Large-Ring Cyclodextrins as Chiral Selectors for Enantiomeric Pharmaceuticals.

Large-ring cyclodextrins (CD) are cyclic glucans composed of 9 or more α-1,4-linked glucose units. They are minor side products of bacterial glucanotransferases (CGTases, EC 2.4.

HPLC-MS with Glass Chips Featuring Monolithically Integrated Electrospray Emitters of Different Geometries.

We present and evaluate an approach for coupling liquid chromatography in glass chips with mass spectrometry via fully integrated electrospray emitters. We developed an instrumental platform which allows a robust and reproducible operation of high performance chip chromatography coupled to mass spectrometry. A comparison of differently shaped emitters, from flat over edged to pulled geometries, revealed that all types performed equally well for typical nano-HPLC flow rates.

Chip-based high-performance liquid chromatography for high-speed enantioseparations.

In this work, the first high-performance chiral liquid chromatography in packed microfluidic chips is presented. The chromatographic separation was performed on a column integrated into the microfluidic glass chip and packed with the particulate chiral stationary phase. Cellulose tris(3,5-dimethylphenylcarbamate) coated on 5-μm fully porous silica was used as chiral stationary phase material.

High-performance liquid chromatography on glass chips using precisely defined porous polymer monoliths as particle retaining elements.

A stable and permanent integration of miniature packed bed separation columns into microfluidic systems is a major issue in nano liquid chromatography. Various approaches like differently shaped retaining elements or the use of key stone effect have been investigated. We show a flexible integration of miniature packed bed separation columns into microfluidic chips utilising common HPLC material achieved by laser-assisted generation of narrow, photopolymerised frits.

Phase-optimized chip-based liquid chromatography.

In this contribution we introduce phase-optimized columns for highly efficient liquid chromatographic separations in microfluidic glass chips. In phase-optimized liquid chromatography the selectivity and geometry of the stationary phase are precisely adjusted to provide an optimal separation of a mixture of interest. The separation of nine polycyclic aromatic hydrocarbons under reversed-phase conditions was investigated.