Amicon
®
Ultra-2 Centrifugal Filter Devices
2
Required Equipment
Centrifuge with swinging bucket or fixed angle rotor with wells/carriers that can accommodate 17 mm × 100 mm tubes (same
well/carrier size as for Amicon
®
Ultra-4 devices and the former Centricon
®
device).
CAUTION:
To avoid damage to the device during centrifugation, make sure it is properly assembled and seated at the bottom of
the rotor. The rim of the concentrate collection tube should be inside the rotor well. Check clearance before spinning.
Suitability
Preliminary recovery and retention studies are suggested to ensure suitability for intended use. See the “How to Quantify
Recoveries” section.
Device Storage
Store at room temperature.
Prerinsing
The ultrafiltration membranes in Amicon
®
Ultra-2 devices contain trace amounts of glycerine. If this material interferes with
analysis, pre-rinse the device with buffer or Milli-Q
®
water. If interference continues, rinse with 0.1 N NaOH followed by a second
spin of buffer or Milli-Q
®
water.
CAUTION:
Do not allow the membrane in Amicon
®
Ultra filter devices to dry out once wet. If you are not using the device
immediately after pre-rinsing, leave fluid on the membrane until the device is used.
How to Use Amicon
®
Ultra-2 Centrifugal Filter Devices
1. Insert the Amicon
®
Ultra-2 device into the filtrate collection tube, making sure that the device is fully seated in the tube.
2.
Add up to 2 mL of sample to the device and cover with concentrate collection tube. Push the tube firmly onto the device.
WARNING:
Failure to fully seat the device in the filtrate collection tube and push the concentrate collection tube firmly onto
the device may result in the device breaking during centrifugation. See figure below.
10K
4
3
2
00
00
00
10K
4
3
2
1
00
20
00
00
00
Make sure both tubes are
fully seated
onto device
Add sample
4
3
2
1
00
20
00
00
00
10K
3.
Place filter device into the centrifuge rotor with one membrane panel facing the center of the rotor (one panel facing up and the
other panel facing down). Make sure the device is seated on the bottom of the rotor well and that the rim of the concentrate
collection tube is completely inside the well. See figures below. Counterbalance with a similar device.
10K
4
3
2
1
00
20
00
00
00
Spin to
concentrate
10K
4
3
00
00
White membrane
panel facing
center of rotor
Orient device correctly in rotor
Seat device fully in well
Rim of tube
Concentrate tube
should be
inside
4.
Spin for approximately 10–60 minutes depending on the MWCO of the device used:
4,000 × g maximum
when using a swinging bucket rotor
7,500 × g maximum
when using a fixed angle rotor
NOTE:
When spinning viscous solutions such as undiluted serum or plasma, do not exceed 5,400 x g.
Refer to Figures 1 and 2 and Tables 2 and 3 for typical spin times.
5.
Remove the assembled device from the centrifuge and separate the Amicon
®
Ultra filter device from the filtrate collection tube.
6. To recover the concentrated solute, invert the Amicon
®
Ultra filter device and concentrate collection tube. Place in centrifuge
and counterbalance with a similar device. Spin for 2 minutes at 1,000 × g to transfer the concentrated sample from the device
to the tube.
NOTE:
For optimal recovery, perform the reverse spin immediately.