1H-NMR (Proton nuclear magnetic) Relaxometry

Instumentelle Analytik (Umwelt- und Bodenchemie)


minispec mq + gradient unit (Bruker)


All nuclei with an odd number of protons and neutrons have an intrinsic magnetic moment – a spin. These spins align along an applied outer magnetic field. If a second magnetic field in orthogonal direction is applied for a short time spins will align along this second field and after switching it off will start to “relax” back into direction of the original field. This can be measured indirectly and gives information about the environment of the spins. Spins in free liquid relax much slower than those enclosed in pores, so that 1H-NMR relaxometry can be used as a non-invasive technique for measurement of pore size distribution (commonly in petroleum exploitation and earth science in general). 1H-NMR relaxometry can also be applied to study pore size distribution in soils. Further applications for example are the determination of water structure (i.e. non-freezing water) and examination of soil – water interactions.