Preparative/Process Chromatography

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.

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).

A sample of PMMA was analysed by Size Exclusion Chromatography with Triple detection, before and after sterilization. Reduction in the molecular weight was shown to be firstly by cleaving the polymer at the branching points.

In this application note, a selection of proteins are separated using Size Exclusion Chromatograpghy (SEC). The molecular weights of their oligomers and aggregates are measured by SEC-MALS and the results discussed.

Triple detection GPC/SEC combines measurements from multiple detectors to offer not only increased amounts of data, but also increased amounts of information, which is made available by the combination of different detectors (and unobtainable using individual detectors separately). The theory of triple detection GPC/SEC is described here.

This application note describes the analyses of a variety of aqueous (water-soluble) cellulose derivatives using the OMNISEC triple detection system and the subtle, yet distinct differences between these different derivatives that can be parsed out by the OMNISEC system

In this application note, molecular weight data from the Viscotek SEC-MALS 20 is combined with measurements of Rg and IV to study the structure of different polysaccharides including pullulan, dextran, hydroxypropyl cellulose (HPC), pectin and gum Arabic. The differences between conformation and Mark-Houwink plots are also studied.

The investigative power of multiple detectors. Here, we describe the analysis of a semi-purified protein mixture containing β-amylase. Step-by-step, we show how different properties of the proteins elicit a specific response in each detector and how coupling this data can be qualitatively and quantitatively evaluated.

Sulaf Assi is a lecturer in forensic sciences at the Faculty of Science and Technology at Bournemouth University, UK.

Hyphenated chromatography techniques enable the selection of representative biomarkers of oxidative stress – and help resolve the huge complexity of lipid oxidation products.