NMR probe for pressure-jump experiments up to 250 bars and 3 ms jump time |
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Authors: | Heuert U Krumova M Hempel G Schiewek M Blume A |
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Affiliation: | Insitut fu?r Physik, Martin-Luther University Halle-Wittenberg, Betty-Heimann-Str. 7, D-06120 Halle/Saale, Germany. |
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Abstract: | We describe the design and performance of a pressure-jump instrument for time-resolved NMR experiments. Initial pressure of up to 250 bars can be produced by means of a HPLC pump and distilled water as a pressure-transmitting liquid. Fast pressure release at a time resolution of 3 ms is achieved using a fast acting valve driven by a piezostack close to the sample chamber. The pressure-jump cell is placed together with two valves in an especially designed NMR probe, which can be used in standard spectrometers with wide-bore magnets. All functions of the instrument are personal computer controlled. The equipment is designed for investigations on systems of biological interest, especially lipid-water dispersions. A theoretical consideration implies that probably the limited speed of valve opening determines the lower boundary of the jump time. The performance is illustrated by time-resolved NMR spectra across the phase transition of a phospholipid-water dispersion after a pressure jump from 100 bars to atmospheric pressure. |
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