Is the column shown on the COA for a chemical reference standard the best column for these compounds?


In some cases the answer is “yes”. In most cases the answer is “no”.


So why would we choose a column that is not the optimal for a specific standard?

It’s because of the large number of reference standards we sell. Each mix needs to have its own validated method. If we were to test each standard with their own column and/or method, production would slow to a crawl.


Stated another way by a product development specialist:

In order to provide certified reference materials, each product manufactured at Restek needs to be analyzed using a validated method.  It is impractical to have an optimized, validated method for each manufactured standard and be able to deliver certified reference materials to our customers that meets their needs in terms of cost and delivery time.


Because some customers are not aware of this, most chromatograms contain following statement (printed directly below the chromatogram):

This chromatogram represents a general set of testing conditions chosen for product acceptance. For optimal results in your lab, conditions should be adjusted for your specific instrument, method, and application.

Also keep in mind that we may sell a standard which was designed for a GC method, but actually test it using a HPLC column, and vice versa. An example of this would be Restek #31607 which was designed for EPA Method 8095 (Explosives by Gas Chromatography) but was tested at Restek using HPLC.


So how would you know which would be the best column choice? I suggest first looking through our application chromatograms using the online search feature

The way I use it is the following: I type in a compound name, followed by a comma, then a space, then another compound name…  For example, if I type methane, ethane, propane, butane the following link shows the results I receive:


You can also try ProEZGC   Please note that this is only for GC columns, and is limited to capillary liquid phase partition (Rtx-1, Rtx-5, Stabilwax, etc…) and not capillary solid phase adsorption (PLOT) or packed or micropacked.


In summary, you should not assume that the column and/or instrument method parameters on the chemical reference standard COA are for the optimal analysis of that reference standard. Instead, one of our other references, such as the chromatogram search tool and/or ProEZGC are better choices for choosing the correct column and method parameters.


Below are additional links which you may find useful, especially the chromatograms. Thank you for reading.

Industry Pages – Environmental Solutions

Industry Pages – Foods, Flavors & Fragrances Solutions

Industry Pages – Clinical, Forensic & Toxicology Solutions

Industry Pages – Food Safety

Industry Pages – Pharmaceutical Solutions

Industry Pages – Medical Marijuana

Industry Pages – Petrochemical & Chemical Chromatography


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