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 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.

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 invention provides a centrifugal separation type FFF device where a rotor can be rotated at a high speed safely so that particles of a smaller size in a sample liquid can be classified. A field flow fractionation device 11 is provided with: a channel 26 that is attached to the inner circumferential surface 53a of the peripheral portion 53 of a rotor 51 and where a classification flow path 38 is created; flow paths 31, 33, 41, 42, 34, 32 for feeding a sample liquid into and out from the classification flow path 38; and a rotational drive mechanism 28 for rotating the rotational axis 24, wherein a channel installation portion 55 is formed on one side of the peripheral portion 53, and a mass balancer portion 56 for adjusting the mass distribution of the rotor 51 is formed on the other side with the rotor base in between.

A centrifugal field-flow fractionation device is provided with a controller for controlling introduction of a liquid sample by a sample introduction part and rotation of the rotor by a motor. The controller rotates the rotor at a first rotational speed when introducing the liquid sample into a flow path. The first rotational speed is faster than a second rotational speed. Therefore, when a liquid sample is introduced into the flow path, high centrifugal force can be applied to the liquid sample, which can suppress the variation of the particles in the liquid sample introduced to the flow path. The controller rotates the rotor at the second rotational speed slower than the first rotational speed with the liquid sample flow in the flow path stopped. Therefore, it is possible to prevent the constant application of high centrifugal force to the liquid sample, thereby suppressing the increase in the length of time required for analysis.