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High-pressure ion chromatography in capillary columns and microfluidic chips

Boekbijdrage - Boekhoofdstuk Conferentiebijdrage

Similar like in high-performance liquid chromatography, ion chromatography (IC) has witnessed a trend toward the use of smaller particle packing materials to increase the separation performance. Without compromising the column length, the use of smaller particles leads to higher operating pressure, since the pressure drop is inversely proportional to the square of the particle diameter. To withstand the higher operating pressures and to improve the solvent compatibility the crosslink density of the polymer beads has been increased from 5% to > 50% for today's particles.To meet the demand for analyzing minute amounts of sample there is also strong interest in miniaturization of column technology. Additional benefits of using smaller column I.D.'s are the increased detection sensitivity, and better compatibility with electrospray-ionization mass spectrometry (especially when using aqueous mobile-phases). This has now resulted in the development of capillary IC columns formats and high-pressure capillary systems that are compatible with alkaline mobile-phase.The present contribution discusses the IC performance limits that can be achieved with capillary columns packed with 4 and 7 µm polymer anion-exchange beads, respectively. When operating in the C-term region of the Van Deemter curve a 26% increase in efficiency and maximum time gain of 45% could be established employing 4 µm packed columns and increasing the operating pressure from 3000 to 5000 psi. In addition, the effects of column temperatures up to 80°C on kinetic performance limits and selectivity are discussed for mono-, di-, and trivalent anions. Finally, a the design of a prototype microfluidic chip for IC will be discussed. Different channel layouts were created using a precision micro-milling robot instrument allowing the engineering of channel diameters of 100 µm I.D. and larger. The possibilities to packed chips with polymer IC bead and the in-situ polymerization of monolithic stationary phases are discussed.
Boek: Oral presentation at the 38th International Symposium on High Performance Liquid Phase Separations and Related Techniques (HPLC 2012) in Anaheim, California (USA) (June 16-21, 2012).
Jaar van publicatie:2012
Trefwoorden:ICS-5000
  • ORCID: /0000-0002-5465-0127/work/74203717