experiment for indirect 15N pulse calibration using 1H observe CPHSQC at fast MAS.

This 1D experiment calibrates 15N pulse width using CPHSQC at fast MAS (1.3mm probe at 60kHz spinning frequency).


https://www.ncbi.nlm.nih.gov/pubmed/25102442 E. Barbet-Massin, A.J. Pell, J.S. Retel, et al., Rapid Proton-Detected NMR Assignment for Proteins with Fast Magic Angle Spinning., JACS 136 (35), pp 12489-12497 (2014).

Sample heating

Frictional heating during ultra fast spinning may heat up a sample by up to 40K.


[https://www.biorxiv.org/content/10.1101/566729v1.full] TmDOTP : An NMR- based Thermometer for Magic Angle Spinning NMR Experiments Dongyu Zhang, Boris Itin, Ann E. McDermott; preprinted


Optimize both CP segments using the sample of interest. Literature recommends using 10% linear ramps, the author finds 20% tangential ramps to perform better.


The experiments were performed with a precipitated microcrystalline u-13C,15N labeled protein

Processing and analysis

Use parameter optimization (popt routine) to observe signal zero-crossing

Pulse Sequence and Parameter Set