Size-exclusion chromatog. (SEC), more commonly referred to as gel permeation chromatog. (GPC), is frequently used to obtain detailed structural information of polymeric materials. Advanced detection capabilities offered by Viscotek provide absolute measurements for mol. weight and deliver detailed structural information such as hydrodynamic size, conformation and polymer branching. In response to Viscotek′s expanding customer base in the academic, bio-pharmaceutical, and industrial markets, a photo-diode array (PDA) detector has been introduced to the already capable tetra detection platform. The PDA allows for compositional anal. of polymer blends and copolymers. For semi-conducting polymers, the PDA detector correlates absorption shifts with mol. weight for the qual. anal. of exciton diffusion lengths and its inherent dependence on mol. weight Bio-pharmaceutical applications, including identifying protein conjugates and fluorescent labels and characterizing loading efficiencies for drug delivery vehicles, have been identified as an important niche for Viscotek′s PDA-GPC detector.