FastGCUsingRapidTemperaturePrograms
Fast temperatureprograms canbeused inGC to speedup theelutionof high
boilingpoint compounds and lateeluters. This is especially useful if compounds
withwidely varyingboilingpoints arepresent in the sample. WhilemanyGCs
canbe temperatureprogrammedat rates 70°C/min. or higher, at higher
temperatures theseprograms canbedifficult tomaintain. The temperatureprofile
also tends tobecome less reproducibleas the temperatureand theprogrammed
ramp rate increases.
Auxiliary heaters, suchas theGCRacer temperatureprogrammer, canbeused
tomaintain thedesired temperaturegradient. TheGCRacer consists of a
resistiveheatingelement that is placedon the floor of theGCoven, anda
controller that connectswith themainPCboardof theGC. InFigures 1and2,
theactual temperature in theovenof anAgilent 6890GC, withandwithout the
GCRacer, is shownat two different temperatureprograms. InFigure3, ahigh-
speedGC separationof volatile compounds is shown. Thiswas donewithand
without theGCRacer, using the instrument conditions given inTable I.
