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1.  Is displacement chromatography more complicated than elution chromatography?

Displacement chromatography is no more complicated than elution chromatography.  In fact, in some ways it is more straightforward.  However, the considerations for optimization are different.  At least initially, it is important that you follow the protocols closely to ensure success.

2.  Do I need to know binding isotherms?           

Isotherms are important to fundamental understanding of all forms of chromatography.  However there is no more need to do detailed isotherm measurements in displacement than there is in elution.  Optimization can be done empirically in both.

3.  Am I limited to certain loadings when using displacement?

Displacement chromatography requires high loadings to set up a good displacement train.  You can load 50-80% of the resin loading capacity.  As a starting point, use 60%. If you do not have enough starting material to load at that level, switch to a smaller column.

4.  Why are the dimensions of the column important?

Well packed columns of proper length work best.  Short columns also work, but recoveries (yields) are lower. 

5.  Why would I operate chromatography in displacement mode vs. elution mode?

Due to the high resolution and high loading characteristics of displacement chromatography, you can obtain higher throughput, higher purity and increased concentrations from each use of the column.  This can be useful if you need to quickly purify large amounts of product in an analytical setting.  Displacement is also very useful for trace component amplification.  If you are trying to isolate a trace component, displacement will concentrate these components while simultaneously removing the main components. 

6.  What concentration displacer should I use?

The displacer works at low concentration;  Start with 5mM.

7.  How do I get the displacer out of my protein?

The displacer only contacts the last few fractions of the last band in the displacement train.  Therefore, if the desired protein is not the last component, the displacer will not be present in the protein.  In the last few fractions of the final component, the low-molecular weight displacer is easily removed via diafiltration.

All of SACHEM's displacers are high purity and are designed with UV chromophores for easy detection. 

8.  What is the level of detection for Expell™, Isolis™ and Propell ™ Displacers?

The level of detection for SACHEM's displacers are <1 ppm by HPLC.

9.  What are the storage conditions for the displacers?

All of SACHEM's displacers can be stored under ambient conditions.  Once diluted in a buffer mixture, the displacer should be used within 2 weeks.    

10.  Can the displacer be reused?

The displacer should not be reused.  Expell™ and Isolis™ displacers are purified chemical entities and the purity of the displacer has a significant impact on the displacement experiment.  

11.  I have only ever seen displacement done on model systems.  Does it really work on real world proteins?

Until now the unavailability of commercially viable displacers has limited the use of displacement chromatography on real world systems.  You can view some example results of SACHEM displacers on various systems under Displacement Chromatography 101 on our website. 

12.  Can this be used for analytical applications?

Displacement can be a useful technique in analytical applications when trying to enrich trace components in a complex mixture because all impurities appear in the tight transition zones.

13. At what stage is displacement best used?

It is possible to use displacement chromatography as early stage capture, after an affinity purification step, in late stage product polishing or to isolate a trace component.

14.  What if I can't get the displacer off of my column?

In most cases, the stated regeneration protocols will efficiently remove the displacers.  For convenience, SACHEM supplies Regenerate™ Solutions which are available for purchase on www.sachemstore.com.  These are available in various pH's. 

15.  What if I need more technical help?

Please contact us at This email address is being protected from spam bots, you need Javascript enabled to view it   or 512-421-4900.  We would be happy to answer your questions.