Reversible Excited-State Photoacids and Photobases as Dynamic Fluorescence Sensors of Protonic Species

A method for measuring pOH comprising:

• connecting a confocal microscope with an electrochemical cell comprising an electrode submerged in an electrolyte comprising a photochemical compound;
• wherein a change in a species concentration in the electrolyte at the electrode changes a fluorescent signal of the photochemical compound;
• measuring the fluorescent signal with the confocal microscope;
• and
• generating a concentration of the species based on the measured fluorescent signal;
• wherein the photochemical compound comprises a photoacid or a photobase;
• wherein the species is selected from the group consisting of:
• OH−, H+, a proton acceptor, a proton donor, a dissolved inorganic carbon, formate, acetate, glycine, and phosphate;
• and
• wherein the measured concentration signal has a time resolution of less than one second, and a spatial resolution of less than one micron.