Robust refocusing of 13C magnetization in multidimensional NMR experiments by adiabatic fast passage pulses.

We show that adiabatic fast passage (AFP) pulses are robust refocusing elements of transverse (13)C magnetization in multidimensional NMR experiments. A pair of identical AFP pulses can refocus selected parts or a complete (13) C chemical shift range in (13)C spectra. In the constant time (13)C-(1)H HSQC, replacement of attenuated rectangular pulses by selective AFP pulses results in a sensitivity enhancement of up to a factor of 1.8. In the 3D CBCA(CO)NH the signal-to-noise ratio is increased by a factor of up to 1.6.