By Madelene on Tuesday, February 25, 2003 - 03:19 am:
Hi
I would like to write a paper were I compare different RP columns for analysis of five different folate forms. In order to elute all forms have I used a gradient program
5 min 6% ACN, 94% phosphate buffer
20 min 25% ACN
25 min 25% ACN
33 min 6% ACN
Now I wold like to show how the peaks separate from each other on different columns and how they look like.
Does anyone have suggestion of a review that I can read. I do not this to be a big part of my paper.
Thanks.
Madelene
By Uwe Neue on Tuesday, February 25, 2003 - 03:55 pm:
The simplest way to measure the overall quality of a gradient separation is to calculate the peak capacity. It is defined as the gradient duration t(g) divided by the average peak width w, + 1:
P = 1 + t(g)/w
Simple to do, simple to calculate.
For the average peak width, you can use a few standard peaks throughout the chromatogram that are resolved in every one of your chromatograms.
In your case, you would probably decide that the gradient time is the linear portion of the gradient, i.e. 20 minutes, and the peak widths you get from the chromatograms.
There is a paper that describes the background to this in J. Separation Science 24 (2001), 921-929.
By Madelene on Tuesday, March 4, 2003 - 04:19 am:
Thank you for your answer. Do you mean that I can measure the peak width at for example 10% for three peaks and let t0 be 20 and then calculate P from this?
Thanks again
Madelene
By Uwe Neue on Tuesday, March 4, 2003 - 06:29 pm:
Exactly!
By Anonymous on Wednesday, March 5, 2003 - 05:27 pm:
isn't the tg = 15 min in madelen's gradient? It seems to me there's a 5 min hold at 6% ACN at the beginning.
By Uwe Neue on Thursday, March 6, 2003 - 12:34 pm: