Instruments for Macromolecule Separation

DNA, RNA and proteins are macromolecules synthesised inside living cells, and they differ from one another in molecular weight, solubility, the charges they carry, and how they absorb light. Several techniques exploit these differences to isolate and characterise them: gel permeation, ion-exchange chromatography, spectroscopy, mass spectrometry, and electrophoresis are all used, chosen mainly on the basis of a molecule's size (and hence its molecular weight). …