Sedimentation Field-flow Fractionation Research Articles

Field-flow fractionation of metallic microparticles in a rotating coiled column

The sedimentation field-flow fractionation in a rotating coiled column has been applied to the separation of silumin (aluminum–silicon alloy) microparticles for the first time. The possibility of preparative purification of metallic powders has been estimated.

New Method for Sorting Endothelial and Neural Progenitors from Human Induced Pluripotent Stem Cells by Sedimentation Field Flow Fractionation.

Human induced pluripotent stem cells (hiPSc) are a very useful solution to create and observe the behavior of specific and usually inaccessible cells, such as human motor neurons. Obtained from a patient biopsy by reprograming dermal fibroblasts (DF), hiPSc present the same properties as embryonic stem cells and can generate any cell type after several weeks of differentiation. Today, there are numerus protocols which aim to control hiPSC differentiation. The principal challenge is to obtain a sufficiently enriched specific cell population to study disease pathophysiology and to provide a good model for further investigation and drug screening. The differentiation process is very costly and time-consuming, because many specific factors and different culture media must be used. In this study, we used Sedimentation Field Flow Fractionation (SdFFF) to prepare enriched populations derived from hiPSc after only 10 days of culture in a classical medium. Based on phenotypic and proteomic characterization, "hyperlayer" elution resulted in a fraction expressing markers of endothelial progenitors while another fraction expressed markers of neural progenitors. The isolation of subpopulations representing various differentiation lineages is of major interest for the production of specialized, cell-enriched fractions and in the preparation of increasingly complex models for the development of new therapeutic tools.

Neural Stem Cell Properties of an Astrocyte Subpopulation Sorted by Sedimentation Field-Flow Fractionation.

Astrocytes encompass a heterogeneous cell population. Using sedimentation field-flow fractionation (SdFFF) method, different, almost pure, astrocyte subpopulations were isolated. Cells were collected from cortex of newborn rats and sorted by SdFFF to obtain different fractions, which were subjected to protein analysis and characterized by immunocytofluorescence. The behavior of the cells was analyzed in vitro, under culture conditions used for neural stem cells. These culture conditions were also applied to cells derived from an adult cortical tissue after traumatic brain injury (TBI). Finally, the astrocytic neural stem-like cells were transplanted in damaged sciatic nerve. Protein analysis indicated a high expression of glial fibrillary acidic protein (GFAP) and vimentin in fraction F3-derived cells. These cells formed neurospheres when cultured with epidermal growth factor and large colonies in a collagen-containing semi-solid matrix. Neurospheres expressed GFAP and nestin and were able in addition to generate neurons expressing MAP2 and oligodendrocytes expressing Olig2. When transplanted in a damaged nerve, cells of F3-derived neurospheres colonized the damaged area. Finally, after TBI in adult rats, cells able to form neurospheres containing a subpopulation of astrocytes expressing vimentin were obtained. Using the SdFFF method, an astrocyte subpopulation presenting stem cell properties was isolated from a newborn rat cortex and from an injured adult rat cortex. The specific activation of this astrocyte subpopulation may provide a potential therapeutic approach to restore lost neuronal function in injured or diseased brain.

Advanced analysis of polymer emulsions: Particle size and particle size distribution by field-flow fractionation and dynamic light scattering

Field flow fractionation (FFF) is an advanced fractionation technique for the analyses of very sensitive particles. In this study, different FFF techniques were used for the fractionation and analysis of polymer emulsions/latexes. As model systems, a pure acrylic emulsion and emulsions containing titanium dioxide were prepared and analyzed. An acrylic emulsion polymerization was conducted, continuously sampled from the reactor and subsequently analyzed to determine the particle size, radius of gyration in specific, of the latex particles throughout the polymerization reaction. Asymmetrical flow field-flow fractionation (AF4) and sedimentation field-flow fractionation (SdFFF), coupled to a multidetector system, multi-angle laser light scattering (MALLS), ultraviolet (UV) and refractive index (RI), respectively, were used to investigate the evolution of particle sizes and particle size distributions (PSDs) as the polymerization progressed. The obtained particle sizes were compared against batch-mode dynamic light scattering (DLS). Results indicated differences between AF4 and DLS results due to DLS taking hydration layers into account, whereas both AF4 and SdFFF were coupled to MALLS detection, hence not taking the hydration layer into account for size determination. SdFFF has additional separation capabilities with a much higher resolution compared to AF4. The calculated radii values were 5nm larger for SdFFF measurements for each analyzed sample against the corresponding AF4 values. Additionally a low particle size shoulder was observed for SdFFF indicating bimodality in the reactor very early during the polymerization reaction. Furthermore, different emulsions were mixed with inorganic species used as additives in cosmetics and coatings such as TiO2. These complex mixtures of species were analyzed to investigate the retention and particle interaction behavior under different AF4 experimental conditions, such as the mobile phase. The AF4 system was coupled online to inductively coupled plasma mass spectrometry (ICP-MS) for elemental speciation and identification of the inorganic additive. SdFFF had a larger separation power to distinguish different particle size populations whereas AF4 had the capability of separating the organic particles and inorganic TiO2 particles, with high resolution.

Initial results on the coupling of sedimentation field-flow fractionation (SdFFF) to inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS) for the detection and characterization of TiO2 nanoparticles

The coupling of SdFFF to ICP-MS/MS might be a prospective tool for the analysis of TiO2 NPs in environmental samples.

Effect of Surface Charge and Elemental Composition on the Swelling and Delamination of Montmorillonite Nanoclays Using Sedimentation Field-flow Fractionation and Mass Spectroscopy

AbstractThe swelling properties of smectite-type clay particles (including montmorillonite) are of interest in various industries. A fundamental understanding of the surface properties of smectite particles at the sub-micron level would facilitate investigation of the effect of distributed properties such as charge and elemental composition. Swelling and delamination of SWy-2 Na-montmorillonite (Na-Mnt) nano-clay particles were studied here using size distributions obtained by sedimentation field-flow fractionation (SdFFF). Fractions were examined by electron microscopy and inductively-coupled optical emission spectroscopy (ICP-OES). Two distinct populations were observed in the size distribution of SWy-2 Na-Mnt particles (bimodal size distribution), with mean equivalent spherical diameters of ~60 nm and 250 nm, respectively. In contrast, the size distribution of STx-1 Ca-montmorillonite (Ca-Mnt) particles showed only one peak with a mean equivalent spherical diameter of ~410 nm, which changed to 440 nm after 4 days of hydration. Analyses of the fractions by ICP-OES obtained along the size distribution of Na-Mnt showed an abundance of Ca and Mg in the fractions below 250 nm, and confirmed the presence of Fe and Mg as isomorphous substituents. Electron micrographs of the fractions obtained from Na-Mnt size distributions were used to calculate the thickness of the clay particles. Bridging forces between pure orMgsubstituted montmorillonite and either Ca2+ or Na+ were calculated using semi-empirical methods. The results demonstrated that swelling and delamination of Na-Mnt clay particles are dictated by properties such as elemental composition and surface charge which are distributed along the size distribution.

Physicochemical and toxicological evaluation of silica nanoparticles suitable for food and consumer products collected by following the EC recommendation.

Specific information about the particle size distribution, agglomeration state, morphology, and chemical composition of four silica samples, used as additives in food and in personal care products, were achieved with a combination of analytical techniques. The combined use of differential centrifugal sedimentation (DCS), sedimentation field flow fractionation (SdFFF), and scanning and transmission electron microscopy (SEM and TEM) allows to classify the water dispersed samples as "nanomaterials" according to the EC definition. The mechanical stirring and the ultrasound treatment were compared as dispersion methods. The particle surface chemical composition, determined by particle-induced X-ray emission (PIXE) and X-ray photoelectron spectroscopy (XPS), assessed the different levels of purity between the pyrogenic and the precipitated silica and highlighted particle surface chemical composition modifications in the outer shell when dispersed by mechanical stirring. The potential toxic effects of silica on intestinal Caco-2 cells were investigated using MTS assay and by measuring lactate dehydrogenase (LDH) release and caspases 3/7 activity after 24h of incubation. No or limited decrease of cell viability was observed for all particles regardless of dispersion procedure, suggesting a relative innocuity of these silica samples.

Sedimentation field-flow fractionation for characterization of citric acid-modified Hβ zeolite particles: Effect of particle dispersion and carrier composition

In this study, sedimentation field-flow fractionation (SdFFF) was, for the first time, applied for determination of size distribution of Hβ zeolite particles modified by citric acid (CA-Hβ). Effects of the particle dispersion and the carrier liquid composition (type of dispersing reagent (surfactant) and salt added in the carrier liquid, ionic strength, and pH) on SdFFF elution behavior of CA-Hβ zeolite particles were systematically investigated. Also the SdFFF separation efficiency of the particles was discussed in terms of the forces such as van der Waals, hydrophobic, and induced-dipole interactions. Results reveal that the type of salt and pH of the carrier liquid significantly affect the SdFFF separation efficiency of the zeolite particles. It was found that addition of a salt (NaN3) into the carrier liquid affects the characteristic of the SdFFF channel surface. It was found that the use of an acidic medium (pH 3.2) leads to a particle–channel interaction, while the use of a basic medium (pH 10.6) promotes an inter-particle hydrophobic interaction. Result from SdFFF was compared with those from scanning electron microscopy (SEM) and dynamic light scattering (DLS). It seems that, once the experimental conditions are optimized, SdFFF becomes a valuable tool for size characterization of the zeolite particles.

New ex-ovo colorectal-cancer models from different SdFFF-sorted tumor-initiating cells.

Despite effective treatments, relapse of colorectal cancer (CRC) is frequent, in part caused by the existence of tumor-initiating cells (TICs). Different subtypes of TICs, quiescent and activated, coexist in tumors, defining the tumor aggressiveness and therapeutic response. These subtypes have been sorted by hyperlayer sedimentation field-flow fractionation (SdFFF) from WiDr and HCT116 cell lines. On the basis of a new strategy, including TIC SdFFF sorting, 3D Matrigel amplification, and grafting of corresponding TIC colonies on the chick chorioallantoic membrane (CAM), specific tumor matrices could be obtained. If tumors had similar architectural structure with vascularization by the host system, they had different proliferative indices in agreement with their initial quiescent or activated state. Protein analysis also revealed that tumors obtained from a population enriched for "activated" TICs lost "stemness" properties and became invasive. In contrast, tumors obtained from a population enriched for "quiescent" TICs kept their stemness properties and seemed to be less proliferative and invasive. Then, it was possible to produce different kinds of tumor which could be used as selective supports to study carcinogenesis and therapy sensitivity.

침강 장-흐름 분획법을 이용한 CdS 양자점 입자의 특성 분석

Abstract: CdS-QD particles are a nano-sized semiconducting crystal that emits light. Their optical propertiesshow great potential in many areas of applications such as disease-diagnostic reagents, optical technologies,media industries and solar cells. The wavelength of emitting light depends on the particle size and thus thequality control of CdS-QD particle requires accurate determination of the size distribution. In this study, CdS-QD particles were synthesized by a simple γ-ray irradiation method. As a particle stabilizer polyvinyl pyrrolidone(PVP) were added. In order to determine the size and size distribution of the CdS-QD particles, sedimentationfield-flow fractionation (SdFFF) was employed. Effects of carious parameters including the the flow rate, externalfield strength, and field programming conditions were investigated to optimize SdFFF for analysis of CdS-QD particles. The Transmission electron microscopy (TEM) analysis show the primary single particle size was~4 nm, TEM images indicate that the primarty particles were aggregated to form secondary particles havingthe mean size of about 159 nm. As the concentration of the stabilizer increases, the particle size tends to decrease.Mean size determined by SdFFF, TEM, and dynamic light scattering (DLS) were 126, 159, and 152 nm,respectively. Results showed SdFFF may become a useful tool for determination of the size and its distributionof various types of inorganic particles. 요약: CdS 양자점 입자는 특정 파장의 빛을 방출하는 반도체 나노 결정으로 이러한 광학적 특성 때문에 질병 진단 시약, 광학기술, 미디어 산업 및 태양전지와 같은 다양한 분야에서 응용되는 물질이다. 방출하는 빛의 색은 입자의 크기에 의존하기 때문에 CdS 양자점 입자의 크기 및 크기분포를 정확하게 분석하는 것이 필요하다. 본 연구에서는 CdS 양자점 입자를 감마-선 조사법(γ-ray irradiation method)을 이용하여 합성하고, 크기 및 크기 분포도를 결정하기 위하여 침강 장-흐름 분획법 (SdFFF)를 이용하였다.

Field-flow fractionation of nano- and microparticles in rotating coiled columns

Field-flow fractionation (FFF) is a very powerful and versatile set of liquid chromatography-like elution methods. However, conventional FFF separations occur in thin channels and the sample weight injected is usually less than 1mg to avoid overloading. The fractionation in a rotating coiled column (RCC), which can be attributed to sedimentation FFF, enables the handling sample weight to be increased at least up to 1g. An uneven distribution of particles in RCC was first observed by Y. Ito et al. in 1966. The work in this direction was continued by P.S. Fedotov et al. in 2000. Regularities of the behaviour of nano- and microparticles of different size and origin in RCCs with different design parameters were systematically studied taking as example silica particles, latex beads, quartz sand, clay minerals, and other samples. The basic principles of the new FFF method were established. The developed method was applied to the speciation analysis of polydisperse environmental samples, in particular, for the separation of soils into silt, clay and sand fractions. For the first time, nano- and submicron particles of street dust have been separated, weighted, characterized by electronic microscopy, and quantitatively analyzed by ICP-MS (after digestion). The elements that may be of anthropogenic origin (Zn, Cr, Ni, Cu, Cd, Sn, Pb) were found to concentrate mainly in <0.3 and 0.3–1μm fractions. It has been shown that the concentrations of Cr, Ni, Zn in the finest fraction (<0.3μm) of street dust can be one order of magnitude higher than the concentrations of elements in bulk sample. The fractionation in RCC was also used for the recovery of a nearly monodisperse fraction (4.5μm) of a chromatographic sorbent based on polystyrene-divinylbenzene; impurities remaining from the synthesis and smaller particles (1–2μm) being removed. Study on the fractionation of synthetic samples has demonstrated the applicability of the method to the preparative separation and purification of polydisperse materials.

Production, Physico-Chemical Characterization and Biodistribution Studies of Lipid Nanoparticles

This study describes the preparation, characterization, in vitro uptake and in vivo biodistribution in mice of solid lipid nanoparticles and nanostructured lipid carriers. The effect of nanoparticle lipid matrix, presence of fluorescent and functionalization by polysorbate 80 on dimensional distribution and morphology have been studied by sedimentation field flow fractionation, photon correlation spectroscopy and cryogenic transmission electron microscopy. The complementary use of different techniques demonstrated that lipid matrix composition, presence of fluorescent dye and polysorbate 80 functionalization have little effect on nanoparticle morphology and size distribution. Uptake of fluorescent nanoparticles was determined in vitro by human brain endothelial cells, showing that nanoparticles treated by polysorbate 80 displayed lower uptake values with respect to the corresponding control nanoparticles. Biodistribution of solid lipid nanoparticles treated by polysorbate 80 was evaluated by fluorescent luminescent imaging after intraperitoneal administration in mice. The in vivo images indicate that nanoparticles were able to reach the brain, even if they prevalently accumulated in liver and spleen.

Biodistribution of nanostructured lipid carriers: A tomographic study

This study describes the preparation, characterization, and biodistribution of radiolabelled nanostructured lipid carriers (NLCs) especially designed for in vivo tomographic study.A preliminary formulative study was conducted in order to incorporate 99mTc based tracer in NLCs. At this aim a 99mTc complex containing a terminal 99mTcN multiple bond ([99mTc]N-DBODC2) has been synthesized and included in NLCs produced by a stirring and ultrasonication method.The morphological and dimensional characteristics of the produced NLCs have been accurately investigated by a number of specific techniques, including: cryogenic transmission electron microscopy, X-ray, photon correlation spectroscopy and sedimentation field flow fractionation. The obtained NLCs were employed for achieving in vivo tomographic images of the rat body by small-animal SPECT scanner that enabled the investigation of NLC biodistribution after intraperitoneal, intravenous, intranasal and oral administration. NLC production protocol allowed to firmly encapsulate the radiotracer within the nanoparticles. In vivo studies evidenced that NLC remained stable in vivo, suggesting their suitability as controlled release system for drugs and radiochemical for therapeutic and diagnostic purposes.Moreover the high resolution images obtained by the SPECT technique allowed to detect NLC presence in brown fat tissue, suggesting NLC therapeutic application for treating human obesity and related metabolic disorders.

Cannabinoid antagonist in nanostructured lipid carriers (NLCs): design, characterization and in vivo study.

This study describes the preparation, characterization, and in vivo evaluation in rats of nanostructured lipid carriers (NLCs) encapsulating rimonabant (RMN) as prototypical cannabinoid antagonist. A study was conducted in order to optimize NLC production by melt and ultrasonication method. NLCs were prepared by alternatively adding the lipid phase into the aqueous one (direct protocol) or the aqueous phase into the lipid one (reverse protocol). RMN-NLCs have been characterized by cryogenic transmission electron microscopy (cryo-TEM), X-ray, photon correlation spectroscopy (PCS) and sedimentation field flow fractionation (SdFFF). Reverse NLCs were treated with polysorbate 80. RMN release kinetics have been determined in vitro by dialysis method. In vivo RMN biodistribution in rats was evaluated after intranasal (i.n.) administration of reverse RMN-NLC. The reverse protocol enabled to prevent the lost of lipid phase and to achieve higher RMN encapsulation efficacy (EE) with respect to the direct protocol (98% w/w versus 67% w/w). The use of different protocols did not affect NLC morphology and dimensional distribution. An in vitro dissolutive release rate of RMN was calculated. The in vivo data indicate that i.n. administration of RMN by reverse NLC treated with polysorbate 80 increased RMN concentration in the brain with respect to the drug in solution. The nanoencapsulation protocol presented here appears as an optimal strategy to improve the low solubility of cannabinoid compounds in an aqueous system suitable for in vivo administration.

Effect of size of Fe3O4 magnetic nanoparticles on electrochemical performance of screen printed electrode using sedimentation field-flow fractionation

Fe3O4 magnetic nanoparticles (MNPs) and Fe3O4-deposited multi-walled carbon nanotubes (Fe3O4@MWCNTs) were synthesized by ultrasonic co-precipitation method. The surface and structural properties of Fe3O4 MNPs and Fe3O4@MWCNTs were characterized by X-ray diffraction, field emission transmission electron microscopy (FE-TEM), X-ray photoelectron spectroscopy, and dynamic light scattering (DLS). Sedimentation field-flow fractionation (SdFFF) was, for the first time, employed to study the influence of synthesis parameters on size distribution of Fe3O4 MNPs. A reasonable resolution for SdFFF analysis of Fe3O4 MNPs was obtained by a combination of 1,600 RPM, flow rate of 0.3 mL min−1, and Triton X-100. The results suggest that lower pH and higher reaction temperature tend to yield smaller Fe3O4 MNPs size. The size distribution of Fe3O4 MNPs obtained from SdFFF was compared with those obtained from TEM and DLS. Also the effect of the particle size of Fe3O4 MNPs on electrochemical property of Fe3O4@MWCNTs-treated screen printed electrode (SPE) was studied. Cyclic voltammetry revealed that SPE treated with MWCNTs yields a significantly enhanced signal than that with no treatment. The SPE signal was even further enhanced with addition of Fe3O4 MNPs. For SPE analysis of dopamine, a liner range of 0.005–0.1 mM with a correlation coefficient of 0.986 was observed. Results revealed that (1) SdFFF is a useful tool for size-based separation and characterization of MNPs; (2) Proposed methods for synthesis of Fe3O4 nanoparticles and Fe3O4@MWCNTs are mild and fast (about 30 min); (3) SPE treated with Fe3O4@MWCNTs shows potential applicability for biosensing.

Characterization of size, morphology and elemental composition of nano-, submicron, and micron particles of street dust separated using field-flow fractionation in a rotating coiled column

For the first time, nano- and submicron particles of street dust have been separated, weighted, and analyzed. A novel technique, sedimentation field-flow fractionation in a rotating coiled column, was applied to the fractionation of dust samples with water being used as a carrier fluid. The size and morphology of particles in the separated fractions were characterized by electronic microscopy before digestion and the determination of the concentration of elements by ICP-AES and ICP-MS. The elements that may be of anthropogenic origin (Zn, Cr, Ni, Cu, Cd, Sn, Pb) were found to concentrate mainly in <0.3 and 0.3–1μm fractions. It has been shown that the concentrations of Cr, Ni, Zn in the finest fraction (<0.3μm) of street dust can be one order of magnitude higher than the concentrations of elements in bulk sample and coarse fractions. For example, the concentrations of Ni in <0.3, 0.3–1, 1–10, and 10–100μm fractions were 297±46, 130±21, 36±10, and 21±4mg/kg, correspondingly. Though the finest particles present only about 0.1mass% of the sample they are of special concern due to their increased mobility and ability to penetrate into the deepest alveolar area of the lungs. For rare earth elements (La, Ce, Pr, Nd, Sm) that are evidently of natural source and may be found in soil minerals, in contrary, higher concentrations were observed in large particles (10–100μm). Sc was an exception that needs further studies. The proposed approach to the fractionation and analysis of nano-, submicron, and micron particles can be a powerful tool for risk assessment related to toxic elements in dust, ash, and other particulate environmental samples.

γ-ray synthesis and size characterization of CdS quantum dot (QD) particles using flow and sedimentation field-flow fractionation (FFF)

Quantum dot (QD) emits light of characteristic wavelength which depends on the size of the QD particles, and thus the quality control of QD requires accurate determination of its size distribution. Field-flow fractionation (FFF) is a separation technique that is well suited for the characterization of colloidal particles. In this study, CdS-QD particles were synthesized by a simple one-step γ-ray irradiation. Then asymmetrical flow FFF (AsFlFFF) and sedimentation FFF (SdFFF) were tested as tools for characterization of the particles. The single crystallite size of CdS-QD was measured to be about 4nm by X-ray diffraction (XRD), UV-VIS absorption spectroscopy, and transmission electron microscopy (TEM). TEM images indicate that the particles were agglomerated to form larger secondary particles (~110nm). Effects of the various experimental parameters of FFF including the type of dispersing agent, the ionic strength of the carrier liquid, and strength of external field were investigated. It was found that, among the dispersing agents tested, a mixture of anionic and nonionic surfactants tends to give better elution of CdS particles than anionic or nonionic surfactants. Results suggest that FFF can provide some advantages over dynamic light scattering (DLS) or TEM for size characterization of CdS particles, and with a proper optimization, FFF (AsFlFFF or SdFFF) could become a useful tool for stability study as well as size analysis of nanoparticles such as the CdS particles synthesized in this study.

Intermethod comparison of the particle size distributions of colloidal silica nanoparticles

There can be a large variation in the measured diameter of nanoparticles depending on which method is used. In this work, we have strived to accurately determine the mean particle diameter of 30–40 nm colloidal silica particles by using six different techniques. A quantitative agreement between the particle size distributions was obtained by scanning electron microscopy (SEM), and electrospray-scanning mobility particle sizer (ES-SMPS). However, transmission electron microscopy gave a distribution shifted to smaller sizes. After confirming that the magnification calibration was consistent, this was attributed to sample preparation artifacts. The hydrodynamic diameter, dh, was determined by dynamic light scattering (DLS) both in batch mode, and hyphenated with sedimentation field flow fractionation. Surprisingly the dh were smaller than the SEM, and ES-SMPS diameters. A plausible explanation for the smaller sizes found with DLS is that a permeable gel layer forms on the particle surface. Results from nanoparticle tracking analysis were strongly biased towards larger diameters, most likely because the silica particles provide low refractive index contrast. Calculations confirmed that the sensitivity is, depending on the shape of the laser beam, strongly size dependent for particles with diameters close to the visualization limit.

Sedimentation field flow fractionation monitoring of in vitro enrichment in cancer stem cells by specific serum-free culture medium.

The development of methods to enrich cell populations for cancer stem cells (CSC) is urgently needed to help understand tumor progression, therapeutic escape and to evaluate new drugs, in particular for colorectal cancer (CRC). In this work, we describe the in vitro use of OncoMiD for colon, a CRC-specific primary cell culture medium, to enrich CRC cell lines in CSC. Sedimentation field flow fractionation (SdFFF) was used to monitor the evolution of subpopulations composition. In these models, medium induced a loss of adherence properties associated with a balance between proliferation and apoptosis rates and, more important, an increased expression of relevant CSC markers, leading to specific SdFFF elution profile changes.

Characterization of Fly Ash by Field-Flow Fractionation Combined with SPLITT Fractionation and Compositional Analysis by ICP-OES

Accurate analysis of fly ash particles is not trivial because of complex nature in physical and chemicalproperties. SPLITT fractionation (SF) was employed to fractionate the fly ash particles into subpopulations inlarge quantities. Then the SF-fractions were analyzed by the steric mode of sedimentation field-flowfractionation (Sd/StFFF) for size analysis. The SF-fractions were also analyzed by ICP-OES. The resultsshowed that the fly ash is mainly co mposed of Fe, Ca, Mg and Mn. No particular trends were observed betweenthe particle size and the concentrations of Fe, Ca, Mg, while Mn, Cu and Zn were in higher concentrations insmaller particles. Sample preparation procedures were established, where the fly ash particles were sieved toremove large contaminants, and then washed with acetone to remove organics on the surface of particles. Thesample preparation and analysis methods developed in this study could be applied to other environmentalparticles.