Foundation GPC Part 4 Organic Gel Permeation Chromatography

Foundation GPC Part 4 – Organic Gel Permeation Chromatography Columns and Applications

Introduction § There 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 application is not shown here, we’ve probably done it! 2 if your

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 3

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 4

Styrene/Divinyl Benzene Columns - PLgel 5

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 6

Adsorption of Polystyrene Standards in DMF 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 Column : 500Å 7 PLgel 5 um 300 x 7. 5 mm

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 8

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Low Molecular Weight High Resolution Separations § Individual pore size columns are ideal for these applications 10

Applications in Standard GPC Solvents § With no danger of shear degradation, 3 um particles can be employed § Extremely high efficiency separations are obtained but only if the dispersion in the system is kept low 11

Combination of Individual Pore Size Columns Traditional approach to increasing operating range of column set 12 MW

PLgel MIXED Bed columns 13

Individual Pore Size or MIXED Gel Columns? PLgel 5µm 10 E 4Å Optimum resolution limited MW range over Both types still have the similar pore volume, just the MW range over which it is available that changes PLgel 5µm MIXED-D Equal resolution over wider range of MW 14

Individual Pore Size Combination Versus MIXED Gel Columns - Calibration Data 15

Individual Pore Size Combination Versus MIXED Gel Columns - Polydisperse Sample Eluent Flow rate Detector 16 THF 1. 0 ml/min UV 254 nm

PLgel MIXED Bed Calibrations 17

PLgel MIXED Bed Application Guide 18

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 19

High Polarity Separations on PLgel § PLgel can be used with very polar solvents § Many samples can be analysed under these conditions 20

High Temperature Applications on PLgel § PLgel is very stable to high temperatures § The same material is used as for low separations 21 temperature

Extreme GPC § In the most extreme case very high temperatures are required § The same PLgel material is employed even under these conditions 22

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 23

Analysis of Multi-Component Systems § Interpreting the complex distributions of samples can challenging § some be Understanding the chemistry used to make the material is a definite help 24

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 25

PLgel LS Columns 26

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PS/DVB mini. MIX Columns 28

mini. MIX Solvent Consumpsion 29

Applications with mini. MIX Columns § Under the right conditions mini. MIX columns perform just as well as their analytical counterparts 30

PS/DVB Preparative Columns 31

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 32

Plus. Pore PS/DVB Columns 33

Plus. Pore Calibrations 34

Advantages of the Plus. Pore Range § With individual pore size columns dislocations are fairly common § The Plus. Pore range contains only one type of packing material with a wide resolving range § Dislocations cannot occur on this type of column 35

Effect of Increased Pore Volume Columns Eluent Flow rate 36 2 x. PLgel 3µm 100Å 300 x 7. 5 mm 2 x. Oligo. Pore 300 x 7. 5 mm THF 1. 0 ml/min Both columns have a similar exclusion limit but Oligo. Pore 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

Applications in with Plus. Pore Columns § The extended pore volume of the Plus. Pore range leads to very high resolution 37

High Resolution Oligo. Pore Separations § The Oligo. Pore column if filled with 6 um packing material, but due to a very large pore volume it gives resolution similar to a 3 um PLgel § As a result of the larger particle size, Oligo. Pore is very resilient to extra-column dispersion 38