We use Millipore’s Amicon® Ultra-4 centrifugal filter devices for aDNA and stable isotope analyses.
The devices could provide fast ultrafiltration, with the capability for high concentration factors. According to manufacturer, high sample recovery (typically greater than 90% of dilute starting solution), and the capability for 80-fold concentration could be guaranteed by the device. Below is our protocol for use.
1. 4 mL of sample (3.5 mL if using a 23° fixed angle rotor) to the Amicon Ultra filter device.
2. Place capped filter device into centrifuge rotor (swinging bucket rotor); counterbalance with a similar device.
3. Spin the device at 4,000 × g maximum for approximately 10–40 minutes.
4. To recover the concentrated solute, insert a pipettor into the bottom of the filter device and withdraw the sample using a side-to-side sweeping motion to ensure total recovery. The ultrafiltrate can be stored in the centrifuge tube.
