Gel Permeation Chromatography (GPC), also known as Size Exclusion Chromatography (SEC), is a technique used in analytical chemistry to separate and characterize macromolecules based on their size or molecular weight. It is commonly employed for polymers and other large molecules.
In GPC, a packed column containing a porous gel material with well-defined pore sizes is used to separate the analyte mixture. The pore sizes of the gel determine the range of molecular weights that can be separated. As the sample solution flows through the column, smaller molecules can easily penetrate the pores and take longer to elute, while larger molecules are excluded from the pores and pass through the column more quickly.
A mixture of standards with known molecular weights is usually utilized to calibrate the system, creating a calibration curve that relates the elution time of the different molecular weights to their respective sizes. The molecular weight of the unknown analyte can then be determined by comparing its elution time to the standard curve.
GPC is typically performed using a high-performance liquid chromatography (HPLC) system, and the separated components are detected by various detectors such as refractive index, ultraviolet, or light scattering detectors. This technique provides valuable information about the average molecular weight, molecular weight distribution, and the degree of polymerization of macromolecules.
Overall, Gel Permeation Chromatography offers a versatile and widely used method for characterizing polymers, especially in quality control, research, and development of materials, where precise knowledge of molecular weight distribution is crucial.
