Simultaneous acquisition of PAR and PAIN spectra

We present a scheme that allows the simultaneous detection of PAR and PAIN correlation spectra in a single two-dimensional experiment. For both spectra, we obtain almost the same signal-to-noise ratio as if a PAR or PAIN spectrum is recorded separately, which in turn implies that one of the spectra may be considered additional information for free. The experiment is based on the observation that in a PAIN experiment, the PAR condition is always also fulfilled. The performance is demonstrated experimentally using uniformly 13 C, 15 N-labeled samples of N–f–MLF–OH and ubiquitin.