Visualization of pH and Ionic Concentration for Dissolving/Forming Crystals

To elucidate the formation and dissolutionDissolution mechanisms of crystals in aqueous solution, monitoring localPh pH or ionic concentrations at or near the solid−fluid interface of crystals is critical. Using fluorescent probesFluorescent probe, which produce different fluorescent intensities depending on pH or the ionic concentration of the solution containing the probes, a two- or three-dimensional visualizationVisualization of the local distribution ofPh pH or ionic concentration around the forming/dissolving crystal is realized. In this chapter, the technique of visualizing ionic concentrations under a microscope using a fluorescent probeFluorescent probe is described, along with examples of visualizedPh pH and calcium ion concentrations during the growth and dissolutionDissolution of calcium carbonateCalcium carbonate. Using this technique, ion migration on the surface of growing/dissolving crystals can be directly measured, and it is expected to generate new insights into the mechanisms of their growth and dissolutionDissolution.