This experiment gives the correlations between protons and other nuclei such as ¹³C (standard) or ¹⁵N. There are absolute value HETCOR and phase sensitive HETCOR versions. A related experiment is the 2-dimensional HMQC experiment.

Absolute value or phase sensitive HETCOR?

1. The absolute value HETCOR is easier to set up and process.
2. The phase sensitive HETCOR gives you narrower lines. You also have the choice to see the CH-groups only or to see the CH- and CH₃ resonances positive and the CH₂ resonances negative.
3. The final work-up of the phase sensitive HETCOR requires phasing in both dimensions, which can be rather time-consuming and difficult, but is do-able. You need to be aware of peaks coming from incomplete cancellations, and have to neglect them in your phasing effort.

HETCOR or HMQC?

HETCOR Advantages:

1. The set-up is shorter.
2. To cancel artifacts, less scans are acquired, so overall HETCOR requires less time to run.
3. ¹H-¹H couplings are removed, while they are present in the normal HMQC. However, you can run a homonuclear decoupled version of the HMQC experiment to also remove those couplings.
4. Variations of the HETCOR can show only methines, or methines and methyls positive and methylenes negative. HMQC does not have these variations.

HMQC Advantages:

1. The sensitivity is 2 to 4 times greater than HETCOR for small molecules, 4 times for large molecules.
2. The ¹H dimension is the "high resolution" dimension; while in HETCOR this is the ¹³C dimension. Typically, ¹H chemical shifts span only ~10ppm, while ¹³C chemical shifts span ~200ppm and are normally well resolved anyway. It is therefore advantageous for the ¹H dimension to have high resolution.