Field-Flow fractionation (FFF)

Technology
Technology details
Name:	Field-Flow fractionation
Category:	Pre-processing (Separation technologies), Post-processing (Separation technologies)
Feedstock:	Food waste, Garden and park waste
Product:	Biomass in different physicochemical fractions

Field-Flow Fractionation (FFF) is a family of high resolution separation techniques especially applicable to macromolecules colloids and particles, and shares the most common likeness with liquid chromatography (LC). The mechanism for separation, however, does not involve interactions with a stationary phase used in LC methods. Instead, a field is applied normal to a laminar flow through a narrow channel, which results in a parabolic flow profile, separating different analytes into distinct regions of the velocity profile. The analytes can be fractionated according to their physicochemical properties such as charge, chemical composition, density, molar mass, and size. Beside analytical purposes, the FFF can also be utilised for preparative purposes.

Feedstock

Origin and composition

Suitable feedstocks are heterogeneous mixtures of different substances in form of dilute suspensions (solids in liquid). Depending on the applied process and technology, solids can be usually separated between the nm-µm range. The FFF is usually applied to separate cells, different kind of nanoparticles, polymers, and proteins for analytical and preparative purposes.

Pre-treatment

• Mechanical separations
  • Centrifugation
  • Membrane filtration
  • Sieving
• Ultrasonication

Process and technologies

Different variants of the FFF are available, which include Asymmetric flow FFF (AF4), centrifugal FFF, electrical FFF (EFFF), split flow thin-cell fractionation (SPLITT), and thermal FFF (TF3). Depending on the applied technology, particles can be separated in dependence of different physicochemical properties.

Asymmetric flow FFF (AF4)

Illustration of a separation channel for asymmetric flow field-flow-fractionation.

Animation of the AF4 separation driven by particle diffusion in a parabolic flow profile. Particles colored in red are the smaller and particles colored in blue are the larger ones. The force applied on the top is the crossflow (indicated by the arrows on the bottom). The elution flow in longitudinal direction is shown with the flow arrows indicating the velocity profile.

The asymmetric flow FFF (AF4) is realised in a separation channel where a separation force is generated in the form of an asymmetric crossflow through a semipermeable membrane and frit. The introduction of the crossflow through the semipermeable membrane holds the macromolecules back, and consequently, they get pushed against the membrane. The macromolecules move back into the channel from the accumulation membrane due to Brownian motion or normal diffusion. Diffusion is a size-dependent phenomenon. Hence, small molecules get access to high flow velocity solvent streams situated closer to the center of the parabolic flow profile. Consequently, macromolecules elute in order of increasing size. AF4 can be coupled with downstream detectors to obtain complementary data, which includes UV-vis spectra from diode array detectors, refractive index measurements, multiangel light scattering, or inductively coupled plasma mass spectroscopy (ICP-MS).

Centrifugal FFF

In centrifugal FFF the separation force is realised via an centrifugal field. Through the induced gravitational field larger particles accumulate at the channel bottom while smaller particles accumulate more at the upper part. The injected particles can be eluted through a parabolic flow-profile in combination with the reduction of the centrifugal field. Due to the large range of applicable centrifugal force the method has its advantage to separate a wide range of different sized particles (usually µm-nm range).

Electrical FFF (EFFF)

This technology combines the FFF with an electric field as an additional separation force. An electrical voltage is imposed between the top and bottom walls. Charged particles migrate toward both walls according to their electrophoretic mobility, which is determined by their sizes and charge densities, and undergo different flow velocities. Besides the separation based on particle size this method adds the capability to separate particles/molecules in dependence of their charge. EFFF is well suited to the fractionation of proteins and measuring protein adsorption on to surfaces.

Split flow thin-cell fractionation (SPLITT)

In Split flow thin-cell fractionation (SPLITT) earth's gravitational force is used to separate different sized particles (usually in µm-range). Usually the suspensions are introduced into the top of a separation channel while a carrier liquid is pumped into the channel from the bottom. The separation of different sized solids occurs along the channel induced by earth's gravity. Two outlets (one at the channel bottom, one at the channel top) separate the particles into a larger and smaller fraction, while the cut-off can be controlled via the channel flows.

Thermal FFF (TF3)

In Thermal FFF the separation force is established by applying a temperature gradient. The top wall of a Thermal FFF channel is heated up, while the bottom wall of the channel is cooled down. The higher the temperature difference between both plates of the separation channel, the higher is the separation force. In order to achieve optimum separation, the temperature difference across the elution time can be adjusted. TF3 is well suited to the separation of polymers and organic solvents.

Products

No products have been identified.

Post-treatment

Currently no post-treatment has been identified.

Technology providers

Technology comparison

Company name	Country	City	Technology subcategory	Technology name	TRL	Capacity [kg/h]	Concentration (max.) [mg/mL]	Processable volume [L]	Separation range [µm]	Feedstock: Food waste	Feedstock: Garden & park waste	Separation according size	Separation according charge
Postnova Analysics GmbH	Germany	Landsberg	Asymmetric flow FFF (AF4)	AF2000 MultiFlow FFF	9	-	-	0.0005-0.0025	0.001-100	●	●	●	●
Wyatt Technology	USA	Goleta	Asymmetric flow FFF (AF4)	Eclipse	9	-	-	-	0.001-10	●	●	●	●

Postnova Analysics GmbH

Field-Flow fractionation (FFF) provider

General information
Company:	Postnova Analysics GmbH
Country:	Germany
Contact:	info@postnova.com
Webpage:	https://www.postnova.com/
Technology and process details
Technology name:	AF2000 MultiFlow FFF	Technology category:	Pre-processing (Separation technologies), Post-processing (Separation technologies)
TRL:	9	Capacity:	kg·h-1
Carrier solution:	Aqueous: any aqueous liquid, pH from 2 - 11 (depending on acid and conditions, please inquire), ionic strength from DI water to saline; Organic: THF, MeOH, etc	Concentration (max.):	mg/mL
Processable volume:	0.0005-0.0025 L	Separation range:	0.001-100 µm
Temperature:	15-25 °C	Other:
Feedstock and product details
Feedstock:	Mixture of various macromolecules colloids, and particles including Aggregates, cell organelles, bioparticles, proteins, liposomes, micelles. humic and fulvic acid, nanoparticles, biopolymers, starches, technical polymers	Product:	Various fractionated (e.g. based on ther physicochemical properties) macromolecules, colloids, and particles including aggregates, cell organelles, bioparticles, proteins, liposomes, micelles. humic and fulvic acid, nanoparticles, biopolymers, starches, technical polymers

Postnova was founded 1997 and is a Field-Flow Fractionation technology provider and innovator in Light Scattering technology, offering solutions used by leading scientists in laboratories worldwide. Their instruments are crucial for the Biopharma industry to fight and cure diseases, in Material Science to develop new high-tech nanomaterials and polymers and in Environmental Research to provide solutions to save the planet.

Wyatt Technology

Field-Flow fractionation (FFF) provider

General information
Company:	Wyatt Technology
Country:	USA
Contact:	support@wyatt.com
Webpage:	https://www.wyatt.com
Technology and process details
Technology name:	Eclipse	Technology category:	Pre-processing (Separation technologies), Post-processing (Separation technologies)
TRL:	9	Capacity:	kg·h-1
Carrier solution:		Concentration (max.):	mg/mL
Processable volume:	L	Separation range:	0.001-10 µm
Temperature:	20-50 °C	Other:
Feedstock and product details
Feedstock:	Mixture of various components including (bio-)polymers, extracellular vesicles, nanoparticles, proteins	Product:	Various fractionated (e.g. based on ther physicochemical properties) macromolecules, colloids, and particles including (bio-)polymers, extracellular vesicles, nanoparticles, proteins

More than 40 years ago, Wyatt Technology's scientists invented commercial light scattering instruments incorporating lasers as their light source. The company is developing laser light scattering hardware, software, training and services to meet customer needs for over three decades. Along they added several related technologies to their product line including dynamic light scattering, refractometry, viscometry, and field-flow fractionation. . Wyatt’s tools are used in discovery, product development, QC and manufacturing settings for determining the properties of novel therapeutics such as nano-drug carriers, vaccines, biopolymers and proteins; as well as synthetic polymers and nanoparticles.

Open access pilot and demo facility providers

Currently no providers have been identified.

Patents

Currently no patents have been identified.