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Sensors, Volume 12, Issue 6 (June 2012), Pages 6764-8437

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Open AccessCorrection Correction: Renaudin, V. et al. Use of Earth’s Magnetic Field for Mitigating Gyroscope Errors Regardless of Magnetic Perturbation. Sensors 2011, 11, 11390-11414
Sensors 2012, 12(6), 8437; https://doi.org/10.3390/s120608437
Received: 1 June 2012 / Accepted: 20 June 2012 / Published: 20 June 2012
PDF Full-text (214 KB) | HTML Full-text | XML Full-text
Abstract
Although the equations’ derivation in our paper published in Sensors 2011 [1] is correct, a typo has been found in the summarizing Equations (48) and (49). The dot on the B in the skew matrix should be removed. [...] Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Multiplex Immunoassay Platforms Based on Shape-Coded Poly(ethylene glycol) Hydrogel Microparticles Incorporating Acrylic Acid
Sensors 2012, 12(6), 8426-8436; https://doi.org/10.3390/s120608426
Received: 3 May 2012 / Revised: 25 May 2012 / Accepted: 5 June 2012 / Published: 20 June 2012
Cited by 12 | PDF Full-text (621 KB) | HTML Full-text | XML Full-text
Abstract
A suspension protein microarray was developed using shape-coded poly(ethylene glycol) (PEG) hydrogel microparticles for potential applications in multiplex and high-throughput immunoassays. A simple photopatterning process produced various shapes of hydrogel micropatterns that were weakly bound to poly(dimethylsiloxane) (PDMS)-coated substrates. These micropatterns were easily
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A suspension protein microarray was developed using shape-coded poly(ethylene glycol) (PEG) hydrogel microparticles for potential applications in multiplex and high-throughput immunoassays. A simple photopatterning process produced various shapes of hydrogel micropatterns that were weakly bound to poly(dimethylsiloxane) (PDMS)-coated substrates. These micropatterns were easily detached from substrates during the washing process and were collected as non-spherical microparticles. Acrylic acids were incorporated into hydrogels, which could covalently immobilize proteins onto their surfaces due to the presence of carboxyl groups. The amount of immobilized protein increased with the amount of acrylic acid due to more available carboxyl groups. Saturation was reached at 25% v/v of acrylic acid. Immunoassays with IgG and IgM immobilized onto hydrogel microparticles were successfully performed with a linear concentration range from 0 to 500 ng/mL of anti-IgG and anti-IgM, respectively. Finally, a mixture of two different shapes of hydrogel microparticles immobilizing IgG (circle) and IgM (square) was prepared and it was demonstrated that simultaneous detection of two different target proteins was possible without cross-talk using same fluorescence indicator because each immunoassay was easily identified by the shapes of hydrogel microparticles. Full article
(This article belongs to the Special Issue Micro and Nano Technologies for Point-of-Care Diagnosis)
Open AccessArticle Evaluation of Complexation Ability Using a Sensor Electrode Chip Equipped with a Wireless Screening System
Sensors 2012, 12(6), 8405-8425; https://doi.org/10.3390/s120608405
Received: 12 April 2012 / Revised: 30 May 2012 / Accepted: 11 June 2012 / Published: 19 June 2012
Cited by 2 | PDF Full-text (591 KB) | HTML Full-text | XML Full-text
Abstract
We fabricated an electrode chip with a structure coated by an insulation layer that contains dispersed SiO2 adsorbent particles modified by an amino-group on a source-drain electrode. Voltage changes caused by chelate molecule adsorption onto electrode surfaces and by specific cation interactions
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We fabricated an electrode chip with a structure coated by an insulation layer that contains dispersed SiO2 adsorbent particles modified by an amino-group on a source-drain electrode. Voltage changes caused by chelate molecule adsorption onto electrode surfaces and by specific cation interactions were investigated. The detection of specific cations without the presence of chelate molecules on the free electrode was also examined. By comparing both sets of results the complexation ability of the studied chelate molecules onto the electrode was evaluated. Five pairs of source-drain electrodes (×8 arrays) were fabricated on a glass substrate of 20 × 30 mm in size. The individual Au/Cr (1.0/0.1 μm thickness) electrodes had widths of 50 μm and an inter-electrode interval of 100 μm. The fabricated source-drain electrodes were further coated with an insulation layer comprising a porous SiO2 particle modified amino-group to adsorb the chelate molecules. The electrode chip was equipped with a handy-type sensor signal analyzer that was mounted on an amplifier circuit using a MinishipTM or a system in a packaged LSI device. For electrode surfaces containing different adsorbed chelate molecules an increase in the sensor voltage depended on a combination of host-guest reactions and generally decreased in the following order: 5,10,15,20-tetrakis(N-methylpyridinium-4-yl)-21H,23H-porphine, tetrakis(p-toluenesulfonate) (TMPyP) as a Cu2+ chelator and Cu2+ > 2-nitroso-5-[N-n-propyl-N-(3-sulfopropyl)amino]phenol (nitroso-PSAP) as an Fe2+ chelator and Fe2+ > 4,7-diphenyl-1,10-phenanthrolinedisulfonic acid, disodium salt (BPDSA) as an Fe2+ chelator and Fe2+ > 3-[3-(2,4-dimethylphenylcarbamoyl)-2-hydroxynaphthalene-1-yl-azo]-4-hydroxybenzenesulfonic acid, sodium salt (XB-1) as a Mg2+ chelator and Mg2+ > 2,9-dimethyl-4,7-diphenyl-1,10-phenanthrolinedisulfonic acid, disodium salt (BCIDSA) as a Cu2+ chelator and Cu2+, respectively. In contrast, for the electrode surfaces with adsorbed O,O'-bis(2-aminoethyl)ethyleneglycol-N,N,N',N'-tetraacetic acid (GEDTA) or O,O'-bis(2-aminophenyl)ethyleneglycol-N,N,N',N'-tetraacetic acid, tetrapotassium salt, hydrate (BAPTA) as a Ca2+ chelator no increase in the detection voltage was found for all the electrode tests conducted in the presence of Ca2+. To determine the differences in electrode detection, molecular orbital (MO) calculations of the chelate molecules and surface molecular modeling of the adsorbents were carried out. In accordance with frontier orbital theory, the lowest unoccupied MO (LUMO) of the chelate molecules can accept two lone pair electrons at the highest occupied MO (HOMO) of the amino group on the model surface structure of the SiO2 particle. As a result, a good correlation was obtained between the LUMO-HOMO difference and the ion response of all the electrodes tested. Based on the results obtained, the order of adsorbed chelate molecules on adsorption particles reflects the different metal ion detection abilities of the electrode chips. Full article
(This article belongs to the Special Issue Selective Chelating Agents)
Open AccessArticle Direct Measurement of Mammographic X-Ray Spectra with a Digital CdTe Detection System
Sensors 2012, 12(6), 8390-8404; https://doi.org/10.3390/s120608390
Received: 8 May 2012 / Revised: 11 June 2012 / Accepted: 12 June 2012 / Published: 18 June 2012
Cited by 17 | PDF Full-text (487 KB) | HTML Full-text | XML Full-text
Abstract
In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate X-ray spectroscopy in mammography (1–30 keV). The DPP system performs a height and shape analysis of the detector pulses, sampled
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In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate X-ray spectroscopy in mammography (1–30 keV). The DPP system performs a height and shape analysis of the detector pulses, sampled and digitized by a 14-bit, 100 MHz ADC. We show the results of the characterization of the detection system both at low and high photon counting rates by using monoenergetic X-ray sources and a nonclinical X-ray tube. The detection system exhibits excellent performance up to 830 kcps with an energy resolution of 4.5% FWHM at 22.1 keV. Direct measurements of clinical molybdenum X-ray spectra were carried out by using a pinhole collimator and a custom alignment device. A comparison with the attenuation curves and the half value layer values, obtained from the measured and simulated spectra, from an ionization chamber and from a solid state dosimeter, also shows the accuracy of the measurements. These results make the proposed detection system a very attractive tool for both laboratory research, calibration of dosimeters and advanced quality controls in mammography. Full article
(This article belongs to the Special Issue Ultra-Small Sensor Systems and Components)
Open AccessReview Fiber Optic-Based Refractive Index Sensing at INESC Porto
Sensors 2012, 12(6), 8371-8389; https://doi.org/10.3390/s120608371
Received: 2 May 2012 / Revised: 4 June 2012 / Accepted: 6 June 2012 / Published: 18 June 2012
Cited by 17 | PDF Full-text (430 KB) | HTML Full-text | XML Full-text
Abstract
A review of refractive index measurement based on different types of optical fiber sensor configurations and techniques is presented. It addresses the main developments in the area, with particular focus on results obtained at INESC Porto, Portugal. The optical fiber sensing structures studied
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A review of refractive index measurement based on different types of optical fiber sensor configurations and techniques is presented. It addresses the main developments in the area, with particular focus on results obtained at INESC Porto, Portugal. The optical fiber sensing structures studied include those based on Bragg and long period gratings, on micro-interferometers, on plasmonic effects in fibers and on multimode interference in a large spectrum of standard and microstructured optical fibers. Full article
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Portugal)
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Open AccessArticle License Plate Recognition Algorithm for Passenger Cars in Chinese Residential Areas
Sensors 2012, 12(6), 8355-8370; https://doi.org/10.3390/s120608355
Received: 20 March 2012 / Revised: 7 June 2012 / Accepted: 7 June 2012 / Published: 15 June 2012
Cited by 17 | PDF Full-text (783 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a solution for the license plate recognition problem in residential community administrations in China. License plate images are pre-processed through gradation, middle value filters and edge detection. In the license plate localization module the number of edge points, the length
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This paper presents a solution for the license plate recognition problem in residential community administrations in China. License plate images are pre-processed through gradation, middle value filters and edge detection. In the license plate localization module the number of edge points, the length of license plate area and the number of each line of edge points are used for localization. In the recognition module, the paper applies a statistical character method combined with a structure character method to obtain the characters. In addition, more models and template library for the characters which have less difference between each other are built. A character classifier is designed and a fuzzy recognition method is proposed based on the fuzzy decision-making method. Experiments show that the recognition accuracy rate is up to 92%. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle A Miniature Integrated Multimodal Sensor for Measuring pH, EC and Temperature for Precision Agriculture
Sensors 2012, 12(6), 8338-8354; https://doi.org/10.3390/s120608338
Received: 30 April 2012 / Revised: 30 May 2012 / Accepted: 1 June 2012 / Published: 15 June 2012
Cited by 20 | PDF Full-text (1140 KB) | HTML Full-text | XML Full-text
Abstract
Making several simultaneous measurements with different kinds of sensors at the same location in a solution is difficult because of crosstalk between the sensors. In addition, because the conditions at different locations in plant beds differ, in situ measurements in agriculture need to
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Making several simultaneous measurements with different kinds of sensors at the same location in a solution is difficult because of crosstalk between the sensors. In addition, because the conditions at different locations in plant beds differ, in situ measurements in agriculture need to be done in small localized areas. We have fabricated a multimodal sensor on a small Si chip in which a pH sensor was integrated with electrical conductivity (EC) and temperature sensors. An ISFET with a Si3N4 membrane was used for the pH sensor. For the EC sensor, the electrical conductivity between platinum electrodes was measured, and the temperature sensor was a p-n junction diode. These are some of the most important measurements required for controlling the conditions in plant beds. The multimodal sensor can be inserted into a plant bed for in situ monitoring. To confirm the absence of crosstalk between the sensors, we made simultaneous measurements of pH, EC, and temperature of a pH buffer solution in a plant bed. When the solution was diluted with hot or cold water, the real time measurements showed changes to the EC and temperature, but no change in pH. We also demonstrated that our sensor was capable of simultaneous in situ measurements in rock wool without being affected by crosstalk. Full article
(This article belongs to the Special Issue Ultra-Small Sensor Systems and Components)
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Open AccessReview Diagnostic Devices for Isothermal Nucleic Acid Amplification
Sensors 2012, 12(6), 8319-8337; https://doi.org/10.3390/s120608319
Received: 2 May 2012 / Revised: 29 May 2012 / Accepted: 7 June 2012 / Published: 14 June 2012
Cited by 57 | PDF Full-text (3895 KB) | HTML Full-text | XML Full-text
Abstract
Since the development of the polymerase chain reaction (PCR) technique, genomic information has been retrievable from lesser amounts of DNA than previously possible. PCR-based amplifications require high-precision instruments to perform temperature cycling reactions; further, they are cumbersome for routine clinical use. However, the
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Since the development of the polymerase chain reaction (PCR) technique, genomic information has been retrievable from lesser amounts of DNA than previously possible. PCR-based amplifications require high-precision instruments to perform temperature cycling reactions; further, they are cumbersome for routine clinical use. However, the use of isothermal approaches can eliminate many complications associated with thermocycling. The application of diagnostic devices for isothermal DNA amplification has recently been studied extensively. In this paper, we describe the basic concepts of several isothermal amplification approaches and review recent progress in diagnostic device development. Full article
(This article belongs to the Special Issue Biomarkers and Nanosensors: New Approaches for Biology and Medicine)
Open AccessArticle Intelligent Lead: A Novel HRI Sensor for Guide Robots
Sensors 2012, 12(6), 8301-8318; https://doi.org/10.3390/s120608301
Received: 23 May 2012 / Revised: 6 June 2012 / Accepted: 6 June 2012 / Published: 14 June 2012
Cited by 17 | PDF Full-text (1313 KB) | HTML Full-text | XML Full-text
Abstract
This paper addresses the introduction of a new Human Robot Interaction (HRI) sensor for guide robots. Guide robots for geriatric patients or the visually impaired should follow user’s control command, keeping a certain desired distance allowing the user to work freely. Therefore, it
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This paper addresses the introduction of a new Human Robot Interaction (HRI) sensor for guide robots. Guide robots for geriatric patients or the visually impaired should follow user’s control command, keeping a certain desired distance allowing the user to work freely. Therefore, it is necessary to acquire control commands and a user’s position on a real-time basis. We suggest a new sensor fusion system to achieve this objective and we will call this sensor the “intelligent lead”. The objective of the intelligent lead is to acquire a stable distance from the user to the robot, speed-control volume and turn-control volume, even when the robot platform with the intelligent lead is shaken on uneven ground. In this paper we explain a precise Extended Kalman Filter (EKF) procedure for this. The intelligent lead physically consists of a Kinect sensor, the serial linkage attached with eight rotary encoders, and an IMU (Inertial Measurement Unit) and their measurements are fused by the EKF. A mobile robot was designed to test the performance of the proposed sensor system. After installing the intelligent lead in the mobile robot, several tests are conducted to verify that the mobile robot with the intelligent lead is capable of achieving its goal points while maintaining the appropriate distance between the robot and the user. The results show that we can use the intelligent lead proposed in this paper as a new HRI sensor joined a joystick and a distance measure in the mobile environments such as the robot and the user are moving at the same time. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessReview Atomic Force Microscopy as a Tool Applied to Nano/Biosensors
Sensors 2012, 12(6), 8278-8300; https://doi.org/10.3390/s120608278
Received: 5 April 2012 / Revised: 1 June 2012 / Accepted: 5 June 2012 / Published: 14 June 2012
Cited by 30 | PDF Full-text (731 KB) | HTML Full-text | XML Full-text
Abstract
This review article discusses and documents the basic concepts and principles of nano/biosensors. More specifically, we comment on the use of Chemical Force Microscopy (CFM) to study various aspects of architectural and chemical design details of specific molecules and polymers and its influence
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This review article discusses and documents the basic concepts and principles of nano/biosensors. More specifically, we comment on the use of Chemical Force Microscopy (CFM) to study various aspects of architectural and chemical design details of specific molecules and polymers and its influence on the control of chemical interactions between the Atomic Force Microscopy (AFM) tip and the sample. This technique is based on the fabrication of nanomechanical cantilever sensors (NCS) and microcantilever-based biosensors (MC-B), which can provide, depending on the application, rapid, sensitive, simple and low-cost in situ detection. Besides, it can provide high repeatability and reproducibility. Here, we review the applications of CFM through some application examples which should function as methodological questions to understand and transform this tool into a reliable source of data. This section is followed by a description of the theoretical principle and usage of the functionalized NCS and MC-B technique in several fields, such as agriculture, biotechnology and immunoassay. Finally, we hope this review will help the reader to appreciate how important the tools CFM, NCS and MC-B are for characterization and understanding of systems on the atomic scale. Full article
(This article belongs to the Section Chemical Sensors)
Open AccessArticle Experimental Artifacts for Morphological Tweaking of Chemical Sensor Materials: Studies on ZnO
Sensors 2012, 12(6), 8259-8277; https://doi.org/10.3390/s120608259
Received: 2 May 2012 / Revised: 29 May 2012 / Accepted: 6 June 2012 / Published: 13 June 2012
Cited by 3 | PDF Full-text (1864 KB) | HTML Full-text | XML Full-text
Abstract
Sensing mechanisms of gases on solid structures are predominantly surface-dominated. Benign surface features in terms of small grain size, high aspect ratio, large surface area and open and connected porosity, are required to realize a successful sensor material. Such morphological artifacts are a
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Sensing mechanisms of gases on solid structures are predominantly surface-dominated. Benign surface features in terms of small grain size, high aspect ratio, large surface area and open and connected porosity, are required to realize a successful sensor material. Such morphological artifacts are a function of the fabrication and processing techniques employed. In this paper, we describe the fabrication of monoshaped and monosized zinc oxide (ZnO) particles by a homogeneous precipitation method, using urea and/or hexmethyltetraamine as the reductant. The effect of operating conditions and experimental variables, such as the relative concentration of the precursors, temperature, and the aging time on the morphology of the resulting particles was studied systematically. These experimental parameters were optimized in order to achieve particles of uniform morphology and of narrow size distribution. Some of these particles were employed for the detection of ammonia gas at room temperature. Full article
(This article belongs to the Special Issue Sensing at the Nano-Scale: Chemical and Bio-Sensing)
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Open AccessArticle An Indoor Navigation System for the Visually Impaired
Sensors 2012, 12(6), 8236-8258; https://doi.org/10.3390/s120608236
Received: 27 April 2012 / Revised: 29 May 2012 / Accepted: 31 May 2012 / Published: 13 June 2012
Cited by 58 | PDF Full-text (873 KB) | HTML Full-text | XML Full-text
Abstract
Navigation in indoor environments is highly challenging for the severely visually impaired, particularly in spaces visited for the first time. Several solutions have been proposed to deal with this challenge. Although some of them have shown to be useful in real scenarios, they
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Navigation in indoor environments is highly challenging for the severely visually impaired, particularly in spaces visited for the first time. Several solutions have been proposed to deal with this challenge. Although some of them have shown to be useful in real scenarios, they involve an important deployment effort or use artifacts that are not natural for blind users. This paper presents an indoor navigation system that was designed taking into consideration usability as the quality requirement to be maximized. This solution enables one to identify the position of a person and calculates the velocity and direction of his movements. Using this information, the system determines the user’s trajectory, locates possible obstacles in that route, and offers navigation information to the user. The solution has been evaluated using two experimental scenarios. Although the results are still not enough to provide strong conclusions, they indicate that the system is suitable to guide visually impaired people through an unknown built environment. Full article
Open AccessArticle A Fast MEANSHIFT Algorithm-Based Target Tracking System
Sensors 2012, 12(6), 8218-8235; https://doi.org/10.3390/s120608218
Received: 13 April 2012 / Revised: 9 May 2012 / Accepted: 22 May 2012 / Published: 13 June 2012
Cited by 4 | PDF Full-text (3880 KB) | HTML Full-text | XML Full-text
Abstract
Tracking moving targets in complex scenes using an active video camera is a challenging task. Tracking accuracy and efficiency are two key yet generally incompatible aspects of a Target Tracking System (TTS). A compromise scheme will be studied in this paper. A fast
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Tracking moving targets in complex scenes using an active video camera is a challenging task. Tracking accuracy and efficiency are two key yet generally incompatible aspects of a Target Tracking System (TTS). A compromise scheme will be studied in this paper. A fast mean-shift-based Target Tracking scheme is designed and realized, which is robust to partial occlusion and changes in object appearance. The physical simulation shows that the image signal processing speed is > 50 frame/s. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Open-WiSe: A Solar Powered Wireless Sensor Network Platform
Sensors 2012, 12(6), 8204-8217; https://doi.org/10.3390/s120608204
Received: 1 May 2012 / Revised: 4 June 2012 / Accepted: 8 June 2012 / Published: 13 June 2012
Cited by 15 | PDF Full-text (738 KB) | HTML Full-text | XML Full-text
Abstract
Because battery-powered nodes are required in wireless sensor networks and energy consumption represents an important design consideration, alternate energy sources are needed to provide more effective and optimal function. The main goal of this work is to present an energy harvesting wireless sensor
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Because battery-powered nodes are required in wireless sensor networks and energy consumption represents an important design consideration, alternate energy sources are needed to provide more effective and optimal function. The main goal of this work is to present an energy harvesting wireless sensor network platform, the Open Wireless Sensor node (WiSe). The design and implementation of the solar powered wireless platform is described including the hardware architecture, firmware, and a POSIX Real-Time Kernel. A sleep and wake up strategy was implemented to prolong the lifetime of the wireless sensor network. This platform was developed as a tool for researchers investigating Wireless sensor network or system integrators. Full article
Open AccessArticle A Novel Sensor for Monitoring of Iron(III) Ions Based on Porphyrins
Sensors 2012, 12(6), 8193-8203; https://doi.org/10.3390/s120608193
Received: 9 April 2012 / Revised: 27 May 2012 / Accepted: 8 June 2012 / Published: 13 June 2012
Cited by 35 | PDF Full-text (202 KB) | HTML Full-text | XML Full-text
Abstract
Three A3B porphyrins with mixed carboxy-, phenoxy-, pyridyl- and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition
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Three A3B porphyrins with mixed carboxy-, phenoxy-, pyridyl- and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used as additive (20 mol% relative to ionophore). The performance characteristics (linear concentration range, slope and selectivity) of the sensors were investigated. The best results were obtained for the membrane based on 5-(4-carboxyphenyl)-10,15,20-tris(4-phenoxyphenyl)-porphyrin plasticized with bis(2-ethylhexyl)sebacate, in a linear range from 1 × 10−7–1 × 10−1 M with a slope of 21.6 mV/decade. The electrode showed high selectivity with respect to alkaline and heavy metal ions and a response time of 20 s. The influence of pH on the sensor response was studied. The sensor was used for a period of six weeks and the utility has been tested for the quantitative determination of Fe(III) in recovered solutions from spent lithium ion batteries and for the quantitative determination of Fe(III) in tap water samples. Full article
(This article belongs to the Section Chemical Sensors)
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