I have a problem with the removal of background of my SERS spectra. The raw spectrum looks like thisNormally I use the Asymetric least square baseline removal after I create a spectrum with a flat line instead of the first big peak and then I subtract it from the original spectrum. In spectra like this when I follow this procedure I get negative values in the beggining after the removal of the background. I am not an expert but negative values should not exist right? Any ideas how to solve this? Thank you all in advance
The ‘baseline’ of your data appears to be something resembling a logistic curve, although perhaps reversed. You will likely have to fit the section where the x- values are greater than 1000, then evaluate it over the entire x-range. See if the approach in Shifting Baselines of Raman Spectra suggests a solution to your problem.
I apologise for my late reply. Actually the first column is the wavenumbers and the rest are several spectra. I just included more than one so I can provide an idea of how they look in general. Do you need me to concert those in another way? Thank you so much for your help!