Single-Sided and Semisingle-Sided NMR Sensors for Highly Diffusive Samples:  Application to Bottled Beverages

Single-sided NMR sensors such as the NMR-MOUSE have been very successfully implemented for quality control applications in the rubber and polymer industries. More recently, single-sided NMR was also applied in characterization of the fat components in foods. Both industrial polymers and the fat components in food exhibit relatively low self-diffusion coefficients on the order of 5 × 10^-11 m²/s or lower. The application of conventional single-sided NMR to highly mobile, watery phases in foods and beverages is hampered by the strong magnetic field gradient present in standard single-sided NMR devices. In this contribution, we present both a single-sided NMR sensor with a reduced magnetic field gradient and another (“semisingle-sided”) sensor design with an open sample bay using a single-sided RF coil. The latter design allows much better sensitivity without sacrificing the necessary open access needed for measurements on entire food packages such as bottles. As a first application, the sensors were used for determining the oxygen content in bottles with superoxygenated table water.

Keywords: TD-NMR; relaxation; diffusion; single-sided NMR; beverages; oxygenated table water