> I am new to CCPN and I am trying to find a way to calculate accurately the line widths and volumes. I am trying to use the Peak separator function (is this the best way in CCPN?) but I would like know if there is a way to determine the accuracy of the final fit.
Hi Afonso, welcome to CCPN!
The standard Analysis peak picker will simply interpolate over the selected spectral region to find a maximum peak point - and then pick that as a peak. Line widths are calculated as the half-width at half-height. The peak picker will then do a simple (Sparky like?) box sum (or truncated box sum, or parabolic fit) to find the volume. NB. If you use this method, it is vitally important that you set a suitable value for the 'boxwidth' in the Peak : Peak Finding : Spectrum Widths tab.
The analytical method peak finder will not be able to cope with over-lapping or merged peaks - and so this is where the peak separator becomes useful. Originally the peak separator code would calculate a (say 95% confidence) value for number of peaks in a region, and each peaks height, width, position and volume, but this has been replaced with a maximum likelihood fit (rendering probabilistic errors useless). However, it will still deconvolve merged peaks and calculate the individual component peaks height, position, width and volume.
I'm currently working on a revised version of the peak separator, after having spoken with people on this list and at the conference. If you have any requests, questions or general advice, please contact me on or off the list!
Best Wishes,
Dan
Daniel O'Donovan
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