Foundation GPC Part 5 – Polar and Aqueous Gel Permeation

Chromatography Columns and Applications

2

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!

3

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

4

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

5

PL Aquagel-OH Columns

6

7

Typical Calibrants

Polyethylene glycol and oxide standards are chemically identical except for the end group

These are common polymer standards for aqueous GPC

8

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

9

Biopolymers Analysis

A thickening agent found in foodstuffs

The MIXED bed column is most suitable to this kind of broad polydispersity sample

10

A blood thickening agent, heparin is fairly low in molecular weight

For these types of samples the individual pore size columns are most suited

11

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

12

13

Analysis of Hydrophobic Polymers

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

14

Analysis of Cationic Polymers

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

15

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

16

PolarGel Columns

17

PolarGel Columns

18

PolarGel-M Calibrations

19

Peak Shapes of Polar Compounds

20

Analysis of Polar Samples

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

21

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