A Fiber-Optic Evanescent Wave O2 Sensor Based on Ru(II)-Doped Fluorinated ORMOSILs

Abstract

A novel fiber-optic evanescent wave sensor (FOEWS) for O(2) detection based on [Ru(bpy)(3)](2+)-doped hybrid fluorinated ORMOSILs (organically modified silicates) has been developed. The sensing element was fabricated by dip-coating the optical fiber with [Ru(bpy)(3)](2+)-doped hybrid fluorinated ORMOSILs composed of n-propyltrimethoxysilane (n-propyl-TriMOS) and 3, 3, 3-trifluoropropyltrimethoxysilane (TFP-TriMOS). Fluorophores of [Ru(bpy)(3)](2+) were excited by the evanescent wave field produced on the fiber core surface and the emission fluorescence was quenched by O(2). Spectroscopic properties have been characterized by FTIR and UV-VIS absorption measurements. By using the presented hybrid fluorinated ORMOSILs, which enhances the coating surface hydrophobicity, the quenching response is increased. The sensitivity of the sensor is 7.5, which is quantified in terms of the ratio I (N2)/I (O2) (I (N2) and I (O2) represent the fluorescence intensities in pure N(2) and pure O(2) environments, respectively). The limit of detection (L.O.D.) is 0.01% (3sigma) and the response time is about 1 s. Meanwhile, the proposed FOEWS has the advantages of easy fabrication, low cost, fast response and suitable sensitivity for oxygen monitoring using a cheap blue LED as light source and coupling a miniature PMT detector directly to the optical fiber probe.

Ratiometric Dissolved Oxygen Sensors Based on Ruthenium Complex Doped with Silver Nanoparticles

“…Recently, several efforts have been made to investigate mesoporous, micro, and nano-based matrix materials to improve the performance [20,21,22,23,24]. It has been indicated that utilizing micro and nano-materials could enhance the performance of ruthenium complex-based sensors; for instance, improving the limit of detection, stability, and emission intensity [10,25,26]. …”

Tuning oxygen sensitivity of ruthenium complex exploiting silver nanoparticles

“…The ruthenium complexes were intensively used in silicone [3], sol-gel [26][27][28][29][30], ORMOSILs (organically modified silicates) or in modified ORMOSILs [12,31,32]. A detailed comparison of the performances of such optical oxygen sensors in terms of matrix materials, sensitivity, working range and detection limit has been reported earlier [25].…”

Simple and compact optode for real-time in-situ temperature detection in very small samples

“…However, the ORMOSILs-coated probe showed several strong peaks due to existing 3,3,3-trifluoropropyltrimethoxysilicane (TFP-TriMOS) and n-propyltrimethoxysilane (n-propyl-TriMOS) and reaction with surface hydroxyl Si-OH of the fiber optic probe. Except for the peaks for asymmetric and symmetric stretching vibration of Si-O-Si bond, 3,442 cm −1 , 2,980 cm −1 , and 1,635 cm −1 correspond to physical absorption of water, stretching vibration of C-H bond, and surface hydroxyl of Si-OH, respectively, several other groups of strong peaks are also shown20. For example, 1,450, 1,375, and 1,317 cm −1 were corresponding to rocking vibration, wagging vibration, and twisting vibration of C-H for CH 2 , respectively; 1,269 and 1,220 cm −1 correspond to asymmetric and symmetric stretching vibration of C-F bond, respectively; and 901 and 838 cm −1 correspond to vibration of Si-C bond1920.…”

“…Except for the peaks for asymmetric and symmetric stretching vibration of Si-O-Si bond, 3,442 cm −1 , 2,980 cm −1 , and 1,635 cm −1 correspond to physical absorption of water, stretching vibration of C-H bond, and surface hydroxyl of Si-OH, respectively, several other groups of strong peaks are also shown20. For example, 1,450, 1,375, and 1,317 cm −1 were corresponding to rocking vibration, wagging vibration, and twisting vibration of C-H for CH 2 , respectively; 1,269 and 1,220 cm −1 correspond to asymmetric and symmetric stretching vibration of C-F bond, respectively; and 901 and 838 cm −1 correspond to vibration of Si-C bond1920. These results indicate that the ORMOSIL-based film has been successfully modified onto the surface of the fiber optic probe.…”