The Ultrafree 0.5 centrifugal filter device is a disposable, single-use filter device used to process aqueous biological solutions in the 0.05 to 0.5 milliliter (mL) range. It is used in any centrifuge that accommodates 2.2 mL centrifuge tubes. Ultrafree 0.5 devices are available with a range of high-flux biomax ultrafiltration (UF) membranes because of its innovative design and excellent membrane performance, the Ultrafree 0.5 device can concentrate most 0.5 mL solutions down to 20 microliters (�L) in about 10 minutes, although some solutions may take longer. The device's novel design and vertical membrane configuration, parallel to the direction of the centrifugal force, reduce concentration polarization. This allows for the highest possible flow rates, even in solutions with high levels of particles. Concentrated protein is retrieved by pipette from a concentrate "pocket" located below the membrane surface. Flow rate is affected by several parameters, including NMWL, solute concentration, viscosity, centrifugal force and temperature. For maximum recovery, select a UF membrane with a NMWL at least three times lower than the molecular weight of your target molecule. Expect longer spin times for starting solutions containing over 5 percent solids. Flow rates are approximately 1.5 times slower when you operate the device at 4 degree C than when you operate it at 25 degree C. Viscous solutions, such as 50 percent glycerol, will take up to five times longer to concentrate than very dilute solutions. The Ultrafree-0.5 centrifugal filter device is not autoclavable. To sterilize, rinse with a 70 percent ethanol solution or treat with ethylene oxide sterilizing gas. Designed for use with biological fluids and aqueous solutions. For single use only. Caution: not for clinical use. Do not use for samples intended for I.V. injection.