Record a conventional 1H spectrum. Note the o1 of the selected resonance.

Record a SPFGE experiment on the selected 1H resonance to be selectively excited. Check for the proper values of p12 and sp2.

a Selective gradient-enhanced 1D COSY experiment with rpar SELCOGP all and change the pulse program to selrelgp

d4 is the J-coupling evolution period (must be optimized to 1/2J(HH)). You can start with a value of 40 ms.

d5 is the second J-coupling evolution period (must be also optimized to 1/2J(HH)). You can start with a value of 40 ms.

A minimum two-scan cycle is needed (ns=2 and ds=2).

Transform the acquired data with and corrects the phase (relay and COSY peaks must present an anti-phase pattern).

The best option is to use the shorter selective 180º pulse that achieve clean excitation of the selected resonance without disturb other resonances. In some cases, the use of long selective pulses can undergo sensitivity losses due to relaxation effects.

The selective ge-1D RELAY experiment can also be recorded using a DPFGE scheme as a starting building block (See the DPFGE experiment for more details).

Multiple-step RELAY experiments can be designed by adding successive RELAY blocks before acquisition. Selective 1D TOCSY experiments using different mixing times is an alternative approach to elucidate spin subsystems.