Gel permeation chromatography

Gel permeation chromatography separates dissolved polymers by hydrodynamic size as they pass through a column of porous particles. Larger molecules usually elute before smaller ones because they enter fewer pores.

Size-exclusion chromatography: A chromatographic method that separates molecules by their access to pores in a stationary phase. Gel permeation chromatography is its polymer-focused form, usually distinguished by organic mobile phases.
Molar-mass distribution: The variation in molecular mass among the molecules in a polymer sample. A chromatogram separates this distribution into elution fractions for quantitative characterization.
Chromatography column: A tube packed with stationary-phase material through which a mobile phase carries sample components. The porous packing creates the size-dependent travel paths used by the technique.
High-performance liquid chromatography: Liquid chromatography performed with small-particle packings and high operating pressures for efficient separations. It is a broader instrumental family; gel permeation chromatography is one mode within liquid chromatography.
Hydrodynamic volume: The effective volume a molecule occupies while moving through a fluid, including its solvated shape and motion. Elution follows polymer hydrodynamic size rather than molecular mass directly.
Number-average molar mass: The total mass of a polymer sample divided by its number of molecules. It is one distribution statistic derived from the measured polymer fractions.
Mobile phase: The fluid that carries sample components through a chromatographic system. Its solvent quality affects polymer solubility, conformation, and interaction with the gel.
Gel filtration chromatography: A size-exclusion chromatography method commonly used with aqueous mobile phases for biomolecules. It uses the same pore-exclusion principle but is conventionally distinguished by aqueous solvents.
Polymer standards: Well-characterized polymers used as reference materials for calibration and measurement. Standards convert elution volume into an estimated polymer size or molar mass.
Weight-average molar mass: A polymer molar-mass average that weights each molecular species by its mass fraction. It emphasizes heavier chains and is commonly reported from polymer chromatography.

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Molecular massRelated: Calibration can estimate polymer molecular masses from elution behavior.