HMQC

Only directly bonded hydrogen and carbons will give cross peaks (quaternary carbons are not seen), which makes interpretation rather straight foreword. As seen in the simulated spectrum below, assignment is made by drawing two lines at a right angle from the 1H spectrum to the 13C spectrum through the cross-peak, which looks like a series of concentric ellipses. Thus, in the spectrum below, C1 is directly attached to H1.