A novel hyphenated technique namely the combination of HPLC with direct analysis in real time (DART) mass spectrometry (MS) is presented. The coupling of HPLC to DART-MS was achieved by a simple interface design with a capillary end piece transferring the HPLC effluent to the ionization region of the DART. Flow rates (0.3-1.6 mL min(-1)) and inner diameters of the capillary (50-150 microm) were harmonized to provide a stable liquid jet. Ionization-related parameters optimized included positioning of the capillary end piece with respect to He outlet of the ionization source and the MS inlet, He heater temperature and He flow rate. Among DART-MS voltages, the grid electrode voltage proved to have the most pronounced effect on signal intensities. A major benefit of this setup is the possibility to employ (commonly not MS-compatible) HPLC eluents such as phosphate buffers up to a phosphate concentration of 120 mM even at typical HPLC flow rates such as 1 mL min(-1) and above without negative side effects like contamination of the ion source or ion suppression. Experiments evaluating the correlation of signal intensity to mass-flow and concentration revealed that DART-MS can be seen as a mass flow sensitive detector. The usability of this hyphenated technique has been tested on the example of four parabenes (measured in the negative ion mode) as well as a set of pyrazine derivatives (measured in the positive ion mode). For the parabenes limits of detection (LOD) in the range of 20-55 microg L(-1) and linear ranges from at least 200-10000 microg L(-1) with correlation coefficients better than 0.997 were obtained.

A screening method for analyzing environmental waters contaminated with UV filters using direct analysis in real-time mass spectrometry (DART-MS) was developed. To demonstrate the suitability of DART-MS a test set of seven organic UV filters, namely benzophenone-3 (BP-3), ethylhexyl dimethyl p-aminobenzoate (OD-PABA), 4-t-butyl-4'-methoxydibenzoylmethane (BM-DBM), homomethyl salicylate (HMS), 2-(ethylhexyl) salicylate (EHS), octocrylene (OC), and 4-methylbenzylidene camphor (4-MBC), was defined. In the first step, standard solutions of the analytes prepared in methanol were investigated in order to determine optimum parameters for the DART-MS. Because of the very low concentrations of UV filters expected in environmental water samples, a pre-concentration step using stir bar sorptive extraction was performed. DART-MS allows the direct, simple and rapid semi-quantitative analysis of the analytes enriched on the surface of the polydimethylsiloxane-coated stir bars. The optimized method provided calibration curves with correlation coefficients R > 0.959, repeatability from 5% (for 4-MBC) to 30% (for BM-DBM) relative standard deviation and limits of detection lower than 40 ng L(-1) for all analytes. Finally, real lake water samples from locations with typical leisure activities were analyzed. Results obtained with the developed DART-MS method were cross-checked by confirmatory analysis using thermodesorption gas chromatography mass spectrometry (TD-GC-MS). Thereby, it could be demonstrated that both analytical methods provide comparable concentrations for the UV filters in the lake water samples.

A method for analysing plastic samples without any sample pretreatment using direct analysis in real time mass spectrometry (DART-MS) was developed. DART-MS allows the direct, simple and rapid identification of polymer additives in plastic products. To demonstrate the suitability of DART-MS for the detection of a wide range of commonly employed stabilising agents, a test set of 21 stabilisers was selected. In a first step standard solutions of these stabilisers in toluene as well as toluene-extracts from polymer samples were analysed. Subsequently, to prove the applicability of the developed DART-MS method also for the direct analysis of plastic products, samples of polypropylene containing a range of stabilisers were prepared using a lab-scale compounder. Polymer samples were cut into 0.5 cm wide pieces and directly placed into the DART ion source. Focusing on the DART ionisation, several parameters like discharge needle potential, potential of the grid electrode and the discharge electrode, the heater temperature and the gas flow had to be varied to guarantee optimum results. Both positive and negative ionisation was tested, whereby the positive ion mode led to higher signal intensities for all analytes. Determination of accurate masses to improve the certainty in signal assignment could be achieved by using PEG 600 as an internal standard for mass calibration. The developed method allowed the detection of all selected additives (including some of their degradation products) in real polymer samples.

Since their discovery in the early fifties mitochondrial granules have been the subject of many researches. Some twenty years ago two hypotheses on their function were introduced. Peachey thought that the granules were a sink of cations and that they would eventually regulate the concentrations of these ions. Alternatively, Barnard thought that the granules were precursors of the mitochondrial inner membrane. There are only a few data on organic constituents of the granules. Phospholipids (e.g., cardiolipin) glycoprotein or lipids, calcium precipitable lipoprotein, cytochrome c oxidase seem to be present in the granules. There has been much debate on whether calcium is present or not. Reports are mostly based on X-ray microanalysis, the result of which depends on preparation techniques. In heart muscle in stimulating situations the NMG (native matrix granules) move towards the inner membrane and are incorporated in it. They appear to create contact sites between inner and outer mitochondrial membranes in which enzymes can function efficiently. It is hypothetized that the system, NMG-contact sites, forms the structural basis of a regulatory mechanism, by which cells can cope with a high and sudden energy demand.

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