Ultra-sensitive optical fiber sensor based on intermodal interference and temperature calibration for trace detection of copper (II) ions

Abstract

An ultrahigh sensitive optical fiber sensor for trace detection of Cu2+ concentration in aqueous solution with temperature calibration has been developed in this article. Based on the intermodal interference, the sensor is coated with a hydrogel sensing membrane with specific binding to Cu2+ on the no-core fiber/single mode fiber/no-core fiber structure by using our new spray coating method. The imidazole group in the sensing film combines with Cu2+ to produce chelation, which changes the refractive index of the sensing film. The Cu2+ at trace concentration can be detected by monitoring the displacement of the interference trough. The experimental limit of detection of 3.0×10−12 mol/L can be achieved with the spectral resolution of 0.02 nm. The sensor has also long-term stability of the concentration measurement with the average standard deviation of 1.610×10−12 mol/L over 2 hours observation time and can be compensated the influence of ambient temperature on concentration detection by conducting the temperature calibration. In addition, the sensor has the advantages of strong specificity, simple fabrication and low cost.

Tetraaza dibromide/SBA15 as a New Optical Sensing Materials for Copper Ion Detection

“…Optical chemical sensors have attracted many researchers due to their cost-effectiveness 7 , compact, miniaturizable and at the same time they are free of electrical interferences 9 . Various methods have been proposed to detect Cu 2+ ion including uorescence method 10 , colorimetric method 11 , surface plasmon resonance method 12,13 and re ectometry methods 8 . Although uorescence and colorimetric methods come up with high sensitivity for Cu 2+ ion detection, these methods required colour complexing, more chemical reagents, a complex experimental procedure, high-cost equipment and a long detection time 2,12 .…”

“…Various methods have been proposed to detect Cu 2+ ion including uorescence method 10 , colorimetric method 11 , surface plasmon resonance method 12,13 and re ectometry methods 8 . Although uorescence and colorimetric methods come up with high sensitivity for Cu 2+ ion detection, these methods required colour complexing, more chemical reagents, a complex experimental procedure, high-cost equipment and a long detection time 2,12 . While surface plasmon resonance method required expensive metal materials such as gold and the process of the sensor is complicated 12 .…”

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A novel of sensitive and selective optical sensor for copper(II) ion sensor based on tetraaza dibromide, 5,5,7,12,12,4,8, immobilized on Santa Barbara Amorphous (SBA-15) has been successfully developed. The inner and outer space of SBA15 allowed a high capacity of TL compound to immobilise onto it.

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A Microfiber Sensor for the Trace Copper Ions Detection Based on Ternary Sensitive film

“…[20] So far, many fiber optic sensing techniques for detecting metal ions have been proposed, and the main detection methods are intensity detection, [15][16][17]21] plasma, [22] fluorescence effect, [23] and interference wavelength detection. [24] The main trends are the preparation of sensitizing coatings, the use of vernier effects, and the preparation of micron structures. [20] Many structures of optic fiber are suitable for metal ion detection such as Bragg grating, [24] D-shaped fiber, [25] tilted fiber Bragg grating [26] , and microfiber.…”

“…[24] The main trends are the preparation of sensitizing coatings, the use of vernier effects, and the preparation of micron structures. [20] Many structures of optic fiber are suitable for metal ion detection such as Bragg grating, [24] D-shaped fiber, [25] tilted fiber Bragg grating [26] , and microfiber. [27] Among them, optic-microfibers offering the possibility of strong evanescent fields out of fiber cladding for high-sensitive measurement provide a new option to explore more efficient and economical ion concentration sensing applications.In this paper, we present a microfiber interferometer sensor based on a ternary one-piece sensitive film (PVA-APTES-ICA (PVA, Poly(vinyl alcohol); APTES, (3-Aminopropyl)triethoxysilane; ICA, Imidazole-2-carboxaldehyde)) for the detection of copper ion concentration.…”