Optical fiber sensor for dual sensing of H2O2 and DO based on CdSe/ZnS QDs and Ru(dpp)32+ embedded in EC matrix

In this study, a simple and cost-effective technique to fabricate a plastic optical fiber sensor for the dual sensing of hydrogen peroxide (H2O2) and dissolved oxygen (DO) was described. The optical fiber dual sensor consisted of CdSe/ZnS core-shell quantum dots (QDs), with oxygen indicators coated on the fiber end of the sensor. An ethyl cellulose (EC) matrix doped with CdSe/ZnS QDs and tris(4,7-dipheny-1,10-phenanthroline)ruthenium(II) (Ru(dpp)3(2+)) served as the sensing materials for H2O2 and DO. The sensing materials for H2O2 and DO were excited with an light emitting diode (LED) of 405 nm, and the two emission wavelengths were separately detected. The optical fiber dual sensor was applied for the monitoring of different H2O2 and DO concentrations. The typical Stern-Volmer plot of an optical fiber dual sensor for the sensing of DO demonstrated linearity, and the attenuation of the relative phosphorescence intensity for the sensing of H2O2 concentrations also demonstrated linearity with the H2O2 concentrations in the tested range. In addition, the results indicated that the phosphorescence properties of the H2O2 sensor are independent of the presence of the DO sensor, with a unique linear response in the range of 0-132 mM. Finally, the DO sensing scheme described herein was intended to compensate for the H2O2 concentration, and the fabricated optical fiber dual sensor may be used for the sensing of H2O2 concentration and DO in the aquaculture applications. (C) 2017 Elsevier B.V. All rights reserved.