Designed for fast nondenaturing concentration of biological samples by membrane ultrafiltration. Up to 30-fold concentration of the sample can be achieved with recovery of the target molecule typically exceeding 95%.Vivaspin(R) sample concentrators are designed for fast nondenaturing concentration of biological samples by membrane ultrafiltration. Up to 30-fold concentration of the sample can be achieved with recovery of the target molecule typically exceeding 95%. The entire process is performed in a single tube with an upper compartment containing sample and lower compartment separated by a semipermeable membrane with a molecular weight cut-off (MWCO) selected by the user. Centrifugation is applied to force solvent through the membrane leaving a more concentrated sample in the upper chamber.Vivaspin(R) sample concentrators cater for sample volumes from 100 mul to 20 ml with a range of molecular weight cutoff values from Mr 3 000 to 100 000. for maximum recovery select a MWCO at