Fiber optic sensors using novel substrates for hydrogen sulfide determination by solid surface fluorescence

Download
2000-10-02
Two different fiber optic sensors were developed for the determination of hydrogen sulfide at ppb concentration levels; a probe-type fiber optic sensor coated with polyethylene oxide containing 0.5 M CdCl2 and a fiber optic sensor utilizing 0.5 M CdCl2-pretreated filter paper as solid substrate. In the first type, CdCl2-polyethyleneoxide (PEO) mixture was coated onto the tip of a fiber optic probe and the probe was exposed to H2S. The methodology is based on the measurement of CdS fluorescence on the surface. Detection limit (3s) of the PEG-coated fiber optic system was 36.0 ppb for H2S and precision at the 0.552 ppm level was 29% R.S.D. For the fiber optic system utilizing CdCl2-pretreated filter paper, two different configurations were devised and evaluated; a bifurcated fiber optic sensor and a single fiber optic sensor. Similar figures were obtained with these two systems; the detection limit (3s) was 4.0 ppb for the bifurcated fiber optic sensor and 4.3 ppb for the single fiber optic sensor, and both sensors had linear responses in the range 0.032-1.0 ppm. Their precisions at 0.299 ppm level were also very similar, 10 and 11% R.S.D., respectively, for the bifurcated and single fiber systems. In addition to the tiber optic sensors developed, various surfactants (sodiumdodecylsulfate (SDS), Aerosol OT, Aerosol A102, Aerosol 501), some cellulosic substances (sodium carboxymethylcellulose (CMC), ethylcellulose, hydroxypropylmethylcellulose! ethylhydroxyethylcellulose, cc-cellulose) and several water-soluble polymers (polyacrylicacid polyethleneoxide (PEO), polyvinylalcohol (PVA)) were dissolved in proper solvents and after mixing with 0.5 M CdCl2, were spread over glass slides. These novel solid substrates were exposed to H2S and fluorescence signal on the surfaces of the glass slides was measured with a luminescence spectrometer. The new substrates were shown to be good alternatives to filter paper for the determination of H2S by room temperature solid surface fluorescence spectrometry.

Suggestions

Intracavity gas detection with fiber loop ring down spectroscopy
Yolalmaz, Alim; Hanifehpour Sadroud, Farhad; Danışman, Mehmet Fatih; Esentürk, Okan (Elsevier BV, 2017-8)
In this study, an easy to construct and sensitive intracavity fiber loop ring down spectrometer was built by commercially available basic components and its application on chemical sensing is presented. System performance was investigated by using various acetylene/nitrogen gas mixtures as a function of total pressure (between 25 and 65 psia) in sensing region and a calibration curve is established. The instrument can achieve a limit of detection of 0.1% without a FBG and/or EDFA or a need for a complicated...
Oxygen vacancies on Pd/TiO2 are detected at low pressures by ESR spectroscopy at ambient temperatures
Üner, Deniz; Yarar, Melis (2022-1-01)
All rights reserved.A low field benchtop electron spin resonance (ESR) (also referred to as electron paramagnetic resonance (EPR)) spectrometer is used to reveal paramagnetic centres such as oxygen vacancies and Ti+3 centres over 0.5%Pd/TiO2. The measurement was performed at room temperature after the sample was reduced in situ under mild hydrogen pressures and evacuated to P < 10–6 Torr. The measurement was possible due to a T1 compensation effect under vacuum: Correlation times at low pressures enabled su...
Dynamical analysis of the fiber optic coils through multiscale numerical modeling and modal tests
Kahveci, Özkan; Yalçınkaya, Tuncay; Department of Aerospace Engineering (2022-4-28)
Fiber optic gyroscopes (FOGs) are common rotation measurement devices in aerospace applications. They have a wide range of diversity in length and winding radius of coils to meet the system requirements. Every dimensional parameter in the coil influences the dynamic response of the system, which eventually leads to measurement errors. In order to eliminate the errors and qualify the system, after the design and production stages, a deep and comprehensive testing procedure follows. In this study, the dynamic...
Determination of kinetic parameters and hydrogen desorption characteristics of MgH2-10 wt% (9Ni-2Mg-Y) nano-composite
Pourabdoli, Mehdi; Raygan, Shahram; Abdizadeh, Hossein; Üner, Deniz (2013-09-10)
Hydrogen desorption kinetic parameters of MgH2 compounds were measured and compared with published gas solid reaction models. The compounds investigated in this study were as-received MgH2, ball milled MgH2, and MgH2 ball milled with 9Ni-2Mg-Y catalyst compound. It was determined that different models were necessary to fit the hydrogen desorption data collected at different temperatures on the same sample, indicating that desorption mechanisms changed with respect to temperature. Addition of (9Ni-2Mg-Y) all...
Tuning the electron beam evaporation parameters for the production of hole and electron transport layers for perovskite solar cells
Coşar, Mustafa Bura; Özenbaş, Ahmet Macit; Department of Metallurgical and Materials Engineering (2019)
This study evaluates the use of electron beam evaporation technique for the deposition of electron and hole transport layers for perovskite solar cells where cell productions were performed in n-i-p structure. NiO and TiO layers were studied for hole transport layer and TiO2 and Nb2O5 layers were deposited for electron transport purposes. To optimize the suitable evaporation parameters for efficient perovskite cell production, single layers of each material were deposited at different conditions of oxygen f...
Citation Formats
A. Eroglu, M. Volkan, and O. Y. Ataman, “Fiber optic sensors using novel substrates for hydrogen sulfide determination by solid surface fluorescence,” TALANTA, pp. 89–101, 2000, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/32531.