Improved convection compensating pulsed field gradient spin-echo and stimulated-echo methods

Citation
Gh. Sorland et al., Improved convection compensating pulsed field gradient spin-echo and stimulated-echo methods, J MAGN RES, 142(2), 2000, pp. 323-325
Citations number
11
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Chemistry & Analysis","Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF MAGNETIC RESONANCE
ISSN journal
1090-7807 → ACNP
Volume
142
Issue
2
Year of publication
2000
Pages
323 - 325
Database
ISI
SICI code
1090-7807(200002)142:2<323:ICCPFG>2.0.ZU;2-3
Abstract
The need for convection compensating methods in NMR has been manifested thr ough an increasing number of publications related to the subject over the p ast few years (J, Magn. Reson. 125, 372 (1997); 132, 13 (1998); 131, 126 (1 998); 118, 50 (1996); 133, 379 (1998)), When performing measurements at ele vated temperature, small convection currents may give rise to erroneous val ues of the diffusion coefficient. In work with high resolution NMR spectros copy, the application of magnetic field gradients also introduces an eddy-c urrent magnetic field which may result in errors in phase and baseline in t he FFT-spectra. The eddy current field has been greatly suppressed by the a pplication of bipolar magnetic field gradients. However, when introducing b ipolar magnetic field gradients, the pulse sequence is lengthened significa ntly. This has recently been pointed out as a major drawback because of the loss of coherence and of NMR-signal due to transverse relaxation processes . Here we present modified convection compensating pulsed field gradient do uble spin echo and double stimulated echo sequences which suppress the eddy -current magnetic field without increasing the duration of the pulse sequen ces. (C) 2000 Academic Press.