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. At very low flow rates below 50 nL·min(-1) very sharp, pulled nanospray emitters turned out to be mandatory for the generation of a stable electrospray.

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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. Several racemic analytes including pharmaceutical products were baseline separated into their corresponding enantiomers under reversed-phase, polar organic and normal-phase conditions, demonstrating the versatility of the glass chip in the field of chiral separations. Van Deemter plots revealed a reduced plate height of 2.2 and a trend to enhanced mass transfer processes for solutes under low retention conditions. The utilization of very short column lengths of down to 12 mm led to ultrafast separations of enantiomers within 5 s.

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Large-ring cyclodextrins (CD) are cyclic glucans composed of 9o rm ore a-1,4-linked glucose units.T hey are minor side products of bacterial glucanotransferases (CGTases,E C2.4.1.19) and have previously been available only in very small amounts for studies of their properties in supramolecular complex formation reactions.W ee ngineered aCGTase to synthesizemainly large-ring CD facilitating their preparation in larger amounts.B yr eversed phase chromatography,w eo btained single CD samples composed of 10 to 12 glucose units (CD10, CD11, and CD12) with ap urity of > 90 %. Their identity was confirmed by high resolution mass spectrometry and fragmentation analysis.Wedemonstrated the non-toxicity of CD10-CD12 for human cell lines by ac ell proliferation assaya nd impedimetric monitoring.W et hen showed that CD10 and CD11 are efficient chiral selectors for the capillary electrophoretic separation of the enantiomeric pharmaceuticals fluvastatin, mefloquine,c arvedilol, and primaquine.CDa re a-1,4-linked cyclic glucans with ad egree of polymerization (DP) between 6t o> 100. Branched a-1,6-CD have also been described. [1] In contrast to larger CD,CD6, CD7, and CD8 (a-, b-, g-CD) have been studied extensively and are produced commercially. [2] They form cone-shaped structures with ahydrophobic cavity and an outer hydrophilic area, enabling the reversible binding of hydrophobic mole-Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.