Figure 3: The pH-dependence of the 17O NMR linewidth of 0.1 M glycine in H2O which contained 1 M NaCl; temperature 40°C; (+) measured at 27.11 MHz; (▲) at 12.2 MHz; (■) at 27.11 MHz after addition of 2 mM EDTA (ethylenediamine-N,N,N,N-tetraacetate). The dashed lines were drawn to follow the experimental points. The solid lines correspond to a nonlinear least-squares fit to one proton titration curve. (★) are values (ms) measured at 27.11 MHz. (Reprinted, with permission, from Helv. Chim. Acta . Copyright 1982, by Swiss Chemical Society.).