2
3
4. Centrifuge at speeds up to 15,000 xg.
5. Once the desired concentration is achieved, remove assembly and recover sample
from the bottom of the concentrate pocket with a pipettor and gel loading tip.
See Table 2 (page 4) for a guide to concentration times. The filtrate tube can be
sealed for storage.
Desalting/Buffer Exchange
1. Concentrate sample to desired level.
2. Empty filtrate container.
3. Refill concentrator with an appropriate solvent.
4. Concentrate the sample again and repeat the process until the concentration of
the contaminating microsolute is sufficiently reduced. Typically, 3 wash cycles will
remove 99% of initial salt content.
Helpful Hints
1.
Flow Rate
Filtration rate is affected by several parameters, including MWCO, porosity, sample
concentration, viscosity, centrifugal force and temperature. Expect significantly longer
spin times for starting solutions with over 5% solids. When operating at 4°C, flow
rates are approximately 1.5 times slower than at 25°C. Viscous solutions such as 50%
glycerin will take up to 5 times longer to concentrate than samples in a predominantly
buffer solution.
2.
Prerinsing
Membranes fitted to Spin-X UF concentrators contain trace amounts of glycerin and
sodium azide. Should these interfere with analysis they can be removed by rinsing fill
volume of buffer solution or deionized water through the concentrator. Decant filtrate
and concentrate before processing sample solution. If you do not want to use the pre-
rinsed device immediately, store it in the refrigerator with buffer or water covering the
membrane surface. Please do not allow the membrane to dry out.
3.
Sterilization of Polyethersulfone Membranes
Polyethersulfone membranes should not be autoclaved as high temperatures will
substantially increase membrane MWCO. To sterilize, use a 70% ethanol solution
or sterilizing gas mixture.
Introduction
Spin-X
®
UF concentrators are disposable, single use only ultrafiltration devices
with polyethersulfone membranes (PES) for the concentration and/or purification
of biological samples. Spin-X UF 500 concentrators are suitable for sample volumes
of 100 to 500 µL. Thevertical membrane design and thin channel filtration chamber
minimizes membrane fouling and provides high speed concentrations, even with
particle laden solutions.
Storage Conditions and Shelf Life
Spin-X UF concentrators should be stored at room
temperature. The devices should be used before the
expiration date printed on the box.
Chemical Compatibility
Spin-X UF concentrators are designed for use with
biological fluids and aqueous solutions. For chemical
compatibility details, refer to Table 3 (page 5).
Centrifugal Operation
Spin-X UF 500 concentrators can be used in a benchtop
fixed angle rotor, accepting 2.2 mL centrifuge tubes. In a
single spin, solutions can be concentrated approximately
100-fold.
Required Equipment
1. Centrifuge with fixed angle rotor (minimum 40°) that
can fit 2.2 mL (11 mm diameter) conical bottom tubes.
2. Fixed or variable volume pipettors with gel loading tips
are recommended for sample addition and removal.
Operation
1. Select the most appropriate membrane cut-off for your sample. For maximum
recovery select a molecular weight cut off (MWCO) at least 50% smaller than the
molecular size of the species of interest.
2. Fill concentrator with up to a maximum volume of 500 µL as shown in Table 1
(Ensure lid is fully seated).
3. Insert assembled concentrator into a centrifuge with a fixed angle rotor. Minimum
rotor angle is 40º. Angle concentrator so that the printed window faces upwards/
outwards.
Corning Spin-X UF
500
–
100
to
500
µL capacity
