Vivaspin® centrifugal concentrators are disposable ultrafiltration devices for the concentration of biological samples. Vivaspin® 500 centrifugal filter units offer a simple, one step procedure for sample concentration with starting volumes up to 500µl. They can effectively be used in fixed angle rotors accepting 2.2ml centrifuge tubes. The patented vertical membrane design and thin channel filtration chamber (US 5,647,990), minimises membrane fouling and provides high speed concentrations. Vivaspin® 500 units are available with PES membrane in a wide range of molecular weight cut-offs. Concentrate recoveries of > 90% can be reached in less than 30 min. The dead stop pocket prevents concentration to dryness.