Application Notes: Polymers

SCM-4 - The 4th International Symposium on the Separation and Characterization of Natural and Synthetic Macromolecules

Hypercrosslinked polystyrene-type (solid-phase extraction) SPE materials exhibit a unique ability to enter p-interactions with aromatic, heterocyclic and unsaturated compounds. This property permits selective extraction and pre-concentration of the above classes of species from non-polar media and fatty matrices. The principle has been exploited for developing analytical protocols to determine polar furan derivatives in mineral transformer oil, polyaromatic hydrocarbons (PAHs) in smoked fish and for the fractionation of polychlorinated aromatic compounds in environmental matrices.

Guest Editor Peter Schoenmakers provides an introduction to LCxLC, and then goes on to talk about peak capacity, sample dimensionality, phase orthogonality, and some of the successes of the technique and the obstacles yet to be overcome.

Polymer Laboratories, now a part of Varian, Inc. has published an application note on Overcoming Compound Volatility with Sub-ambient ELSD. Sub-ambient evaporative light scattering detection is valuable in the analysis of semi-volatile compounds. The Varian 385-LC has been specifically developed to operate at sub-ambient evaporation temperatures, using a Peltier cooled evaporation tube. This application note shows that sub-ambient ELSD at 20 ?C, as delivered by the new Varian 385-LC, increases the accuracy of measurement by minimizing compound volatility effects.

The pyrolysis fragments are first refocused on the top of the GC column, then separated and finally detected by the MS. At the end of the GC run the SEC flow is resumed again and the entire process is repeated.

This report shows the steps involved in the development of a new polymethyl methacrylate (PMMA) calibration standard for polar organic GPC applications.

In this instalment of "Sample Preparation Perspectives", columnist Ron Majors discusses advanced topics such as multimodal SPE, restricted-access media, molecular imprinted polymers, immunoaffinity extraction phases and other class-or compound-specific sorbents...

Molecularly imprinted polymers (MIPs) are synthetic polymeric materials that mimic immunosorbents. They are widely used as sorbents for solid-phase extraction (SPE). The most common way to synthesize them is bulk polymerization because of its simplicity and versatility. This produces a hard monolith that has to be ground and sieved to obtain particles in the desired size range. However, the partial loss of the materials as fine dusts; the irregular shape of the particles produced and their wide size distribution, have led to a search for different polymerization methods to offset the drawbacks of the bulk polymerization process.

MIP Technologies has signed an exclusive global distribution agreement with Supelco, a division of Sigma-Aldrich. The agreement is for the distribution of analytical and preparative molecularly imprinted polymer (MIP) separation products.

Highly selective sorbents for solid-phase extraction (SPE) are desirable tools for the development of selective and sensitive methods for trace analysis. Molecular imprinting is an emerging technique that can yield analyte- or group-selective polymeric sorbents.