Figure 1.
The pH dependence of CEST from iopamidol. The CEST spectra of iopamidol (inset) show changes in the CEST signals at 4.2 and 5.6 ppm over a range of pH 5.82 to 7.67. These experimental results were fit with the Bloch-McConnell equations to directly determine the pH-independent rate, k0, and pH-dependent rate, kb, of chemical exchange. CEST spectra are not shown for samples at pH 6.08 and 7.42, and for the sample at 39 mM at pH 6.72.