The present invention an apparatus and method of injecting a liquid borne sample into a field flow fractionator and a method of forming a top plate and spacer. In an embodiment, the field flow fractionation unit includes a top plate including a sample injection inlet port, a sample injection outlet port, and a spacer including a separation channel cavity defining at least a portion of the separation channel, a sample injection inlet cavity configured to be in fluid contact with the separation channel and located substantially beneath the sample injection inlet port, a sample injection outlet cavity configured to be in fluid contact with the separation channel and located substantially beneath the sample injection outlet port, such that the injection inlet and outlet paths are configured to define an injection channel that is essentially perpendicular to the length of the separation channel spanning the width of the separation channel cavity.

A centrifugal field-flow fractionation device includes an annular rotor, an arc-shaped channel member, a rotation drive unit, and a restriction unit. A channel member 16 is provided along an inner peripheral surface of the rotor, has therein a channel 161 for a liquid sample by laminating a plurality of layers, and has an inlet for the liquid sample to the channel 161 and an outlet for the liquid sample from the channel 161. By rotating the rotor, particles in the liquid sample in the channel 161 are classified by centrifugal force. A restriction spacer 64 restricts the channel 161 from being compressed to a height less than a certain height when the channel member 16 is compressed and deformed in a laminating direction.

A centrifugal field-flow fractionation device capable of improving analysis performance and shortening analysis time is provided. A first channel 111 communicating with a channel member is formed on a rotational shaft 11 that rotates together with a rotor. A second channel 644 communicating with the first channel 111 is formed on a fixing portion 60 fixed in a state of facing the rotational shaft 11 along a rotational axis L. A mechanical seal 66 having a pair of seal rings 661 and 662 that come into contact with each other and a biasing member 663 is provided to attach one seal ring 661 to the rotational shaft 11 and the other seal ring 662 to the fixing portion 60. The biasing member 663 biases the pair of seal rings 661 and 662 in a direction in which the pair of seal rings come in contact with each other. Since the rotational shaft 11 can be rotated at a high speed and the liquid sample can be fed at a high pressure, the analysis performance can be improved and the analysis time can be shortened.

A continuous field flow fractionator includes a sample inject port, a frit inlet port, a first fraction outlet port, a second fraction outlet port, and a third fraction outlet port. A first flow out of the first fraction outlet port is configured to extract a sample-free solvent. A second flow out of the second fraction outlet port is configured to extract an increased concentration of small molecules of a sample. A third flow out of the third faction port is configured to extract a remainder of the sample.

The present invention relates to an asymmetric flow field-flow fractionation device (1) configured to separate a sample (8) of particles (12) dispersed in a liquid mobile phase (11), the device including a fractionation microchannel (2) comprising a sample inlet, a sample outlet, an auxiliary microchannel (3) comprising an auxiliary outlet, a semipermeable membrane (10) separating the fractionation microchannel (2) and the auxiliary microchannel (3), said membrane being permeable to liquid and being configured to maintain the particles (12) in said fractionation microchannel (2), the fractionation microchannel (2) being superimposed on the auxiliary microchannel (3), wherein the device (1) comprises two layers (19), each layer being with a microfabricated recess (14) which thickness (t) is less than 100.sub.IJm, the membrane (10) being mechanically held in between the two layers (19), the recesses (14) respectively defining the fractionation microchannel (2) and the auxiliary microchannel (3) on each side of the membrane (10).

A method for determining the density of particles includes passing a carrier fluid and particles through a fractionation cell at a predetermined rate, where the carrier fluid has a predetermined density, the fractionation cell has a housing including a first axial end and a second axial end and the fractionation cell defines an interior carrier fluid flow-through channel, and an upper fluid outlet and a lower fluid outlet positioned below the upper fluid outlet, passing the carrier fluid and the particles through the upper fluid outlet and the lower fluid outlet, measuring a first concentration of particles passing through the upper fluid outlet, measuring a second concentration of particles passing through the lower fluid outlet, and determining a density of the particles based at least in part on the first concentration and the second concentration of particles.

The present disclosure describes a field flow fractionator including (1) a top plate assembly including (a) a first non-corrosive material, and (b) at least three fluid fittings machined (simpler) into the material, (2) a spacer, (3) a membrane, (4) a bottom plate assembly including (a) a second non-corrosive material, (b) a cavity machined into the second non-corrosive material, (c) a frit configured to be placed into the cavity, and (d) at least one bottom plate o-ring configured to seal the bottom plate assembly to the spacer, and (5) where the top plate assembly, the spacer, the membrane, and the bottom assembly define a separation channel. In an embodiment, the at least three fluid fittings including a fitting for an in-flow, a fitting for an out-flow, and a fitting for a cross-flow.

Provided is a centrifugal field-flow fractionation device that can stably press a fixing member toward an inner peripheral surface of a rotor by a wedge-shaped member, even when a relatively large centrifugal force acts on the wedge-shaped member. An arc-shaped (C-shaped) fixing member 17 is provided along an inner peripheral surface of a channel member 16 on a side of a rotation axis of the channel member 16. A wedge-shaped member 18 is attached between opposite ends of the fixing member 17 and applies a force in a direction of spreading the opposite ends apart, to thereby press the fixing member 17 toward the inner peripheral surface of the rotor 14. The wedge-shaped member 18 has a pair of contact surfaces 184 that respectively come into contact with the opposite ends of the fixing member 17. The pair of contact surfaces 184 include tapered surfaces that gradually taper down toward the rotor 14, so that the distance between the contact surfaces 184 gradually shortens as the contact surfaces 184 come close to the rotor 14.

Provided is a centrifugal field-flow fractionation device capable of suppressing deformation of a channel member. Pressure in a channel formed inside the channel member in a centrifugal field-flow fractionation device 1 is increased by a pressure increasing mechanism 8 provided downstream of the centrifugal field-flow fractionation device 1. In this manner, an inner surface of the channel is pressed outward by a liquid sample in the channel, and an outer peripheral surface and an inner peripheral surface of the channel member can be suppressed from being recessed toward the channel side.

The present disclosure describes a field flow fractionator (FFF). In an embodiment, the FFF includes a spacer including a core, and a coating covering the core. In an embodiment, the FFF includes a spacer including a core, and a coating covering the core, a bottom block including pins, and a top block including mating holes to receive the pins, where the spacer is configured to be positioned between the top block and the bottom block. In an embodiment, the FFF includes a spacer including a core including an opening, a top side, and a bottom side, a first coating covering the top side, and a second coating covering the bottom side, a top block configured to press on the first coating along a first periphery of the opening, and a bottom block configured to press on the second coating along a second periphery of the opening.