By Anonymous on Wednesday, January 30, 2002 - 09:25 am:
There are two modes available for GC carrier. Can anyone explain how to choose the proper mode? Are there any rules? Thanks.
By Anonymous on Wednesday, January 30, 2002 - 10:32 am:
My older GCs can do only constant pressure mode, my newer Agilent ones have EPC so I can do either. Since carrier flow decreases somewhat as temperature increases, I find that I use constant flow mode when I encounter larger, less volatile compounds using temperature programming, to decrease run times.
By Leon on Friday, February 1, 2002 - 03:43 pm:
The answers to these question can be found a paper [1] and in a debate [2,3] on this subject.
References:
1. Blumberg, L. M.; Wilson, W. H.; Klee, M. S. "Evaluation of Column Performance in Constant Pressure and Constant Flow Capillary Gas Chromatography ". J. Chromatogr. A 1999, 842/1-2, 15.
2. Grob, K. "Increasing GC Separation Efficiency by Electronic Pressure Control?". J. High Resolut. Chromatogr. 1994, 17, 556.
3. Blumberg, L. M.; Berger, T. A.; Klee, M. S. "Constant Flow versus Constant Pressure in a Temperature-Programmed Gas Chromatography". J. High Resolut. Chromatogr. 1995, 18, 378.
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