Sample Preparation

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.

When it comes to microsampling for quantitative bioanalysis, the devil is certainly in the details. But we should learn from our mistakes – not retreat back into convention.

The Morphologi G3-ID enables simultaneous physical and chemical characterization of particle samples, enabling outlier particles to be identified as being part of a product formulation or genuine foreign particle contaminants.

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