LCGC Europe-08-01-2018

LCGC Europe

Vol 31 No 8 LCGC Europe August 2018 Regular Issue PDF

August 01, 2018

LCGC Europe August 2018 Regular Issue PDF

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Click the title above to open the LCGC Europe July 2018 regular issue in an interactive PDF format.

The Vital Role of Blanks in Sample Preparation

August 01, 2018

Sample Preparation Perspectives

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Too often, analysts follow prescribed methods, including the processing of “blanks”, without fully understanding the rationale behind the various steps. This month we’ll look at the types of blanks used in an analytical procedure and why they are used. We will focus on those defined by U.S. regulatory agencies.

Advantages of Supported Liquid Extraction

August 01, 2018

The Essentials

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In this excerpt from LCGC Europe’s e-learning platform, CHROMacademy.com, the advantages of supported liquid extraction (SLE) are discussed.

Analyzing Thermoreversible Bonding and Debonding in Macromolecular Systems by Temperature-Dependent Size-Exclusion Chromatography

August 01, 2018

Features

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The potential of TD SEC for in situ analyses of thermoreversibly bonded polymers is discussed. TD SEC allows the evolution of the polymer’s molar mass distribution to be monitored during temperature-sensitive bonding and debonding reactions. Through quantitative evaluation of the chromatograms, the reaction-influencing parameters can be studied, which is crucial for the effective development of novel functional materials. By using TD SEC, the effect of polymer size and flexibility on the debonding temperatures of DA polymers was confirmed, their debonding and bonding ability studied, and the de-crosslinking of thermoreversibly cross-linked DA polymers assessed. TD SEC offers a versatile platform for a broad variety of different polymer materials and to assess a variety of different analytical questions.

Pressure Tuning: Increasing the Flexibility of Comprehensive Two-Dimensional Gas Chromatography

August 01, 2018

Features

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Comprehensive two-dimensional gas chromatography (GC×GC) offers significant improvement for volatile chemical separation. Selecting suitable first (1D) and second dimension (2D) columns normally requires consideration of the chemical composition of a sample. Replacing one of these dimensions with a two-column ensemble (for example, 1D1 + 1D2 for the 1D column), provided with a pressure tuning makeup gas between them, varies the relative retentions of compounds before the modulation step according to the junction pressure. This makes it possible to alter the apparent polarity of the 1D ensemble, and this alters peak positions in the 2D GC×GC space. This article presents an account of studies that suggest this offers potential for improved operation for a GC×GC laboratory.