Centrifugal filter concentrates large samples fast

Millipore has developed a centrifugal filter, the Centricon Plus-70, for concentrating and desalting proteins, antibodies, viruses from chromatography fractions, and cell culture supernatants. It can also be used for exchanging buffers. The new centrifugal filter is a convenient alternative to stirred cells, lyophilization, or precipitation and dialysis techniques. The Centricon Plus-70 device can concentrate 70 ml down to 350 µl in 25 minutes, with typical concentration factors in the range 50–200 and sample recoveries greater than 90 percent. The device features a “deadstop” that prevents samples from spinning to dryness. The device contains Millipore’s proprietary low-binding Ultracel regenerated cellulose membrane.