Split-flow Thin Cell Fractionation Research Articles

Fractionation and characterization of starch granules using field-flow fractionation (FFF) and differential scanning calorimetry (DSC)

Starch is one of the main carbohydrates in food; it is formed by two polysaccharides: amylose and amylopectin. The granule size of starch varies with different botanical origins and ranges from less than 1 μm to more than 100 μm. Some physicochemical and functional properties vary with the size of the granule, which makes it of great interest to find an efficient and accurate size-based separation method. In this study, the full-feed depletion mode of split-flow thin cell fractionation (FFD-SF) was employed for a size-based fractionation of two types of starch granules (corn and potato) on a large scale. The fractionation efficiency (FE) of fraction-a for corn and potato granules was 98.4 and 99.4%, respectively. The FFD-SF fractions were analyzed using optical microscopy (OM) and gravitational field-flow fractionation (GrFFF). The respective size distribution results were in close agreement for the corn starch fractions, while they were slightly different for the potato starch fractions. The thermal properties of FFD-SF fractions were analyzed, and the results for the potato starch showed that the peak temperature of gelatinization (Tp) slightly decreases as the size of the granules increases. Additionally, the enthalpy of gelatinization (ΔH) increases when the granule size increases and shows negative correlation with the gelatinization range (ΔT).

Mathematical modeling of full feed depletion split-flow lateral-transport thin self-adjustable channels (FFD-SPLITT-SA)

The article contains a description of both the mathematical modeling of particles separation in self-adjustable channel for Split Flow Thin Cell Fractionation (SPLITT), and the channel design concept. The channel is designed to work in full feed depletion mode (FFD-SPLITT). By using different diameters of outlets, the channel has the ability to self-adjust the flow rates at the outlets. Moreover, in order to increase the throughput of the sample only one splitter, positioned at the end of the separation cell, was used. Channel construction, which is based on the SPLITT cell developed by J.C. Giddings, has an innovative approach. All the parameters affecting the separation are automatically tuned through modification of the channel structure, and that in turn stems from mathematical model based on fluid mechanics.

대용량 splitter less full-feed depletion SPLITT 분획법 (Large scale FFD-SF)에서의 분획효율(FE)및 시료처리량(TP)의 최적화

Split-flow thin cell fractionation (SPLITT fractionation, SF) is a particle separation technique that allows continuous (and thus a preparative scale) separation into two subpopulations based on the particle size or the density. In SF, there are two basic performance parameters. One is the throughput (TP), which was defined as the amount of sample that can be processed in a unit time period. Another is the fractionation efficiency (FE), which was defined as the number % of particles that have the size predicted by theory. Full-feed depletion mode (FFD-SF) have only one inlet for the sample feed, and the channel is equipped with a flow stream splitter only at the outlet in SF mode. In conventional FFD-mode, it was difficult to extend channel due to splitter in channel. So, we use large scale splitter-less FFD-SF to increase TP from increase channel scale. In this study, a FFD-SF channel was developed for a large-scale fractionation, which has no flow stream splitters (‘splitter less’), and then was tested for optimum TP and FE by varying the sample concentration and the flow rates at the inlet and outlet of the channel. Polyurethane (PU) latex beads having two different size distribution (about 3~7 µm, and about 2~30 µm) were used for the test. The sample concentration was varied from 0.2 to 0.8% (wt/vol). The channel flow rate was varied from 70, 100, 120 and 160 mL/min. The fractionated particles were monitored by optical microscopy (OM). The sample recovery was determined by collecting the particles on a 0.1 µm membrane filter. Accumulation of relatively large micron sized particles in channel could be prevented by feeding carrier liquid. It was found that, in order to achieve effective TP, the concentration of sample should be at higher than 0.4%.

대용량 중력장 SPLITT Fractionation: 분획효율에 미치는 채널 두께와 유속의 영향

SPLITT fractionation (SF) allows continuous (and thus a preparative scale) separation of micron- sized particles into two size fractions ('fraction-a' and 'fraction-b'). SF is usually carried out in a thin rectangular channel with two inlets and two outlets, which is equipped with flow stream splitters at the inlet and the outlet of the channel, respectively. A new large scale splitter-less gravitational SF (GSF) system had been assembled, which was designed to eliminate the flow stream splitters and thus is operated by the full feed depletion (FFD) mode (FFD-GSF). In the FFD mode, there is only one inlet through which the sample is fed. There is no carrier liquid fed into the channel, and thus prevents the sample dilution. The effects of the sample-feeding flow rate, the channel thickness on the fractionation efficiency (FE, number % of particles that have the size predicted by theory) of FFD-GSF was investigated using industrial polyurethane (PU) latex beads. The carrier liquid was water containing 0.1% FL-70 (particle dispersing agent) and 0.02% sodium azide (used as bactericide). The sample loading rate was varied from about 4 to 7 L/hr with the sample concentration fixed at 0.01%. The GSF channel thickness was varied from 900 to 1300 µm. Particles exiting the GSF channel were collected and monitored by optical microscopy (OM). Sample recovery was monitored by collecting the fractionated particles on a 0.45 µm membrane filter. It was found that FE of fraction-a was increased as the channel thickness increases, and FE of fraction-b was increased as the flow rate was increased. In all cases, the sample recovery has higher than 95%. It seems the new splitter-less FFD GSF system could become a useful tool for large scale separations of various types of micron-sized particles. 요약 : SPLITT 분획법(Split-flow thin cell fractionation, SF)은 입자성 물질이나 거대분자를 크기에

Implementation of splitter-less SPLITT fractionation and its application to large scale-fractionation of sea sediment

The split-flow thin cell fractionation (SF) is a useful tool for separating colloidal particles or macromolecules into two or more fractions in a preparative scale. In a conventional design, the SF channel is equipped with flow stream-splitters at the inlet and the outlet of the channel, which may cause deterioration of the resolution due to the disturbance in the flow stream by the imperfection of the splitter geometry. In this study, a new splitter-less SF channel was implemented, which was designed to operate only in the full-feed depletion (FFD) mode (FFD-SF). Without the splitters, it was possible to make the channel much larger than conventional ones (about 25 times larger in the channel volume), and thus obtain a much higher sample throughput ( TP, amount of the sample that can be processed in a unit time period). The new splitter-less FFD-SF system was tested and optimized using polyurethane (PU) latex spheres, and then applied successfully to a large scale separation of sea sediment. A series of three steps of FFD-SF operations (with each step repeated, and there were 6 steps in total) yielded separation of the sea sediment into four fractions having diameter ranges of larger than 10 µm, between 5 and 10 µm, between 2 and 5 µm, and smaller than 2 µm. TP of the three FFD-SF operations were 37.3, 22.1, and 17.9 kg/h, and the fractionation efficiencies ( FE) of the four size fractions were 80.5, 73.7, 79.1 and 86.1%. Results suggest the new splitter-less FFD-SF system could be a useful tool for large scale separation of complex particulates such as environmental particles.

Behaviour of environmental aquatic nanocolloids when separated by split-flow thin-cell fractionation (SPLITT)

A split-flow thin-cell (SPLITT) system in different operating modes was used to size fractionate colloids and particles in a lake water. The unperturbed lake water sample and eluent fractions (nominally a < 1 μm; b > 1 μm) were analysed with atomic force microscopy (AFM) to assess the quality of the separation, in particular to quantify the contamination of the b (> 1 μm) fraction with nanocolloids (defined here as material < 100 nm in size). Particle size distribution (PSD) results from AFM indicated that there was substantial contamination with nanocolloids. This contamination was, most likely, from diffusive transport across flow regimes within the SPLITT and this is supported by the fact that vertical distances between laminar flow regimes within the SPLITT channel are similar in magnitude, but slightly larger than the mean distances travelled by diffusion during the residence time of particles within the channel. Nevertheless, AFM surface density data showed that the concentration of nanoparticles in the a fraction was 6–9 times higher than in the b fraction, depending on the SPLITT mode, indicating that contamination of the b fraction was limited. Fluorescence data using monodisperse, low molar mass standards confirm the AFM results, with substantial contamination of the b fraction by the fluorescent molecular probes. The increased contamination of the b fraction of the standard molecular probes compared to natural nanocolloids is likely because they are smaller and more diffusive than the average of the natural material. Due to this contamination and the likelihood that these small colloids bind a large fraction of metals, SPLITT can only be used for metal fractionation and speciation in combination with other methods capable of performing further metal speciation analysis.

Size Fractionation and Characterisation of Fresh Water Colloids and Particles: Split-Flow Thin-Cell and Electron Microscopy Analyses

Split-flow thin-cell (SPLITT) was employed in conventional mode (CSF), to size-fractionate colloids and particles from a selected freshwater. Imaging and quantification by calculations of particle size distributions (PSDs) and shape factors were performed on sample analyzed by conventional high vacuum scanning electron microscopy (SEM) and environmental SEM (ESEM), to investigate the ability of SPLITT to make accurate and nonperturbing separations. SEM and ESEM images of unperturbed and SPLITT-generated fractions were used in order to obtain qualitative and quantitative information about the properties of colloids and particles. Particle size distributions (PSDs) showed that separations were very good, agreeing with theoretical behavior. ESEM PSDs showed that up to 87-88% of the material in the a fraction (expected to be <1 microm) was in fact less than 1 microm and in the b fraction (>1 microm) 87-95% of the material was the expected size. The SEM data indicated a slightly higher contamination of the b fraction with the presence of submicron colloids. Moreover, analysis of conformations indicated significant nonsphericity in unfractionated colloids and particles, but after SPLITT fractionation, shape factors showed that particles were significantly more spherical than before separation.

The POC / 234Th ratio of settling particles isolated using split flow-thin cell fractionation (SPLITT)

The common assumption that the ratio between particulate organic carbon (POC) and particulate 234Th obtained from shallow sediment traps and filterable particles are representative of the ratio in the total particle settling flux should be treated with caution in view of well-known biases associated with tethered shallow sediment traps and the decoupling between size and settling velocity of many natural particle regimes. To make progress toward reliably constraining the POC / 234Th ratio on truly settling particles, we have tested here a settling collection technique designed to remove any hydrodynamic bias; split flow-thin cell fractionation (SPLITT). These first results from a North Sea fjord and an open Baltic Sea time-series station indicates that the POC / 234Th ratio on the more complete particle-settling spectrum, isolated with SPLITT, was higher than the POC / 234Th ratio obtained simultaneously from tethered shallow sediment traps in seven out of seven parallel deployments with an average factor of 210%. The POC / 234Th ratio from the SPLITT was either in the same range or higher than that obtained on filtered “bulk” particles. To explain this novel data we hypothesize that the slowest settling fraction is organic-matter rich and does not strongly complex 234Th (i.e., high POC / 234Th). We suggest that this ultra-slow sinking fraction is better collected by SPLITT than with tethered sediment traps because of minimized hydrodynamic bias. This was tested using the ratio of POC / Al as a tracer of detrital mineral-ballast influenced settling velocity. The higher POC / Al ratios in SPLITT samples relative to in traps is consistent with the hypothesis that SPLITT is better suited for collecting also the slow-settling component of sinking particles. This important slow-settling component appears to here consist primarily of non-APS/TEP components of plankton exudates or other less-strongly 234Th-complexing organic matter. Further applications of the SPLITT technique are likely to return increasingly new insights on the composition (including “truly settling” POC / 234Th) of the total spectrum of particles settling out of the upper ocean.

Functional separation of colloids and gravitoids in surface waters based on differential settling velocity: Coupled cross‐flow filtration—split flow thin‐cell fractionation (CFF‐SPLITT)

Given recognized challenges with shallow sediment trap and 234Th‐based particle flux studies, it behooves us to test the picture of surface ocean fluxes provided by such investigations with alternative and new analytical techniques. To this end, cross‐flow filtration (CFF) has been coupled with split flow thin‐cell fractionation (SPLITT) to afford active but mild separation of aquatic particles through a dynamic settling‐velocity discrimination. Operation parameters have been developed to yield accurate settling‐velocity cutoffs in the range &gt;0.1–&gt;10 m d−1, element recoveries in the range 85–110%, and minimal influence of CFF preconcentration up to at least a factor 110. Chemical fingerprints of truly settling matter (i.e., gravitoids) in coastal waters provided by the CFF‐SPLITT technique demonstrated that gravitoidal particles settling out of surface waters exhibit distinctly different compo‐sition than the bulk filterable particles. For instance, both gravitoidal POC and P belonged in a coastal Baltic regime largely to a slowly settling (1–2 m d−1) particle pool (presumably amorphous organic aggregates), which was decoupled from a more rapidly settling (&gt;4 m d−1) Si‐containing particle pool (presumably diatom dominated). Both of these biogenic gravitoid pools were in turn distinct from an Fe‐containing gravitoid pool settling &gt;4 m d−1, which, in contrast to POC, P, and Si gravitoids, had a geochemical composition similar to that of bulk particles.

Size–elemental characterization of suspended particle matter by split-flow thin cell fractionation and slurry analysis–electrothermal atomic absorption spectrometry

An analytical methodology is presented for characterizing SPM (suspended particle matter) from natural waters by using the coupling between the SPLITT (split-flow thin) cell separation and elemental spectroscopic identification. The results of a systematic study validating direct slurry elemental analysis by ETAAS (electrothermal atomic absorption spectrometry) are reported for the determination of Al and Fe in mineral particulates, considered representative models of real SPM. Slurry analysis of clay-like particle materials was accurate in the particle size range up to 25 μm, provided that slurry concentrations met quantitative sampling conditions. The coupled SPLITT–ETAAS technique was then evaluated for the dimensional and elemental characterization of the same samples. The developed procedure was applied to a real SPM sample from the Po river, where trace elements of environmental interest were determined for the whole fraction in the 0.2–25 μm dimensional range as well as for some sub-fractions obtained by SPLITT fractionation.

Continuous split flow-thin cell fractionation of starch particles

The fractionation of starch granules was investigated using a SPLITT (split flow-thin) cell, a relatively new system for fast, continuous binary separations. The effect of such basic separation parameters as carrier composition, relative flow-rates and sample concentration on the SPLITT cell performance were exploited. The obtained starch fractions were checked by both optical microscopy and sedimentation/steric field flow fractionation (Sd/StFFF). The sedimentation field flow fractionation technique was employed for the starch sample using the density compensation procedure.

Fractionation and size analysis of magnetic particles using FFF and SPLITT technologies

Field-flow fractionation (FFF) and split-flow thin cell fractionation (SPLITT fractionation) provide high resolution size- or mass-based separation of particulate samples. FFF is an analytical technique, whereas SPLITT fractionation operates on a preparative scale. In this work, the FFF and SPLITT technologies were applied to the size analysis and separation of magnetic beads. The optimization of operating conditions was investigated.

Preparative particle separation by continuous SPLITT fractionation

Split-flow thin-cell fractionation (SF) was one of Cal Gidding's later inventions in the field of separation science. In the mid 1980's, he began work on this technique, which is in many ways similar to field-flow fractionation (FFF), but which ultimately offers yet another dimension to his list of credits: preparative separations. SF is applicable to particles and macromolecules and offers advantages similar to FFF techniques in separation speed, resolution, breadth in applicable size range, gentleness, and flexibility of separation conditions. However, SF singularly offers the possibility for continuous operation and thus preparative scale throughputs. After more than 10 years of developmental work by the Giddings research group, SF has now become a reliable high-resolution technique for separation of particles in the micron size range. In this article, the factors influencing resolution, throughput, and scale-up of SF are considered and discussed. Preparative scale separation using gravitational SF is shown by the separation of silica and synthetic diamond particles. © 1997 John Wiley & Sons, Inc. J Micro Sep9: 261–273, 1997