Contrast Enhancement of Magnetic Resonance Images of Chemical Waves in the Belousov-Zhabotinsky Reaction

A detailed investigation is presented of the role of ortho-, pyro-, and metaphosphates on the contrast enhancement of magnetic resonance images of chemical waves in the Mn2+-catalyzed Belousov-Zhabotinsky (B-Z) reaction. Separate measurements of the TI and T2 relaxation parameters for the reduced and oxidized states of B-Z-like mixtures are reported for varying concentrations of H3P04, Na3P04, Na4P207, and NasP3010. From these measurements, the contrast expected for chemical wave structures in MRI experiments is predicted. Measurements taken during a B-Z reaction demonstrate the validity of these predictions. It is concluded that the most appropriate contrast agents for studies of the dynamics of the chemical waves are Na4P2O7 and NasP3010, particularly for the study of 3-D structures in large containers. Some 31P spectroscopic measurements are also reported. It is concluded that such experiments canied out at 2 T will be of only limited value.