Construction and performance of an NMR tube with a sample cavity formed within magnetic susceptibility-matched glass

► We constructed a new type of salt-tolerant NMR tube, with magnetic susceptibility-matched glass. ► The quasi-rectangular slot, sandwiched by the matched glass, provides good field homogeneity. ►The new tube provides low RF sample heating and good signal-to-noise ratio, even for lossy samples. ►Any cavity sizes and shapes can be created within these cylindrical tubes adaptable for NMR probes. ► Radial orientation at any angles can be performed, using probes with the sample positioning unit.