Fig. 3. Correlated spectroscopy (COSY) (top) and total correlation spectroscopy (TOCSY) (bottom: _mix = 70 ms) nuclear magnetic resonance (NMR) spectra of a peat fulvic acid (FA) (left) and humic acid (HA) (right) with sections of chemical shift indicated in Tables 3 (COSY) and 4 (TOCSY). For reasons of clarity only one set of boxes is shown (exception B_T); the dotted box indicated in the TOCSY spectra has identical chemical shift range to the dotted box within Fig. 4 (see text).