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Want to know how to properly choose a column – please step inside

28 Dec 2020

Often times in technical service there will be a request for a column that can provide a certain separation on a lone pair of analytes.  Take for example, the separation of CO from CH4 from one another. This separation is very easily done on any porous polymer column. What is sometimes not taken into account are other components of the sample, such as potential impurities, as well as the sample matrix itself. In the example of CO separating from CH4, if air (N2/O2) is present, then that narrows the choice down to a mol sieve column, which will resolve N2, O2 (air), and CO from one another. Otherwise, all three gases would coelute on any porous polymer column, which will cause issues for quantitating CO. Unless cryogenics is employed, the separation of (N2/O2/CO) would be very problematic on porous polymers.  The point here is that the more that is known about the analysis and sample, the more tailored and accurate a column recommendation can be made.

Knowing the answers to the key questions in the list below should greatly improve the accuracy of any column recommendation, whether it is HPLC or GC.

  • What is the overall goal of the analysis?
  • Is there a method being followed? If so, which one?
  • What are all of the analytes of interest?
  • What are the approximate relative concentrations of the analytes?
  • What are the expected or known impurities, and approximate relative concentrations of each, if known?
  • What is the sample matrix?
  • What is the ending diluent to be injected?
  • What is the instrument make and model, as well as the type of injection port and detector?

For help on choosing the proper column, please get in touch with us. We will likely ask many of the questions above, so we can help get you on the road to successful chromatography.