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In carrier gas hot extraction the calibration of low amounts of non-metals with masses of a few micrograms with small uncertainty remains a challenge. To achieve high flexibility a high precision gas mixture pump was combined with an automated syringe drive. The gas mixing pump allows filling the syringe with different gas compositions; the automated syringe drive allows matching to modulate the signal profiles to those of real samples. The system was designed and its experimental potential explored. The resulting calibration curves were comparable to those obtained by calibration using solid materials of sufficient purity and stoichiometry. However smaller uncertainties and lower limits of quantification (i.e. 0.5 µg and 0.6 µg for O and N, respectively) were found using the gas calibration device.
Due to its high energy density hydrogen is a capable energy carrier to store the electrical energy surplus resulting from energy production by wind and solar energy in chemical energy. In this context, corrosion stable, pressure resistant glasses offer a promising opportunity for long term hydrogen storage e.g. at high pressure in glass capillaries.
In this context, investigations of hydrogen permeation and diffusion can provide important fundamental knowledge to evaluate the applicability. Different sample geometries as planary, bulb shaped, capillary shaped, as well as powders are compared in order to evaluate the experimental operability and the sensitivity of each approach. Limiting factors are e.g. gas thight sealing of planar samples, wall thickness of small glass bulbs, availability of glass capillaries and a defined grain of powders. High pressure experiments and the application of fast furnaces to ensure quick heating to the extraction temperature using vacuum hot extraction coupled with MS. The correctness is ensured comparing the obtained results of the mentions geometries emong each other as well as with literature data.
The H2 effusion from H2 saturated glass powders, H2 permeation through the wall of blown glass bulbs, and H2 permeation through the wall of glass capillaries were applied to evaluate the permeability of hydrogen gas in a barium-aluminoborosilicate (BABS) glass. To validate these methods, two commercial glasses (vitreous silica and borosilicate) were used as a reference. Permeation values obtained from the different experiments agreed within a factor of 3 or less. The H2 permeability of BABS glass at temperatures close to ambient was found to be at least 3 orders of magnitude below that of borosilicate and silica glasses. The powder method, which requires minimal sample preparation efforts, turned out to provide easy access to the measurement of H2 permeability of glasses down to P = 3.9 × 10- 21 mol s- 1 Pa- 1 m- 1.