CHANGING COLUMN

Question

Hi. Ive been using a DB-624 column to determine VOCs in a 6890N GCMS instrument for a few months. What parameters should I take into account to determine whether I have to change my current column? I know that resolution is mandatory but I was wondering if I need to consider other concepts such as baseline shifting, column bleeding and so on. Also it would be great if u share some URLs and sources to read about this. Thanks.

Dr. Know · Accepted Answer

Hi Midwar, 
 as long as you are happy with the results and trust them, there is no need for change. As you mentioned already resolution between two critical peaks can be something to consider change. 
 If bleed is not influencing your results and acceptable, it is ok. And you can always condition the column according the procedure mentioned in the user manual. 
 You can also define a suitability test for your analysis like using the lowest concentration standard, calculate the signal/noise ratio and define an acceptable limit for it. Or define retention factor changes/times as kick out criteria. 
 Be aware that this sometimes a system suitability test including your instrument, if signals are lower the ion source maybe dirty and the column is fine. 
 Regards, 
 Norbert

CHANGING COLUMN

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