Sample Preparation

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This whitepaper reviews the methods available for measuring the key characteristics of polymers focusing on the benefits and value of gel permeation / size exclusion chromatography (GPC/SEC). Much of the paper talks exclusively about polymers, however many of the principles discussed are equally applicable to proteins or protein conjugate materials.

Traditionally in GPC, the sample dissolution solvent and the mobile phase are one and the same. However, a closer look at the demands of sample solvent and mobile phase suggests that this should not always be the case.

The complementarities of two techniques, dynamic light scattering (DLS) and static light scattering detector coupled with a size exclusion chromatography system (SEC-LS), are illustrated by studying a number of samples where a thermally denatured and aggregated protein sample were dosed at different levels into a non-denatured protein sample.

In this application note, intrinsic viscosity measurements were performed on the sRAGE protein to establish whether the detector was able to detect and characterize the conformational change induced by the presence of calcium. Light scattering molecular weight measurements were also performed. Data are also presented showing that the conformation of sRAGE changes in the presence and absence of calcium.

A new instrument could help with obtaining pure components from complex natural samples.

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.

This article explores the role of different components within drilling muds, including barite and calcium carbonate. The need to achieve optimum particle sizes is examined, the application of laser diffraction is considered within this context. Fast, efficient and having a wide measurement range, laser diffraction delivers accurate, precise and reproducible particle size information. Offering automated analysis, it is a preferred method for drilling mud particle sizing and the focus of ongoing API efforts to develop a standard in this area.

The newest addition to the popular ‘10 ways to…’ series of educational papers provides practical guidance on developing high performance suspension products with enhanced consumer appeal. ‘10 ways to...control rheology by changing particle properties’ explores how controlling particle characteristics, such as particle size distribution, concentration and zeta potential, enables formulators to engineer suspension performance. Suspensions are used in the formulation of a wide range of every day products from medicines, drinks and foodstuffs to paints, inks and coatings. This paper is therefore valuable to formulators working across a wide range of industries.

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.