Wolfgang Radke

Articles

Gel permeation chromatography/size-exclusion chromatography (GPC/SEC) columns are filled with porous particles differing in particle and pore sizes. Typical particle sizes in analytical GPC/SEC range from sub-2-µm particles applied in oligomer and protein separations to approximately 20 µm for separations of ultrahigh molar mass macromolecules (1,2). While the effect of combining columns of different pore sizes has previously been discussed in GPC/SEC Tips & Tricks (3,4), the effect of combining columns of different particle sizes has not been addressed before. 

Tips & Tricks GPC/SEC  Particle Size and the Effect of Mixing Columns of Different Particle Size

While gel permeation chromatography/size-exclusion chromatography (GPC/SEC) of uncharged molecules in organic eluents in most cases is a straightforward task, aqueous GPC/SEC of polyelectrolytes usually requires more parameters to be considered and optimized. This instalment of Tips & Tricks explains more.

Tips & Tricks: Aqueous GPC/SEC: Influence of Salt and pH

The intensity of the light scattering signal depends on concentration, molar mass, and the specific refractive index increment, dn/dc, of the sample. dn/dc therefore usually needs to be known to derive molar masses by gel permeation chromatography/size-exclusion chromatography-light scattering (GPC/SEC-LS). How to overcome the issue of unknown refractive index increments is outlined in this instalment of Tips & Tricks. In particular, a new approach to derive molar masses by GPC/SEC-LS that requires only the molar mass of a reference material, and not the dn/dc of the sample or of the reference material, is introduced.

Tips & Tricks: New and Old Approaches to Handle Unknown dn/dc in GPC/SEC-LS

Combinations of detectors are often used in gel permeation chromatography/size-exclusion chromatography (GPC/SEC) to measure absolute molar masses or chemical compositions as a function of elution volume. Such multidetector setups require the correction of the delay volume between the detectors for correct data processing. This instalment of Tips & Tricks explains more.

Author | Wolfgang Radke