Literatura académica sobre el tema "Flow field flow fractionation (Fl-FFF)"
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Artículos de revistas sobre el tema "Flow field flow fractionation (Fl-FFF)":
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Kim, Suhan, Sungyun Lee, Chung-Hwan Kim y Jaeweon Cho. "A new membrane performance index using flow-field flow fractionation (fl-FFF)". Desalination 247, n.º 1-3 (octubre de 2009): 169–79. http://dx.doi.org/10.1016/j.desal.2008.12.022.
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Lim, Seongbeen, Sangyoup Lee, Soohoon Choi, Jihee Moon y Seungkwan Hong. "Evaluation of biofouling potential of microorganism using flow field-flow fractionation (Fl-FFF)". Desalination 264, n.º 3 (diciembre de 2010): 236–42. http://dx.doi.org/10.1016/j.desal.2010.05.042.
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Pellegrino, J., S. Wright, J. Ranvill y G. Amy. "Predicting membrane flux decline from complex mixtures using flow-field flow fractionation measurements and semi-empirical theory". Water Science and Technology 51, n.º 6-7 (1 de marzo de 2005): 85–92. http://dx.doi.org/10.2166/wst.2005.0625.
Resumen
Flow-Field Flow Fractionation (Fl-FFF) is an idealization of the cross flow membrane filtration process in that, (1) the filtration flux and crossflow velocity are constant from beginning to end of the device, (2) the process is a relatively well-defined laminar-flow hydrodynamic condition, and (3) the solutes are introduced as a pulse-input that spreads due to interactions with each other and the membrane in the dilute-solution limit. We have investigated the potential for relating Fl-FFF measurements to membrane fouling. An advection-dispersion transport model was used to provide ‘ideal’ (defined as spherical, non-interacting solutes) solute residence time distributions (RTDs) for comparison with ‘real’ RTDs obtained experimentally at different cross-field velocities and solution ionic strength. An RTD moment analysis based on a particle diameter probability density function was used to extract “effective” characteristic properties, rather than uniquely defined characteristics, of the standard solute mixture. A semi-empirical unsteady-state, flux decline model was developed that uses solute property parameters. Three modes of flux decline are included: (1) concentration polarization, (2) cake buildup, and (3) adsorption on/in pores, We have used this model to test the hypothesis—that an analysis of a residence time distribution using Fl-FFF can describe ‘effective’ solute properties or indices that can be related to membrane flux decline in crossflow membrane filtration. Constant flux filtration studies included the changes of transport hydrodynamics (solvent flux to solute back diffusion (J/k) ratios), solution ionic strength, and feed water composition for filtration using a regenerated cellulose ultrafiltration membrane. Tests of the modeling hypothesis were compared with experimental results from the filtration measurements using several correction parameters based on the mean and variance of the solute RTDs. The corrections used to modify the boundary layer mass transfer coefficient and the specific resistance of cake or adsorption layers demonstrated that RTD analysis is potentially useful technique to describe colloid properties but requires improvements.
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Plavchak, Christine L., William C. Smith, Carmen R. M. Bria y S. Kim Ratanathanawongs Williams. "New Advances and Applications in Field-Flow Fractionation". Annual Review of Analytical Chemistry 14, n.º 1 (5 de junio de 2021): 257–79. http://dx.doi.org/10.1146/annurev-anchem-091520-052742.
Resumen
Field-flow fractionation (FFF) is a family of techniques that was created especially for separating and characterizing macromolecules, nanoparticles, and micrometer-sized analytes. It is coming of age as new nanomaterials, polymers, composites, and biohybrids with remarkable properties are introduced and new analytical challenges arise due to synthesis heterogeneities and the motivation to correlate analyte properties with observed performance. Appreciation of the complexity of biological, pharmaceutical, and food systems and the need to monitor multiple components across many size scales have also contributed to FFF's growth. This review highlights recent advances in FFF capabilities, instrumentation, and applications that feature the unique characteristics of different FFF techniques in determining a variety of information, such as averages and distributions in size, composition, shape, architecture, and microstructure and in investigating transformations and function.
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Giordani, Stefano, Valentina Marassi, Anna Placci, Andrea Zattoni, Barbara Roda y Pierluigi Reschiglian. "Field-Flow Fractionation in Molecular Biology and Biotechnology". Molecules 28, n.º 17 (23 de agosto de 2023): 6201. http://dx.doi.org/10.3390/molecules28176201.
Resumen
Field-flow fractionation (FFF) is a family of single-phase separative techniques exploited to gently separate and characterize nano- and microsystems in suspension. These techniques cover an extremely wide dynamic range and are able to separate analytes in an interval between a few nm to 100 µm size-wise (over 15 orders of magnitude mass-wise). They are flexible in terms of mobile phase and can separate the analytes in native conditions, preserving their original structures/properties as much as possible. Molecular biology is the branch of biology that studies the molecular basis of biological activity, while biotechnology deals with the technological applications of biology. The areas where biotechnologies are required include industrial, agri-food, environmental, and pharmaceutical. Many species of biological interest belong to the operational range of FFF techniques, and their application to the analysis of such samples has steadily grown in the last 30 years. This work aims to summarize the main features, milestones, and results provided by the application of FFF in the field of molecular biology and biotechnology, with a focus on the years from 2000 to 2022. After a theoretical background overview of FFF and its methodologies, the results are reported based on the nature of the samples analyzed.
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Remmo, Amani, Norbert Löwa, Julija Peter y Frank Wiekhorst. "Physical characterization of biomedical magnetic nanoparticles using multi-detector centrifugal field-flow fractionation". Current Directions in Biomedical Engineering 7, n.º 2 (1 de octubre de 2021): 327–30. http://dx.doi.org/10.1515/cdbme-2021-2083.
Resumen
Abstract The unique magnetic properties of magnetic nanoparticles (MNP) combined with their small size already led to numerous medical applications. Accurate determination of their magnetic properties is a key requirement enquired by users, that is impeded by the ever-present distribution of MNP sizes. Field flow fractionation (FFF) techniques may help to overcome these limitations by first separating the particles before characterization. In this study, we demonstrate the use of centrifugal FFF coupled to online detectors for fractionation, structural, and magnetic characterization of MNP. The primary goal is to establish a reproducible centrifugal FFF (CF3) method for MNP fractionation We show that CF3 has the same capability as other FFF techniques in resolving the bimodal hydrodynamic size distribution present in the commercial MNP system Resovist® but is faster and more straightforward through its technical approach.
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Markx, Gerard H., Juliette Rousselet y Ronald Pethig. "DEP-FFF: Field-Flow Fractionation Using Non-Uniform Electric Fields". Journal of Liquid Chromatography & Related Technologies 20, n.º 16-17 (septiembre de 1997): 2857–72. http://dx.doi.org/10.1080/10826079708005597.
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Phelan Jr., Frederick R. y Barry J. Bauer. "Simulation of nanotube separation in field-flow fractionation (FFF)". Chemical Engineering Science 62, n.º 17 (septiembre de 2007): 4620–35. http://dx.doi.org/10.1016/j.ces.2007.04.019.
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Scherer, Christian, Sergey Noskov, Stefanie Utech, Christoph Bantz, Waltraut Mueller, Korinna Krohne y Michael Maskos. "Characterization of Polymer Nanoparticles by Asymmetrical Flow Field Flow Fractionation (AF-FFF)". Journal of Nanoscience and Nanotechnology 10, n.º 10 (1 de octubre de 2010): 6834–39. http://dx.doi.org/10.1166/jnn.2010.2973.
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Suwanpetch, Rabiab, Juwadee Shiowatana y Atitaya Siripinyanond. "Using flow field-flow fractionation (Fl-FFF) for observation of salinity effect on the size distribution of humic acid aggregates". International Journal of Environmental Analytical Chemistry 97, n.º 3 (19 de febrero de 2017): 217–29. http://dx.doi.org/10.1080/03067319.2017.1296141.
Tesis sobre el tema "Flow field flow fractionation (Fl-FFF)":
1
Edwards, Thayne Lowell. "Microfrabricated Acoustic and Thermal Field-Flow Fractionation Systems". Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/6981.
Resumen
Arguments for miniaturization of a thermal field-flow fractionation system ( and #956;-ThFFF) and fabrication of a micro-scale acoustic field-flow fractionation system ( and #956;-AcFFF) using similar methods was presented. Motivation for miniaturization of ThFFF systems was established by examining the geometrical scaling of the fundamental ThFFF theory. Miniaturization of conventional macro-scale ThFFF systems was made possible through utilization of micromachining technologies. Fabrication of the and #956;-ThFFF system was discussed in detail. The and #956;-ThFFF system was characterized for plate height versus flow rate, single component polystyrene retention, and multi-component polystyrene separations. Retention, thermal diffusion coefficients, and maximum diameter-based selectivity values were extracted from separation data and found comparable with macro-scale ThFFF system results. Retention values ranged from 0.33 to 0.46. Thermal diffusion coefficients were between 3.0ױ0-8 and 5.4ױ0-8 cm2/sec?? The maximum diameter-based selectivity was 1.40.
While the concept of an acoustic FFF sub-technique has been around for decades, the fabrication methods have not been available until recently. The theory was developed in full including relating sample physical properties to retention time in the FFF system. In addition to the theory, the design and fabrication of the and #956;-AcFFF was presented. Design results from an acoustic modeling program were presented with the determination of the acoustic resonant frequency. The acoustic-based systems was designed around the model results and characterized by electrical input impedance, fluidic, plate height, polystyrene suspension retention, and polystyrene mixture separation studies.
The and #956;-AcFFF system was able to retain a series of nanometer scale polystyrene samples. However, the retention data did not follow normal mode retention but did reveal the location of the steric inversion point for the power level used, around 200 nm. The results of the multiple component separation confirmed this results as the sample, which contained 110, 210, and 300 nm diameter samples, was not resolved but only broadened.
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Ngaza, Nyashadzashe. "Thermal field-flow fractionation (Thermal FFF) and asymmetrical flow field-flow fractionation (AF4) as new tools for the analysis of block copolymers and their respective homopolymers". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/95836.
Resumen
Thesis (MSc)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Polystyrene-block-poly(ethylene oxide) (PS-b-PEO) copolymers contain a hydrophilic PEO block and a hydrophobic PS block. PS and PEO have different affinities for most organic solvents and as a result, the PS-b-PEO copolymers are difficult to characterize in solution. In order to achieve a complete characterization of their molecular heterogeneity different techniques have been used. Recently FFF has become a cutting edge technology for polymer analysis because it possesses a number of advantages over conventional SEC and other liquid chromatographic techniques. The mild operating conditions allow the analysis of delicate and sensitive complex analytes such as complex polymer assemblies. The ability to analyze polymers with ultrahigh molar masses has also contributed to its significance in the characterization of polymers. In this study, the FFF behaviour of PS-b-PEO copolymers as well as PS and PEO homopolymers was investigated using Thermal FFF in different organic solvents and AF4. The aim of the study was the correlation of the thermodynamic quality of the solvents and the elution behaviour of the polymers. Unfortunately, PEO homopolymers have been found to interact with the membrane in AF4. Therefore, they were best characterized in organic solvents using Thermal FFF. In contrast to AF4 no specific interactions occurred due to the absence of a membrane. Results for Thermal FFF showed that in all utilized solvents, PS and PEO homopolymers were separated in the direction of increasing molar mass. For PS-b-PEO copolymers the retention in selective (good) solvents for PS was dependent on the molar mass of the PS block in the block copolymer. This was explained by the fact that in poor solvents PEO adopts a collapsed coil conformation while PS is present in extended random coil conformation. Results also showed that polymer retention was dependent on the temperature programme utilized. The fractionations by Thermal FFF indicated that some of the PS-b-PEO copolymer samples contained PS and PEO homopolymers as by-products. After semi-preparative fractionation these homopolymers were qualitatively identified using FTIR spectroscopy.
AFRIKAANSE OPSOMMING: Polistireen-blok-poli(etileenoksied) (PS-b-PEO) ko-polimere bevat 'n hidrofiliese politetileen oksied (PEO) blok en 'n hidrofobiese polistireen (PS) blok. PS en PEO het verskillende affiniteite vir die meeste organiese oplosmiddels, dit bemoeilik die karakterisering van PS-b-PEO ko-polimere in oplossing. Ten einde 'n volledige karakterisering van hul molekulêre heterogeniteit te bepaal moet ‘n verskeidenheid van tegnieke gebruik word. Onlangs het veldvloeifraksionering (FFF) baie grond gewen tov polimeer analise, aangesien dit verskeie voordele het bo tradisionele chromatografiese tegnieke soos grootte-uitsluitingschromatografie (SEC). Die ligte operasionele omstandighede laat die ontleding van ‘n verskeidenheid van polimere toe, enige iets van delikate polimeer komplekse tot ultra hoë molekulêre massa. In hierdie studie is die FFF gedrag van PS-b-PEO ko-polimere asook PS en PEO homopolimere ondersoek met behulp van Termiese FFF(ThFFF) in verskillende organiese oplosmiddels en onsimmetriese vloei-veldvloeifraksionering(AF4). Die doel van die studie was om die verband tussen die termodinamiese gehalte van die oplosmiddels en die eluering gedrag van die polimere te bepaal. Analise van PEO homopolimere was onsuksesvol aangesien daar interaksie was met die membraan. PEO is dus net geanaliseer in organise oplosmiddels met behulp van ThFFF, aangesien daar geen membraan is nie. Analise met ThFFF het gewys dat skeiding plaasvind volgens ‘n toename in molekulêre massa in organise oplosmiddels. Vir PS-b-PEO ko-polimere die retensie in selektiewe (goeie) oplosmiddels vir PS was afhanklik van die molekulêre massa van die PS blok in die ko-polimeer. ‘n Moontlike teorie is dat die PEO blok ‘n ineengestorte spoel struktuur vorm terwyl die PS blok ‘n uitgestrekte lukraake vorm aan neem. Resultate het ook getoon dat die polimeer retensie afhanklik was van die temperatuur program wat gebruik is. Die fraksionering deur ThFFF het aangedui dat sommige van die PS-b-PEO kopolimeer monsters bestaan het uit PS en PEO homopolimere as by-produkte. Hierdie is kwalitatief bewys deur analise van die fraksies na fraksionering van die ko-polimere met behulp van FTIR spektroskopie.
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Thepchalerm, Chalao. "Influence of Hevea brasiliensis latex compartments on the storage hardening of natural rubber : study of the mesostructure by AF4-MALS and of the mineral element composition by ICP-MS". Thesis, Montpellier, SupAgro, 2014. http://www.theses.fr/2014NSAM0016/document.
Resumen
Le but de la présente étude était de vérifier l'influence de deux compartiments du latex d'Hevea brasiliensis, les lutoïdes et le sérum C, sur le durcissement au stockage et sur la mésostructure du caoutchouc naturel (NR). L'implication des composants minéraux du latex a fait l'objet d'un focus spécial. La mésostructure du NR a été étudié par fractionnement par couplage flux-force à flux asymétrique couplé à un détecteur à diffusion de lumière multiangulaire (AF4-MALS) et par chromatographie d'exclusion de tailles équipée d'un détecteur de diffusion de lumière multiangulaire (SEC- MALS). La spectrométrie de masse couplée à une torche à plasma (ICP- MS) a été utilisée pour déterminer la composition en éléments minéraux du NR.L'AF4 - MALS et l'ICP-MS n'ayant jamais été utilisées pour l'analyse du NR, les méthodes ont été développées. Pour l'AF4 - MALS, la meilleure séparation entre les deux populations principales, chaînes de polyisoprène isolées (pelote statistique) et les microagrégats (Gel<1μ), a été obtenue avec une diminution linéaire, plutôt qu'exponentielle, du flux croisé. Pour l'ICP-MS, les optimisations réalisées concernent la quantité de NR à échantillonner, la méthodologie de solubilisation des cendres, la concentration des solutions de cendres et la gestion des interférences m/z . Tous les éléments, excepté le soufre, ont été analysés en utilisant un mélange H2/He comme gaz de collision-réaction (mode CCT H2/He). La teneur en soufre a été déterminée par le rapport m/z égal à 48 (32S16O+) en mode CCT O2.Les différents compartiments du latex des champs (crème, skim, sérum C et lutoïdes) ont été séparés par centrifugation à grande vitesse. L'évolution de la mésostructure des films obtenus à partir de ces trois latex; latex des champ (FL), le latex de crème (CL) et de latex de skim (SK), par un procédé de structuration lente (échantillons stockés à température ambiante dans le laboratoire pendant 3 mois) a été suivie par SEC- MALS. Le skim n'étant pas sensible au processus de structuration lente, le nombre des étapes de centrifugation a été réduit. La stabilité des lutoïdes a été étudiée par un paramètre qualitatif (état visuel des lutoïdes après centrifugation) et un paramètre quantitatif (indice d'éclatement ou BI). Bien que les deux méthodes n'aient pas donné de résultats strictement corrélées, le BI peut être un bon indicateur de la stabilité des lutoïdes. Pour les échantillons de FL, une bonne corrélation entre la stabilité des lutoïdes et le durcissement au stockage (P) a été observée. Pour déterminer si des composés du C-sérum étaient également impliqués dans le durcissement au stockage, des expériences supplémentaires ont été effectuées en ajoutant des quantités variables de sérum C ou de lutoïdes à des particules de caoutchouc purifiées. L'augmentation à la fois de les quantités de sérum C et des lutoïdes a entrainé une augmentation du durcissement au stockage (P).La mésostructure des films et des feuilles séchées de l'air (ADS) préparés à partir des FL et CL a été analysée par SEC-MALS et AF4-MALS. Pour les échantillons d'ADS, quelle que soit la technique utilisée, les échantillons de FL présentaient des Mw, Mn et Gel>1μ supérieurs aux échantillons de CL. Cette différence entre échantillons de FL et de CL n'a pas été observée pour les échantillons de filmsThe aim of the present work was to study the influence of two Hevea brasiliensis latex compartments, namely lutoids and C-serum, on the storage hardening and on mesostructure of natural rubber (NR). A special focus was done on the involvement of mineral components of latex. The NR mesostructure was studied by asymmetrical flow field-flow fractionation coupled to a multiangular light scattering detector (AF4-MALS) and by size exclusion chromatography equipped with a multiangular light scattering detector (SEC-MALS). Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the mineral element composition of NR.As AF4-MALS and ICP-MS were never used for NR analysis, the methodologies were developed. For AF4-MALS, the best separation between the two main populations, namely isolated polyisoprene chains (random coil) and microaggregates (Gel<1µ) was given by a linear decrease, rather than exponential, of the cross-flow. For ICP-MS, the optimizations were in terms of amount of NR to be sampled, ash solubilisation methodology, ash solutions concentrations and m/z interference management. All elements, except sulfur, were determined using a mixture H2/He as collision-reaction gas (CCT H2/He mode). Sulfur content was determined through the m/z equal to 48 (32S16O+) in the CCT O2 mode.The different compartments of the whole field latex (cream, skim, C-serum and lutoids) were separated by high speed centrifugation. The mesostructure evolution of films obtained from these 3 lattices; whole field latex (FL), cream latex (CL), and skim latex (SK), by a slow structuring process (samples stored at room temperature in the laboratory for 3 months) was followed by SEC-MALS. As it was observed that the skim was not sensitive to the slow structuring, the centrifugation steps were reduced.Lutoid stability was studied by a qualitative parameter (visual lutoid status after centrifugation) and a quantitative parameter (bursting index or BI). Although the two methods could not provide strictly correlated results, BI can be a good indicator of lutoid stability. For the FL samples, a good correlation between the lutoid stability and storage hardening (ΔP) was observed. To determine if some compounds of C-serum are also involved in the storage hardening, additional experiments were done adding variable quantities of C-serum or lutoids to purified rubber particles. The storage hardening (ΔP) increased by the increase of both C-serum and lutoid quantities.The mesostructure of films and air dried sheet (ADS) made from FL and CL lattices (obtained from reduced centrifugation process) were analyzed by SEC-MALS and AF4-MALS. Concerning the ADS samples, whatever the technique used, FL samples exhibited a higher Mw, Mn, and Gel>1µ than CL samples. This difference between FL and CL samples was not observed for film samples. The microaggregates (Gel<1µ) were presented in all samples but the FL samples had more compact microaggregates, with a much higher Mw than the CL samples. Moreover, AF4 showed that the structure of microaggregates was very different between ADS and film samples. The Mw of microaggregates of ADS was 2 to 4 times higher than that of films. The mineral elements were determined only on samples from ADS (FL and CL). The main elements in NR were K, P, Mg, and S, in decreasing order. The purification of rubber particles affected the decrease in the element contents. During the storage of the latex at room temperature, only calcium content decreased, for both FL and CL samples
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Maknun, Luluil. "Development of mass spectrometric analytical methods for the determination of iron complexes in plants and bacteria and for the determination of cobalt using bimetallic nanoparticles". Electronic Thesis or Diss., Pau, 2023. http://www.theses.fr/2023PAUU3039.
Resumen
L'objectif principal de cette recherche est le développement de méthodes analytiques utilisant une technique de séparation couplée à la spectrométrie de masse pour l'analyse de complexes de fer de faible poids moléculaire et une technique de single-particle ICP MS pour la détection de nanoparticules bimétalliques.Dans la première partie, une méthode utilisant la chromatographie liquide avec spectrométrie de masse à double détecteur, spectrométrie de masse (MS) à haute résolution par électrospray (HRAM) et spectrométrie de masse à couplage inductif (ICPMS), a été développée pour les complexes du fer (Fe) de faible poids moléculaire, appelés 'sideophore', dans un échantillon d'un sol. La complexité des échantillons étudiés, les faibles concentrations et la labilité des analytes ont posé un défi dans le développement de méthodes pour leur identification et leur quantification. Pour éliminer la matrice, une extraction en phase solide (SPE) a été développée dans des conditions acides pour purifier la majeure partie des complexes 56Fe-sidérophore et concentrée par évaporation. Les complexes 56Fe-sidérophore ont été identifiés par chromatographie d'exclusion stérique rapide (FastSEC) - Orbitrap MSn sur la base de la masse moléculaire exacte (+ 1 ppm) et de la fragmentation MS2 ou MS3. Leur capacité à échanger facilement le 56Fe naturel contre le 58Fe ajouté a été démontrée par SEC avec détection par l'ICP MS et l'ESI MS. La méthode a été appliquée à l'analyse de tourbe prélevée dans la partie orientale des montagnes pyrénéennes françaises. Dix-neuf sidérophores appartenant à quatre classes différentes ont été identifiés et quantifiés sans avoir besoin d'un standard authentique. Les résultats ont été validés à l'aide de la détection ICP MS du fer en comparant la somme des complexes de fer déterminés par échange isotopique - ESI MS dans chaque pic observé par FastSEC-ICP MS.Dans la deuxième partie du manuscrit, une méthode utilisant la spectrométrie de masse à plasma à couplage inductif -ICP-MS en mode particule unique (SP-ICP-MS) et en mode conventionnel couplée au fractionnement d'écoulement de champ (FlFFF) a été développée. Les conditions de synthèse de nanoparticules bimétalliques (BNP) Ag-Au ont été optimisées pour appliquer celles-ci à la détection colorimétrique basée sur le concept d'agrégation. Les BNP Ag-Au, synthétisés par la réduction par le citrate des ions Ag et Au, ont été utilisées comme capteurs pour la détection du Co2+. Pour mieux comprendre la détection colorimétrique du Co2+ à l'aide de BNP Ag-Au, divers mélanges de solutions ont été étudiés, notamment : (i) uniquement des BNP Ag-Au ; (ii) BNP Ag-Au avec thiosulfate; (iii) BNP Ag-Au avec thiosulfate et éthylènediamine; et (iv) Ag-Au BNPs avec thiosulfate, Co2+ et éthylènediamine. SP-ICP-MS a été utilisé pour déterminer la taille du noyau, la distribution de taille et la concentration en nombre de particules, ainsi que l'hétérogénéité des particules synthétisées en utilisant diverses concentrations de citrate et un rapport de métal. FlFFF-ICP-MS a également été utilisé pour observer la taille hydrodynamique et le rapport d'intensité du signal de Ag et Au dans les BNP et donc pour étayer les informations obtenues à partir de SP-ICP-MS. La combinaison des techniques proposées dans des conditions appropriées a permis de surveiller la réaction de détection colorimétrique. Les informations supplémentaires du fractogramme fournies par FlFFF-ICP-MS ont également été utiles pour comprendre l'agrégation des BNP due au complexe [Co(II)(en)3]2+ autour de la surface des BNP. En outre, par rapport à la détection colorimétrique classique, la limite de détection (LOD) pour la détection des ions Co2+ a été réduite de 20 fois, du niveau ppb au niveau pptThe research focuses on an analytical method development using chromatography coupled to mass spectrometry for the analysis of low molecular weight iron complexes. In the second part, the study explores the utilization of bimetallic nanoparticles for Co2+ detection.In the first part, a method using liquid chromatography with two detector mass spectrometry, i.e., electrospray high-resolution accurate mass (HRAM) mass spectrometry (MS) and inductively coupled mass spectrometry (ICP-MS), was developed for the analysis of low molecular weight iron (Fe) complexes, called ‘siderophores'. The complexity of the samples, their low concentrations, and the lability of the iron complexe were challenges in the development of methods for their identification and quantification. For the sample clean-up, solid phase extraction (SPE) using acidic conditions was developed to purify the samples, followed by evaporation to dryness. The individual 56Fe-siderophore complexes were identified by fast size-exclusion chromatography (FastSEC) - Orbitrap MSn based on the exact molecular mass (+ 1 ppm) and MS2. Their capability of exchanging the natural 56Fe with the spiked 58Fe was demonstrated by SEC with ICP-MS and ESI-MS detection. The method was applied to the analysis of peat collected in the Eastern part of the French Pyrenean mountains. Nineteen siderophores belonging to four different classes were presumptively identified and quantified. The results were compared with ICP-MS detection of iron and matching of the sum of the moles of iron complexes determined by the isotopic- ESI-MS within each peak as eluted from the fastSEC column.In the second part, a method using inductively coupled plasma mass spectrometry in the single particle mode and the conventional mode coupled to a flow field flow fractionation was developed to select suitable conditions for the synthesis of Ag-Au bimetallic nanoparticles and to monitor the colorimetric changes due to aggregations. Ag-Au BNPs, synthesized by using citrate reduction of Ag and Au ions, were used as sensors for the detection of Co2+. To better understand the colorimetric sensing of Co2+ using the Ag-Au BNPs, various mixtures were studied, viz. (i) only Ag-Au BNPs; (ii) Ag-Au BNPs with thiosulfate; (iii) Ag-Au BNPs with thiosulfate and ethylenediamine; and (iv) Ag-Au BNPs with thiosulfate, Co2+ and ethylenediamine. SP-ICP-MS was used to determine the core size, size distribution, and number concentration, as well as the heterogeneity of the particles synthesized by using various citrate concentrations and metal ratios. Fl-FFF-ICP-MS was also used to observe the hydrodynamic size and the Ag: Au signal intensity ratio of the BNPs to support information obtained from the SP-ICP-MS. The combination of the proposed techniques has been applied to monitor the reaction during colorimetric sensing. Additional information from fractograms provided by Fl-FFF-ICP-MS was also useful for the understanding of the aggregation of BNPs arising from the [Co(II)(en)3]2+ complex surrounding the surface of the BNPs. Furthermore, when compared to colorimetric sensing, the limit of detection for Co2+ ion, using the BNPs and SP-ICP-MS, were 20-fold lower, decreasing from ppb to ppt levels
Libros sobre el tema "Flow field flow fractionation (Fl-FFF)":
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Chromatography of polymers: Characterization by SEC and FFF. Washington, DC: American Chemical Society, 1993.
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Provder, Theodore. Chromatography of Polymers: Characterization by SEC and FFF (Acs Symposium Series). An American Chemical Society Publication, 1998.
Capítulos de libros sobre el tema "Flow field flow fractionation (Fl-FFF)":
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Wiedmer, Susanne K. y Gebrenegus Yohannes. "Characterization of Liposomes by FFF". En Field-Flow Fractionation in Biopolymer Analysis, 207–21. Vienna: Springer Vienna, 2011. http://dx.doi.org/10.1007/978-3-7091-0154-4_14.
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Wahlund, Karl-Gustav y Lars Nilsson. "Flow FFF – Basics and Key Applications". En Field-Flow Fractionation in Biopolymer Analysis, 1–21. Vienna: Springer Vienna, 2011. http://dx.doi.org/10.1007/978-3-7091-0154-4_1.
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Palais, Caroline, Martinus Capelle y Tudor Arvinte. "Studies of Loose Protein Aggregates by Flow Field-Flow Fractionation (FFF) Coupled to Multi-Angle Laser Light Scattering (MALLS)". En Field-Flow Fractionation in Biopolymer Analysis, 103–12. Vienna: Springer Vienna, 2011. http://dx.doi.org/10.1007/978-3-7091-0154-4_7.
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Lesher, Emily K., Aimee R. Poda, Anthony J. Bednar y James F. Ranville. "Field-Flow Fractionation Coupled to Inductively Coupled Plasma-Mass Spectrometry (FFF-ICP-MS): Methodology and Application to Environmental Nanoparticle Research". En Field-Flow Fractionation in Biopolymer Analysis, 277–99. Vienna: Springer Vienna, 2011. http://dx.doi.org/10.1007/978-3-7091-0154-4_17.
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"Field Flow Fractionation (FFF)". En Encyclopedia of Biophysics, 759. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-16712-6_100319.
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Rolland-Sabaté, Agnès, Serge Battu, Frédéric Bonfils, Karim Chelbi y Michel Martin. "Field-Flow Fractionation (FFF)". En Advances in Physicochemical Properties of Biopolymers (Part 1), 137–83. BENTHAM SCIENCE PUBLISHERS, 2017. http://dx.doi.org/10.2174/9781681084534117010008.
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Kato, Haruhisa. "Field-flow fractionation (FFF) with various detection systems". En Characterization of Nanoparticles, 249–64. Elsevier, 2020. http://dx.doi.org/10.1016/b978-0-12-814182-3.00016-x.
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Lespes, Gaëtane, Sandrine Huclier, Serge Battu y Agnès Rolland Sabaté. "Field flow fractionation (FFF): practical and experimental aspects". En Particle Separation Techniques, 621–57. Elsevier, 2022. http://dx.doi.org/10.1016/b978-0-323-85486-3.00005-6.
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Amarasiriwardena, Dula, Atitaya Siripinyanond y Ramon M. Barnes. "FLOW FIELD-FLOW FRACTIONATION-INDUCTIVELY COUPLED PLASMA-MASS SPECTROMETRY (FLOW-FFF-ICP-MS): A VERSATILE APPROACH FOR CHARACTERIZATION OF TRACE METALS COMPLEXED TO SOIL-DERIVED HUMIC ACIDS". En Humic Substances, 215–26. Elsevier, 2000. http://dx.doi.org/10.1016/b978-1-85573-807-2.50022-9.
Actas de conferencias sobre el tema "Flow field flow fractionation (Fl-FFF)":
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Steindl, Johannes, Rafael Eduardo Hincapie, Ante Borovina, Christoph Puls, Johann Badstöber, Gerhard Heinzmann y Torsten Clemens. "Improved EOR Polymer Selection Using Field-Flow Fractionation". En Abu Dhabi International Petroleum Exhibition & Conference. SPE, 2021. http://dx.doi.org/10.2118/207700-ms.
Resumen
Abstract Various polyacrylamide polymers have been successfully applied in chemical EOR projects. These polymers are characterised by high molecular weights (MW) to achieve high viscosifying power. The molecular weight distribution (MWD) of the polymers has a major impact on polymer properties and performance. Measuring the molecular weight distribution is challenging using conventional methods. Field-Flow Fractionation (FFF) enables the determination of the distribution to select and quality check various polymers. Polymers with high molar masses (> 1 MDa) are used for EOR to obtain highly viscous aqueous solutions. The MWD of the polymers is crucial for the solution characteristics. Conventional analysis of polymers is performed using either viscometry – which is able to determine the average MW but does not give information on MWD, or size-exclusion chromatography – which is restricted to molecular weights of < 20 MDa. FFF is based on the analytes flowing at different speeds in a channel dependent on their size and mass. This effect leads to separation, which is then used to determine the MWD. FFF allows to determine the MW and MWD of various ultra-high molecular weight polyacrylamides (HPAAMs). The FFF measurements showed, that despite similar MWs are claimed, substantial differences in MWD are observed. This technology offered the quantification the MWD of HPAAMs up to a MW of 5 GDa. Furthermore, gyration radii of the HPAAM molecules were determined. Selecting polymers on viscosifying power only is not addressing issues related to different MW and MWDs such as selective polymer retention and degradation of the high molar mass part of the distribution. The results were used to improve the polymer selection for chemical EOR projects. Overall, this work presents a new technique for analysis of ultra-high molecular weight EOR polymers, which enables the possibility to determine the full range of polymer MWD. This available information enhances the EOR polymer selection process addressing selective polymer retention and mechanical degradation in addition to the viscosifying power of polymers.
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Marchis, Andreea y Adrian Neculae. "Numerical simulation of bioparticle separation by dielectrophoretic field-flow-fractionation (DEP-FFF)". En TIM 2013 PHYSICS CONFERENCE. AIP Publishing LLC, 2014. http://dx.doi.org/10.1063/1.4903032.
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Borovina, Ante, Rafael E. Hincapie Reina, Torsten Clemens, Eugen Hoffmann, Jonas Wegner y Johannes Steindl. "Polymer Selection for Sandstone Reservoirs Using Heterogeneous Micromodels, Field Flow Fractionation and Corefloods". En SPE Improved Oil Recovery Conference. SPE, 2022. http://dx.doi.org/10.2118/209352-ms.
Resumen
Abstract Incremental oil recovery due to polymer flooding results from acceleration of oil production along flow paths and improving sweep efficiency. To achieve favorable economics, polymers should have a high viscosifying power and low adsorption. However, in addition, incremental oil production from various rock qualities needs to be maximized. We developed a workflow using a layered micromodel, corefloods and Field-Flow Fractionation (FFF) to determine the Molecular Weight Distribution (MWD) for the selection of polymers addressing heterogeneous reservoirs. We have designed micromodels consisting of two layers with different permeabilities, one four times larger than the other. The micromodel structure is based on the characteristics of a real sandstone core, with the dimensions 6 cm × 2 cm. These micromodels were used as preliminary screening of the polymers incorporating heterogeneity effects. Subsequently, single- and two-phase core experiments were performed to determine injectivity effects and displacement efficiency of the selected polymers. In addition, FFF was used to measure the molecular weight distribution, gyration radii and conformance of the polymers. Based on the workflow a polymer was selected. All polymers were tested at target viscosity at 7 1/s shear rate. Micromodel experiments showed that tested polymers are leading to improved sweep efficiency of heterogeneous structure. The displacement efficiency within the higher permeable layer was similar for the investigated polymers whereas the oil recovery from the lower permeable layer showed differences. FFF revealed that the MWD's of the tested polymers were different. The MWD of one of the polymers showed a large number of larger molecules compared with the other polymers. This polymer did not lead to the highest oil recovery in the micromodel. Injectivity and propagation of the higher MW polymer in both single- and two-phase core-floods was falling behind the other polymers. Measurements of the MWD of the core effluent showed that for all tested polymers the larger molecules are initially retained more than the smaller molecules. The polymer with the smallest molecules and narrow MWD showed the best propagation characteristics in the core. Owing to the good performance of this polymer in terms of sweep efficiency improvement, injectivity, and propagation, this polymer was selected for a field application. Therefore, the novelty presented here can be summarised as follow: Heterogeneous micromodels were used to screen polymers for one-dimensional displacement efficiency and sweep efficiency effects Single- and two-phase core floods in combination with Field-Flow Fractionation revealed the impact of the molecular weight distribution (MWD) on polymer injectivity, propagation and retention Selection of polymers need to include MWD to find the most effective polymer Polymer selection needs to take near-wellbore and reservoir effects (micro- and sweep efficiency in heterogeneous reservoirs) into account
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Song, Minghao y Hongwei Sun. "Simulation and Experimental Research for Microparticles in Microchannels With Dielectrophoretic Field-Flow Fractionation". En ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39133.
Resumen
The Dielectrophoretic Field-flow Fractionation (DEP-FFF) is a very promising separation technique for particles and biological molecules. To further explore this technology, we conducted a computational and experimental investigation of a single particle movement in a PDMS microfluidic channel under DEP force, where both electrokinetic effects and particle hydrodynamics are considered. The model was first validated with dipole moment theory, and a polystyrene particle (∼10 μm) behavior in a non-uniform electric field created by a pair of non-symmetrical electrodes was then studied numerically. The simulation results were compared with experimental results and a good agreement was obtained. Further research is underway to study the behavior of non-spherical particles (such as nanowire, nanorod, and nanofiber) in other microfluidic systems.
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Darabi, Jeff. "Numerical Analysis of Dielectrophoretic-Based DNA Separation and Trapping". En ASME 2022 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/fedsm2022-87076.
Resumen
Abstract In this study, dielectrophoresis (DEP) has been coupled with field-flow fractionation (FFF) for the sorting and trapping of the biological particles. A numerical simulation is performed to compute particle trajectories under the influence of DEP, drag, gravitational, and buoyancy forces, as well as Brownian motion. The simulation was performed using OpenFOAM CFD software. Both positive and negative DEP methods are examined as possible separation techniques for DNA fragments. Positive DEP forces are used to attract the particles to the electrodes and trap them in groups of similar particles while a combination of negative DEP forces and field flow fractionation (FFF) are used to levitate the particles within the fluid flow to certain flow trajectories. The results obtained from this study, including electric field simulations, particle trajectories, elution times, and trapping lengths are presented.
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Isogai, Akira. "Determination of Length and Width of Nanocelluloses from Their Dilute Dispersions". En Advances in Pulp and Paper Research, Oxford 2017, editado por W. Batchelor y D. Söderberg. Fundamental Research Committee (FRC), Manchester, 2017. http://dx.doi.org/10.15376/frc.2017.2.801.
Resumen
Length/width and their distribution of nanocelluloses, prepared from wood pulps with or without chemical pretreatment, are key factors in application to high-strength and light-weight composites, transparent optical films, gas-barrier films, electronic devices, etc. Although microscopy images provide some length/width information, the number of measurable nanocellulose elements is limited. In this paper, three methods to determine nanocellulose lengths and widths are presented. The field-flow-fractionation (FFF) method combined with static light scattering was applied to dilute aqueous TEMPO-oxidised cellulose nanofibril (TOCN) dispersions to obtain avarage lengths, length distributions, and widths of different TOCNs. Although TOCN elements with lengths > 300 nm could not be separated properly according to their lengths by the FFF system, TOCNs with lengths < 300 nm were adequately separated, depending on the lengths by the FFF system, and provided length/length distributions and widths, well corresponding to those obtained from microscopy images. Intrinsic viscosities of TOCNs with different lengths and widths were obtained viscosities of TOCNs with different lengths and widths were obtained using shear viscosity measurement of dilute aqueous TOCN dispersions.