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Impact of Electron Beam Irradiation on Thermoplastic Polyurethanes Unraveled by Thermal Field-Flow Fractionation. Polym Degrad Stab 2021. [DOI: 10.1016/j.polymdegradstab.2020.109423] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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2
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Tadjiki S, Beckett R. Experimental verification of the steric-entropic mode of retention in centrifugal field-flow fractionation using illite clay plates. J Chromatogr A 2018; 1538:60-66. [PMID: 29397986 DOI: 10.1016/j.chroma.2018.01.041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 01/13/2018] [Accepted: 01/18/2018] [Indexed: 10/18/2022]
Abstract
The commonly used theory to describe the normal Brownian mode of field-flow fractionation (FFF) assumes the particles to be point masses and hence the shape is ignored. Beckett and Giddings extended this theory to include the effect of thin rods and discs being forced very close to the accumulation wall. By including the decrease in the entropy this causes, they derived new expressions for the retention of such nonspherical particles in FFF. The steric-entropic theory predicts that when the sample cloud thickness is less than the major dimension of the rods or discs then particles elute earlier than predicted by the Brownian mode theory. This leads to an underestimation of the buoyant mass and equivalent spherical diameter calculated from FFF data. In this paper we report for the first time experimental data for the retention of thin illite particles in centrifugal FFF that agrees well with these steric-entropic predictions. Not only do the size distributions calculated using the Brownian mode theory shift to lower size when the field is increased but the shift in the retention ratio of the peak maxima of the FFF fractograms could be predicted fairly accurately by the steric-entropic equations.
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Affiliation(s)
- Soheyl Tadjiki
- Water Studies Centre and School of Chemistry, Monash University, Clayton Campus, Melbourne, VIC, 3800, Australia.
| | - Ronald Beckett
- Water Studies Centre and School of Chemistry, Monash University, Clayton Campus, Melbourne, VIC, 3800, Australia
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Williams PS. Fractionating power and outlet stream polydispersity in asymmetrical flow field-flow fractionation. Part II: programmed operation. Anal Bioanal Chem 2016; 409:317-334. [PMID: 27838749 DOI: 10.1007/s00216-016-0007-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 09/08/2016] [Accepted: 10/04/2016] [Indexed: 11/26/2022]
Abstract
Asymmetrical flow field-flow fractionation (As-FlFFF) is a widely used technique for analyzing polydisperse nanoparticle and macromolecular samples. The programmed decay of cross flow rate is often employed. The interdependence of the cross flow rate through the membrane and the fluid flow along the channel length complicates the prediction of elution time and fractionating power. The theory for their calculation is presented. It is also confirmed for examples of exponential decay of cross flow rate with constant channel outlet flow rate that the residual sample polydispersity at the channel outlet is quite well approximated by the reciprocal of four times the fractionating power. Residual polydispersity is of importance when online MALS or DLS detection are used to extract quantitative information on particle size or molecular weight. The theory presented here provides a firm basis for the optimization of programmed flow conditions in As-FlFFF. Graphical abstract Channel outlet polydispersity remains significant following fractionation by As-FlFFF under conditions of programmed decay of cross flow rate.
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Affiliation(s)
- P Stephen Williams
- Cambrian Technologies Inc., 1772 Saratoga Avenue, Cleveland, OH, 44109, USA.
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Separation and characterization of food macromolecules using field-flow fractionation: A review. Food Hydrocoll 2013. [DOI: 10.1016/j.foodhyd.2012.04.007] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Håkansson A, Magnusson E, Bergenståhl B, Nilsson L. Hydrodynamic radius determination with asymmetrical flow field-flow fractionation using decaying cross-flows. Part I. A theoretical approach. J Chromatogr A 2012; 1253:120-6. [DOI: 10.1016/j.chroma.2012.07.029] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Revised: 06/18/2012] [Accepted: 07/02/2012] [Indexed: 11/24/2022]
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Magnusson E, Håkansson A, Janiak J, Bergenståhl B, Nilsson L. Hydrodynamic radius determination with asymmetrical flow field-flow fractionation using decaying cross-flows. Part II. Experimental evaluation. J Chromatogr A 2012; 1253:127-33. [DOI: 10.1016/j.chroma.2012.07.005] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 06/18/2012] [Accepted: 07/02/2012] [Indexed: 11/29/2022]
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7
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Martin M, Beckett R. Size Selectivity in Field-Flow Fractionation: Lift Mode of Retention with Near-Wall Lift Force. J Phys Chem A 2012; 116:6540-51. [DOI: 10.1021/jp212414e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Michel Martin
- Ecole Supérieure de Physique et de Chimie Industrielles, Laboratoire de Physique et Mécanique des Milieux Hétérogènes (PMMH - UMR 7636 CNRS - ESPCI-ParisTech - Université Pierre et Marie Curie 6 - Université Paris Diderot), 10 rue Vauquelin, 75231 Paris Cedex 05, France
| | - Ronald Beckett
- Water Studies Centre, School of Chemistry, Monash University, Clayton, Victoria 3800, Australia
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STEPHEN WILLIAMS P, LEE SEUNGHO, CALVIN GIDDINGS J. CHARACTERIZATION OF HYDRODYNAMIC LIFT FORCES BY FIELD-FLOW FRACTIONATION. INERTIAL AND NEAR-WALL LIFT FORCES. CHEM ENG COMMUN 2007. [DOI: 10.1080/00986449408936272] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- P. STEPHEN WILLIAMS
- a Department of Chemistry , Field-Flow Fractionation Research Center, University of Utah , Salt Lake City, Utah, 84112
| | - SEUNGHO LEE
- a Department of Chemistry , Field-Flow Fractionation Research Center, University of Utah , Salt Lake City, Utah, 84112
| | - J. CALVIN GIDDINGS
- a Department of Chemistry , Field-Flow Fractionation Research Center, University of Utah , Salt Lake City, Utah, 84112
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Leeman M, Wahlund KG, Wittgren B. Programmed cross flow asymmetrical flow field-flow fractionation for the size separation of pullulans and hydroxypropyl cellulose. J Chromatogr A 2006; 1134:236-45. [PMID: 16963058 DOI: 10.1016/j.chroma.2006.08.065] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2004] [Revised: 07/04/2006] [Accepted: 08/01/2006] [Indexed: 11/16/2022]
Abstract
Different functions for the programming of the cross flow in asymmetrical flow field-flow fractionation were studied with the aim to find the flow conditions most suitable for the molar mass distribution analysis of high molecular weight polysaccharides. A mixture of four differently sized pullulans covering the molar mass range 5.8 x 10(3)-1.6 x 10(6) g mol(-1) were used as a model sample. Two types of programs were studied, linear and exponential decays, both with and without initial periods of a constant cross flow. For comparison, nonprogrammed runs, i.e. using constant cross flow, were studied. It was found that exponentially decaying cross flow gave the most uniform molar mass selectivity across the fractogram. The programmed cross flow was applied to the molar mass distribution analysis of a technical quality of hydroxypropyl cellulose.
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Affiliation(s)
- Mats Leeman
- Department of Technical Analytical Chemistry, Center for Chemistry and Chemical Engineering, Lund University, SE-221 00 Lund, Sweden.
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Schure MR, Palkar SA. Accuracy estimation of multiangle light scattering detectors utilized for polydisperse particle characterization with field-flow fractionation techniques: a simulation study. Anal Chem 2002; 74:684-95. [PMID: 11838697 DOI: 10.1021/ac011006p] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The coupling of field-flow fractionation (FFF) and multiangle light scattering (MAIS) detectors is complementary in that the MALS system allows particle characterization when a narrow dispersity particle population is present in the detector. The fractionation process provides this narrow dispersity. Utilizing discrete particle simulations of FFF and optical calculations based on both the Mie theory of particle scattering and Rayleigh-Gans-Debye (RGD) scattering theory, the extent of polydispersity that can be tolerated for accurate particle quantitation is explored. It is found that flow, electrical, and sedimentation FFF provide adequate separation for accurate particle quantitation by MALS. The Mie theory is more accurate than the RGD theory, which is known to deviate at higher particle size. Low error in the measurement of mean diameters is found when only the particle diameter is of interest. It is shown that the reconstruction of the particle size distribution from time slice data is distorted due to errors in concentration, which result from finite polydispersity and other effects. A number of procedures are evaluated in restoring the size distribution to higher accuracy. None of these procedures is deemed of general purpose and none of these is reliable. The best results are obtained when fractionation is conducted under the minimal possible outlet polydispersity and when steric effects are minimized. In addition, best results are had for inherently narrow dispersity colloidal materials.
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Affiliation(s)
- Mark R Schure
- Theoretical Separation Science Laboratory, Rohm and Haas Company, Spring House, Pennsylvania 19477, USA
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Williams PS, Giddings MC, Giddings JC. A data analysis algorithm for programmed field-flow fractionation. Anal Chem 2001; 73:4202-11. [PMID: 11569810 DOI: 10.1021/ac010305b] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An algorithm that employs numerical integration for analysis of field-flow fractionation (FFF) data is presented. The algorithm utilizes detector response, field strength, and channel flow rate data, monitored at discrete time intervals during sample elution to generate a distribution of sample components according to particle size or molecular weight. The field strength and channel flow rate may either be held constant or programmed as functions of time, and it is not necessary for these programs to follow specific mathematical functions. If experimental conditions are monitored during a run, the algorithm can account for any deviation from nominal set conditions. The algorithm also allows calculation of fractionating power for the actual conditions as monitored during the run. The method provides greatly increased flexibility in the application of the FFF family of techniques. It removes the limitations on experimental conditions incurred by adherence to analytically available solutions to FFF theory, allowing ad hoc variation of field strength and other experimental parameters as necessary to increase sensitivity and specificity of the method. An implementation of the algorithm is described that is independent of the FFF technique (i.e., independent of field type) and mode of operation. To reduce computation time, it uses mathematical techniques to reduce the required number of numerical integrations. This is of particular importance when the perturbations to ideal FFF theory, such as those due to the effects of hydrodynamic lift forces, particle-wall or particle-particle interactions, and secondary relaxation, necessitate relatively lengthy numerical calculations.
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Affiliation(s)
- P S Williams
- Department of Biomedical Engineering, The Cleveland Clinic Foundation, Ohio 44195, USA.
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Levin S, Nudelman R, Reschiglian P, Pasti L. Simulation of fractograms of fat emulsions in power-programmed sedimentation field-flow fractionation (SdFFF). J Pharm Biomed Anal 1995; 13:869-77. [PMID: 8562610 DOI: 10.1016/0731-7085(95)01313-a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A quasi-empirical approach to the simulation of fractograms was examined to verify that the elution behavior of emulsions in power-based field programmed sedimentation field-flow fractionation (SdFFF) is consistent and predictable. The approach was applied to Intralipid, a commercial soybean emulsion and to an investigational medium chain triglyceride emulsion. The simulations predicted the fractograms that were obtained under various conditions of field strength, field decay and velocity of the suspending fluid, using distribution parameters obtained from one preliminary measurement of size distribution profile. Predicted fractograms were compared to experimental ones, under various fractionating powers. Good agreement was observed in most cases, in which interference of the secondary relaxation effects was not effective. The agreement confirmed the applicability of the approach to emulsions and that the simulations can be used instead of actual experiments for the optimization of their characterization by power-programmed SdFFF.
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Affiliation(s)
- S Levin
- Pharmaceutical Chemistry Department, School of Pharmacy, The Hebrew University of Jerusalem, Israel
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Levin S, Klausner E, Muchtar S. Characterization of submicron MCT o/w emulsions using sedimentation field-flow fractionation (FFF) with power field programming. J Pharm Biomed Anal 1994; 12:1115-21. [PMID: 7803561 DOI: 10.1016/0731-7085(94)e0031-u] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Sedimentation field-flow fractionation (SdFFF) operated with power-based field programming, was shown to be effective in the characterization of submicron investigational pharmaceutical emulsions. Field programming, in which the decrease of field strength with time gradually decreases the retention of sample components, extends the capabilities of sedimentation field flow fractionation in handling polydisperse and multicomponent samples. The emulsions were made of medium chain triglycerides (MCT) oil in water emulsified by phospholipids. They were analysed by different rates of field decay and different flow rates. Identical size distribution profiles were obtained under all circumstances, using the appropriate stop-flow times. Fractions were collected from the SdFFF eluting bands, and diameters were analysed by photon correlation spectroscopy, showing good agreement with values given by the FFF instrument at high flow rates and low rates of field decay. Accurate and highly reproducible size distribution profiles were obtained under various conditions. The detector response was shown to consist mostly of light scattering and was linear with concentration.
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Affiliation(s)
- S Levin
- Pharmaceutical Chemistry Department, School of Pharmacy, Hebrew University of Jerusalem, Israel
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