Void Time GC Column

Question

Anyone idea how to determine/calculate the "void time" for a GC column? Value is needed for System Suitability tests in OpenLab...

Dr. Know · Accepted Answer

Hi BartSmet, 
 just like every textbook will say, inject methane and then the retention time is your t 0 . If you don't have methane, natural gas will do. No gas at all, inject pentane, the error is small. For the last two the first peak eluting is your t 0 . 
 If you want to do it perfectly you could also inject some n-alkanes and extrapolate to a C0, but the methods above will work. 
 Calculating is not a good option as your real column length is not well known, you only know the nominal length. 
 Regards, 
 Norbert

Void Time GC Column

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