Foundation GPC Part 5 – Polar and Aqueous Gel Permeation Chromatography Columns and Applications

Introduction There are a wide variety of columns available for polar and aqueous GPC This presentation shall introduce the most common types of column This information can act as a reference Applications on the various columns shall also be discussed We have performed many applications on our columns, so even if your application is not shown here, we’ve probably done it!

Column Types The factor that principally controls which type of column is selected for a GPC experiment is the solvent Many polymer dissolve in only very limited numbers of solvents The columns used must be compatible with the solvent of choice Most importantly, the size exclusion mechanism must be maintained Polymer Laboratories have one range of GPC column for aqueous solvents and one for any type of solvent The properties of each range that must be considered when selecting them for an application shall be presented

Aqueous GPC A growing number of polymers are water soluble Interest in recycling, renewable resources and biomedical applications has led to increased interest in this area There are lots of different chemistries of packing materials employed for aqueous GPC Different manufacturers use different column types Columns are available as individual or MIXED type and in a range of pore, particle and column dimensions, just like the organic GPC columns We shall also discuss a new packing material that can be used in organic and aqueous solvents

PL Aquagel-OH Columns

Typical Calibrants Polyethylene glycol and oxide standards are chemically identical except for the end group These are common polymer standards for aqueous GPC

For biological polymers such as starches and other polysaccharides, pullulans provide a more realistic result

Biopolymers Analysis A thickening agent found in foodstuffs The MIXED bed column is most suitable to this kind of broad polydispersity sample

A blood thickening agent, heparin is fairly low in molecular weight For these types of samples the individual pore size columns are most suited

High Molecular Weight Analysis High molecular weight samples are best analysed on individual pore size columns The large particle size reduces the potential for shear degradation

Analysis of Hydrophobic Polymers Hydrophobic samples will interact in pure water Methanol is added to the eluent to inhibit interactions

Analysis of Cationic Polymers Cationic polymers require reduced pH to run System imbalance peaks result from preparing the samples in a strong acid

Analysis of Hydrophobic, Anionic Polymers These standards are anionic and hydrophobic An increased pH and methanol are required for the analysis WWater soluble polymers with a UV chromophore

PolarGel Columns

PolarGel Columns

PolarGel-M Calibrations

Peak Shapes of Polar Compounds

Analysis of Polar Samples These materials can interact with PS/DVB columns The more polar surface of PolarGel is well suited to this application

Analysis in Unusual Solvents Acetone cannot be used for GPC with PS/DVB, the samples do not elute properly The more polar surface of the PolarGel column allows GPC to be performed