Gel Permeation Chromatography (GPC), also referred to as Size Exclusion Chromatography (SEC), is a valuable tool for the characterization of molecular weight, average molecular weight, and molecular weight distribution for polymers. It is often necessary to separate polymers, both to analyze them as well as to purify the desired product. When characterizing polymers, it is important to consider the polydispersity index (PDI) as well the molecular weight. Polymers can be characterized by a variety of definitions for molecular weight including the number average molecular weight (Mn), the weight average molecular weight (Mw) (see molar mass distribution), and the size average molecular weight (Mz). GPC allows for the determination of PDI as well as Mn, Mw, and Mz.
Impact Analytical has extensive expertise and instrument capability in this area. We can characterize polymers from all classes, using solvent systems from tetrahydrofuran (THF), to hexafluroisopropanol (HFIP), to aqueous. We offer both differential refractive index (DRI) and multi-angle laser light scattering (MALLS) detection. Standard calibration is used to give relative molecular weight with DRI analysis, while MALLS detection gives “true” molecular weight.
Examples of polymer systems characterized include:
- Acrylonitrile butadiene styrene (ABS)
- Polyquaternium compounds
- Epoxy materials
- Hindered amine light stabilizers (HALS)
- Polyethylene glycol
- Polyvinyl chloride (PVC)
- Polyamide (Nylon)
- Hyaluronic acid-based polymer