Beer-Lambert Law
The Beer-Lambert Law relates the absorbance of a solution to its concentration and the path length light travels through it:
A = ε · l · c
A = absorbance, ε = molar absorptivity (L/mol·cm), l = path length (cm), c = concentration (mol/L)
Transmittance T relates to absorbance: A = −log₁₀(T)
Applications in biochemistry
Beer-Lambert is fundamental to spectrophotometry — measuring protein concentration at A₂₈₀, DNA/RNA at A₂₆₀, cell density at A₆₀₀, and colorimetric assays. Most lab instruments display absorbance directly.