Pellicular resins

New types of ion exchange resins have also been developed to meet the specific needs of high-performance liquid chromatography (HPLC) (Chapter 8). These include pellicular resins and microparticle packings (e.g. the Aminex-type resins produced by Bio-Rad). A review of the care, use and application of the various ion exchange packings available for HPLC is given in Ref. 19. 

Modern IEC. Improved stationary phases22 similar to those developed for the other types of LC have led to improved separations by IEC. The old resins described above were followed by pellicular resins that were much more efficient and incompressible but had lower capacities. As is the case in the other forms of LC, they have been largely replaced by small mi-croporous particles, silica and polymeric, that have the ionic groups directly on the particle or attached to a ligate or polymer on the particle surface. 

Ion exchange desalination - DESAL , SIROTHERM Membrane desalination - Reverse Osmosis, Electrodialysis Continuing fixed bed counterflow development Condensate polishing systems Ion Chromatography analysis, and Pellicular resins Polymeric adsorbents... 

For anion chromatography, a binary pellicular resin (Figure 10.5) is used in the separator column. The core of the resin... 

To achieve this increase in IC column efficiency, IE resins had to be developed that differed significantly from those of conventional resins. Table 4.18 taken from an earlier article compares the properties of conventional IE resins to those required for IC (98). A decrease in IE capacity by about two orders of magnitude permitted the use of eluents for IC whose concentrations are three orders of magnitude lower than those used in conventional IE analysis. Eluent concentrations in IC are routinely prepared at the millimolar level. The favorable IE properties were realized with the development of surface-agglomerated pellicular resins. Such a pellicular... 

HPLC chromatographs are relatively simple instruments composed of a hydraulic system, a column, a detector and a recorder. Many commercial instruments are available, and instruments can be readily built from components. For nucleotides, pellicular resins are usually used. This material consists of microglass beads coated with a thin layer of an anion exchange resin. The detector is a micro UV detector with a wavelength at 254 nm. 

Polymer ion exchange columns are packed with pellicular resins for anion or cation exchange applications. 

Pellicularized resins, i.e., glass beads coated with co(polystyrene-DVB), and functionalized (benzyl halides) glass or silica beads. The swelling of the support is independent of the solvent, and eliminates failure sequences, but the resin capacity is low... 

The formation of truncated sequences has been attributed to steric factors and alkylation of chain ends by residual chloromethyl groups. The most common situation, however, is one in which the growth of the peptide chain in some of the sites may stop prematurely due to the limiting size of the cavity in the polymer. To overcome this problem, low cross-linked resins with low functionalization have been employed. Truncated sequences do not pose a problem either, when pellicular resins are used. It is difficult to assign a proper explanation for the formation of failure sequences other than to propose a statistical failure of some amino acids being incorporated into certain peptide chains. The formation of failure sequences can only be minimized by choosing proper, i.e., different, sets of experimental conditions for coupling different amino acids. 

Townsend, R. R., Hardy, M. R., Hindsgaul, O., and Lee, Y. C., 1988, High performance anion-exchange chromatography of oligosaccharides using pellicular resins and pulsed amperometric detection. Anal. Biochem. 174 459-470. 

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