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3 Analysis Tools
Spectroscopy Tools
Interpret IR, NMR, and Mass Spectra with interactive reference tools. Enter your experimental data and identify peaks, shifts, and fragments instantly.
4000-400 cm⁻¹
IR Spectrum Interpreter
Infrared Spectroscopy
Enter wavenumber peaks to identify functional groups. Search by group name to find expected absorption ranges. Complete IR correlation table included.
- ✓Peak identification from wavenumber input
- ✓Functional group search
- ✓30+ absorption entries with examples
- ✓Grouped by category with color coding
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¹H & ¹³C
NMR Chemical Shift Analyzer
Nuclear Magnetic Resonance
Look up proton (¹H) and carbon (¹³C) chemical shifts. Identify environments from ppm values. Includes solvent reference table and visual shift scale.
- ✓¹H and ¹³C shift identification
- ✓Visual chemical shift scale
- ✓NMR solvent reference table
- ✓Environment search by keyword
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m/z Analysis
Mass Spec Analyzer
Mass Spectrometry
Identify fragment losses, common ions, and isotope patterns. Predict M/M+1/M+2 ratios from molecular formula. Check the nitrogen rule and explore McLafferty rearrangement.
- ✓Fragment loss identifier
- ✓Isotope pattern predictor
- ✓Common ion database
- ✓Nitrogen rule checker
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How to Choose the Right Technique
Start with the question you need to answer.
“What functional groups are present?”
IR Spectroscopy
IR detects bond vibrations. Each functional group (O-H, C=O, N-H, etc.) absorbs at characteristic frequencies, making IR the first choice for identifying functional groups.
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“What is the molecular structure / connectivity?”
NMR Spectroscopy
NMR reveals how atoms are connected. Chemical shifts indicate electronic environment, splitting patterns show neighboring protons, and integration gives relative numbers of protons.
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“What is the molecular weight / formula?”
Mass Spectrometry
MS measures molecular weight directly from the molecular ion peak. Fragmentation patterns reveal structural subunits, and isotope patterns identify elements like Cl, Br, and S.
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Spectroscopy Study Guide
General Workflow for Unknown Identification
- Mass Spec first — determine molecular weight and molecular formula from the molecular ion peak and isotope pattern.
- Calculate degrees of unsaturation (DBE) from the formula to assess rings and double bonds.
- IR next — identify functional groups (O-H, C=O, N-H, C-H, etc.) to narrow structural possibilities.
- NMR last — determine connectivity, symmetry, and detailed structure from chemical shifts, splitting, and integration.
- Confirm — ensure all spectra are consistent with the proposed structure.
Key Concepts
- Degrees of Unsaturation: DBE = (2C + 2 + N - H - X) / 2. A benzene ring contributes 4.
- Nitrogen Rule: Odd molecular weight implies an odd number of nitrogen atoms.
- D₂O Shake: Exchangeable protons (O-H, N-H) disappear after adding D₂O in NMR.
- 13 Rule: Divide (MW - nitrogen correction) by 13 to estimate number of carbons as a starting point.
- Isotope Patterns: Cl gives M:M+2 = 3:1; Br gives M:M+2 = 1:1; S gives a noticeable M+2.
Part of the VerChem Tools collection.