Nanoporous Zeolite Thin Film-Based Fiber Intrinsic Fabry-Perot Interferometric Sensor for Detection of Dissolved Organics in Water

Abstract

A fiber optic intrinsic Fabry-Perot interferometric (IFPI) chemical sensor was developed by fine-polishing a thin layer of polycrystalline nanoporous MFI zeolite synthesized on the cleaved endface of a single mode fiber. The sensor operated by monitoring the optical thickness changes of the zeolite thin film caused by the adsorption of organic molecules into the zeolite channels. The optical thickness of the zeolite thin film was measured by white light interferometry. Using methanol, 2-propanol, and toluene as the model chemicals, it was demonstrated that the zeolite IPFI sensor could detect dissolved organics in water with high sensitivity.

Chronology of Fabry-Perot Interferometer Fiber-Optic Sensors and Their Applications: A Review

“…One more exciting application is the use of a low-coherence FPI in constructing a surgical tool integrated with a force sensor (FS) which can be used during micro-surgery (e.g., vitreoretinal surgery) [ 152 ]. In addition, an intrinsic FPI sensor fabricated with a nanoporous zeolite thin film was used to detect dissolved organics in water [ 153 ].…”

A Fiber Optic Interferometric Sensor Platform for Determining Gas Diffusivity in Zeolite Films

“…The reflected interferogram quality depends on the smoothness of the zeolite film surface due to light scattering effects. To ensure a strong reflected optical signal, the outer surface of the as synthesized zeolite film was finely polished by an Ultra-Tech precision polishing system [ 16 ]. The zeolite film-coated fiber was dried at 80 °C in an oven and subsequently calcined at 550 °C in air for 4 h to remove the SDA molecules from the zeolite pores with both heating and cooling rates of 5 °C/min.…”

“…The interferogram expressed by Equation (1) is influenced by the source light spectrum. Thus, for eliminating the source light modulation, the interferogram was normalized by a reference spectrum reflected from a cleaved fiber endface before splicing the sensor to the system [ 16 ]. The optical measurement of the dynamic adsorption processes used the following procedure: (1) the baseline interferogram was measured when the signal was stabilized after degassing without adsorbate gas in the sensor chamber; (2) measurement was then switched to monitoring single wavelength reflectance at a 10 Hz recording speed during which the sample gas was introduced by opening the valve located between the sample gas tank and sensor (or to the sample gas flow); (3) when the single wavelength reflectance was stabilized (i.e., adsorption reached equilibrium), the interferogram was scanned and recorded again; and (4) the adsorbate partial pressure in the flow was increased by a small increment and the operation procedure was repeated for staircase measurement.…”

Creation of a new portable biosensor for water toxicity determination

“…1 10 −12 M (0.092 ppm)) -more sensitive than many other approaches (e.g. chemical −2 ppm [64], polymeric membranes −0.1 ppm [65] and quartz chemical sensors array (400 ppm) [66]) and below guidelines established by the US Environmental Protection Agency (EPA) for drinking water [67]. Finally, cells were exposed to different concentrations of formaldehyde (Fig.…”