The Magic here is not a "random lucky strike". It is PSS ability to design stationary phases that cover the full range of polarity, inherently, thus preventing interactions between polymer and stationary phases during a SEC analysis.
The PSS Magic Triangle is a visual aid for the quick selection of analysis matrix, where the three sides represent sample, mobile phase, and stationary phase. By applying the principle of "like dissolves alike" you will ensure interaction free GPC/SEC chromatography. Generally, the sample polarity mandates the polarity of the solvent and consequently that of the stationary phase and calibration standard.
*click for higher resolutionConstruct a triangle by drawing a base line from the polarity of a sample to the mobile phase, draw a perpendicular from the middle of the segment and the Magic Triangle will form pointing to the appropriate stationary phase.
This concept is also applicable for aqueous GPC/SEC. The magic triangle for aqueous systems takes the pH value instead of the stationary phase into account.
The tool also works to decide what kind of calibration standard will work better under given conditions, or what pH will work best with a given column.
Additional Column Selection Considerations:
|
1- Field of Application |
Column Choice |
|
Product screening at
constant peak resolution |
Analytical mixed bed (linear) columns |
|
Highest resolution
and maximum information Use the column combinations recommended by PSS to avoid column mismatch. |
Multiple analytical
single porosity columns (combination) comparison linear vs. column combination |
|
Very fast results
needed in process control and high throughput screening |
HighSpeed columns |
|
Solvent saving, small sample amounts |
Microbore columns |
|
Preparative sample fractionation, sample collection |
Preparative columns |
|
GPC/SEC-light scattering or Triple detection |
Lux columns |
| Aqueous |
Suprema SupremaLux Proteema Novema MCX |
| Organic |
SDV SDVLux GRAM POLEFIN POLEFINLux |
| 2- Column Particle Size |
from 3 μm up to 20 μm |
| Higher
solvent viscosity |
Higher particle size |
| High Sample Molar Masses | Higher particle sizes. |
3- Column Porosity |
30 Å to 10 000 Å |
| To separate low molecular weight products | use small porosities. |
| higher molecular weight | higher porosity |
Single porosity columns
show a high resolution in a narrow molecular
weight range. A wide molecular weight range at constant high resolution
is covered when columns with single porosities are coupled in series
(column combination).
Examples for single porosity columns:
* SDV 1 000 Å, separation range: 100 - 60 000
Da
* GRAM 3 000 Å, separation range: 5 000 - 5
000 000 Da
* SUPREMA 1 000 Å, separation range: 100 - 1
000 000 Da
Examples for recommended column combinations (series of single
porosity
columns):
* SDV 100 Å + 1 000 Å + 10 000Å +
precolumn (low molar masses)
* GRAM 30 Å + 1 000 Å + 1 000Å +
precolumn (medium molar masses)
* SUPREMA 100 Å + 3 000 Å + 3 000Å
+ precolumn (high molar masses)
Linear or mixed bed columns provide a very wide porosity range
therefore offering a broad separation range with a smaller resolution.
Examples for linear columns:
* SDV linear M separation range: 100 - 1 000 000 Da
* GRAM linear, separation range: 500 - 1 000 000 Da
* SUPREMA linear XL, separation range: 1 000 - 4 000
000 Da
In all cases use precolumns for the protection of the main columns.
PSS offers a wide variety of column dimensions and will manufacture custom sizes upon request.
Type I.D x Length (mm)
Guard columns 8 x 50; 4,6 x 30; 20 x 50
Analytical 8 x 300 and 8 x 600
Microbore 4,6 x 250
Preparative 20 x 600
HighSpeed 20 x 50
Analytical, High Speed and guard Columns may be purchased online. Email us or request a quote for analytical columns (8x600), Microbore and Preparative columns.
Browse our entire selection of columns here.
