Fluorescence Spectroelectrochemical Sensor for 1-Hydroxypyrene

摘要

A spectroelectrochemical sensor was demonstrated for annorganic compound whose oxidation proceeds through annelectron transfer-chemical reaction-electron transfern(ECE) mechanism to generate new chemical species thatnare used for detection by fluorescence. The polycyclicnaromatic hydrocarbon 1-hydroxypyrene (1-PyOH) servednas a representative model analyte. The spectroelectrochemicalnproperties of 1-PyOH in solution were explorednwith an optically transparent thin layer electrode. Electrochemicalnoxidation of 1-PyOH under acidic conditionsnproceeds via the ECE mechanism to a diquinonepyrene,nwhich shows reversible electrochemistry and fluorescesnat 425 nm in its reduced form, dihydroxypyrene. Thensensor consisted of a tin-doped indium optically transparentnelectrode coated with a Nafion thin-film (20 nm) thatnrapidly preconcentrated the analyte at the sensor surface.nFluorescence in the film was excited by the evanescentnwave from attenuated total reflection spectroscopy. Electrochemicalnmodulation of dihydroxypyrene fluorescencenat 425 nm in the 500 to -200 mV (vs Ag/AgCl) potentialnrange was used for indirect detection of 1-PyOH. Thenspectroelectrochemical sensor calibration curve had anrange of 5 × 10-9 to 1 × 10-6 M with a calculatedndetection limit of 1 × 10-9 M.