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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: e_spirit on June 18, 2005, 06:17:47 AM

Title: Why a GC-column has a maximum temperature?
Post by: e_spirit on June 18, 2005, 06:17:47 AM

Hi, Guys!

I have a problem with one question from my pre-exam. Can you please help me with that. here it is:

"explain why a GC-column has a maximum temperature?"

Any help will be highly appreciated!  :)

Title: Re:Why a GC-column has a maximum temperature?
Post by: Dude on June 18, 2005, 12:18:18 PM

GC capillary columns typically use polydimethylsiloxane, polyethylene glycol or polystyrene as the stationary phase.  If the column is overheated, the stationary phase will degrade (separation capabilty will be reduced or lost).  The upper temperature limit scales with the thermal stability of the stationary phase [DB-1 (siloxane based) type columns usually can last up to about 325 C, Carbowax (polyethylene glycol I believe) will break down around 250 C].