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Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 

Silica particles encapsulated poly(styrene-divinylbenzene) monolithic stationary phases for mu-high performance liquid chromatography.

In the paper we demonstrate a new approach for the preparation and application of continuous silica bed columns that involve encapsulation (entrapment) of functionalized silica microparticles, which can be used as packing material in micro high performance liquid chromatography (mu-HPLC) and capillary electrochromatography (CEC). Like traditional packed columns, these capillaries possess characterized silica particles that offer high phase ratio and narrow pore size distribution leading to high retention and separation efficiency, respectively. More importantly, immobilization of the microparticles stabilizes the separation bed and eliminates the need for retaining frits. The developed capillary columns were fabricated in exactly the same way as a packed capillary column (slurry packing) but with an additional entrapment step. This immobilization of the packed bed was achieved by in situ polymerization of styrene and divinylbenzene in presence of decanol as a porogen and azobisisobutyronitrile as thermal initiator. Silica particles with different particle sizes and pore sizes ranging from 60 to 4000A were studied. In addition different modified silica was used, including C-18 reversed phase, anion exchange and chiral stationary phases. Efficient separation of polyphenolic compounds, peptides, proteins and even DNA mutation were achieved using the developed technique depending on the properties of the silica particles used (particles pore size). For example, using 3mum ProntoSIL C-18 particles with 300A pore size, separation efficiencies in the range of 120,000-200,000plates/m were obtained for protein separation, in a 6cmx200mum i.d. capillary column. Using encapsulated silica C-18 with 1000A pore size, separation of DNA homo and hetero duplexes were achieved under denaturing HPLC conditions for mutation detection. In addition, nucleotides were separated using anion exchange material encapsulated with poly(styrene-divinylbenzene) (PS/ DVB), which indicated that the chromatographic properties of the silica packing material were still active after polymerization. The prepared capillary columns were found to be stable and could easily be operated continuously up to a pressure of 350bar without column damage and capillary can be cut to any desired length.[1]

References

  1. Silica particles encapsulated poly(styrene-divinylbenzene) monolithic stationary phases for mu-high performance liquid chromatography. Bakry, R., St??ggl, W.M., Hochleitner, E.O., Stecher, G., Huck, C.W., Bonn, G.K. Journal of chromatography. A. (2006) [Pubmed]
 
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