Decreasing the theoretical plates

Discussions about GC and other "gas phase" separation techniques.

8 posts Page 1 of 1
H
Hi folks just one question. I am using the DB-624 column with USP<467> method for IPA determination. Theoretical plates are 6000 but I want to decrease to 4000 or less without compromising the reproducibility. Any idea how I can do that


Thanks in advance
Hi Murshad,

Increasing the column ID and/or film thickness should help in lowering the plate count without affecting the reproducibility of the separation if this is the desired goal. Just check the USP requirements for the allowable adjustments and perform a verification study.
MattM
I agree with Matt.
Thanks for your inputs.

Actually I want to degrade the column to the level that plate count decreases to half. Changing the column dimensions or any modification in any operational parameter is not an option.

Thanks in advance
Hello again, Murshad,

You said:

Actually I want to degrade the column to the level that plate count decreases to half. Changing the column dimensions or any modification in any operational parameter is not an option.


Is it not the case currently that a GC column may be increased in ID by 50% and the film thickness by 100% by the USP?

https://www.fda.gov/downloads/ScienceRe ... 173085.pdf
MattM
Murshad wrote:
Thanks for your inputs.

Actually I want to degrade the column to the level that plate count decreases to half. Changing the column dimensions or any modification in any operational parameter is not an option.

Thanks in advance


I don't understand why one would degrade a column by purpose to get less plates?
If you have plates in excess you may trade them in for getting things done faster (higher flow rates or use shorter column).
But that seems not to be what you want.

other ideas: start overloading your column or use a suboptimal injection solvent/settings or make lousy connections to get your peaks broader... [/silly mode off]
Huh??

I don't want to change anything but I want to degrade the performance.

I don't get it.

Best regards,

AICMM
This does not make any sense at all. Why on earth would you want to reduce the plate count ?

Peter
Peter Apps
8 posts Page 1 of 1

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