TECHNOLOGY Polypure utilizes a patent protected purification technology as a means to prepare high purity polymer products. This technology is accompanied by common organic synthesis methods to produce PEG compounds for a variety of applications. In order to maintain a consistent quality, product characterization and quality control are performed on a regular basis by analytical HPLC and mass spectrometry. Sample Displacement ChromatographyLiquid chromatography separation is used in industrial processes, and is a high cost operation. The process takes advantage of the difference in elution behaviour for sample components that are solubilized in a mobile (liquid) phase, when the solution is passed through a stationary (solid) phase. The stationary phase is usually packed in a column, and the liquid flow is generated by one or more pumps. Due to the need for high resolution, small particles are used and high pressure is generated. For this reason, equipment and devices are costly, especially for large scale operations.
The purification technology employed by Polypure is based on a more efficient technique, Sample Displacement Chromatography (SDC). The technique optimizes the competition effects between sample components when the concentrated sample solutions are introduced at the top of a series of columns at conditions that is optimized for binding. Strong binding species take possession of the first binding positions in the columns, thus forcing weaker binders to follow the liquid flow to the next vacant positions. This continuous sorting process proceeds until all components have found a binding site, or have been washed out of the column. At this point, the sample components are located in different parts of the column system, and can be extracted separately. The SDC technique has many advantages compared to more conservative chromatographic methods, and results in more cost–effective separation processes. The stationary phase has often a large contribution to overall cost, but is utilized in SDC to the full extent. Sample loading is commonly 50-100 gram of material per litre of column. Additionally, the sample solutions are favourably highly concentrated. We usually operate with 10-20% solutions. For most separation mechanisms, aqueous solutions are preferred for separation. The choice of extracting solvent can be made by criteria such as cost, safety and stability. This allows us to use inexpensive solvents, like methanol for reversed phase applications. It also results in a high concentration of recovered product, typically 50-200 gram/litre solvent.
The method is used for fractionation of polydisperse PEG into the individual components. The purified PEG oligomers can be further modified in a controlled manner by chemical means. Reaction procedures are established to introduce functional groups to obtain value enriched products. 
The reaction and isolation processes are monitored by high resolution analysis to secure the product quality. Additionally, products and intermediates are purified by the SDC technology to ensure consistently pure compounds. The use of monodisperse polymers and integrated purification technology results in exceptionally high performance products.
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