Developments in the Preparation of Organic Polymer Monoliths for the Separation of Small Molecules - - Chromatography Online
Developments in the Preparation of Organic Polymer Monoliths for the Separation of Small Molecules


LCGC Europe
Volume 27, Issue 6, pp. 284-295

Organic polymer monoliths are mainly used to separate macromolecules in gradient elution liquid chromatography (LC) because of their favourable porous structure. The main reason for the poor behaviour of organic polymer monoliths when separating small molecules isocratically was attributed to the lack of small pores with a stagnant mobile phase, and the resulting low surface area. Recent efforts have improved the separation power of organic polymer monoliths for small molecules, offering column efficiencies up to 50,000–80,000 plates/m. This review describes recent developments in the preparation of organic polymer monoliths suitable for the separation of small molecules in the isocratic mode, and discusses the main factors affecting the column efficiency.


Photo Credit: Günay Mutlu/Getty Images
It has been over 20 years since Hjertén published a paper describing the development and application of a "continuous polymer bed" (1). The "macroporous polymers membranes" described by Svec and Tennikova (2) followed and "continuous rods" were later introduced by Svec and Fréchet (3). These continuous materials initiated extensive research of the novel types of stationary phases that consisted of one piece of porous material filling a whole volume of a cylindrical column, later named "monolithic stationary phases" (4). Since then, monolithic stationary phases have been established as useful members of a family of stationary phases with inorganic silica-based (5) and organic polymer-based matrices (6–8).

The morphology of monolithic materials with an interconnected network of micrometre-sized flow-through pores enables high flow of the mobile phase at moderate back-pressures and fast separations. Silica-based monoliths are suitable for the separation of small molecules (5,9) while polymer monoliths have been successfully used for fast gradient separations of synthetic and natural polymers (10). The high temperature and chemical stability of organic polymer monoliths in the separation of low molecular compounds triggered significant efforts in tailored preparations of polymer-based, highly efficient monolithic stationary phases suitable for fast and efficient analysis of low molecular compounds. This topic has been recently reviewed by Svec (11) and Nischang (12).




This article attempts to summarize current progress in the preparation of organic polymer monoliths suitable for the separation of small molecules. Numerous protocols including adjusting the polymerization mixture composition, controlling the polymerization time and temperature, and post-polymerization surface modifications are discussed.


ADVERTISEMENT

blog comments powered by Disqus
LCGC E-mail Newsletters
Global E-newsletters subscribe here:




 

LCGC COLUMNISTS 2014

Column Watch | Ronald E. Majors: Ron Majors, established authority on new column technologies, keeps readers up-to-date with new sample preparation trends in all branches of chromatography and reviews developments. LATEST: Standardized Testing of Silica as a Base Material for Difficult Bonded-Phase Preparative Applications


Perspectives in Modern HPLC: Michael W. Dong is a senior scientist in Small Molecule Drug Discovery at Genentech in South San Francisco, California. He is responsible for new technologies, automation, and supporting late-stage research projects in small molecule analytical chemistry and QC of small molecule pharmaceutical sciences. LATEST: Seven Common Faux Pas in Modern HPLC


MS — The Practical Art: Kate Yu brings her expertise in the field of mass spectrometry and hyphenated techniques to the pages of LCGC. In this column she examines the mass spectrometric side of coupled liquid and gas-phase systems. Troubleshooting-style articles provide readers with invaluable advice for getting the most from their mass spectrometers. LATEST: Radical Mass Spectrometry as a New Frontier for Bioanalysis


LC Troubleshooting: LC Troubleshooting sets about making HPLC methods easier to master. By covering the basics of liquid chromatography separations and instrumentation, John Dolan is able to highlight common problems and provide remedies for them. LATEST: How Much Retention Time Variation Is Normal?


More LCGC Chromatography-Related Columnists>>

LCGC North America Editorial Advisory Board>>

LCGC Europe Editorial Advisory Board>>

LCGC Editorial Team Contacts>>


Source: LCGC Europe,
Click here