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Single-electrolyte isotachophoresis: on-chip analyte focusing and separation

Promotor: Thomas Hankemeier, Co-promotores: Heiko van der Linden, Paul Vulto

J.W. Quist
20 maart 2014
Thesis in Leiden Repository

The unification of isotachophoresis (ITP) and electric field gradient focusing (EFGF) is proposed, based on theoretical considerations and experimental evidence from previous literature. This unification increases the versatility of each EFGF method. A novel isotachophoretic separation method is developed which is based on one of the EFGF techniques, namely micro/nanofluidic concentration polarization devices, This novel method, coined depletion zone isotachophoresis (dzITP), requires a single electrolyte only, which is a simplification over conventional isotachophoresis. Moreover, positioning of focused analyte zones, selective release of individual analyte zones and continuous filtering based on ionic mobility differences is possible. Furthermore, it is shown that microvalves in PDMS chip devices can act as nanochannels upon closure, giving rise to a wide range of concentration polarization phenomena. Compounds can be concentrated over 1000-fold and subsequently be released. These techniques give novel possibilities for bioassays and sample preparation.