Another method in determining protein size is zonal centrifugation. Also known as band or gradient centrifugation, this technique relies on the concept of the sedimentation coefficient. Since the velocity of a particle depends on its mass, particles with higher mass will sediment faster than particles with less mass. To use this technique, a density gradient is first created in a test tube (usually with sucrose) with the highest density at the bottom. The purpose of the density gradient is to prevent convective flow. A sample of proteins is then placed on top of the gradient and then centrifuged. The proteins separate accordingly to their sedimentation coefficient into bands which can then be collected by creating a hole at the bottom of the tube.

En la centrifugación zonal la muestra a analizar se deposita en la parte superior de un gradiente de densidades previamente formado. A causa de la fuerza centrífuga las partículas se mueven a velocidades que dependen de la masa y sedimentan en diferentes zonas del gradiente. La densidad máxima del gradiente no ha de exceder a la de las partículas a separar.