A sucrose gradient is a type of density gradient used to obtain the centrifugal separation of differently sized particles. Sucrose gradients are made by layering sucrose solutions of decreasing concentrations into a centrifuge tube to create a gradient of decreasing density or viscosity.
Centrifugation is a technique used to separate small particles of different size, shape or density by subjecting mixtures of particles to high rotational speeds. Particles with different attributes sediment or migrate at different rates during centrifugation, allowing them to be isolated. Several types of centrifugal separation techniques rely on the use of density gradients such as sucrose gradients to stabilize or differentiate separate groups of sedimenting particles.