Monday, April 16, 2007


26 years ago a simple, short and humble article explained how to tackle the problem of automatic phase correction and also gave a working recipe.

M.M. Siegel, "The use of the modified simplex method for automatic phase correction in Fourier-transform nuclear magnetic resonance spectroscopy", Anal. Chim. Acta, 133, 103-108 (1981).

None of the articles appeared afterwards has been more useful and you could safely ignore them all. The method of Siegel is rarely cited, for mysterious reasons, but it really stands out. Although it assumes the complete absence of baseline distortions, a condition which is never satisfied in practice, the performance is more than acceptable, generally speaking. The method cannot be used blindly, and should be followed by manual refinement, but still saves hours of time to those who adopt it.
Last night (see previous post) I gave the link to a poster that will be exhibited next week at the 48th ENC Conference. This morning I read the poster again and eventually I understood it. My rating doesn't change, though. Do you wonder how could I rate a method before understanding it? When I can't understand the equations I resort to common sense, and it rarely fails. That poster says so many implicit things than demolishing it point by point would be easy and funny for this blogger, if only it had been authored by someone called Bruker or ACD. It would have been the replica of Manchester United-Roma (hey! I have just written a pindaric flight!).
The two companies behind the poster are to be praised for the many amazing things they are doing, compared to their small size, so I feel really bad at the mere thought of criticizing their poster here. Just a caveat: the new method called eDISPA does not derive from DISPA and has nothing to do with the latter, despite the poster wants you to swallow such a genealogy. Substantially I am giving you good news because, as I wrote in the other post, DISPA doesn't work. Apparently Stan and Carlos liked the name "eDISPA", or couldn't find anything better, or had not enough pictures to fill the poster, so they invented a fake relation.
To make it short, the poster exclusively comes from the legitimate and laudable desire to go to the ENC with something new to show. In case you are lucky enough to attend the event, don't forget to visit the MestreLab boot and bring my salute.
To learn more about optimization in general, the book Sequential Simplex Optimization can be downloaded for free.
If you can't wait for the future download iNMR 2.1.8 and admire automatic phase correction in action today.


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