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A new photodiode array (PDA) detector for the TDAmax size exclusion chromatography system from Viscotek, a Malvern company, provides a powerful and flexible tool for the rapid analysis of a wide range of proteins and biopolymers. These include identifying protein conjugates and complexes, aggregation and stability and determining concentration ratios. Size exclusion chromatography (SEC), also known as gel permeation chromatography (GPC), has further applications in examining loading efficiencies for drug delivery platforms, correlating these with molecular weight or size.

The TDAmax is a comprehensive GPC/SEC system with an integrated triple or tetra detector array. By capturing absorption spectra across the UV-Vis wavelength range, the new PDA detector provides a fingerprint, the full absorption chromatogram, of each ‘time slice' of the sample as it elutes from the column. Measurement times are just 30 to 40 minutes, making the system highly productive.

UV detection is used routinely to identify protein and polymer species as they elute, and can differentiate between components when other detection methods cannot. However, a conventional system measures at a single wavelength. In contrast, the new PDA detector captures data across the range 190 to 500 nm, allowing users to select wavelengths of interest after the analysis has been carried out. Viscotek's powerful OmniSEC™ software package allows data to be displayed as information-rich 3-D images that simplify interpretation.

Gel Permeation Chromatography (GPC), also known as Size Exclusion Chromatography (SEC), is a chromatographic technique that employs specialized columns to separate natural and synthetic polymers, biopolymers and nanoparticles on the basis of size. When GPC/SEC is coupled with advanced detectors a range of additional parameters can be determined, including intrinsic viscosity, molecular size, and long chain branching.