Fig. 2.
(A) pH-dependent FTIR spectra of KP1212 from pH* = 1.6 (red) to 13.9 (blue) at 25 °C. (B) Populations of protonated, neutral, and deprotonated KP1212 as a function of pH* obtained from the first three components of SVD analysis. The solid lines show fits of the Henderson–Hasselbalch equation with pKa1 and pKa2 (see SI Appendix for details). (C–E) SVD reconstructed IR spectra representative for the protonated, neutral, and deprotonated KP1212 spectra. The gray curves in C and D are the experimental FTIR spectra of CMP at pH* 1.6 and 7.4, respectively.