Spectrus: Generating spectra difference plots to highlight subtle changes in UV/Vis spectra

Description
Small spectral changes between two UV/Vis measurements (e.g., before and after reaction, or different pH) can be easier to see in a difference plot. Spectrus supports subtracting one spectrum from another.

Solution

1. Import the two UV/Vis spectra to be compared into the same project.
2. Confirm that both spectra:
   • Are on the same wavelength range and resolution.
   • Are properly baseline‑corrected.
3. Go to Process > Subtract:
   • Select one sample spectrum as the main spectrum.
   • Choose the other spectrum as the one to subtract.
4. Adjust scaling of the background if necessary to avoid over‑ or under‑subtraction.
5. Examine the resulting difference plot:
   • Positive and negative bands highlight where absorbance has increased or decreased.
6. Use this information to:
   • Identify small changes due to binding, pH shifts, or minor structural modifications.
   • Prepare illustrative figures for reports or presentations.