Axial compression packing
1. Pour the resin slurry into the column.
2. Mix the slurry directly inside the column (for example, pilot
scale columns) using a plastic paddle. During mixing, keep
the paddle on top of the settled resin.
For larger axial compression columns (for example,
˃20 cm i.d.) the resin slurry is typically transferred with aid of
the automation of the column hardware. In these cases, use
a column filling speed of 200–300 cm/hr.
3. Pack the column using a packing speed of 60cm/hr for the
top adapter and a packing factor of 1.15–1.20. Under these
conditions the packing factor and compression factor are
the same for POROS™ resins.
4. Flow condition the packed bed by applying flow at the
highest processing flow rate in downflow for 1–2 CV.
5. Perform a column qualification test. See “Qualify the
column” on page3.
Qualify the column
To qualify the integrity of a packed column, determine HETP
(height equivalent to a theoretical plate) and asymmetry using
a non-binding analyte (a “plug”). Degas solutions before use to
avoid gassing out during operation.
Recommended column qualification conditions
Parameter Recommendation
Flow rate 100cm/hr
Equilibration buer 0.1 M sodium chloride
Plug solution 1 M sodium chloride
Plug volume 2–4% of column volume
Setting specifications
Qualification results depend on several factors, including the:
• Test solutions
• Flow rate
• Column/system hold-up volume
After you define a column qualification procedure for a specific
setup, the results can be used as reference and should be kept
constant when comparing results.
Tests with special solute samples under defined conditions are
useful for comparing the bed integrity before use. These tests
have limits in predicting the performance of the column with
real samples under real conditions (1). Qualification acceptance
criteria should be based on the process performance with scale-
down models rather than theoretical values for small molecule
tracers. Qualification acceptance criteria should also take into
consideration scale-up limitations.
(1) PDA Technical Report 14. Validation of Column-Based
Chromatography Processes for the Purification of Proteins.
Chromatography condition optimization
Equilibration/binding conditions guidelines
50 mM Tris-HCl pH7.5, 125mM NaCl or PBS pH7.0–7.5 is a
good starting buer for equilibration. The pH of the equilibration
buer and load sample must be in the range of 6–8.
Wash conditions guidelines
After the load, wash unbound material from the column with the
equilibration buer. Generally, a 5–10CV wash is sucient to
remove all unbound proteins from the column. Samples with high
impurity levels may require a longer wash to return to a stable
baseline.
Washing with a secondary or intermediate wash can increase
impurity removal and make impurity clearance more predictable
especially when there is interaction with the protein of interest
and the impurity. High‑salt washes such as 1 M NaCl, varying pH
either up or down, and the use of additives such as amino acids,
glycols, or chaotropic agents can be used for washing to improve
purity.
Elution conditions guidelines
20 mM acetic acid, pH 4.0–4.5.
Regeneration conditions guidelines
After the wash step remove the impurities bound by the resin
with a low pH solution such as 0.1M phosphoric acid (pH 1.7).
Generally, 3–5CV is sucient to regenerate the resin.
Resin cleaning and storage
Column cleaning and lifetime study considerations
To avoid contaminant buildup and to ensure long column lifetime,
strip the column every cycle and clean the column in place (CIP)
with a stronger solution, if needed, after 10–20 cycles.
In any cleaning method, reversing the flow direction is
recommended to help flush out particulates and to prevent
contamination of the lower part of the bed. Also, slow the flow
rate to give several minutes' exposure to the regeneration solution
at each step of the cleaning protocol, for example 3–5CV at
4–6 minutes residence time.
The resin is acid stable and has limited caustic stability. For
cleaning, use solutions in the range of pH 2–10. Test cleaning
solutions in this order, then optimize cleaning based on results:
• 0.1–0.5 M citric acid
• 0.5–1.0 M acetic acid
• 0.5 M phosphoric acid
• 2 M urea
• 2 M guanidine hydrochloride
• 20% ethanol (with or without acid)
• 20% isopropanol (with or without acid)
POROS™ CaptureSelect™ FcXP Anity Resin User Guide 3