About the instrument

The OMNISEC multi-detector GPC/SEC system is a Gel Permeation Chromatography (GPC) / Size Exclusion Chromatography (SEC) system to accurately determine the molecular weights and concentrations of proteins. It can be used to analyze the purity of a sample, to determine the oligomeric state of proteins and protein complexes, and to quantify the different species present in a sample. Thus, it is a powerful tool for taking control of the performance, quality and value of your protein and other biomolecules.

The OMNISEC system available in our core facility combines analytical SEC with an integrated triple-detector (Refractive Index, Light Scattering and UV/VIS PDA). Moreover, the temperature-controlled column oven is equipped with different columns for high-resolution analysis of proteins and other biomolecules covering a broad fractionation range. 

We offer the following columns from Cytiva:

  • Superdex 30 Increase 10/300 GL (100-7000 Da)
  • Superdex 75 Increase 10/300 GL (3000-70 000 Da)
  • Superdex 200 Increase 10/300 GL (10 000-600 000 Da)
  • Superose 6 Increase 10/300 GL (5000-5000 000 Da)

How does it work?

Size-exclusion chromatography is a technique in which solute molecules are separated according to their hydrodynamic radius as they enter and exit the pores of a porous gel packing matrix in a column. The OMNISEC multi-detector GPC/SEC system is composed of a pump, a temperature controlled autosampler and a column oven. As the sample elutes, it is analyzed by three detectors in series. The refractive index (RI) detector determines the concentration of a sample by measuring the RI difference between a reference fluid and a sample fluid. The analysis is based on the deflection principle of refractometry where the deflection of a light beam is changed when the composition in the sample flow-cell changes in relation to the reference cell. The diode-array based UV/Vis spectrometer records the absorbance of a sample at any wavelength from 190­­­–900 nm. This might be very useful in discerning between analytes with dissimilar absorbance spectra. The light scattering detector combines a 90° Right-Angle Light Scattering (RALS) with a 7° Low-Angle Light Scattering (LALS). While the RALS detector provides high sensitivity for smaller molecules, the LALS detector is more accurate for larger molecules. By combining both detectors into a hybrid system, the signal-to-noise ratio can be maximized for accurate determination of the molecular weight of the molecules present in a sample.