ENrich™ SEC 70
ENrich™ SEC 650
High-Resolution
Size Exclusion Columns
Instruction Manual
Catalog numbers
780-1070
780-1650
Please read these instructions before you use ENrich SEC
high-resolution size exclusion media. If you have any questions or
comments regarding these instructions, please contact your
Bio-Rad Laboratories representative.
Table of Contents
Section 1: Characteristics of the ENrich
Size Exclusion Columns .......................................... 1
1.1 Introduction .............................................................1
1.2 The ENrich SEC Separation Media ........................... 1
1.3 Connection to the NGC™ and Other
Chromatography Systems ....................................... 2
Section 2 : Use of the ENrich SEC Columns ............................ 3
2.1 Preparation for Initial Use ......................................... 3
2.2 Equilibrating and Running the Column ..................... 3
2.3 Sample Considerations ............................................ 4
2.4 Sample Elution ......................................................... 4
2.5 Column Calibration .................................................. 4
Section 3 : Care of the ENrich SEC Columns ........................... 6
3.1 Regular Maintenance ............................................... 6
3.2 Bed Height Adjustment ............................................ 6
3.3 Column Cleaning ..................................................... 7
3.4 Frit Replacement ..................................................... 7
3.5 Storage Conditions .................................................. 9
Section 4 : Ordering Information ..............................................10
Section 1: Characteristics of the
ENrich™ Size Exclusion Columns
1.1 Introduction
ENrich prepacked columns for size exclusion chromatography are
designed for rapid and reproducible high-resolution separation of
biomolecules. Each column contains a unique, high-performance
size exclusion media based on spherical polymer beads modified
to provide quick, differential size–based diffusion.
1.2 The ENrich SEC Separation Media
ENrich SEC media is available with different exclusion limits
and separation ranges. The prepacked columns contain 10 μm
beads, which produce excellent resolution of biomolecules at low
backpressures. SEC 70 is ideal for separating biomolecules up
to 70,000 Da and SEC 650 is used for larger biomolecules up to
650,000 Da.
The 10 μm particle size and narrow particle size distribution
provide excellent resolution of biomolecules at high flow rates and
with relatively low backpressures. The hydrophilic ENrich media
demonstrates extremely low nonspecific binding of biomolecules
accompanied by high recovery of biological activity.
Stability
The columns are stable over the pH range 2–12, allowing easy
cleaning and regeneration.
ENrich SEC Instruction Manual 1
The ENrich support is compatible with aqueous solutions of 6 M
guanidine-HCl and 8 M urea. Detergents and organic solvents
such as methanol, ethanol, and isopropanol may also be used.
In some cases, alcohols and stability agents such as glycerol
may increase the column backpressure. Care should be taken
to maintain a flow rate at which the backpressure is below the
maximum operating pressure.
Table 1. ENrich SEC media and column characteristics.
SEC 70 SEC 650
Linear separation range, Da
Column dimensions,
diameter x height, mm
Column volume, ml 24 24
Nominal particle size, µm 10 ± 2 10 ± 2
Recommended flow rates, ml/min* 0.5–1.0 0.75–1.25
Maximum recommended flow rates,
ml/min*
Maximum operating pressure 600 psi,
Recommended sample volume, µl
Efficiency, plates/m
Working pH range 2–12 2–12
Operating temperatures, °C 4–40 4–40
* At room temperature. Viscosity may increase at lower temperatures, which will reduce the
recommended flow rates.
500–70, 000 500–650, 000
10 x 300 10 x 300
1.5 2.0
4.1 MPa, 41 bar
<250 <250
>20,000 >20,000
600 psi,
4.1 MPa, 41 bar
1.3 Connection to the NGC™ and Other
Chromatography Systems
The ENrich columns are fitted with 10-32 type female fittings on either
end. Standard 10-32 fittings can be used to plumb the column to a
Bio-Rad® NGC™ chromatography system or another vendor’s systems.
Adaptors are available for connection to systems that use 1/4-28 fittings
(catalog # 750-0564).
2 ENrich SEC Instruction Manual
Section
: Use of the ENrich
2
Columns
2.1 Preparation for Initial Use
The column is supplied in 20% ethanol. To remove the storage
buffer, pump deionized, filtered water at a flow rate of 0.5 ml/min
or less for 30 ml, or just over one column volume (CV). The
backpressure will decrease as the ethanol is washed from the
column. After this water step you may equilibrate your column as
described below.
Warning: Do not exceed a maximum pressure of 600 psi
(4.1 MPa, 41 bar).
2.2 Equilibrating and Running the Column
1. Always use filtered (0.22–0.45 μm filter) and degassed buffers.
This will prolong the life of your column. To avoid bacterial
growth, contamination, and poor column performance, use
only freshly prepared buffers.
2. Residual ionic charges on the ENrich column are negligible.
However, a running buffer with ionic strength of at least
100 mM NaCl is recommended. Phosphate buffered saline
(PBS) is an example of a commonly used buffer appropriate for
ENrich SEC media.
3. The buffer should contain any cofactors or protease inhibitors
previously identified as being essential to maintain enzyme
activity.
4. Equilibrate the column with at least 2 CV (~50 ml) of the buffer.
5. Calibrating the column with a gel filtration standard
(catalog #151-1901) is an important step for molecular weight
determination and for tracking column performance.
ENrich SEC Instruction Manual 3
2.3 Sample considerations
1. Always filter (0.22–0.45 μm filter) and/or centrifuge your
sample to remove any particulates.
2. In size exclusion chromatography, mass loading is less critical
than the volume of the sample. As a general rule, to obtain
maximum performance, the sample volume should not
exceed 1% of the bed volume (that is, ~0.25 ml for a 24 ml
CV) and the sample concentration should not exceed 20 mg
protein/ml. Larger volumes can be applied, but resolution may
decrease.
2.4 Sample Elution
All species within the sample should elute within 1 full CV. The flow
rate for optimal resolution depends on sample composition and
purity. In general, lower flow rates provide greater performance.
Optimal flow rates for both ENrich SEC 70 and ENrich SEC 650
columns are 0.5–1.25 ml/min (see Table 1).
2.5 Column Calibration
Use the Bio-Rad size exclusion standards (catalog #151-1901).
One vial contains 18 mg of a lyophilized mixture of thyroglobulin
(Mr 670,000), bovine γ-globulin (Mr 158,000), chicken ovalbumin
(Mr 44,000), equine myoglobin (Mr 17,000), and vitamin B12
(Mr 1,350).
4 ENrich SEC Instruction Manual
ENrich SEC 70 media
ENrich SEC 650 media
Figure 1. Typical chromatograms for ENrich SEC media. Detection at 280 nm.
Absorbance at 280 nm may be greater depending on sample concentration. Time
may change depending on flow rate. A. thyroglobin; B. IgG; C. ovalbumin;
D. myoglobin; E. vitamin B12.
ENrich SEC Instruction Manual 5
Section 3
: Care of the ENrich SEC
Column
3.1 Regular Maintenance
To maintain performance, the column should be stored in 20%
ethanol, as described below, for storage periods longer than
2 days. Always run at least one CV of water between 20% ethanol
and running buffers.
If the column is exposed to air or if air bubbles are trapped in
the column.
1. Wash the column in the forward direction with 30 ml of water
at 0.25–0.5 ml/min.
2. Wash the column with 30 ml of 20% ethanol at
0.25–0.5 ml/min. Note that the backpressure will increase in
ethanol. Do not exceed 600 psi (4.1 MPa).
3. Wash the column with 30 ml of deionized water at the usual
operating flow rate as recommended in Table 1.
4. Re-equilibrate the column with the desired buffer.
If the column begins to show abnormally high backpressure.
If the backpressure increases abnormally, it is likely that the
column needs to be cleaned and/or the frit at the top of the bed
is clogged. First, clean the column using the method described in
section 3.3. If this is not sufficient, replace the top frit as described
in section 3.4.
3.2 Bed Height Adjustment
Under certain conditions of buffer composition, high flow rates,
or long-term use, the resin bed may compress, creating a void
between the frit and the top of the bed. Normally, the void can
be eliminated by turning the adjusting nut clockwise until the frit
just touches the top of the bed. If the bed compresses at high
flow rates, stop the pump and loosen the top fitting, then use
the adjusting nut to remove the void, retighten the top fitting, and
resume pumping buffer. If the bed has compressed from long-term
use, replace the top frit as a precaution.
6 ENrich SEC Instruction Manual
3.3 Column Cleaning
Careful preparation (especially filtration) of the sample and the
buffers will maintain the column’s performance and extend
its lifetime. Normally, washing with a few CV of running buffer
with an ionic strength of at least 100 mM NaCl will remove
most contaminants. However, if there is a decrease in column
performance (that is, increasing backpressures or a drop in
resolution), then steps 1 and 2 of the cleaning protocol described
below should be used.
Always reverse the flow during this procedure so any substances
that may be trapped at the top of the column are quickly removed.
During this operation do not exceed more than 50% of the
recommended maximum flow rate (see Table 1). Ensure that the
backpressure stays below the maximum operating pressure.
1. Wash with 2 x 1 ml injections of 2.0 M NaCl followed by 1 CV
of buffer.
2. Wash with 2 x 1 ml injections of 1.0 M NaOH followed by 2 CV
of buffer.
If the column performance has still not returned, the additional
steps below can be followed:
3. Wash with 2 x 1 ml injections of 50% acetic acid followed by
2 CV of buffer.
4. If lipid contamination is suspected, first wash with at least
1 CV of deionized water. Then wash with 1 CV of 70% ethanol
followed by 2 CV of water. The flow rate may need to be
slowed significantly during the 70% ethanol wash.
Before use, re-equilibrate with at least 2 CV of equilibration buffer.
3.4 Frit Replacement
The top frit may need to be replaced after extensive column use
or if increasing backpressures are noticed. Always try to clean the
column in the reverse direction (as described in section 3.3) before
replacing the frit. A frit kit containing a frit removal tool, 2 O-rings,
and 2 frits is available.
Figure 2 shows a column diagram to assist in the replacement of
the top frit.
ENrich SEC Instruction Manual 7
Lock nut
Adaptor
Fig. 2. Column diagram.
Adjusting nut
Upper retainer
Lower retainer
1. Start a slow flow rate of buffer (0.5 ml/min or less) through the
column.
2. Remove the lower end tubing and fitting from the column.
Firmly hold the bottom of the column over a sink or container.
3. Loosen the lock nut by turning it clockwise.
4. Raise the adaptor a few millimeters by slowly by turning the
adjusting nut counterclockwise.
5. Unscrew the upper retainer. Let it rest on the bottom retainer.
6. Slowly pull out the upper adaptor from the glass column. Allow
the buffer flow to maintain the integrity of the top of the bed.
7. Stop the pump. Plug the bottom of the column. Set the
column upright in a beaker. Remove the tubing and fitting from
the top of the adaptor.
8. Remove the frit from the adaptor by hooking one end of the
frit removal tool/tweezer into the frit in a sideways motion with
slight downward pressure.
9. Push the new frit into the end of the adaptor.
10. Replace the O-rings if they appear worn or torn. If the O-rings
are replaced, wet them with buffer before the next step.
11. Add a few drops of buffer to the top of the resin bed. Insert the
adaptor and push it down to the bed. Some buffer should flow
out the top of the column.
12. Screw on the upper retainer.
13. Lower the adaptor to the top of the bed by turning the
adjusting nut clockwise.
14. Tighten the lock nut by turning it counterclockwise.
8 ENrich SEC Instruction Manual
3.5 Storage Conditions
To prevent bacterial growth in the column, it must be stored
correctly. For short-term storage (up to 2 days), store it in freshly
prepared buffer. For long-term storage, first wash the column
with 30 ml of deionized water and then with a storage solution of
20% ethanol. Use a flow rate of 0.5 ml/min or less. Ensure that
the backpressure stays below the maximum operating pressure.
Always store the column with plugs at each end. Store the column
in a safe place at room temperature or 4°C. Never allow the
column to freeze.
If, during storage or shipment the column might be exposed to
temperatures above 35°C, briefly (3 min under vacuum) degas the
20% ethanol storage solution before use.
ENrich SEC Instruction Manual 9
Section
Catalog # Description
780-1070 ENrich SEC 70 10 x 300 Column, 10 x 300 mm
780-1650 ENrich SEC 650 10 x 300 Column, 10 x 300 mm
780-0093 ENrich 10 Frit Kit, includes 2 frits, 1 frit remover, 2
151-1901 Gel Filtration Standard, 6 vials
: Ordering Information
4
O-rings
10 ENrich SEC Instruction Manual
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