DETERMINATION OF OXYGEN BY A NUCLEAR MAGNETIC-RESONANCE METHOD

A NMR technique is described for the determination of magnetic susceptibilities Δχv of oxygen solutions using a field-axis variation method. The technique is applied to the titration of oxygen in benzene or hexafluorobenzene solutions contained in sealed sample tubes under pressures of 1 to 6 atm. The validity of the method was checked by using both nuclei of each solvent, i.e., 1H (at 90 and 250 MHz) and 13C{1H} (22.63 and 62.86 MHz) for C6H6; 19F (84.67 and 250 MHz) and 13C{19F} for C6F6. The sensitivity limit is expecd to be Δχv = 0.03 × 10-6 and [O2] = 10-3 mole · dm-3 (for 1H or 19F nuclei). This method might be used for a remote control of the oxygen content in organic solvents for oxygen pressures higher than 1 atm. © 1979.