Abstract: 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.

Abstract: A collection container for separating and collection particles suspended in a sample fluid added to the collection container includes at least one barrier-forming fluid which is immiscible relative to the sample fluid and which has a specific gravity which is different from the specific gravity of the sample fluid. The barrier-forming fluid is situated in the collection container to be in contact with the sample fluid and to form with the sample fluid a fluidic imaging barrier at the interface between the sample fluid and the barrier-forming fluid. The particles suspended in the sample fluid will separate therefrom when centrifugal or gravitational forces are applied to the container and will collect at the fluidic imaging barrier for imaging by an optical imaging system.

Abstract: 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.