Gas Chromatography

This article explores how multiple detectors, particularly light scattering detectors, may be used for size-exclusion chromatography (SEC) in protein analysis. Using a light scattering detector as part of a multi-detector Size Exclusion Chromatography system provides the accurate molecular weight (MW) data needed to assess the activity, safety and clinical efficacy of therapeutic proteins.

The latest advances in the widely used technique of size exclusion chromatography (SEC) break new ground in terms of accuracy and sensitivity. This article assesses the information provided by multi-detector SEC and the potential benefits of recent innovations for polymeric food additive characterization.

Detecting and controlling mutagenic impurities in pharmaceuticals is challenging. What is ICH M7 and what do you need in your analytical toolbox?

When disruptive technology comes along, it can be hard to defend the technique under attack for some applications – even if we have embraced it for decades.

In this application note, a mixture of four proteins was characterized in a single SEC measurement using multiple detectors. The generally consistent response to the RI to proteins makes it a useful total protein concentration detector, while the UV detector can be used to measure the concentration of individual proteins when the extinction coefficient is known. This is particularly useful for proteins that elute in the solvent peak making RI measurements unreliable. Finally, light scattering measurements allow each peak to be identified by its molecular weight.

The ideal solvent for a material may not provide a sufficient refractive index difference for light scattering detection. This example of a biodegradable polymer shows how SELS is used to increase dn/dc to give enhanced detection sensitivity

In this application note, a purified polyclonal antibody (IgG) is separated using Size Exclusion Chromatography (SEC) and characterized using the Viscotek SEC-MALS 20, allowing calculation of molecular weight and radius of gyration (Rg).

Then & Now, with Katie Banaszewski, Method Development Scientist III at Now Foods, Bloomingdale, Illinois, USA.

The story behind direct mass spectrometric detection of chiral molecules using MS-PECD – a winner of The Analytical Scientist Innovation Awards (TASIAs).

The proteome is practically infinite in its complexity. If we are ever going to fully unravel its secrets, the best separation tools – and the best know-how – must be combined. Here, four experts discuss the broad importance of proteomics, the potential of multidimensional liquid chromatography, and the challenges inherent in gaining insight beyond the “tip of the proteo-berg.”