Nanosep® centrifugal devices do not have a dead stop volume, but some moisture is always retained in the membrane. Therefore, even if the device appears to have spun to dryness, in most cases the retentate can be recovered by pipetting a small volume of buffer over the surface of the membrane. It is how ever possible to set a dead stop volume by placing buffer below the insert, please refer to the Nanosep® concentration guide.  The Microsep™ Advance and Macrosep® Advance Centrifugal Devices do have built-in dead stop volumes.