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Chromatography

Gel Permeation / Size Exclusion Chromatography (GPC/SEC) is an analytical technique used to characterize the molecular weight of polymers.

Gel permeation chromatography (GPC), also known as size exclusion chromatography (SEC), is one method which characterizes a polymer.  This method specifically measures the average molecular weight and molecular weight distribution of polymer samples (Mw, Mn, Mz, and PDI). Depending on the type of detector utilized, absolute and/or relative molecular weight measurements can be obtained.

Project Guidance from Polymer Experts

As leading provider of polymer testing, SGS Polymer Solutions offers a comprehensive suite of chromatography services. Our ISO accredited chromatography laboratory is equipped with world-leading instrumentation and employs an elite mix of scientists and engineers. From your first point of contact and for the duration of your project, you’ll be supported by Polymer Experts. You can be sure your testing experience is seamless and your individual project requirements met precisely.

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: 

Detectors

  • Measurement of absolute molecular weights using multi-angle light scattering (MALS)
  • Relative molecular weight measurements using refractive index (RI) or UV/Vis absorbance detectors

Mobile Phases

  • Organic solvents like THF, DMF, DMAc, THF, Chloroform, and others
  • Aqueous solutions that are pH buffered
  • High temperature trichlorobenzene TCB for analysis of olefins such as LDPE, LLDPE, HDPE, UHMWPE, PP, and copolymers
  • High-temperature chloronaphthalene for polyphenylene sulfide (PPS)
  • Hexafluoroisopropanol for nylons, polyesters, and high glycolide content PLGA

“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.”

Jason Todd, M.Sc.
Principal Scientist, SGS Polymer Solutions

Experience

  • Determining molecular weight changes due to processing conditions as a result of:
    • Extrusion 
    • Injection molding 
    • Sterilization of medical devices
    • Controlled aging of medical devices 
  • Quality control for lot release testing 
  • Confirmation of molecular weight after synthesis
  • Failure Analysis of polyesters and nylons
  • Analysis of Implantable medical devices
  • Analysis of packaging materials
  • Analysis of chitosan and cellulose
  • Analysis of heparin by USP

Instrument and Sample Considerations

At SGS Polymer Solutions we offer GPC analysis using virtually any solvent system, including hexafluoroisopropanol HFIP.  We can also derivatize polymers like polyether ether ketone PEEK to make them soluble for GPC analysis. Samples submitted for GPC testing must be soluble in an organic solvent or in water. The minimum sample size for GPC Analysis is 20 mg but often request a few hundred mg for ease of sample preparation. 

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