cryoprobe at 298 K without a 2H lock. The magnet was shimmed using the 1H FID. The 1H spectrum has two resonances, a broad one at ~2.2 ppm (Δν1/2 = 30 Hz) and a narrower one (Δν1/2 = 4 Hz) at ~3.8 ppm due to liquid and gaseous acetone, respectively. The large 30 Hz line width for the liquid resonance is due to the magnetic susceptibility discontinuity boundary between the droplet of liquid with the glass and vapour interfaces. There may also be broadening as the droplet resides near the edge of the homogeneous region of the magnetic field. A DOSY spectrum, acquired with δ = 0.5 msec and Δ = 4.9 msec, illustrates the vastly different molecular diffusion rates between the liquid and gaseous phases of acetone. An EXSY spectrum, acquired with a 2 second mixing time, clearly shows exchange peaks between the liquid and the gas phases, illustrating the liquid-gas equilibrium.
* C.J. Jameson. Chem. Rev. 91, 1375-95 (1991).