Steric field-flow fractionation
AssigneeUniversity of Utah
InventorJohn C. Giddings
Life of this patent
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Abstract
A steric field-flow fractionation system including a flow channel adapted for use with a carrier stream of fluid having particles suspended therein and a force field disposed across the flow channel to cause migration of the particles to a restraining wall, thereby forming layers of particles at the restraining wall. The strength of the force field is adjusted sufficiently high to maintain the particles of a given class at the restraining wall such that particle distance from the wall is a function of steric hindrance. Particle displacement by flow along the channel is thereby determined by particle size, permitting fractionation of the particles based on differential migration of the various sizes of particle classes.
Claims15
In a field-flow fractionation system including a flow channel formed between opposing surfaces of channel walls and a force field disposed across said channel with a field gradient in a direction of one of said wall surfaces which operates as a restraining wall, the improvement comprising a method for steric field-flow fractionation including the step of applying a force field in sufficient relative strength with respect to particles contained within said channel to cause migration of a given class of said particles toward and against said restraining wall such that the mean Brownian displacement of said particles from the restraining wall is approximately equal to or less than the mean radius of said class of particles.
In a field-flow fractionation system including a flow channel formed between opposing surfaces of channel walls and a force field disposed across said channel with a field gradient in a direction of one of said wall surfaces which operates as a restraining wall, the improvement comprising a method for steric field-flow fractionation including the step of applying said force field in sufficient relative strength with respect to particles contained within said channel to cause formation of a layer of a given class of said particles against said restraining wall, layer thickness being controlled by the steric exclusion of particles from the space occupied by said restraining wall.
In a field-flow fractionation system including a flow channel formed between opposing surfaces of channel walls and a force field disposed across said channel with a field gradient in a direction of one of said wall surfaces which operates as a restraining wall, the improvement comprising a method for steric field-flow fractionation including the step of applying a force field having sufficient strength relative to particle size to maintain substantially all particles of a given class in layers in contact or near contact with said restraining wall such that the distance of the particles from the restraining wall is a function of said particle radii.
Dependencies are inferred from the claim text.