human plasma.

    Al Lawati, Haider A J; Kadavilpparampu, Afsal Mohammed; Suliman, FakhrEldin O


    Microfluidic based chemiluminescence (CL) detector having novel channel design for enhanced mixing has been developed and investigated in terms of its applicability with micellar mode of liquid chromatography (MLC). The newly developed detector was found to be highly sensitive and an alternative detection technique to combine with capillary MLC. This combination was successfully employed for direct detection of a model analyte using Ru(III)-peroxydisulphate CL system. The selected analyte, buspirone hydrochloride (BUS), was detected selectively at therapeutic concentration levels in human plasma without any sample pretreatment. By incorporating eight flow split units within the spiral channel of microfluidic chip, an enhancement of 140% in CL emission was observed. We also evaluated the effect of non- ionic surfactant, Brij-35, which used as mobile phase modifier in MLC, on CL emission. The CL signal was improved by 52% compared to aqueous-organic mobile phase combinations. Various parameters influencing the micellar chromatographic performance and the CL emission were optimized. This allowed highly sensitive analysis of BUS with limit of detection (LOD) of 0.27 ng mL(-1) (3σ/s) and limit of quantification (LOQ) of 0.89 ng mL(-1) (10σ/s). The analyte recovery from human plasma at three different concentration level ranges from 88% to 96% (RSD 1.9-5.3%). The direct analysis of BUS in human plasma was achieved within 6 min. Therefore, combining microfluidic CL detection with micellar mode of separation is an efficient, cost-effective and highly sensitive technique that can utilize MLC in its full capacity for various bioanalytical procedures.

  5. The effect of polymeric additives on the solubilisation of a poorly-soluble drug in micellar solutions of Pluronic F127.

    Oliveira, Cristiane P; Vasconcellos, Luiz C G; Ribeiro, Maria Elenir N P; Ricardo, Nágila M P S; Souza, Ticiane V de P; Costa, Flávia de M L L; Chaibundit, Chiraphon; Yeates, Stephen G; Attwood, David


    The solubilisation of griseofulvin in 1wt% aqueous micellar solutions of Pluronic F127 at 37°C has been modified by adding polyethylene glycol PEG 35000 or poly(vinylpyrrolidone) PVP K30. The solubilisation capacity expressed in terms of unit weight of F127 is increased by the addition of 0.5wt% PEG 35000 to a value approaching double that of a 2.5wt% solution of F127 alone, but there is no advantage in adding 0.5wt% PVP K30.

  6. Study to determine the technical and economic feasibility of reclaiming chemicals used in micellar polymer and low tension surfactant flooding. Final report. [Ultrafiltration membranes and reverse osmosis membranes

    Stephens, R.H.; Himmelblau, A.; Donnelly, R.G.


    Energy Resources Company has developed a technology for use with enhanced oil recovery to achieve emulsion breaking and surfactant recovery. By using ultrafiltration membranes, the Energy Resources Company process can dewater an oil-in-water type emulsion expected from enhanced oil recovery projects to the point where the emulsion can be inverted and treated using conventional emulsion-treating equipment. By using a tight ultrafiltration membrane or a reverse osmosis membrane, the Energy Resources Company process is capable of recovering chemicals such as surfactants used in micellar polymer flooding.

  7. Combination of hollow fiber-based liquid-phase microextraction with sweeping techniques in micellar electrokinetic chromatography for the determination of Strychnos alkaloids in human urine

    Xiao Huan Zang; Cai Rui Li; Qiu Hua Wu; Chun Wang; Dan Dan Han; Zhi Wang


    A new method for the enrichment of Strychnos alkaloids in biological samples via liquid-phase rnicroextraction (LPME) based on porous polypropylene hollow fibers in combination with on-line sweeping in micellar electrokinetic chromatography was developed. The calibration curve was linear over the range of 20-200 ng mL-1 for both strychnine and brucine in human urine sample. The detection limits (S/N = 3:1) for strychnine and brucine were 1 ng mL-1 and 2 ng mL-1, respectively. The LPME-sweeping method has been successfully applied to the analysis of strychnine and brucine in real urine samples.

  8. Enantioselective Cycloetherification in a Micellar Catalysis System%胶束催化体系中的对映选择性环醚化反应

    Bhupesh S. SAMANT; Sunil S. BHAGWAT


    The enantioselective cycloetherification of substituted keto phenols into their corresponding dihydrobenzofuran derivatives was carried out using hydrogen peroxide and chiral quatemary ammonium iodide in micellar media. This approach increased the conversion rate of cycloetherification and also widened the scope of this particular reaction for various substituted keto phenols with electron withdrawing as well as electron donating functionalities. The use of a surfactant in the cycloetherification reaction increased the yield of the corresponding enantioselective dibydrobenzofuran four times. The conversion rate of keto phenols into their corresponding dihydrobenzofuran derivatives was proportional to the concentration of the surfactant used in the reaction.

  9. Cationic gemini pyrrolidinium surfactants based sweeping-micellar electrokinetic chromatography for simultaneous detection of nine organic pollutants in environmental water.

    Tian, Yu; Wei, Ran; Cai, Bo; Dong, Jinfeng; Deng, Bin; Xiao, Yuxiu


    A series of novel cationic gemini surfactants with pyrrolidinium head groups, 1,1'-(butane-1,s-alkyl) bis (1-alkylpyrrolidinium) (Cn-4-CnPB, n=12, 14, 16), were employed as carriers in sweeping-micellar electrokinetic chromatography (sweeping-MEKC) for simultaneous detection of nine organic water pollutants, including polycyclic aromatic hydrocarbons, sulfonamides and steroids. The sweeping and separation conditions were optimized. Cn-4-CnPB (n=12, 14, 16) were compared with cetyltrimethylammonium bromide (CTAB) in terms of their abilities to preconcentrate and separate the nine analytes. Under the optimized conditions, the sensitivity enhancement factors based on the peak height (SEFsHeight) were ca. 310-580 of C16-4-C16PB, which were higher than those of C14-4-C14PB (120-290) and C12-4-C12PB (110-160). Meanwhile, the SEFsHeight of C16-4-C16PB were higher than those of 30% (v/v) methanol-modified CTAB (140-320). The C16-4-C16PB based sweeping-MEKC, coupled with offline solid phase extraction and UV detection (228nm), was used to analyze spiked environmental water samples. The nine analytes were successfully separated and detected. The limit of detection (S/N=3) was in range of 2.79-3.76ng/mL, and the recovery ranged from 70.8% to 95.5% with the RSDs less than 9.89%. This study confirms that the C16-4-C16PB based sweeping-MEKC has significant advantages over the CTAB based sweeping-MEKC and it is a promising method for sensitive and simultaneous detection of polycyclic aromatic hydrocarbons, sulfonamides and steroids in environmental water samples.

  10. Highly Selective Derivative Spectrophotometry for Determination of Nickel Using 1-(2-Pyridylazo)-2-naphthol in Tween 80 Micellar Solutions

    Eskandari, Habibollah [University of Mohaghegh Ardebili, Ardebil (Iran, Islamic Republic of)


    A spectrophotometric and first derivative spectrophotometric method was developed in aquatic Tween 80 micellar solutions for selective determination of nickel without using any pre-separation step. 1-(2-Pyridylazo)- 2-naphthol (PAN), as a sensitive chromogenic complexing agent formed a red-colored Ni(II)-PAN complex in Tween 80 media with satisfactory solubility and stability. Conditions such as pH, PAN concentration, type and concentration of micellizing agent were optimized. Molar absorptivity of Ni-PAN complex was found 4.62 x 10{sup 4} L cm{sup -1} mol{sup -1} at 569 nm, under the optimum condition. Calibration graphs were derived by zero, first and second derivative spectrophotometry at maximum wavelengths of 569, 578 and 571 nm with linear ranges of 30-1800, 20-2500 and 30-2000 ng mL{sup -1}, respectively. Precision as standard deviation as well as accuracy as recovery percent were in the range of 1-20 ng mL{sup -1} and 93.3-103.3%, respectively, for the entire of the linear ranges. Spectrophotometric detection limit was 3 ng mL{sup -1} and effects of diverse ions on the first derivative determination of nickel were studied to investigate selectivity of the method. Interferences of cobalt and copper on the nickel determination were prevented using o-phenanthroline as masking agent. The recommended procedures were applied to the various synthetic and stainless steel alloys, tea leaves and human hair, with satisfactory results.

  11. Validation of a micellar liquid chromatographic method for determination of caffeine and non-steroidal anti-inflammatories.

    El Sherbiny, Dina; Wahba, Mary E K


    An accurate, simple, sensitive and selective micellar liquid chromatographic method has been developed for the simultaneous determination of caffeine (CAF) and two non-steroidal anti-inflammatory drugs, namely ibuprofen (IBU) and ketoprofen (KET). The chemometric approach was applied to the optimization of separation of the studied drugs. To optimize their separation, the effect of six experimental parameters on retention was investigated by means of multivariate analysis. Separation was conducted using an ODS C18 (150 × 4.6 mm i.d.) stainless steel column at ambient temperature with UV detection at 260 nm. A mobile phase composed of 40 mM sodium dodecyl sulphate (SDS), 10% 1-propanol and 0.3% tri-ethylamine in 0.02 M phosphoric acid adjusted to pH 3 has been used at a flow rate of 1 mL/min. Regression models were characterized by both descriptive and predictive ability (R(2) ≥ 97.9% and R(cv)(2) ≥ 96.2%) and allowed the chromatographic separation of the drugs with a good resolution and a total analysis time within 15 min. The calibration curves were rectilinear over the concentration ranges of 2.0-25.0, 1.5-15.0 and 1.0-10.0 µg/mL for IBU, KET and CAF, respectively, with detection limits of 1.2, 1.0 and 0.6 µg/mL, and quantification limits of 1.6, 1.2 and 0.8 µg/mL, respectively. The results obtained were in good agreement with those obtained by the comparison method.

  12. Colloidal chirality in wormlike micellar systems exclusively originated from achiral species: Role of secondary assembly and stimulus responsivity.

    Zhao, Wenrong; Hao, Jingcheng


    Colloidal chirality in wormlike micellar systems exclusively originated from achiral species and discussion of the role of secondary assembly of fiber-like aggregates in chirality generation were presented in this paper. Herein, formation of colloidal wormlike micelles for the first time incorporated chirality and redox-responsiveness into one design via noncovalent interaction. A dual-stimuli-responsive gel of wormlike micelles which were designed by employing a dual-responsive cationic surfactant (FTMA) and a strong gelator (AzoNa4) and regulated by redox reaction and host-guest inclusion is presented. Both the redox and host-guest interaction play an important role in regulating the viscosity and supramolecular chirality of gels of the wormlike micelles. The supramolecular chirality and viscosity of the wormlike micelle gels were switched reversibly by exerting chemical redox onto the ferrocenyl groups. For the amphiphile FTMA containing redox-active ferrocenyl group, reversible control of the oxidation state of ferrocenyl groups leads to the charge and hydrophobicity changes of FTMA, therefore change its self-assembly behavior. Of equal interest, β-CD successfully detached the wormlike micelles via the recognition-inclusion behavior with FTMA and invalidate the H-bond and hydrophobic interaction between FTMA and AzoH4. This designed system provides a new strategy to tune the supramolecular chirality of colloidal aggregates and explore the specific packing mode detail within the micelles or the secondary assembly of the inter-micelles. We anticipate this dual-responsive H-bond-directed chiral gel switch could propose a new strategy when researchers designing new, multi-responsive functional gel materials.

  13. The membrane protein LeuT in micellar systems: aggregation dynamics and detergent binding to the S2 site.

    Khelashvili, George; LeVine, Michael V; Shi, Lei; Quick, Matthias; Javitch, Jonathan A; Weinstein, Harel


    Structural and functional properties of integral membrane proteins are often studied in detergent micellar environments (proteomicelles), but how such proteomicelles form and organize is not well understood. This makes it difficult to evaluate the relationship between the properties of the proteins measured in such a detergent-solubilized form and under native conditions. To obtain mechanistic information about this relationship for the leucine transporter (LeuT), a prokaryotic homologue of the mammalian neurotransmitter/sodium symporters (NSSs), we studied the properties of proteomicelles formed by n-dodecyl-β,D-maltopyranoside (DDM) detergent. Extensive atomistic molecular dynamics simulations of different protein/detergent/water number ratios revealed the formation of a proteomicelle characterized by a constant-sized shell of detergents surrounding LeuT protecting its transmembrane segments from unfavorable hydrophobic/hydrophilic exposure. Regardless of the DDM content in the simulated system, this shell consisted of a constant number of DDM molecules (∼120 measured at a 4 Å cutoff distance from LeuT). In contrast, the overall number of DDMs in the proteomicelle (aggregation number) was found to depend on the detergent concentration, reaching a saturation value of 226±17 DDMs in the highest concentration regime simulated. Remarkably, we found that at high detergent-to-protein ratios we observed two independent ways of DDM penetration into LeuT, both leading to a positioning of the DDM molecule in the second substrate (S2) binding site of LeuT. Consonant with several recent experimental studies demonstrating changes in functional properties of membrane proteins due to detergent, our findings highlight how the environment in which the membrane proteins are examined may affect the outcome and interpretation of their mechanistic features.

  14. Positron studies on reverse micellar systems of AOT/isooctane/water

    Ferreira Marques, M.; Lopes Gil, C.; Lima, A.; Burrows, H.; Da GraÇa Miguel, M.


    AOT/Isooctane and water/AOT/Isooctane systems have been studied by positron annihilation techniques. Studies of the binary system show that AOT is a strong positron scavenger and support the idea of polydisperse aggregates. Results, for the ternary system, indicate the presence of monomers, even when aggregates are present, and show that Ps is in a water-free region. The effects of the addition of nitrobenzene, sodium nitrobenzoate and 4-phenylbutyric acid to the ternary system are studied. P...

  15. Bioanalytical method for the estimation of co-administered esomeprazole, leflunomide and ibuprofen in human plasma and in pharmaceutical dosage forms using micellar liquid chromatography.

    Talaat, Wael


    The present study represents a connection between basic science and clinical applied science through providing a bioanalytical method for the analysis of certain co-administered drugs used for the treatment of rheumatoid arthritis. The studied drugs are esomeprazole, leflunomide and ibuprofen. The proposed bioanalytical method is a simple reversed phase high performance liquid chromatographic method using micellar mobile phase. The method is conducted using a Shim-pack VP-ODS (150 mm × 4.6 mm ID) stainless steel column at ambient temperature with ultraviolet detection at 285 nm. The micellar mobile phase consisted of 0.1 m sodium dodecyl sulfate, 10% n-propanol, 0.3% triethylamine in 0.02 m orthophosphoric acid (pH 3.5) and is pumped at a flow rate of 1.0 mL/min. The calibration curve was rectilinear over the concentration range of 0.1-5.0, 0.5-10.0 and 1.0-20.0 μg/mL for esomeprazole, leflunomide and ibuprofen respectively. The proposed method was successfully applied to the analysis of these drugs in dosage forms. The method is extended to the in-vitro, in-vivo determination of these drugs in spiked and real human plasma samples.

  16. Micellar effect on the sensitivity of spectrophotometric Mo(VI) determination based on the formation of gallic acid complex providing evidence for the polyoxoanion structure of molybdate ions

    Tascioglu, Senay [Department of Chemistry, Faculty of Arts and Sciences, Gazi University, Ankara (Turkey)]. E-mail:; Sendil, Olcay [Department of Chemistry, Faculty of Arts and Sciences, Gazi University, Ankara (Turkey); Beyreli, Sivekar [Department of Chemistry, Faculty of Arts and Sciences, Gazi University, Ankara (Turkey)


    In this study effects of anionic (sodium dodecyl sulfate, SDS), cationic (cetyltrimethylammonium bromide, CTAB) and nonionic (Triton X-100, TX100) micelles on the sensitivity of spectrophotometric molybdenum(VI) (Mo) determination based on the formation of a binary complex with gallic acid (GA) were investigated. Micellar CTAB was found to enhance the formation of Mo-GA complex. SDS micelles exerted an inhibitory effect while TX100 micelles had no effect on the complex formation. By the optimization of experimental conditions, the determination limit of the method suggested in the literature was lowered from 5.2 x 10{sup -5} to 4.6 x 10{sup -6} and to 5.7 x 10{sup -7} M, in the absence and presence of CTAB, respectively. The mechanism of the effect of CTAB was investigated by spectrophotometric titrations and it was concluded that CTAB did not form a ternary complex with Mo and GA. The stoichiometry of the complex, deduced from the results of spectrophotometric titrations, provided evidence for the formation of para-Mo{sub 7}O{sub 4} {sup 6-} polyanions at pH 4.5, indicating to the formation of a charge transfer complex between these ions and GA in micellar medium.

  17. Investigation of the surfactant type and concentration effect on the retention factors of glutathione and its analogues by micellar electrokinetic chromatography.

    Kazarjan, Jana; Mahlapuu, Riina; Hansen, Mats; Soomets, Ursel; Kaljurand, Mihkel; Vaher, Merike


    In the present study, a micellar electrokinetic chromatographic method was used to determine the retention factors of hydrophilic monomeric and homodimeric forms of glutathione analogues. Ionic-liquid-based surfactant, 1-tetradecyl-3-methylimidazolium chloride, as well as cetyltrimethylammonium bromide and phosphate buffer (pH 7.4) were employed in the experiments. Since the studied peptides possess a negative charge under physiological conditions, it is expected that the peptides interact with the oppositely charged 1-tetradecyl-3-methylimidazolium chloride and cetyltrimethylammonium bromide micelles via hydrophobically assisted electrostatic forces. The dependence of the retention factor on the micellar concentration of 1-tetradecyl-3-methylimidazolium chloride and cetyltrimethylammonium bromide is nonlinear and the obtained curves converge to a limiting value. The retention factor values of GSH analogues were in the range of 0.36-2.22 for glutathione analogues and -1.21 to 0.37 for glutathione when 1-tetradecyl-3-methylimidazolium chloride was used. When cetyltrimethylammonium bromide was employed, the retention factor values were in the range of 0.27-2.17 for glutathione analogues and -1.22 to 0.06 for glutathione. If sodium dodecyl sulfate was used, the retention factor values of glutathione analogues with carnosine moiety were in the range of -1.54 to 0.38.

  18. Adsorption of the anionic surfactant sodium dodecyl sulfate on a C18 column under micellar and high submicellar conditions in reversed-phase liquid chromatography.

    Ortiz-Bolsico, C; Ruiz-Angel, M J; García-Alvarez-Coque, M C


    Micellar liquid chromatography makes use of aqueous solutions or aqueous-organic solutions containing a surfactant, at a concentration above its critical micelle concentration. In the mobile phase, the surfactant monomers aggregate to form micelles, whereas on the surface of the nonpolar alkyl-bonded stationary phases they are significantly adsorbed. If the mobile phase contains a high concentration of organic solvent, micelles break down, and the amount of surfactant adsorbed on the stationary phase is reduced, giving rise to another chromatographic mode named high submicellar liquid chromatography. The presence of a thinner coating of surfactant enhances the selectivity and peak shape, especially for basic compounds. However, the risk of full desorption of surfactant is the main limitation in the high submicellar mode. This study examines the adsorption of the anionic surfactant sodium dodecyl sulfate under micellar and high submicellar conditions on a C18 column, applying two methods. One of them uses a refractive index detector to obtain direct measurements of the adsorbed amount of sodium dodecyl sulfate, whereas the second method is based on the retention and peak shape for a set of cationic basic compounds that indirectly reveal the presence of adsorbed monomers of surfactant on the stationary phase.

  19. A review on development of analytical methods to determine monitorable drugs in serum and urine by micellar liquid chromatography using direct injection.

    Esteve-Romero, Josep; Albiol-Chiva, Jaume; Peris-Vicente, Juan


    Therapeutic drug monitoring is a common practice in clinical studies. It requires the quantification of drugs in biological fluids. Micellar liquid chromatography (MLC), a well-established branch of Reverse Phase-High Performance Liquid Chromatography (RP-HPLC), has been proven by many researchers as a useful tool for the analysis of these matrices. This review presents several analytical methods, taken from the literature, devoted to the determination of several monitorable drugs in serum and urine by micellar liquid chromatography. The studied groups are: anticonvulsants, antiarrhythmics, tricyclic antidepressants, selective serotonin reuptake inhibitors, analgesics and bronchodilators. We detail the optimization strategy of the sample preparation and the main chromatographic conditions, such as the type of column, mobile phase composition (surfactant, organic solvent and pH), and detection. The finally selected experimental parameters, the validation, and some applications have also been described. In addition, their performances and advantages have been discussed. The main ones were the possibility of direct injection, and the efficient chromatographic elution, in spite of the complexity of the biological fluids. For each substance, the measured concentrations were accurate and precise at their respective therapeutic range. It was found that the MLC-procedures are fast, simple, inexpensive, ecofriendly, safe, selective, enough sensitive and reliable. Therefore, they represent an excellent alternative for the determination of drugs in serum and urine for monitoring purposes.

  20. A dispersive liquid-liquid micellar microextraction for the determination of pharmaceutical compounds in wastewaters using ultra-high-performace liquid chromatography with DAD detection.

    Montesdeoca-Esponda, Sarah; Mahugo-Santana, Cristina; Sosa-Ferrera, Zoraida; Santana-Rodríguez, José Juan


    A dispersive liquid-liquid micellar microextraction (DLLMME) method coupled with ultra-high-performance liquid chromatography (UHPLC) using Diode Array Detector (DAD) detector was developed for the analysis of five pharmaceutical compounds of different nature in wastewaters. A micellar solution of a surfactant, polidocanol, as extraction solvent (100 μL) and chloroform as dispersive solvent (200 μL) were used to extract and preconcentrate the target analytes. Samples were heated above critical temperature and the cloudy solution was centrifuged. After removing the chloroform, the reduced volume of surfactant was then injected in the UHPLC system. In order to obtain high extraction efficiency, the parameters affecting the liquid-phase microextraction, such as time and temperature extraction, ionic strength and surfactant and organic solvent volume, were optimized using an experimental design. Under the optimized conditions, this procedure allows enrichment factors of up to 47-fold. The detection limit of the method ranged from 0.1 to 2.0 µg/L for the different pharmaceuticals. Relative standard deviations were <26% for all compounds. The procedure was applied to samples from final effluent collected from wastewater treatment plants in Las Palmas de Gran Canaria (Spain), and two compounds were measured at 67 and 113 µg/L in one of them.

  1. Use of biopartitioning micellar chromatography and RP-HPLC for the determination of blood-brain barrier penetration of α-adrenergic/imidazoline receptor ligands, and QSPR analysis.

    Vucicevic, J; Popovic, M; Nikolic, K; Filipic, S; Obradovic, D; Agbaba, D


    For this study, 31 compounds, including 16 imidazoline/α-adrenergic receptor (IRs/α-ARs) ligands and 15 central nervous system (CNS) drugs, were characterized in terms of the retention factors (k) obtained using biopartitioning micellar and classical reversed phase chromatography (log kBMC and log kwRP, respectively). Based on the retention factor (log kwRP) and slope of the linear curve (S) the isocratic parameter (φ0) was calculated. Obtained retention factors were correlated with experimental log BB values for the group of examined compounds. High correlations were obtained between logarithm of biopartitioning micellar chromatography (BMC) retention factor and effective permeability (r(log kBMC/log BB): 0.77), while for RP-HPLC system the correlations were lower (r(log kwRP/log BB): 0.58; r(S/log BB): -0.50; r(φ0/Pe): 0.61). Based on the log kBMC retention data and calculated molecular parameters of the examined compounds, quantitative structure-permeability relationship (QSPR) models were developed using partial least squares, stepwise multiple linear regression, support vector machine and artificial neural network methodologies. A high degree of structural diversity of the analysed IRs/α-ARs ligands and CNS drugs provides wide applicability domain of the QSPR models for estimation of blood-brain barrier penetration of the related compounds.

  2. Extension of the analytical kinetics of micellar relaxation: Improving a relation between the Becker-Döring difference equations and their Fokker-Planck approximation

    Babintsev, I. A.; Adzhemyan, L. Ts.; Shchekin, A. K.


    Relaxation of micellar systems can be described with the help of the Becker-Döring kinetic difference equations for aggregate concentrations. Passing in these equations to continual description, when the aggregation number is considered as continuous variable and the concentration difference is replaced by the concentration differential, allows one to find analytically the eigenvalues (to whom the inverse times of micellar relaxation are related) and eigenfunctions (or the modes of fast relaxation) of the linearized differential operator of the kinetic equation corresponding to the Fokker-Planck approximation. At this the spectrum of eigenvalues appears to be degenerated at some surfactant concentrations. However, as has been recently found by us, there is no such a degeneracy at numerical determination of the eigenvalues of the matrix of coefficients for the linearized difference Becker-Döring equations. It is shown in this work in the frameworks of the perturbation theory, that taking into account the corrections to the kinetic equation produced by second derivatives at transition from differences to differentials and by deviation of the aggregation work from a parabolic form in the vicinity of the work minimum, lifts the degeneracy of eigenvalues and improves markedly the agreement of concentration-dependent fast relaxation time with the results of the numerical solution of the linearized Becker-Döring difference equations.

  3. Micellar effect on metal-ligand complexes of Co(II, Ni(II, Cu(II and Zn(II with citric acid

    Nageswara Rao Gollapalli


    Full Text Available Chemical speciation of citric acid complexes of Co(II, Ni(II, Cu(II and Zn(II was investigated pH-metrically in 0.0-2.5% anionic, cationic and neutral micellar media. The primary alkalimetric data were pruned with SCPHD program. The existence of different binary species was established from modeling studies using the computer program MINIQUAD75. Alkalimetric titrations were carried out in different relative concentrations (M:L:X = 1:2:5, 1:3:5, 1:5:3 of metal (M to citric acid. The selection of best chemical models was based on statistical parameters and residual analysis. The species detected were MLH, ML2, ML2H and ML2H2. The trend in variation of stability constants with change in mole fraction of the medium is explained on the basis of electrostatic and non-electrostatic forces. Distributions of the species with pH at different compositions of micellar media are also presented.

  4. Environmentally Benign Mortar-Pestle-Induced Acylation and O-Alkylation of Aromatic and Heteroaromatic Compounds under Solvent-Free Micellar Conditions and Computation of Their Drug Likeliness Properties

    Kancharla Rajendar Reddy


    Full Text Available Environmentally benign mortar-pestle-induced practical methods have been developed for the acylation and O-alkylation of aromatic and heteroaromatic compounds under solventfree micellar conditions, which were found to efficiently afford moderate to excellent yields of products.

  5. Small angle neutron scattering study of temperature-independent formulation of mixed micellar structures

    V K Aswal; A G Wagh


    SANS measurements have been performed on mixed systems of ionic surfactant sodium dodecyl sulphate (SDS) and nonionic surfactant polyoxyethylene 10 lauryl ether (C12E10). The total concentration of the mixed system was kept fixed (10 wt%) and the ionic to nonionic surfactant ratio varied in the range 0 to 1. The temperature effect on the structures of mixed micelles has been studied for temperatures between 30 and 75° C. Micelles of pure ionic and nonionic surfactants show opposite trends when the temperature is increased. Sizes of pure ionic micelles decrease and those of nonionic micelles increase with increase in temperature. We show a formulation balancing these two effects which is temperature-independent and consists of about 25% of ionic surfactants in the mixed system. Contrast variation SANS measurements by contrast matching one of the surfactant components to the solvent suggest homogeneous single mixed micelles of the two components in the mixed systems.

  6. Calix-arene silver nanoparticles interactions with surfactants are charge, size and critical micellar concentration dependent.

    Tauran, Yannick; Brioude, Arnaud; Shahgaldian, Patrick; Cumbo, Alessandro; Kim, Beomjoon; Perret, Florent; Coleman, Anthony W; Montasser, Imed


    The interactions of silver nanoparticles capped by various calix[n]arenes bearing sulphonate groups at the para and/or phenolic faces with cationic, neutral and anionic surfactants have been studied. Changes in the plasmonic absorption show that only the calix[4]arene derivatives sulphonated at the para-position interact and then only with cationic surfactants. The interactions follow the CMC values of the surfactants either as simple molecules or mixed micelles.

  7. Simultaneous Separation of Eight Benzodiazepines in Human Urine Using Field-Amplified Sample Stacking Micellar Electrokinetic Chromatography.

    Oledzka, Ilona; Kulińska, Zofia; Prahl, Adam; Baczek, Tomasz


    A novel approach for the simultaneous quantification of eight benzodiazepines (BZDs) using dispersive liquid-liquid microextraction (DLLME) and field-amplified sample stacking (FASS) combined with micellar electrokinetic chromatography (MEKC) was investigated and evaluated in the context of precision, accuracy, sensitivity, linearity, detection and limits of quantification (LOQ). The absolute recovery rates of BZDs were above 90.65%. The limits of detection (LOD) were 20 ng/mL for chlordiazepoxide, estazolam, temazepam and midazolam, and 30 ng/mL for clonazepam, lorazepam, lormetazepam and medazepam, while the LOQ was set at 50 ng/mL for chlordiazepoxide, estazolam, temazepam and midazolam, and 100 ng/mL for clonazepam, lorazepam, lormetazepam and medazepam. Linearity was confirmed in the range of 50-2,000 ng/mL for chlordiazepoxide, estazolam, temazepam and midazolam, and 100-2,000 ng/mL for clonazepam, lorazepam, lormetazepam and medazepam, with a correlation coefficient greater than 0.9987 for all analytes. The elaborated procedure meets all the requirements of analytical methods. During the extraction procedure, a mixture of 1 mL of ethanol and 500 µL of dichloromethane, used as the disperser and extraction solvent, respectively, was rapidly injected into 3 mL of a urine sample. A significant improvement in sensitivity was achieved when DLLME was used to extract BZDs from the urine sample and FASS as an on-line preconcentration technique was developed. For the best separation of analytes, the running buffer was composed of 30 mM SDS, 10 mM sodium tetraborate and 15% methanol (pH 8.8), whereas a sample buffer was composed of 10 mM SDS and 2 mM sodium tetraborate. Moreover, a fused-silica capillary [inner diameter (i.d.) of 75 µm and length of 50 cm], photodiode array detection, pneumatic injection for 15 s and a voltage of 23 kV were applied. The applicability of the method has been confirmed for the analysis of BZD in urine samples collected from patients who

  8. Investigating cold gelation properties of recombined highly concentrated micellar casein concentrate and cream for use in cheese making.

    Lu, Y; McMahon, D J; Vollmer, A H


    Highly concentrated micellar casein concentrate (HC-MCC), a potential ingredient for cheese making, contains ~20% casein with ~70% of serum proteins removed by microfiltration and diafiltration of skim milk, followed by vacuum evaporation. Our objective was to investigate cold gelation properties of recombined concentrated milk (RCM) by mixing thawed frozen HC-MCC and cream under different casein levels, pH, and protein-to-fat ratios, and with addition of sodium citrate or calcium. The HC-MCC was recombined with cream using low shear at 50°C for 30 min, and rheological measurements were conducted. Cold-gelling temperature [the temperature at which storage modulus (G')=loss modulus (G″)] was linearly correlated with casein levels from 8.6 to 11.5% (R(2)=0.71), pH from 6.6 to 7.0 (R(2)=0.96), and addition of sodium citrate from 0 to 0.36mmol/g of casein (R(2)=0.80). At pH 7.0, gelation occurred at 12, 26, and 38°C with 9, 10, and 11% casein, respectively. At pH 6.6, 6.8, and 7.0, RCM with 12% casein gelled at a mean temperature of 12, 26, and 37°C, respectively. Adding calcium chloride at 0.17mmol/g of casein significantly increased cold-gelling temperature from 18 to ≥50°C, whereas no significant change was observed at levels up to 0.12mmol/g of casein. Different protein to fat ratios ranging from 0.8 to 1.2 did not significantly influence gelling temperature. In transmission electron micrographs of RCM with 12% casein, casein micelles were nonspherical and partially dissociated into small protein strands. Upon addition of calcium chloride at 0.21mmol/g of casein, casein micelles were more spherical and retained colloidal structure with the presence of aggregated casein micelles. These gelation processes of RCM with or without addition of trisodium citrate were both reversible. We propose that cold gelation of RCM occurs when protein strands that have been partially released from the casein micelles entangle, restrict their mobility, and form a fine

  9. Nanodrug-enhanced radiofrequency tumor ablation: effect of micellar or liposomal carrier on drug delivery and treatment efficacy.

    Marwan Moussa

    Full Text Available PURPOSE: To determine the effect of different drug-loaded nanocarriers (micelles and liposomes on delivery and treatment efficacy for radiofrequency ablation (RFA combined with nanodrugs. MATERIALS/METHODS: Fischer 344 rats were used (n = 196. First, single subcutaneous R3230 tumors or normal liver underwent RFA followed by immediate administration of i.v. fluorescent beads (20, 100, and 500 nm, with fluorescent intensity measured at 4-24 hr. Next, to study carrier type on drug efficiency, RFA was combined with micellar (20 nm or liposomal (100 nm preparations of doxorubicin (Dox; targeting HIF-1α or quercetin (Qu; targeting HSP70. Animals received RFA alone, RFA with Lipo-Dox or Mic-Dox (1 mg i.v., 15 min post-RFA, and RFA with Lipo-Qu or Mic-Qu given 24 hr pre- or 15 min post-RFA (0.3 mg i.v.. Tumor coagulation and HIF-1α or HSP70 expression were assessed 24 hr post-RFA. Third, the effect of RFA combined with i.v. Lipo-Dox, Mic-Dox, Lipo-Qu, or Mic-Qu (15 min post-RFA compared to RFA alone on tumor growth and animal endpoint survival was evaluated. Finally, drug uptake was compared between RFA/Lipo-Dox and RFA/Mic-Dox at 4-72 hr. RESULTS: Smaller 20 nm beads had greater deposition and deeper tissue penetration in both tumor (100 nm/500 nm and liver (100 nm (p<0.05. Mic-Dox and Mic-Qu suppressed periablational HIF-1α or HSP70 rim thickness more than liposomal preparations (p<0.05. RFA/Mic-Dox had greater early (4 hr intratumoral doxorubicin, but RFA/Lipo-Dox had progressively higher intratumoral doxorubicin at 24-72 hr post-RFA (p<0.04. No difference in tumor growth and survival was seen between RFA/Lipo-Qu and RFA/Mic-Qu. Yet, RFA/Lipo-Dox led to greater animal endpoint survival compared to RFA/Mic-Dox (p<0.03. CONCLUSION: With RF ablation, smaller particle micelles have superior penetration and more effective local molecular modulation. However, larger long-circulating liposomal carriers can result in greater intratumoral drug

  10. Analysis of red inks by micellar electrokinetic capillary chromatography with laser-induced fluorescence detection.

    Król, Małgorzata; Gondko, Klaudia; Kula, Agnieszka; Kościelniak, Paweł


    A combination of MEKC with a--highly sensitive but not commonly used--LIF detector was tested regarding the possibility of differentiation of red inks. The separation process was conducted in a fused silica capillary (id 50 μm, 60/50 cm total/effective length) in BGE consisting of 40 mM sodium borate, 20 mM SDS and 10% v/v ACN with 30 kV applied. The optimized temperature of storage and capillary was 10 and 25°C, respectively. The samples were prepared using 20 dots (ø 0.5 mm), extracted in 35 μL BGE and diluted with 30 μL of water. The proposed method showed excellent repeatability and reproducibility (RSD (tm ) < 0.8 and < 2.5%, respectively). It was applied to group identification and differentiation of different brands, models, and batches of red printing, stamp, and pen inks. It was demonstrated that differentiation can be performed effectively on the basis of migration times and ratios of peak areas. The high efficiency of the developed method was indicated by discriminating power ranging from 87.3 to 98.8%, for stamp and pen inks, respectively. The results showed that the proposed procedure can be valuable for an objective examination of the red parts of questioned documents.

  11. Novel synthesis and characterization of nanocrystalline thoria from oxalate precursor via reverse micellar route

    Gupta, R.; Aggarwal, S.K. [Bhabha Atomic Research Centre, Mumbai (India). Fuel Chemistry Div.; Gupta, S.K. [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry Div.


    Nanoparticles of thorium oxalate were synthesized by the reaction of thorium nitrate and ammonium oxalate by the microemulsion method. The ThO{sub 2} nanoparticles were obtained by heating thorium oxalate nanoparticles at 500 C in air. The oxalate and oxide nanoparticles of thorium were characterized by transmission electron microscopy (TEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and selected area electron diffraction (SAED). X-ray diffraction studies showed the mono-phasic nature of the powder thoria. The particle size was obtained from X-ray line broadening ({proportional_to} 10 nm) and transmission electron microscopy ({proportional_to} 10 nm). Dynamic light scattering (DLS) was used to calculate the average grain size of the particles. SAED confirmed the nanocrystalline nature of thoria particles. High resolution transmission electron microscopy (HRTEM) was also carried out to understand the morphology of the system. The monodisperse nanoparticles of thoria are promising for future reactor technologies. (orig.)

  12. Structural and Mechanical Hysteresis at the Order-Order Transition of Block Copolymer Micellar Crystals

    Theresa A. LaFollette


    Full Text Available Concentrated solutions of a water-soluble block copolymer (PEO20-(PPO70-(PEO20 show a thermoreversible transition from a liquid to a gel. Over a range of concentration there also exists an order-order transition (OOT between cubically-packed spherical micelles and hexagonally-packed cylindrical micelles. This OOT displays a hysteresis between the heating and cooling transitions that is observed at both the macroscale through rheology and nanoscale through small angle neutron scattering (SANS. The hysteresis is caused by the persistence of the cubically-packed spherical micelle phase into the hexagonally-packed cylindrical micelle phase likely due to the hindered realignment of the spherical micelles into cylindrical micelles and then packing of the cylindrical micelles into a hexagonally-packed cylindrical micelle phase. This type of hysteresis must be fully characterized, and possibly avoided, for these block copolymer systems to be used as templates in nanocomposites.

  13. Photoactive bile salts with critical micellar concentration in the micromolar range.

    Gomez-Mendoza, Miguel; Marin, M Luisa; Miranda, Miguel A


    The aggregation behavior of bile salts is strongly dependent on the number of hydroxyl groups. Thus, cholic acid (CA), with three hydroxyls, starts forming aggregates at 15 mM, while deoxycholic, chenodeoxycholic or ursodeoxycholic acids, with two hydroxyls, start aggregating at 5-10 mM; for lithocholic acid, with only one hydroxyl group, aggregation is observed at lower concentration (2-3 mM). Here, the singular self-assembling properties of dansyl and naproxen derivatives of CA (3β-Dns-CA and 3β-NPX-CA, respectively) have been demonstrated on the basis of their photoactive properties. Thus, the emission spectra of 3β-Dns-CA registered at increasing concentrations (25-140 μM) showed a remarkable non-linear enhancement in the emission intensity accompanied by a hypsochromic shift of the maximum and up to a three-fold increase in the singlet lifetime. The inflection point at around 50-70 μM pointed to the formation of unprecedented assemblies at such low concentrations. In the case of 3β-NPX-CA, when the NPX relative triplet lifetime was plotted against concentration, a marked increase (up to two-fold) was observed at 40-70 μM, indicating the formation of new 3β-NPX-CA assemblies at ca. 50 μM. Additional evidence supporting the formation of new 3β-Dns-CA or 3β-NPX-CA assemblies at 40-70 μM was obtained from singlet excited state quenching experiments using iodide. Moreover, to address the potential formation of hybrid assemblies, 1 : 1 mixtures of 3β-Dns-CA and 3β-NPX-CA (2-60 μM, total concentration) were subjected to steady-state fluorescence experiments, and their behavior was compared to that of the pure photoactive derivatives. A lower increase in the emission was observed for 3β-NPX-CA in the mixture, while a huge increase was experienced by 3β-Dns-CA in the same concentration range (up to 60 μM total). A partial intermolecular energy transfer from NPX to Dns, consistent with their reported singlet energies, was revealed, pointing to the

  14. High-order derivative spectrophotometric determination of uranium in a cationic micellar medium

    Agnihotri, N.K.; Singh, V.K.; Singh, H.B. [Delhi Univ. (India). Dept. of Chemistry


    A derivative spectrophotometric method is developed for the determination of U{sup VI} with 1,4-dihydroxy-9,10-anthracenedione in the presence of cetylpyridinium chloride. The 1:1 complex at pH 5.6 shows maximum absorbance at 600 nm; Beer`s law is obeyed in the range 4.76 x 10{sup -1}-19.04 {mu}g ml{sup -1}. The molar absorption coefficient and Sandell`s sensitivity of the complex are 1.19 x 10{sup 4} l mol{sup -1} cm{sup -1} and 2.00 x 10{sup -2} {mu}g cm{sup -2}, respectively. The proposed method is applied to the determination of U{sup VI} in mixtures containing various amounts of Th{sup IV} and Be{sup II} without pre-separation using second-order derivative absorption plots. A rapid procedure for the simultaneous determination of UO{sub 2}{sup II} and Be{sup II} in binary mixtures is also reported. (author).

  15. Selectivity of Brij-35 in Micellar Liquid Chromatographic Separation of Positional Isomers

    Najma Memon


    Full Text Available Implementation of Brij-35, a nonionic surfactant, as a mobile phase for separation of positional isomers is investigated. Chromolith C-18 SpeedROD is used as a stationary phase. The effect of surfactant and organic modifier (propanol concentration on the separation of some selected isomers is studied and evaluated in terms of linear solvation energy relationship (LSER. Shape selectivity is assessed by α value of sorbic and benzoic acid, which is found to be 1.339 by using mobile phase composed of 0.5% aqueous solutions of Brij-35 and propanol in 9 : 1. Isomers of parabens, nitroanilines, nitrophenols, and quinolinols are successfully separated using mobile phases composed of various percentages of surfactant and propanol. System constants for nonionic MLC using LSER analysis show that hydrogen bond basicity and dipolarity may be major contributors to selectivity, while excess molar refraction helps fine-tuning the separation which also imparts unique selectivity to nonionic surfactants as compared to ionic ones.

  16. El Dorado Micellar-Polymer Demonstration Project. Second annual report, July 1975--May 1976

    Rosenwald, G.W. (ed.)


    Laboratory oil displacement tests were conducted using Shell Oil Co. and Union Oil Co. chemical formulations in both Berea and El Dorado Admire Sandstone cores. Total relative mobility of the oil-water bank created during chemical flooding was measured in Admire Sandstone cores. The values ranged from 0.018 to 0.065 reciprocal centipoise. Four observation wells were drilled, cored, and logged during the year. They were cased with fiberglass and are now being used to monitor fluid properties. A tracer test was conducted by injection of chemical tracers into each of the 18 injection wells. Results indicate that there is no gross channeling in the reservoir. The same conclusion was drawn from results of interference tests. Performance forecasting was utilized to show that maintaining the bottom-hole injection pressures at 400 psia and the producing pressures at 30 psia would increase throughput rates and result in acceptable project life for the 6.4-acre, five-spot patterns. Injection well rates relative to the central injector were computed. These rates will be used as a guide for the operation of injection wells. This plan corresponds to operation at constant bottom-hole pressures for a homogeneous reservoir of uniform thickness. Construction of the fresh water system and injection plant was completed. The injection plant has performed satisfactorily. Injection of pretreatment fluid was started in both patterns on November 18, 1975.Severe loss of injectivity was experienced during the first week of injection. Several likely causes were identified and corrective actions taken. More moderate injectivity problems have continued throughout this reporting period. Additional preventive measures have been undertaken to improve the quality of injected fluids. A procedure was developed to stimulate and clean-up wells damaged by the injection fluid. A preliminary evaluation indicates that combination solvent-acid treatments will increase injection rates to the desired level.

  17. The use of biopartitioning micellar chromatography and immobilized artificial membrane column for in silico and in vitro determination of blood-brain barrier penetration of phenols.

    Stępnik, Katarzyna E; Malinowska, Irena


    Biopartitioning Micellar Chromatography (BMC) is a mode of micellar liquid chromatography that uses C18 stationary phases and micellar mobile phases of Brij35 under adequate experimental conditions and can be useful to mimic human drug absorption, blood-brain barrier distribution or partitioning processes in biological systems. BMC system can be useful in constructing good predictive models because the characteristics of the BMC system are similar to biological barriers and extracellular fluids. Immobilized Artificial Membrane (IAM) chromatography uses stationary phase which consists of a monolayer of phosphatidylcholine covalently immobilized on an inert silica support. IAM columns are thought to mimic very closely a membrane bilayer and are used in a HPLC system with a physiological buffer as eluent. In this paper the usefulness of BMC and IAM system for in silico and in vitro determination of blood-brain barrier (BBB) penetration of phenols has been demonstrated. The most important pharmacokinetic parameters of brain have been obtained for the determination of BBB penetration, i.e. BBB permeability - surface area product (PS), usually given as a logPS, brain/plasma equilibration rate (log(PS×fu,brain)) and fraction unbound in plasma (Fu). Moreover, the relationships between retention of eighteen phenols and different parameters of molecular size, lipophilicity and BBB penetration were studied. Extrapolated to pure water values of the logarithms of retention factors (logkw) have been compared with the corresponding octanol-water partition coefficient (logPo-w) values of the solutes. In addition, different physicochemical parameters from Foley's equation for BMC system have been collated with the chromatographic data. The Linear Solvation Energy Relationship (LSER) using Abraham model for the describing of phenols penetration across BBB has been used. Four equations were developed as a multiple linear regression using retention data from IAM and BMC system (QRAR

  18. Pseudo Peak Phenomena in Micellar Electrokinetic Capillary Chromatography by Using Cationic Surfactant%阳离子表面活性剂胶束电动毛细管色谱中的假峰现象

    陈冠华; 杨更亮; 田益玲; 陈义


    Using cetyltrimethylammonium bromide as pseudo stationary phase, the origin of pseudo peak in micellar electrokinetic capillary chromatography was investigated, relating to the fact that under certain conditions two peaks might come arise from a single component. Experiments further showed that the relative areas of the two peaks of an analyte were dependent on the reation time and temperature, under which reactions between analyte and surfactant occurred, and also dependent on concentration of surfactant in sample solutions. The results suggested that the interaction between analyte and surfactant is a slow process, and a stable substance might be formed via the interaction and lead to the formation of pseudo peaks. The fast interaction mechanism between the solute and the micelle could be queried according to the experimental results.%研究了以十六烷基三甲基溴化铵为准固定相的胶束电动毛细管色谱中假峰的起源.指出在一定条件下,一个组分可能出现两个峰.实验表明,被分析物双峰的相对峰面积取决于被分析物与表面活性剂反应的时间、温度以及表面活性剂在样品中的浓度.这意味着被分析物与表面活性剂之间的反应是一个慢过程,这种相互作用能够产生一种稳定的物质,并导致假峰的形成.根据实验结果,溶质与胶束之间的快速相互作用机理应被质疑.

  19. 巴比妥类安眠药在胶束液相色谱中的保留行为%Study on the retention behavior of barbitals in micellar liquid chromatography

    蒋文慧; 程向炜; 褚建新


    Objective The retention characteristics of barbitals in micellar liquid chromatography ( MLC )was investigated. Methods Using sodium dodecyl sulfate (SDS) as mobile phase, the effect of SDS micelle concentrations,pH, organic modifiers concentrations, and column temperature on the retention behavior of barbitals was investigated. Results The experimental results showed: with increasing SDS micelle concentrations,organic modifiers concentrations and column temperature, the capacity factor (k') of barbitals decreases.Conclusion There is a good linear relationship between the capacity factor (k') and SDS micelle concentrations,organic modifier concentrations, and column temperature. There is a nonlinear relationship between the retention time of barbitals ( tR ) and the pH value of mobile phase.%目的 研究巴比妥类安眠药在胶束液相色谱中的保留行为,为其应用提供理论基础.方法 选择阴离子型表面活性剂十二烷基硫酸钠(SDS)为流动相,分别考察胶束浓度、流动相pH、有机改性剂浓度、柱温等对巴比妥类安眠药保留行为的影响.结果 随着胶束浓度增加,有机改性剂浓度增加以及柱温的升高,巴比妥类安眠药在色谱柱上保留能力降低.结论 巴比妥类安眠药容量因子与表面活性剂SDS的浓度、有机改性剂浓度以及柱温成良好的线性关系,而巴比妥类安眠药的保留时间与流动相的pH值呈非线件关系.

  20. Otimização do processo de extração de β-xilosidase por sistemas micelares reversos Optimization of β-xylosidase extraction process using reversed micellar systems

    Daniela Vieira Cortez


    Full Text Available A enzima β-xilosidase, produzida pelo fungo Penicillium janthinellum, foi extraída pelo sistema micelar reverso formado pelo agente tensoativo catiônico CTAB em isoctano, hexanol e butanol. Os efeitos combinados da concentração de CTAB e de butanol sobre a extração da enzima foram estudados empregandose a metodologia de superfície de resposta. A partir dos resultados obtidos, foi proposto um modelo matemático para descrever o processo de extração da β-xilosidase na região de trabalho estudada. De acordo com a equação do modelo, podem ser obtidos valores máximos de recuperação de 35,05 ± 6,40% nas seguintes condições: pH 8,0, concentração de CTAB 0,2 M, concentração de hexanol 5% e concentração de butanol 20%. Nestas condições, foram realizados novos experimentos e o valor médio de recuperação obtido foi de 38%.β-xylosidase, produced by Penicillium janthinellum, was extracted by using the reversed micellar system of the CTAB (cetyl trimethyl ammonium bromide cationic surfactant containing isooctane, hexanol and butanol. The combined effects of CTAB and butanol concentrations on enzyme extraction were studied by using the surface response methodology. As a function of the results, it was proposed a mathematical model to describe the process of β-xylosidase extraction. This model predicted a maximal enzyme extraction yield of 35.05±6.4% under the following conditions: pH = 8.0, CTAB = 0.20 M, hexanol = 5% (v/v, and butanol = 20% (v/v. Experimentally, a recovery value of about 38% was attained, and showed that the model is appropriate.