UV-Vis spectroscopy measures how much light a sample absorbs (Beer-Lambert law); chromatography separates a mixture as components migrate at different rates through a stationary phase.
A = ε·b·c (Beer-Lambert)
%T = 10^(−A) × 100
Rf = distance(spot) / distance(solvent front)
- Mode — switches between the spectroscopy beam/cuvette rig and the chromatography column.
- Analyte concentration — raises absorbance (dims the transmitted beam) and increases loaded sample band intensity.
- Wavelength — selects where on the spectrum you're measuring; absorbance peaks near the analyte's characteristic wavelength.
- Mobile-phase polarity — changes how fast each compound band migrates down the chromatography column, changing separation and Rf.
Real-world use: labs run UV-Vis assays to quantify concentration and TLC/HPLC chromatography to identify and purify mixture components.