Time domain baseline correction (NMR)

Here we show how to baseline correct dataset in the time domain before applying FFT.

The example spectra were downloaded from this page where you can find some explanations on this kind of process.

[1]:

import spectrochempy as scp

SpectroChemPy's API - v.0.8.2.dev7
©Copyright 2014-2025 - A.Travert & C.Fernandez @ LCS

[2]:

path = scp.preferences.datadir / "nmrdata" / "bruker" / "tests" / "nmr" / "h3po4"
fid = scp.read_topspin(path, expno=4)
prefs = scp.preferences
prefs.figure.figsize = (7, 3)
fid.plot(show_complex=True)

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MPL Configuration directory: /home/runner/.config/matplotlib
Stylelib directory: /home/runner/.config/matplotlib/stylelib

 WARNING | (UserWarning) Error reading the pulse program

[2]:

../../_images/userguide_processing_td_baseline_2_4.png

[3]:

spec = scp.fft(fid)
spec.plot(xlim=(5, -5))

[3]:

../../_images/userguide_processing_td_baseline_3_1.png

We can see that in the middle of the spectrum there are an artifact (a transmitter spike) due to different DC offset between imaginary.

In SpectroChemPy, for now, we provide a simple kind of dc correction using the dccommand.

[4]:

dc_corrected_fid = fid.dc()
spec = scp.fft(dc_corrected_fid)
spec.plot(xlim=(5, -5))

[4]:

../../_images/userguide_processing_td_baseline_5_1.png

[5]:

path = scp.preferences.datadir / "nmrdata" / "bruker" / "tests" / "nmr" / "cadmium"
fid2 = scp.read_topspin(path, expno=100)
fid2.plot(show_complex=True)

 WARNING | (UserWarning) Error reading the pulse program
 WARNING | (UserWarning) (956,)cannot be shaped into(1024,)

[5]:

../../_images/userguide_processing_td_baseline_6_2.png

[6]:

spec2 = scp.fft(fid2)
spec2.plot()

[6]:

../../_images/userguide_processing_td_baseline_7_1.png

[7]:

dc_corrected_fid2 = fid2.dc()
spec2 = scp.fft(dc_corrected_fid2)
spec2.plot()

[7]:

../../_images/userguide_processing_td_baseline_8_1.png