A Low-Field Portable Nuclear Magnetic Resonance (NMR) Microfluidic Flowmeter

This paper presents a portable and contactless microfluidic flowmeter based on the Nuclear Magnetic Resonance (NMR) principle, which can measure flow rates up to 2.7 ml/min with
$\pm 16\ \mu \mathrm{l}/\min$
(±0.6% full-scale) error. It consists of a millimeter-size RF coil wound around a microfluidic channel, custom readout electronics and a 0.5 T permanent magnet with 50 ppm inhomogeneity. To our knowledge, this is the first reported low-field NMR microfluidic flowmeter.