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A blog on the latest applications, articles, & research on chromatography solutions in sample preparation, Ion Chromatography (IC),
High Pressure Liquid Chromatography (HPLC), Ion Chromatography-Mass Spectrometry (IC-MS), Gas Chromatography (GC),
Gas Chromatography-Mass Spectrometry (GC-MS and GC-MS/MS), and software (Chromeleon CDS, LIMS, and ProteinCenter).

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Capillary Ion Chromatography: Tips & Techniques!

  
  
  
  
  
  

capillary ion chromatography IC cubeRecently, the applications team in Sunnyvale, California, released a great technical note focusing on tips and techniques to maximize the benefits of using capillary ion chromatography (IC).

As mentioned in earlier blog posts, the key benefit of capillary IC is that it helps chemists save time, labor, and reduce operating cost, while increasing the productivity and reproducibility of ion analysis.  How?  Since the system operates at such low flow rates (~10 µl/min), it is practical to operate a capillary IC system 24/7, so the system is ready to run samples at any time!  Also, the Eluent Generator module (EG) is able to produce eluent automatically from deionized water for up to 18 months under continuous operation, making gradient separations as easy as isocratic.

Here is a section excerpted from Technical Note 113, Practical Guidance for Using CapillaryAnion Chromatography, (downloadable PDF) focusing on critical practices!

Critical Practices for Improving Capillary Ion Chromatography

  1. Use precision-cut tubing, blue connectors, and blue ferrules for all connections.
  2. Minimize the void volume between the tubing and the connection.
  3. Hydrate and install all cartridges in the IC Cube (image above) according to the Dionex ICS-5000 Operator’s Manual (downloadable PDF).
  4. Diligently remove air from the system initially and after any change to the system, including turning off the pump. The pump is designed to ramp the pump speed to prevent pressure surges. This is a useful function but can interfere with attempts to stabilize the flow rate. To override this function, enter the desired flow rate, then turn the pump on, off, and on again.
  5. Always keep the capillary IC system running as it is designed to remain on at all times. The μL/min flow rates of the capillary IC system have the advantages of low consumption of water and consumables and low waste generation, allowing the system to remain on at all times with minimal additional costs. These same low flow rates may cause longer equilibration times than standard bore systems, defeating any advantages of turning the system off.
  6. If the system does need to be shut down, open the purge valve on the pump after turning it off to relieve the pressure in the pulse damper. Otherwise the eluent will continue to flow for several column volumes, filling the column and suppressor with water and slowing re-equilibration once the system is restarted.

The technical note (link to downloadable PDF above) covers many such topics including the Flow Path, IC Cube, carbonate removal device, tubing tips, autosampler tips, low-level analysis, direct large loop injections, large volume injections using a monolith concentrator column among others.

Let us know of any topics you would like covered in capillary IC in the Comments box below. Our experts will be pleased to respond to your questions. We look forward to hearing from you!

Comments

When I visited the booth at PittCon, the folks in the booth largely warned me away from the technique when they learned the samples were environmental. As I understood the situation, when you have a largely uncontrolled matrix, and (or) analyte concentrations that vary widely, traditional IC is the way to go.  
 
I currently have a 2mm system and it has RT stability issues due to matrix. This problem exacerbated (as was explained) if I went to capillary. 
 
Greg
Posted @ Thursday, April 12, 2012 3:39 PM by Greg Pronger
Hi Greg, 
Thanks for your comment. 
 
Just spoke to one of our experts in this area and he says that are no problems running environmental samples on a capillary system as long as typical precautions are taken which means that the samples must be filtered. Also, the resins for 2 mm columns and capillary columns are the same.  
 
Let me know if you would like to chat with someone in detail. I am happy to facilitate. 
 
Best regards 
Sonya 
Posted @ Thursday, April 12, 2012 5:00 PM by Sonya Pelia
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