Erythrosin B encapsulated in a fluoropolymer matrix for dissolved oxygen optical sensing in aggressive aqueous environments

A robust thin film dissolved oxygen sensor was fabricated by trapping erythrosin Bin a flexible fluoropolymer matrix. Strong phosphorescence, which was partially quenched by dissolved oxygen, was observed when the sensor was immersed in water. Residual phosphorescence, which was not quenched by dissolved oxygen, was attributed to the presence of aggregated dye species. The sensor was optically transparent, resistant to contamination, with good mechanical properties. Fast response, coupled with good sensitivity and resistance to leaching, were also exhibited by this system. The Stern-Volmer (SV) plot exhibited marked downward turning at higher oxygen concentrations. A linear plot was obtained when the SV equation was modified to account for the varying sensitivity of dye molecules in the matrix to the quencher.