Chemically resolved NMR velocimetry

Of particular relevance to process engineering is the potential sensitivity of NMR imaging to fluid displacement, which allows measurement of fluid velocities (in the range mm/s to m/s), even in opaque fluids, in three spatial dimensions (NMR velocimetry). The chemical sensitivity of the NMR technique has often been overlooked in NMR velocimetry implementations, but we present one protocol for the simultaneous measurement of fluid velocity for the separate components of a flowing mixture of chemical compounds. The fluid flow in the expansion/contraction pipe system is found to be fully characterised in three spatial dimensions. Thus, chemically resolved NMR velocimetry allows a five-dimensional (three spatial, one temporal and one chemical shift) measurement to be made, non-invasively and in optically opaque liquids.