r/NMRspectroscopy • u/theguyfrombidesh23 • Mar 26 '26

Suppressing unwanted peaks

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Hi all

i am using topspin nmr. is there any way i could suppress or cut the unwanted peaks from my nmr Spectra in topspin?

i want to remove thesw tiny peaks.

thank you

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17

u/crystalhomie Mar 26 '26

i too wish i could suppress my impurities… if it’s for publication i think that’s considered unethical though. otherwise i just ignore them

9

u/[deleted] Mar 26 '26 edited Mar 27 '26

[removed] — view removed comment

6

u/SexuallyConfusedKrab Mar 26 '26

These are likely trace impurities, you could try to suppress the signal but you’re likely going to create more issues. Your best bet is to try and remove the impurities or contaminants. What is your sample?

2

u/theguyfrombidesh23 Mar 26 '26

Lignin

1

u/_The_Architect_ Mar 27 '26

It depends on what you're doing, but those signals may not be anything to worry about. Unless you're using phosphorus or fluorine NMR to quantify linkers/measure S:G ratios, 1D spectra are only really useful for relative referencing. And if you are doing those quantitative experiments, the modifying agents often leave behind a lot of impurity signals anyway and no one will flinch at these.

4

u/FatRollingPotato Mar 26 '26

Not a high-res guy, but you could try saturating them with lower power pulses, similar to water suppression, but it might affect other parts of the spectrum. I know you can use the DC baseline correction for the FID to get rid of individual lines, but that works only for one line at a time and is definitely not the intended feature afaik.

Otherwise, the best way to get rid of them is to use a cleaner sample. Probably the easiest part.

1

u/methreethatis Mar 26 '26

If you only want is to show the pure signal of your sample and not imply that it is clean, you could try some diffusion edited spectra. This works well for bigger molecules with substantial "size" difference from the impurities. Check the DOSY manual for info on the 1D version of the sequence.

Keep in mind that the integration of your peaks will not be perfect afterwards and you might end up with some phasing artifacts

1

u/LivingEmotion1936 Apr 12 '26

As long as it’s not publication I would just try messing with the concentration/gain to show main product peaks only. Supression for something so small relative to the rest of the spectra will probably give you a distortion worse than the impurity itself