Please apply zero filling in your processing using nmrPipe command "-zf 2"
Please use the 2PI-Kaiser window function for apodization in the NMRPipe software
with the command “SP -off 0.5 -end 0.896 -pow 3.684” to achieve desired peak shape (Voigt).
Beside nmrPipe .ft1 format, you can also use Topspin text file generated using command "totxt" or CSV format from some software (two columns by space, ppm and amplitude).
You need to keep the imaginary part if you want to run manual phase correction.
Please adjust P0 first, then P1. Anchor point will be set to center of the visible region of the spectrum. Click on "Apply P1" to actually apply the phase correction.
Step 3 Baseline correction (optional)
A appreciate baseline correction can only be defined by the user, based on the experimental conditions. That is, the user need to define the smoothness parameter
and positive spectrum parameter then apply the baseline correction after satisfying result.
The smoothness parameter is the weight of the smoothness constraint in the baseline estimation. The larger the value, the smoother the baseline. Typical values are from 1e8 to 1e13
The positive spectrum parameter is the weight of the constraint that the baseline should be below the spectrum. The larger the value, the less the baseline will be allowed above the spectrum (to accommodate noise). Typical values are from 1.0 to 2.0
Important: phase correction is no longer allowed after baseline correction.
Reference: Baseline Correction for NMR Spectroscopic Metabolomics Data Analysis (Yuanxin Xi and David M Rocke); BMC Bioinformatics 2008, 9:324
Step 4 Spectrum deconvolution
DEEP Picker model selection
Model 1 was optimized for peak width (defined as Full Width as Half Height) from 8 to 20, with 12 points as optimal value
Model 2 was optimized for peak width from 4 to 12, with 8 points as optimal value
The default model, DEEP Auto, will estimate median peak width, then run cubic spline interpolation to adjust it to 6.0 and apply model 2.
For spectrum with very heterogeneous peak width, set a compromise interpolation step (for model 2). A step of 0.5 means spectral size will be doubled.
(optional) Pseudo 2D fitting of multiple spectra
This plot supports pan and zoom operations. You can also pan or zoom on single X or Y axis by setting cursor on X or Y axis.
Deconvoluted peaks will only show when zoomed in to certain scale. Black: experiment; Red: Reconstruction; Green: deconvoluted peaks.
Magenta: total spectrum from all matched compounds
This plot supports pan and zoom operations. You can also pan or zoom on single X or Y axis by setting cursor on X or Y axis.
Deconvoluted peaks will only show when zoomed in to certain scale. Black: experiment; Red: Reconstruction; Green: deconvoluted peaks.
Magenta: total spectrum from all matched compounds
Reference
