Calculator
Paste wavenumbers and intensities as comma or newline separated values. Use the same count for both series.
Example data table
This table illustrates typical FTIR peak regions and what they often suggest.
| Region (cm-1) | Common assignment | Notes |
|---|---|---|
| 3200-3600 | O-H / N-H stretch | Broad bands may indicate hydrogen bonding. |
| 2850-2960 | C-H (sp3) stretch | Strong in alkanes and many polymers. |
| 1650-1750 | C=O stretch | Shifts with conjugation, amides, and esters. |
| 2100-2260 | C≡N / C≡C stretch | Often sharp, medium intensity bands. |
| 1000-1300 | C-O stretch | Alcohols, ethers, and esters show bands here. |
Formula used
- Transmittance to absorbance: A = -log10(T), with T in 0-1.
- Absorbance to transmittance: T = 10^(-A).
- Linear baseline: subtract a line between first and last points.
- Smoothing: moving average with window w.
- Peak rule: local maximum with prominence above threshold.
- Area: trapezoid integration on processed absorbance.
- Beer-Lambert: c = Amax / (ε·l) using maximum absorbance.
This supports quick screening and reporting. Confirm assignments with reference libraries and instrument context.
How to use this calculator
- Choose whether your input is transmittance or absorbance.
- Paste wavenumbers and intensities using commas or new lines.
- Set baseline correction and smoothing for cleaner peaks.
- Adjust the prominence threshold to control peak sensitivity.
- Press Analyze Spectrum to view peaks and previews.
- Use Download CSV or Download PDF to export results.
Tip: If your spectrum is noisy, increase smoothing before lowering the threshold.
FAQs
1) What does this analyzer calculate?
It converts transmittance and absorbance, applies baseline correction and smoothing, detects prominent peaks, estimates area, and generates CSV/PDF exports for reporting.
2) Can it identify compounds automatically?
It provides broad functional-group hints based on peak ranges. Confirm identities using reference spectra, library matching, and instrument-specific settings.
3) Why use absorbance for peak detection?
Absorbance often linearizes Beer-Lambert behavior and makes peaks easier to compare. Many workflows convert transmittance to absorbance before analysis.
4) What is the best smoothing window?
Start with 3 to 7 points. Increase slowly if noise dominates. Too much smoothing can flatten narrow peaks and shift peak positions.
5) My peaks are missing. What should I change?
Lower the prominence threshold, reduce smoothing, or verify your scaling. Ensure transmittance is in 0-100 percent or 0-1 fraction correctly.
6) How does the concentration estimate work?
It uses c = Amax/(ε·l) with the maximum absorbance. This is a rough estimate and assumes a valid ε and consistent optical path.
7) Is the PDF export compatible everywhere?
The PDF is generated without external libraries and targets basic viewers. For styled charts, export CSV and format the report in your preferred tool.
Meta description: Analyze FTIR peaks with smart preprocessing tools. Convert absorbance or transmittance quickly. Export clean reports for faster lab decisions today.
Tagline: Upload wavenumbers and intensities to reveal peaks. Baseline and smooth signals for clarity. Download tables and reports to share with teammates.