Double-Resonance Decoupling for Resolution Enhancement of 31P Solid-State MAS and 27Al →31 P MQHETCOR NMR

27 Al decoupling has been used to remove residual J-coupling interactions between 31 P and 27 Al in microporous aluminophosphates AlPO 4 -14 and AlPO 4 -40. In combination with 1 H high-power decoupling, 27 Al adapted decoupling yields 31 P spectra with optimal sensitivity and resolution. The importance of double-resonance decoupling is further demonstrated by incorporating this technique in the MQHETCOR sequence. Unambiguous assignment of all the AlPO 4 -14 nuclear magnetic resonances is achieved by combining multiple-quantum evolution in the 27 Al dimension and double-resonance decoupling in the 31 P acquisition domain.