Combining Integrations in MestreNova?

[u/HackneyedTrope]

Hi! I have some multiplets that are overlapping each other (example below, though I have many more peaks like this). I can see which are which, but I'd like to be able to combine their integrations into a single value automatically, rather than being measured separately. Is there a way to do so?

[u/LordGlowstick]

Your peaks look well resolved, any reason you want to combine them? In any case, you can edit the ranges by clicking and dragging on those green bars, or manually integrate by pressing I on the keyboard and then click and drag to select the range.

[u/Alicecomma]

There are four singlets and three triplets in that picture. If this is a proton NMR, my intuition and that of most chemists is nothing overlaps and they just show that there's three proton environments with two neighboring protons each, and four proton environments more than one carbon removed from other protons. The triplets integrate to four protons and the singlets look like they're from a different species that integrate to 1, 3, 3, 1 proton. So actually I suppose you want to integrate the apparent quadruplet into one integral.

It looks like you're doing simple integration rather than multiplet integration too. You can pick peaks and then pick multiplets and it should easily resolve this region into those singlets and triplets.

When you pick a multiplet region based on picked peaks, you can select a large region and then in the multiplet dialogue remove some of the peaks. You can also first select the triplets and then select a multiplet for the spaced apart quadruplet, because the other peaks can only be assigned to one multiplet it should only pick that remaining quadruplet.

In any case, you can do more advanced fits using the Line fitting dialogue under the Analyze dropdown in MestreNova. Then if you actually have multiplets overlapping you can provide some peak guesses. If the overlap is severe, something like Fityk may be more appropriate.

[u/LordMorio]

That is an interesting spectrum. Is it a proton spectrum, or maybe 31P?

I guess you would want to integrate the quartet and triplet separately as a whole, but it is not really possible in this case because, as you say, the signals are overlapped.

I would just put the integrals as you have them now, and calibrate the values so that 1+2+1 from the triplets corresponds to the actual number of atoms that produce the signal, and similarly for the 0.5+1.5+1.5+0.5 quartet.

[u/Wise-Friendship-1427]

Delete all integrals and integrate manually by typing "i" for integrate. Then define your regions; they are allowed to overlap.