  A diamond-based sensor utilizing nitrogen-vacancy (NV) center ensembles
permits the analysis of micron-sized samples through NMR techniques at room
temperature. Current efforts are directed towards extending the operating range
of NV centers into high magnetic fields, driven by the potential for larger
nuclear spin polarization of the target sample and the presence of enhanced
chemical shifts. Especially interesting is the access to J-couplings as they
carry information of chemical connectivity inside molecules. In this work, we
present a protocol to access J-couplings in both homonuclear and heteronuclear
cases with NV centers at high magnetic fields. Our protocol leads to a clear
spectrum exclusively containing J-coupling features with high resolution. This
resolution is limited primarily by the decoherence of the target sample, which
is mitigated by the noise filtering capacities of our method.
