Improved Integrated Waveguide Absorbance Optodes for Ion-Selective Sensing

Abstract

The first prototype of a technologically improved integrated waveguide absorbance optode (IWAO) was developed and tested with a membrane based on a new H+-selective ketocyanine dye and a cadmium ionophore. It was designed with curved instead of rectilinear planar waveguides. Results demonstrated the suitability of the new IWAOs to be employed as sensing platforms, which confer versatility, robustness, and mass production capabilities besides high sensitivity on conventional bulk optodes, as well as the usefulness of such dyes in developing ion-selective membranes in combination with a selective ionophore. The sensor integration as a detector in a flow injection system (FIA) was proposed to obtain an automated, simple, and sufficiently reproducible (RSD <5%) analytical methodology with a sample throughput of 55 h(-1). Very sensitive optodes were obtained, and detection limits on the order of 20 ppb were achieved. Because of the ionophore employed, the optode system showed excellent selectivity over alkali and alkaline-earth metals with the exception of samples containing lead and cadmium ions, where the membrane responded to both analytes. The proposed procedure combines all the advantages of the FIA systems, the simplicity of optical detection, ion recognition selectivity, and sensitivity of ketocyanine dyes, and the features achieved using the integrated device, which comprise an improved sensitivity and short response times as well as robustness, easy handling, and mass production.

OPTICAL PLANAR WAVEGUIDE SENSOR BASED ON (Yb,Nb):RTP/RTP(001) SYSTEM FOR THE ESTIMATION OF METAL COATED CELLS

“…Metal-tagget objects to be counted biological and chemical sensing [14,[20][21]. We have conducted 3-D simulations by using BeamProp software in order to provide the optimized design with high sensitivity.…”

“…These crystals are orthorhombic, with the space group Pna 21 . These crystals are well known for their large electro-optical coefficients, high nonlinear coefficients and low dielectric constants which make them attractive for electro-optic applications such as modulators and Q-switches [1].…”

Application Progress of Optical Waveguide Sensor in the Gas Detection

“…。近 年来，国内外先后研制出各种光波导气体传感器 [3][4][5][6] ， 光波导离子传感器 [7,8] ，光波导湿度传感器 [9] ，光波导 生物传感器 [10] 和物理传感器 [11] 等等。光波导传感器 光波导传感器在气体检测中的应用进展 具有更有利于实现多功能集成，紧凑封装和批量生 产，低耗高效，容易实现在线检测等一系列跟其他结 构的传感器无法比拟的优势。玻璃光波导传感元件作 为新一代微型化、集成化和智能化传感器系统的重要 组成部分，在传感器领域中占有越来越重要的地位 [12,13] 。 平面光波导(OWG)由覆盖层， 衬底(substrate)和导 波层(waveguide layer)所组成 [14] ， 覆盖层通常指的是空 …”

A 2D MEMS grating based CMOS compatible poly-SiGe variable optical attenuator

“…E.g. the membranes used in the absorbance based optodes which are susceptible to degradation due to excessive optical power [3]. Also, with increasing popularity of Visible Light communications (VLC), use of VOAs in the visible wavelength is becoming more and more popular [4].…”