foundation gpc part 4 – organic gel permeation chromatography columns and applications
DESCRIPTION
Foundation GPC Part 4 – Organic Gel Permeation Chromatography Columns and Applications. Introduction. There are a wide variety of columns available for organic GPC This presentation shall introduce the most common types of column This information can act as a reference - PowerPoint PPT PresentationTRANSCRIPT
Foundation GPC Part 4 – Organic Gel Permeation Chromatography
Columns and Applications
2
Introduction
There are a wide variety of columns available for organic 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 two main ranges of GPC column for organic solvents
The properties of each range that must be considered when selecting them for an application shall be presented
4
Organic GPC
The vast majority of commercially important polymers are only soluble in organic solvents such as tetraydrofuran, toluene or trichlorobenzene
For these applications a column packed with material compatible with these solvents must be chosen
Almost universally columns packed with insoluble porous beads of polystyrene cross-linked with divinyl benzene are used (PS/DVB)
The majority of manufactures use columns of this type
5
Styrene/Divinyl Benzene Columns - PLgel
6
PLgel solvent Compatibility
Columns can be used in a wide range of solvents
Transfer between solvents is possible assuming care is taken
The column user guide details the procedure
7
Adsorption of Polystyrene Standards in DMF
Column : PLgel 5um 500Å 300x7.5mm
PS/DVB columns are excellent in many solvents, but remember that although the column may be used in certain solvents this does not mean SEC will occur - the example here is polystyrene standards running in DMF
8
PLgel Column Range
The extensive range of products has variation in pore size, particle size and column dimensions
The packing materials are identical in terms of surface chemistry
9
10
Low Molecular Weight High Resolution Separations
Individual pore size columns are ideal for these applications
11
Applications in Standard GPC Solvents
With no danger of shear degradation, 3um particles can be employed
Extremely high efficiency separations are obtained but only if the dispersion in the system is kept low
12
Combination of Individual Pore Size Columns
Traditional approach to increasing MW operating range of column set
13
PLgel MIXED Bed columns
14
Individual Pore Size or MIXED Gel Columns?
PLgel 5µm 10E4Å
Optimum resolution over limited MW range
PLgel 5µm MIXED-D
Equal resolution over wider range of MW
Both types still have the similar pore volume, just the MW range over which it is available that changes
15
Individual Pore Size Combination Versus MIXED Gel Columns - Calibration Data
16
Individual Pore Size Combination Versus MIXED Gel Columns - Polydisperse Sample
Eluent THF
Flow rate 1.0 ml/min
Detector UV 254nm
17
PLgel MIXED Bed Calibrations
18
PLgel MIXED Bed Application Guide
19
Applications on MIXED Bed Columns
These samples are complex with polymer and oligomer components
MIXED columns with a wide resolving range are ideal in these cases
20
High Polarity Separations on PLgel
PLgel can be used with very polar solvents
Many samples can be analysed under these conditions
21
High Temperature Applications on PLgel
PLgel is very stable to high temperatures
The same material is used as for low temperature separations
22
Extreme GPC
In the most extreme case very high temperatures are required
The same PLgel material is employed even under these conditions
23
Unusual Peak Shapes in GPC
Not all peaks are Gaussian
Multimodal peaks are common in complex polymers
The presence of oligomers leads to complex chromatograms
24
Analysis of Multi-Component Systems
Interpreting the complex distributions of some samples can be challenging
Understanding the chemistry used to make the material is a definite help
25
Troublesome Applications on PLgel
Some applications are at the border of what is possible on PLgel columns
It may be that in these cases alternative packing materials will be required
26
PLgel LS Columns
27
28
PS/DVB miniMIX Columns
29
miniMIX Solvent Consumpsion
30
Applications with miniMIX Columns
Under the right conditions miniMIX columns perform just as well as their analytical counterparts
31
PS/DVB Preparative Columns
32
Comparative Preparative Separations
Preparative columns give identical chromatography to analytical columns under the right conditions Method development can be performed on the analytical columns, reducing the risk of damage to expensive preparative coluns
33
PlusPore PS/DVB Columns
34
PlusPore Calibrations
35
Advantages of the PlusPore Range
With individual pore size columns dislocations are fairly common
The PlusPore range contains only one type of packing material with a wide resolving range
Dislocations cannot occur on this type of column
36
Columns 2xPLgel 3µm 100Å 300x7.5mm 2xOligoPore 300x7.5mm
Eluent THFFlow rate 1.0ml/min
Effect of Increased Pore Volume
Both columns have a similar exclusion limit but OligoPore has greater pore volume than PLgel 100Å. Hence the slope of the curve is shallower leading to greater resolution for columns of the same efficiency
37
Applications in with PlusPore Columns
The extended pore volume of the PlusPore range leads to very high resolution
38
High Resolution OligoPore Separations
The OligoPore column if filled with 6um packing material, but due to a very large pore volume it gives resolution similar to a 3um PLgel
As a result of the larger particle size, OligoPore is very resilient to extra-column dispersion