Which technique is primarily used to separate and analyze large molecules in biological samples?

Electrophoresis is the technique primarily used to separate and analyze large molecules, particularly nucleic acids and proteins, in biological samples. It works on the principle of applying an electric field to a gel or other medium containing the molecules. This causes the molecules to migrate based on their size and charge; smaller molecules move faster than larger ones.

Electrophoresis can be used in various applications, including DNA fingerprinting, RNA analysis, and protein separation. It is especially effective for analyzing complex mixtures, where the separation of large macromolecules is crucial for subsequent analysis.

In contrast, gas chromatography is better suited for volatile compounds and does not effectively separate large biological molecules. HPLC is a powerful method for smaller molecules and can separate large molecules, but it is generally more advantageous for small to moderately sized compounds rather than very large biomolecules. Mass spectrometry is a technique used for measuring the mass-to-charge ratio of ions and can provide information about the structure of the molecules, but it usually requires prior separation techniques for large molecules.