Spectroscopy and calibration curves
Beer–Lambert solver with absorbance ↔ transmittance, a calibration-curve fitter (linear, through zero, or quadratic) with R², LOD/LOQ and back-calculated unknowns, and light conversions between wavelength, wavenumber, frequency, and photon energy with the visible colour.
Added
How to use it
-
Beer–Lambert — A = ε·l·c. Fill any three of absorbance, molar absorptivity (L mol⁻¹ cm⁻¹), path length (cm), and concentration (mol/L); the fourth is solved. A = −log₁₀ T, so 1 absorbance unit passes 10 % of the light. Above about A = 1.5 stray light makes most spectrophotometers non-linear — dilute the sample.
-
Calibration curve — paste standards as "concentration, response" pairs. The fit is least squares; through zero forces the intercept to 0. The table shows residuals; sy/x is the residual standard deviation. Limits follow the ICH Q2 convention: LOD = 3.3·sy/x/slope and LOQ = 10·sy/x/slope. Unknowns are back-calculated (multiplied by any dilution factor) and flagged when they fall outside the range of the standards.
-
Light — convert between nm, µm, cm⁻¹, THz, eV, and kJ/mol with E = hc/λ (exact SI constants). Visible wavelengths get an approximate sRGB swatch, a colour name, and the complementary colour a solution of that absorbance would appear.
| For learning and planning. Validate real methods with your own replicate standards and blanks. |
Feedback is a gift. Something to improve, a feature to add, or a bug? Tell me.
Runs entirely in your browser; nothing you type leaves this page.