Calculator Inputs
Use one page layout overall. The input fields below switch to 3, 2, and 1 columns by screen size.
Peak Visualization
The chart updates with your submitted peak or with the sample dataset before calculation.
Example Data Table
This example uses simple chromatographic points with a baseline of 8 and demonstrates trapezoidal integration.
| Time (min) | Signal (mAU) | Baseline-Corrected Signal (mAU) |
|---|---|---|
| 4.80 | 10 | 2 |
| 4.90 | 32 | 24 |
| 5.00 | 70 | 62 |
| 5.10 | 35 | 27 |
| 5.20 | 11 | 3 |
Approximate trapezoidal area for this example is 11.55 mAU × min.
Formula Used
1. Baseline-Corrected Height
h = Peak Height − Baseline
This removes the constant baseline contribution before integration.
2. Triangle Approximation
A = 0.5 × Base Width × h
Use this when the peak is nearly symmetric and a quick estimate is acceptable.
3. Gaussian Approximation
A = h × σ × √(2π)
When FWHM is given, the calculator converts it using σ = FWHM / 2.35482.
4. Trapezoidal Integration
A = Σ [((yi + yi+1) / 2) × (xi+1 − xi)]
This is useful for raw detector points and irregular peak shapes.
5. Optional Concentration Estimate
Estimated Concentration = (Peak Area / Response Factor) × Dilution Factor
6. Optional Area Percent
Area % = (Peak Area / Total Chromatogram Area) × 100
How to Use This Calculator
- Select the integration method that matches your available data.
- Enter retention time, height, baseline, and width information.
- For raw chromatogram data, choose trapezoidal mode and paste X,Y points.
- Set time, signal, and concentration units for readable outputs.
- Add a response factor or total chromatogram area if needed.
- Submit the form to show results above the calculator.
- Review the Plotly graph to visually inspect the peak profile.
- Export your current result set with the CSV or PDF buttons.
Frequently Asked Questions
1. What does peak area represent in chemistry?
Peak area represents the total detector response across a chromatographic peak. It often correlates with analyte amount better than peak height, especially when peaks broaden or slightly shift.
2. When should I use trapezoidal integration?
Use trapezoidal integration when you have raw X,Y detector points or when the peak shape is not perfectly Gaussian. It is also useful for asymmetric peaks and manually exported chromatogram data.
3. Why is baseline correction important?
Baseline correction removes constant background signal from the detector response. Without correction, the calculated area can be overstated, especially for small peaks or noisy chromatograms.
4. What is the difference between FWHM and sigma?
FWHM is the full width at half maximum. Sigma describes Gaussian spread. They are linked mathematically, so the calculator can convert one to the other for Gaussian area estimation.
5. Can I estimate concentration from peak area?
Yes. If you know the response factor from calibration, the calculator can estimate concentration from peak area. The dilution factor adjusts the result when samples were diluted before analysis.
6. Is triangle approximation accurate enough?
Triangle approximation is quick but simplified. It works best for nearly symmetric peaks. For irregular, tailing, or fronting peaks, trapezoidal integration usually gives a more realistic area estimate.
7. Which units should I use for area?
Area units combine signal and time, such as mAU × min or counts × s. The calculator automatically displays the result using the units you choose in the form.
8. Can this replace validated laboratory software?
This tool is useful for learning, checking, and preliminary calculations. It does not replace validated chromatography software, instrument integration methods, or formal quality-controlled laboratory workflows.