Resolution enhancement in proton double quantum magic-angle spinning spectra by constant-time acquisition.

Although very fast MAS rate (>60 kHz) paves a way to obtain a sufficient resolution in the 1H double-quantum magic-angle spinning (DQMAS) experiments to probe 1H proximities, the 1H resolution still limits wider applications below its potential use. Here, the combination of the DQMAS experiment with the constant-time (CT) acquisition approach is demonstrated, giving an increased peak-separation power in the DQ dimension. The advantages and disadvantages in terms of sensitivity and resolution of the conventional and CT approaches are discussed.