Continuous Inline Magnetic Resonance Relaxometry Measurements on Moving Fluids

Nuclear magnetic resonance (NMR) measurements of moving samples are limited by the depletion of the sample during long experiments, making it difficult to apply NMR relaxometry techniques to moving fluid samples for various manufacturing and reaction monitoring applications. Traditional techniques for compensating for flow-induced artificial relaxation in postprocessing do not work for samples with unknown or variable flow rates, which is a significant barrier to the widespread adoption of NMR monitoring systems for existing processes. In this work, we present a compact NMR coil geometry that removes the effect of sample depletion during long experiments on moving samples, making it possible to perform flow-agnostic measurements on samples with variable or uncontrolled flow rates. We evaluate this coil geometry using relaxometry experiments on fast-flowing water samples and demonstrate its potential for process monitoring with real-time measurements of the dairy concentration.