UV Detection for the Viscotek GPC/SEC systems

As well as an alternative concentration detector, a UV detector is an excellent tool for the compositional analysis of co-polymers or protein conjugates.

There are two UV options for Viscotek GPC/SEC systems:

The first is a programmable UV detector that allows the monitoring of a single wavelength during the experiment.

The OmniSEC software collects the RI and UV signals and processes them together to establish the RI/UV ratio across the chromatographic peaks. This allows calculation of the % composition of two components in the sample with respect to the molecular weight – for example, styrene/butadiene or protein/PEG. The software can then also calculate the correct dn/dc value at each retention volume allowing accurate molecular weight measurement by light scattering.

The second option is to add a photodiode array (PDA) detector.  A PDA measures the absorbance of the UV light at all wavelengths simultaneously.  The addition of a PDA detector allows the mapping of the molecular weight to the full UV spectrum and opens a new window on the compositional variation of the macromolecules under investigation.

The OmniSEC software records the spectrum and can display a 3D plot of the absorption vs wavelength vs elution volume for easy chemical identification. The software can also display the absorption vs wavelength vs molecular weight, a useful feature when two different kinds of macromolecules are conjugated. Finally the wavelength can be chosen post acquisition for convenient composition measurements and calculations.

More information

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