The mechanism of pyrene fluorescence quenching by selective and nonselective quenchers during sol-gel transition

The process of pyrene fluorescence quenching by potassium iodide, acrylamide, and gaseous oxygen in silane sol during sol-gel transition was investigated. Pyrene fluorescence emission spectra were recorded vs concentrations of the added quencher on consecutive days of the gelling process. When using 0, 20, and 100% oxygen in the gas mixture as a quencher, time-resolved measurements were also made. On this basis, Stern-Volmer constants were determined on consecutive days of the gelling process, availability of fluorophore molecules to the quencher, and also rate constants of pyrene quenching by acrylamide, iodide ions, and oxygen were specified. Moreover, diffusion coefficients were determined for acrylamide and potassium iodide in the silane gel formed. The mechanism of fluorophore quenching in sol of growing viscosity and in gel was discussed in view of using this carrier in the construction of sensors and optical biosensors.[PUBLICATION ABSTRACT]