Single bead detection with an NMR microcapillary probe

► A NMR microcapillary probe has been developed for single magnetic beads. ► We numerically analyze the magnetic field around a single bead. ► NMR spectra are simulated for different probe coil volumes. ► Detection limit volume was enhanced 600-fold compared to a conventional 5 mm NMR probe. ► 1 μm single magnetic beads were observed with a SNR of 30.