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A Sample Spinner for Vibration-Sensitive Liquid-State Experiments with Application to Diffusion-Ordered 2D NMR

1993; Academic Press; Volume: 104; Issue: 2 Linguagem: Inglês

10.1006/jmra.1993.1215

1096-0864

Daqiang Wu, W. S. Woodward, Charles S. Johnson,

Neural Networks and Applications

Signal overlap in the NMR dimension significantly complicates the construction and analysis of 2D diffusion-ordered (DOSY) spectra. Such problems can often be reduced or even eliminated by extending the NMR domain of a DOSY experiment into two dimensions, giving a 3D-DOSY spectrum. To date such experiments have generally sacrificed some signal-to-noise ratio and have required extensive and time-consuming phase cycling. A new family of pulse sequences with internal diffusion encoding (IDOSY) has been introduced which avoids both of these problems. It is often straightforward to incorporate convection compensation in such sequences at no cost in signal-to-noise ratio. Here, some of the problems caused by convection in DOSY are described and illustrated, and the efficacy of convection compensation in the 2DJ-IDOSY and COSY-IDOSY experiments is demonstrated.