Ratiometric Sensing of Hydrogen Peroxide Utilizing Conformational Change in Fluorescent Boronic Acid Polymers.

We demonstrate that the copolymers containing boronic acid and pyrene units can be utilized for the fluorometric sensing of hydrogen peroxide (H ₂ O ₂ ) in aqueous solutions. The copolymer exists in a relatively extended conformation in the absence of H ₂ O ₂ , whereas the polymer chain is contracted by the reaction of boronic acid moieties with H ₂ O ₂ to form phenol groups. This conformational change induces aggregation of the originally isolated pyrene groups. As a result, relative intensity of excimer emission with respect to monomer emission increases with H ₂ O ₂ concentration. Accordingly, the present methodology enables us to measure H ₂ O ₂ by means of ratiometric fluorescence change in the range of 0-30  μ M.