Multiplex MQMAS NMR of quadrupolar nuclei.

A multiplex phase cycling method (N. Ivchenko et al., J. Magn. Reson. 160 (2003) 52-58) has been used to record two-dimensional MQMAS spectra with a very short phase cycling. A straightforward procedure has been developed to easily process the data. Combining this Multiplex approach and the new Soft-Pulse-Adding-Mixing (SPAM) method considerably increases the signal-to-noise ratio of the conventional MQMAS experiment. The Multiplex acquisition procedure is much simpler than the echo/anti-echo method recently proposed, and has been applied with success to record (87)Rb spectra of RbNO(3) and (27)Al 3Q and 5Q MQMAS NMR of microporous aluminophosphate AlPO(4)-14.