The ge-2D ROESY experiment allows to obtain a 2D ROESY spectrum with two scans per t₁ increment provided that the S/N ratio is adequate. The main advantage of such approach is the large reduction in the total acquisition time compared with a conventional 2D ROESY experiment although sensitivity loss are present due to coherence selection. The ROESY experiment permits to trace out through-space proton-proton connectivities via dipolar couplings or exchange processes.
 

Easy implementation on any AVANCE spectrometer equipped with pulsed field gradients.

2D ROESY experiments must be recorded in a  phase sensitive mode. For this reason, gradients are usually incorporated using the echo-antiecho approach ( 97JMR145-125 ) or inserting an strong spin-lock or a z-filter pulse prior to acquisition ( 94JMRA263-109 , 95JACS6064 , and 97JMR145-125 ). In such cases, phase-sensitive 2D ROESY maps can be quickly obtained for concentrated samples in reduced times but sensitivity losses due to coherence selection and difussion effects are present. 2D ROESY experiments can include gradient-based  solvent suppression schemes as, for instance, the WATERGATE  ( 92JB661 ) or DPFGE ( 96JMRB82-112 and 97JMR93-129 ) schemes optionally combined with a water-flip-back pulse prior to acquisition and the WET scheme during the preparation period ( 95JMRA295-117 ). Modified WATERGATE and DPFGE schemes for multiple-solvent suppression ( 96JMRB124-110 and 98JB437 ) purposes can also be included. The ROESY pulse sequence can also be used to study dynamic or chemical exchange processes (see ge-2D EXSY experiment).

This experiment is acquired an processed using the same experimental conditions as described for its phase cycle version. The only difference is the presence of the gradients. Thus, the user only need to define the strength, duration, shape of the gradients and the recovery delay. More details on practical implementation of ge-2D NOESY experiments on AVANCE spectrometers can be found in

Tutorials: 2D homonuclear experiments

Tutorials: 2D gradient-based homonuclear experiments

Tutorials: 2D gradient-based homonuclear experiments in H₂O

The ge-2D NOESY experiment is usually recorded in routine and automation modes with minor required modifications if a predefined parameter set is available. The most important parameter to consider is the duration of the mixing time.

List of available gradient-enhanced ROESY pulse programs for AVANCE spectrometers.

In a ROESY spectrum, cross-peaks correlate chemical shifts between homonuclear spins via dipolar coupling or exchange processes.

Related experiments:

2D homonuclear experiments

2D gradient-based homonuclear experiments