Article

Asymmetrical Flow Field Flow Fractionation for the Investigation of Interactions of Intermolecular Multifunctional Polymers
Albena Lederer and Susanne Boye
Asymmetric flow field flow fractionation (AF4) has the potential to characterize the interactions in multifunctional polymers, such as complexation and aggregation. This article describes the merits of AF4 coupled to light scattering and UV detectors to characterize drug delivery systems. The results are supported with dynamic light scattering, AFM and ultra-filtration techniques. The analytes investigated are dendritic polymers, which are three-dimensional nanostructures with a high number of peripheral groups.

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LC Troubleshooting
Troubleshooting Basics, Part III: Retention Problems
John W. Dolan
What causes peaks to appear where they don't belong?

Sample Preparation Perspectives
Hollow Fiber Liquid-Phase Microextraction in the 3-Phase Mode (HF³LPME) – How to Make it
Ron Majors, Astrid Gjelstad, Hamidreza Taherkhani1, Knut Einar Rasmussen, and Stig Pedersen-Bjergaard
This article describes practical aspects of hollow fiber liquid-phase microextraction in the 3-phase mode (HF³LPME). We highlight important practical issues related to the supported liquid membrane (SLM), the hollow fibre, and the extraction itself, as these issues are important for successful HF³LPME. We also discuss practical work with electromembrane extraction (EME), which is related to the HF³LPME device, but uses an electrical potential as the driving force for the extraction.

Practical Data Handling
Variable Selection and Reduction in Multivariate Calibration and Modelling in The Pharmaceutical Industry
Yvan Vander Heyden, Jan Andries and Mohammad Goodarzi
Multivariate calibration and modelling are often used in the pharmaceutical industry to build predictive models. Many different modeling techniques can be used. However, each of these techniques usually requires either a variable selection step to limit the number of variables to build the model, or create so-called latent variables to build the simple models. Many variable selection methods have been applied. An overview of these will be discussed In cases where latent variables are used, the models based on the entire data set usually are not as good as when first informationless variables are eliminated. In such cases different possibilities exist to reduce the number of variables used to calculate the latent variables.

The Nexera MP UHPLC Front End System for LCMS
Shimadzu’s Nexera MP UHPLC as a Front End system is perfect for LCMS analysis conducted in pharmacokinetics and synthesis stages in drug detection processes. The new SIL-30ACMP Multiplate Autosampler used in the Nexera MP is best suited for LC/MS analysis. It has the industry-best micro-volume injection repeatability, the world’s highest injection speed and the lowest carryover. Read more