It can be helpful to record a standard COSY experiment under identical conditions to ensure unambiguous assignments.

a 2D ¹H-¹H Double-Quantum (DQ) spectrum with and change the pulse program to dqsqf

It is generally recommended that Double-Quantum (DQ) experiments be run without sample spinning.

In contrast to COSY experiments, the spectral width in the F1 dimension (double-quantum frequencies) will be twice that in the F2 dimension. The most important parameter to optimize is the fixed duration delay. As a general trend, d4 is optimized to 1/(4*J(HH)) (d2=50 ms for J(HH)=5 Hz). Finally, the read pulse before acquisition (p0) can be set to 90º or 135º.

The number of scans is determined as a function of the sample concentration (minimum phase cycle, ns 32 and ds 4).

List of Related Experiments:

Phase-cycle 2D experiments
Gradient-enhanced 2D experiments
Gradient-enhanced 2D experiments for H₂O