Abstract: There is disclosed an NMR cell system for supercritical fluid measurements. This cell system has an NMR cell in which convection is prevented. A reactive gas and a reactive liquid can be smoothly introduced into the NMR cell. The oxygen (air) inside the NMR cell can be removed before measurement. The NMR cell system comprises a cylindrical cell, a cell holder, and an external pumping system. The cylindrical cell and the cell holder are made of a nonmagnetic material that withstands high temperatures, high pressures, and strong acidity. A pipe is mounted inside the cell holder to connect the external pumping system into the cell. A high-pressure cell for use with an NMR spectrometer is also disclosed. This high-pressure cell comprises a pressure-proof cell for receiving a sample, a pressure transfer tube for transmitting pressure to the sample in the cell, and a coupling portion for coupling together the pressure-proof cell and the tube.

Abstract: A nuclear magnetic resonance apparatus incorporating a first trans-receiver coil, an internal lock coil, a decoupling coil, means for tuning said coils to desired frequencies, a first trans-receiving system for supplying the first trans-receiver coil with a first nuclear (such as .sup.1 H) resonance RF wave and detecting the first nuclear resonance F.I.D. signal, a second trans-receiving system for supplying the first trans-receiving coil with a second nuclear (such as .sup.13 C) resonance RF wave and detecting the second nuclear resonance F.I.D. (Free Inductance Decay) signal, a third trans-receiving system for supplying the internal lock coil with a third nuclear (such as .sup.2 D) resonance RF wave and detecting the third nuclear resonance signal, and a transmission system for supplying the first nuclear resonance RF wave to the decoupling coil, it being possible in said apparatus to observe different types of nucleus, viz; .sup.1 H and .sup.