Spectrus: Handling solvent peaks and reference signals in NMR spectrum

Description
Solvent peaks and reference compounds (e.g., TMS, residual solvent signals) are often present in NMR spectra. Properly identifying and, where needed, excluding these peaks is important for clear assignments and integrals.

Solution

After importing the NMR spectrum, identify known solvent and reference peaks:

1. Use Table of Solvents under Analysis tab to identify common chemical shifts for the solvents. Look for TMS or internal standard signals. In Spectrus, annotate these peaks:
   • Add “Solvent” or “Reference” labels in peak annotations.
   • Right-click on a known solvent peak, click Set Reference and select the solvent from the table. Check Add Annotation and Add Dark Region and click OK.
2. For integration:
   • Exclude or separately handle solvent peaks if they do not represent analyte protons.
   • Use reference peaks only if they are intentionally part of quantitation.
3. For automatic assigning:
   • Navigate to Analysis > Detect Solvent/Water Signals > Auto Detect to automatically assign common solvent and water peaks in the spectrum.
   • Review any assignments that fall on known solvent peaks and correct them if needed.
4. For reporting:
   • Clearly indicate which peaks are solvent/reference so they are not confused with analyte signals.