About Gel Permeation Chromatography

Gel Permeation Chromatography (GPC) is also known as Size Exclusion Chromatography (SEC).  GPC is used to measure the molecular weight distribution of a polymer sample.  The molecular weight measurement may be performed using multi-angle light scattering (MALS) in order to obtain the absolute molecular weight.  Column Calibration is another GPC technique used in which a sample is calibrated against a known standard.  Column calibration is especially useful for samples with very low molecular weights.  It is also useful for samples that are dissolved in a solvent that has a poor response from the light scattering device.  

 

  • Approaches

    There are many analytical uses for GPC Analysis.  Some of the most common ways we use GPC/SEC to meet our clients needs include: 
    • The analysis of polymer materials to determine molecular weight distributions
    • Measurement of absolute molecular weights using light scattering
    • Analysis of molecular size and polymer chain conformation in solution using a differential viscometer detector
    • Relative molecular weight measurements using refractive index or UV/vis absorbance detector
    • Molecular weight analysis of polymers in organic solvents
    • Analyzing water soluble polymers in aqueous mobile phases
    • The quantitative analysis of low molecular weight molecules such as antioxidants, light stabilizers, plasticizers, lubricants and spin finishes
    • Preparative SEC with fraction collection for deformulation and contamination analysis.

    We can provide GPC analysis using virtually any solvent system, including hexafluoroisopropanol (HFIP), which is the preferred GPC solvent for polyamides, polyesters, and nylons.  As stated by Jason Todd, one of our Chromatography Experts,  "The use of HFIP as a GPC solvent allows us to provide high quality molecular weight data on commercially important polymers. HFIP is advantageous because it allows the GPC analysis to be performed at room temperature. Other solvents for these plastic materials typically require high temperatures for solubility. Higher temperatures increase the risk of sample degradation during analysis. HFIP also provides higher quality GPC results compared to the high temperature solvents."

  • Sample Considerations

    Samples submitted for GPC/SEC testing must be soluable in an organic solvent or in water. 

    The minimum sample size for GPC Analysis is 20 mg.

    Contact us to talk through your specific sample considerations and analysis needs.

  • Experience

    Examples of our experience with SEC Analysis/GPC Analysis include:

    • Size Exclusion Chromatography in Hexafluoroisopropanol for engineering polymers (GPC in HFIP)
    • Determining the change in molecular weight due to processing conditions, sterlization conditions, or after synthesis
    • Failure Analysis Testing
    • Analysis of implantable medical devices
    • Analysis of packaging materials, to include medical packaging materials