14 Simplifying Entangled Polymer Synthesis
University of Houston, USA, researchers have recently developed and verified a new route for synthesising superior forms of entangled or knotted polymers with pre-designed characteristics for use in applications such as drug delivery and smart coatings. Using a Viscotek 270max triple detector gel permeation chromatography (GPC) system from Malvern Instruments, the Houston team successfully confirmed the innovative synthesis of interlocking polymer rings (catenanes) by atom transfer radical polymerisation (ATRP) from templated initiators. By combining refractive index (RI), viscosity and light scattering detection, the 270max provides reliable molecular weight data and easy detection of the degree of synthesis throughout the method development, as well as verifying the character of final polymers imaged using atomic force microscopy (AFM).
“The Viscotek 270max is critical to verifying this new method of polymerisation,” explained Professor Rigoberto Advincula, Department of Chemistry, University of Houston. “These are high molecular weight polymers and ring closure is a thermodynamically difficult reaction that must be done under dilute conditions. Using the triple detection offered by 270 max, we were able to effectively characterise the molecular weight of our sample and detect the degree of ring closure versus the amount of non-closed polymer.” The University of Houston’s initial success implies that it will be possible to synthesise superior knotted polymers for applications in coatings, lubricants and surface modifiers, among others. In terms of polymer theory, Professor Advincula’s team also plans to make catenated and knotted block co-polymers. The project has been funded by the National Science Foundation (USA). A paper outlining the new method is being published in Chemical Communication from the Royal Society of Chemistry and is now available online.
The Viscotek 270max from Malvern Instruments is a complete, advanced, multidetector GPC/SEC system suitable for all macromolecular applications, particularly research. Circle no. 37
Expanded Chromatography and SPE Media Offerings Porex Corporation has enhanced its comprehensive line of POREX®
Chromatography and SPE Media solutions with versatile, high-performance porous materials and filters designed to endure the most
challenging chromatography applications. POREX Chromatography and SPE Media exemplify the critical design standards and precision moulding required for today’s technological products and can be used in a wide variety of demanding life science filtration, separation, extraction and purification applications including drug discovery, protein precipitation and dissolution. “Porex strives to create innovative solutions that solve the specific challenges of our healthcare and life science customers,” said William Midgette, President and CEO of Porex. “Porex scientists and engineers work hard to deliver industry-leading products such as our POREX Chromatography and SPE Media solutions that meet our customers’ needs and exceed their expectations.” As part of the Porex technical performance and certification program, POREX Chromatography and SPE Media products can be further optimised through use of a proprietary process to help eliminate potential methodology impurities from moulding, packaging and environmental issues.
Porex Chromatography and SPE Media products include: affinity filters and supports – used in pipette tips, 96 well plates, spin down and gravity flow centrifuge columns, affinity filters and supports are designed as a support in critical peptide, protein, and oligonucleotide purification and concentration procedures; dissolution filters – used in conjunction with pharmaceutical tablet and capsule products to help filter contaminates during the dissolution testing process; protein crash/ protein precipitation filters – used to remove precipitated protein during mixing and incubation without plugging, breakthrough, or acetonitrile and other organic solvent leakage, thus eliminating time-consuming centrifugation and transfer steps; and SPE frits and filters – used in SPE columns, cartridges, 48 and 96 well plates and pipette tips, our chromatography frits facilitate column flow through and allow for organic solvent filtration and high sensitivity analysis.
Circle no. 38 ADVERTORIAL New Hydrogen Generators
LNI Schmidlin SA has developed new hydrogen generators. The NM-Plus and PG-Plus are both of them maintenance free and have capabilities for cascading. They employ the newest membrane technology available and includes the exclusive no maintenance auto drying technology. The pure gas of the NM-Plus (99,9999%) is ideal for operation with gas analysers, as fuel gas for flame tools. All kind of carrier gas application, like GC and GC-MS (Mass Spectrometry), and as safe source of pure hydrogen in plasma chambers and other isolated environments.
Circle no. 40
Zero Air and Ultra Zero Air Stations
They includes a built-in compressor for to supply oil free and dry air. A catalytic oven removes the hydrocarbons down to 0.1 ppm and in addition a set of specific PSA filters to remove
the CO2, CO, HC, NOx, SO2 and O3 contaminants and moisture down to 0.1 ppm.
Typical flow rates are 6 l/min and 30 l/min. The uses of ZAS and UZAS reduce the operating costs significantly.
Circle no. 41
Whisper Nitrogen Generator
The Whisper nitrogen generator has been developed using the membrane technology to meet the specific requirements in terms of flow, purity and pressure in LC-MS applications. It can be also used for the evaporation of solvents in samples being analysed. The model exists in different flow rates, with or without internal compressor. A specific model called Whisper Hybrid has been specially designed for ABI LC-MS applications.
Circle no. 42 Circle no. 39
INTERNATIONAL LABMATE - JANUARY/FEBRUARY 2012
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