We introduce an approach for the integration of high performance liquid chromatography and droplet microfluidics on a single high-pressure resistant microfluidic glass chip. By coupling these two functionalities, separated analyte bands eluting from the HPLC column are fractionated into numerous droplets in a continuous flowing oil phase. The compartmentalization of the HPLC-eluate in a segmented flow was performed with droplet sizes of approximately 1 nL and with droplet frequencies reaching up to 45 Hz. This approach prevents peak dispersion and facilitates post column processing of chromatographic fractions on chip. A reliable generation of droplets is also possible in reversed phase gradient elution mode as demonstrated by applying a solvent gradient from 20% to 100% acetonitrile. A chip design with an incorporated dosing unit enabled the directed postcolumn addition of reagents to individual droplet fractions. The capability of this dosing function was successfully evidenced by post column addition of a reagent which quenches the fluorescence signal of the analytes. The chip-integration of gradient HPLC, fractionation, detection and post column addition of reagents opens up new avenues to perform multistep chemical processes on a single lab-on-a-chip device.

We present a microfluidic platform that contains a micro flow reactor for on-chip biomolecule labelling that is directly followed by a separation bed for continuous free-flow electrophoresis and has an integrated hydrogel-based near-infrared fluorescent pH sensor layer. Using this assembly, labelling of protein and peptide mixtures, their separation via free-flow isoelectric focusing and the determination of the isoelectric point (pI) of the separated products via the integrated sensor layer could be carried out within typically around 5 minutes. Spatially-resolved immobilization of fluidic and sensing structures was carried out via multistep photolithography. The assembly was characterized and optimized with respect to their fluidic and pH sensing properties and applied in the IEF of model proteins, peptides and a tryptic digest from physalaemine. We have therefore realized continuous sample preparation and preparative separation, analyte detection, process observation and analyte assignment capability based on pI on a single platform the size of a microscope slide.

By shielding the micro droplets from the electrospray potential, negative influences on the droplet formation and movement can be prevented.

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The hydrogenation properties of the intermetallic compounds MgPd 2 and Pd 2 Zn, crystallizing in the Co 2 Si type, were studied by in situ thermal analysis (DSC) under hydrogen pressure. Pd 2 Zn does not show any reaction with hydrogen while MgPd 2 reversibly forms the hydride MgPd 2 H. Neutron diffraction on the deuterides reveals the compositions MgPd 2 D 0.861(6) (ambient) and MgPd 2 D 0.97(1) [308(2) K, 2.56(5) MPa deuterium] with hydrogen (deuterium) occupying distorted [MgPd 5 ] octahedral voids. Quantum mechanical calcu-