Sample Test: 100mM Urea ¹⁵N, 100mM CH₃OH ¹³C in DMSO-d₆ sample.

The triple resonance test is performed from the basic 1H parameter set and defining NUC2 13C and NUC3 15N. The pulse program is zgfbig

The offsets must be specified as:

O1P=4ppm (1H)
O2P=49.5ppm (¹³C)
O3P=76ppm (¹⁵N)

Use the following values:

p1=high-power 90º ¹H observe pulse

pl12 and pl13 are the power levels for 13C and 15N decoupling (See Low-power 90º ¹³C decouple pulse calibration (for GARP)

Low-power 90º ¹⁵N decouple pulse calibration (for GARP)). CPDPRG2 (garp), PCPD2 (80u), CPDPRG3 (garp), PCPD3 (180u) are the parameters that define decoupling at both channels.

ns=4

It is very important to use a long recycle delay, usually d1=5*T1(¹H) (d1<5 s).

The spectrum must be shown effective decoupling in the signals resonating at 3.18ppm and 5.45 ppm.

It is important to give enough delay in between two scans to keep the temperature stable during the experiment. Make sure the temperature unit is connected to the probehead. For 2D experiment make AQ<400ms. Use all necessary filters.