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Ulrich Panne

Publications and source records attributed to Ulrich Panne.

5 recordsLinked to original sources
PubMed2005

Characterization of sewage plant hydrocolloids using asymmetrical flow field-flow fractionation and ICP-mass spectrometry.

Asymmetrical flow field-flow fractionation (AF4) was applied to characterize aquatic colloids from biological sewage plants and to infer information of colloidal loads, sources, and sinks within the plants, resp. the colloidal interaction with the aqueous phase and the sewage sludge. To characterize the colloids further, especially the distributions of colloid associated heavy metals, the AF4 system was coupled to an inductively coupled plasma mass spectrometer (ICP-MS). The size distribution is determined by AF4 with UV absorbance and fluorescence detection after a calibration by monodisperse polystyrene sulfonate standards (PSS). Samples from different sewage plants and from different depths and locations within a plant were compared. The fulvic/humic acid fraction with a particle diameter d(p) < 10 nm appeared to be comparable in all samples and decreases only slightly along the plants, whereas larger colloids with d(p) > 10 nm almost completely passed into the sewage sludge. The concentrations of the initial colloidal heavy metals decreased along the plants.

Colloids↗
PubMed2004

Microanalysis by laser-induced plasma spectroscopy in the vacuum ultraviolet.

A new setup for microanalysis by laser-induced plasma spectroscopy in the VUV range is presented and described in detail. The system features an integrated ablation and detection module with a newly designed VUV echelle system. The echelle permits a full spectral coverage between 150 and 300 nm with a resolving power lambda/Deltalambda between 11,000 and 15,000. At present, the ablation module permits a microanalysis with a crater size of 25 microm and a nominal depth resolution with an ablation rate of 150 nm/pulse. The VUV performance was demonstrated for bulk analysis of steel; detection limits for sulfur, carbon, and phosphorus were in the lower milligram per kilogram range. The VUV scanning and mapping performance for heterogeneous matrixes was illustrated for mineral bottom ash samples from a waste incineration process.

Journal Article↗
PubMed2003

Methods for studying synaptosomal copper release.

Cu is thought to play an important role in the pathogenesis of several neurodegenerative diseases, such as Wilson's, Alzheimer's, and probably in prion protein diseases like Creutzfeld-Jakob's disease. Until now, no method existed to determine the concentration of this cation in vivo. Here, we present two possible approaches combined with a critical comparison of the results. The successful use of fluorescent ligands for the determination of Ca2+-concentrations in recent years encouraged us to seek a fluorophore which specifically reacts to Cu2+ and to characterize it for our purposes. We found that the emission of TSPP (tetrakis-(4-sulfophenyl)porphine) at an emission wavelength of 645 nm is in vitro highly specific to Cu2+ (apparent dissociation constant Kd=0.43 +/- 0.07 microM at pH 7.4). It does not react with the most common divalent cations in the brain, Ca2+ and Mg2+, unlike most of the other dyes examined. In addition, Zn2+ quenches TSPP fluorescence at a different emission wavelength (605 nm) with a Kd of 50 +/- 2.5 microM (pH 7.0). With these findings, we applied the measurement of Cu with TSPP to a biological system, showing for the first time in vivo that there is release of copper by synaptosomes upon depolarisation. Our findings were validated with a completely independent analytical approach based on ICP-MS (inductively-coupled-plasma mass-spectrometry).

Animals↗
PubMed2002

Process analysis of recycled thermoplasts from consumer electronics by laser-induced plasma spectroscopy.

An experimental setup for direct elemental analysis of recycled thermoplasts from consumer electronics by laser-induced plasma spectroscopy (LIPS, or laser-induced breakdown spectroscopy, LIBS) was realized. The combination of a echelle spectrograph, featuring a high resolution with a broad spectral coverage, with multivariate methods, such as PLS, PCR, and variable subset selection via a genetic algorithm, resulted in considerable improvements in selectivity and sensitivity for this complex matrix. With a normalization to carbon as internal standard, the limits of detection were in the ppm range. A preliminary pattern recognition study points to the possibility of polymer recognition via the line-rich echelle spectra. Several experiments at an extruder within a recycling plant demonstrated successfully the capability of LIPS for different kinds of routine on-line process analysis.

Electronics↗