M. Bourdonneau et B. Ancian, RAPID-PULSING ARTIFACT-FREE DOUBLE-QUANTUM-FILTERED HOMONUCLEAR SPECTROSCOPY - THE 2D-INADEQUATE EXPERIMENT REVISITED, Journal of magnetic resonance [1997], 132(2), 1998, pp. 316-327
Citations number
67
Categorie Soggetti
Physics, Atomic, Molecular & Chemical","Biochemical Research Methods
Rapid pulsing artifacts are observed in the conventional phase-cycled
carbon-13 2D INADEQUATE experiment. By using the product operator form
alism, it is shown that they result from the effects of imperfect 90 d
egrees and 180 degrees excitation pulses on the most abundant molecule
s containing only one isolated carbon-13 nucleus. The labeled longitud
inal magnetization remaining at the end of one scan is recycled by the
subsequent acquisition, giving rise to multiple-quantum (p = 0, +/-1,
+/-2,...) artifacts in the F-1 dimension. By considering pairs of sca
ns instead of single scans, a new phase cycle is proposed. It is based
on a scheme for compensating for imperfections in the excitation clus
ter by a proper combination of the pulse phases in two consecutive sca
ns, Because the artifacts are 90 degrees out of phase compared to the
desired signal, a concomitant rearrangement of the receiver phase achi
eves suppression of all unwanted signals. Experiments are presented on
menthol dissolved in CDCl3 as a test compound. Improvements in spectr
um quality as well as increased sensitivity are discussed. (C) 1998 Ac
ademic Press.