pulssikenttäNMR

Pulssikenttä-NMR, also known as pulsed field gradient NMR (PFG-NMR), is a nuclear magnetic resonance technique that utilizes a pulsed magnetic field gradient to measure diffusion coefficients of molecules in a sample. This technique is particularly valuable as it allows for the non-invasive study of molecular motion without the need for labels or perturbation of the sample. The core principle involves applying a magnetic field gradient pulse, which causes spins of diffusing molecules to dephase. A second, identical gradient pulse is then applied, which can rephase the spins if the molecules have not moved. By varying the timing and strength of these gradient pulses, one can measure the extent of diffusion over a given period. The resulting signal decay is directly related to the root-mean-square displacement of the molecules. PFG-NMR has found widespread applications in various fields, including chemistry, biology, and materials science. It is used to study the self-diffusion of liquids, the transport of molecules across membranes, the aggregation of proteins, and the structure and dynamics of polymers. The ability to measure diffusion at the molecular level makes PFG-NMR a powerful tool for understanding complex systems and processes.