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ion-selective electrode

Ruigang Xie, Lingli Zhou, Cuiling Lan, Fangfang Fan, Ruifeng Xie, Hongyu Tan, Tiansheng Xie, Lingmin Zhao
Nanostructured carbon black (CB) was first employed directly in this paper for the simultaneous electrochemical determination of trace Pb(II) and Cd(II) using differential pulse anodic stripping voltammetry. The morphology and surface properties of conductive CB were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy and Raman spectroscopy. Special pore structures, as well as surface chemical functional groups, endow CB with excellent catalytic and adsorption properties...
July 2018: Royal Society Open Science
L Vorster, S Naidoo, N Stauf, C Holmgren, H Benzian
A high dental caries burden coupled with a lack of water or salt fluoridation make it imperative that toothpastes available to the South African consumer demonstrate adequate potential for caries control and contain between 1000ppm and 1500ppm total fluoride (TF), with at least 1000ppm F in free available/soluble form. METHODS: The objective was to determine TF, total soluble fluoride (TSF) and insoluble fluoride (IF) concentrations in 22 fluoride toothpastes commercially available in South Africa...
August 9, 2018: Community Dental Health
Duried Alwazeer, Christophe Riondet, Rémy Cachon
The intracellular pH (pHin ) of Leuconostoc mesenteroides subsp. mesenteroides 19D was evaluated by two different methods, fluorescent probe and ion-selective electrode. Two fluorescent probes 5 (and-6)-carboxyfluorescein diacetate succinimidyl ester (cFDASE) and 5 (and-6)-carboxy-2',7'-dichlorofluorescein diacetate succinimidyl ester (cDCFDASE) were tested to evaluate the intracellular pH (pHin ) of living cells at a medium pH (pHex ) ranged from 5.0 to 6.5. Salicylic acid was used as a probe for the ion-selective electrode method...
August 13, 2018: Current Microbiology
F M Trefz, I Lorenz, P D Constable
An ion-selective electrode (ISE) handheld meter (LAQUAtwin B-731; Horiba) has recently become available for the measurement of potassium concentrations [K+ ] in biological fluids. The ISE meter has the potential to facilitate the diagnosis and treatment of potassium balance disorders of critically ill cattle. The objective of this study was to characterise the analytical performance of the ISE meter in a study sample of hospitalised calves with a broad range of plasma [K+ ]. For the purpose of the study, whole blood and plasma samples from 125 calves (age≤3months) were used for analysis...
August 2018: Veterinary Journal
Rahul Agarwal, Manoj Kumar Sharma
Separation of uranium (U) from interfering lanthanide ions (Ln3+ ) in aqueous medium is important in view of sustainable nuclear power production and remediation of radioactive waste. Separation of U in aqueous medium by electrochemical means is still unexplored. Herein, we report electrochemical separation of U from interfering lanthanides ions in 0.1 M KCl on poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) modified platinum (PEDOT:PSS/Pt) electrode. U in solution commonly exists as uranyl (UO2 2+ )...
August 13, 2018: Inorganic Chemistry
Mona N Sweilam, John Robert Varcoe, Carol Crean
A miniaturized, flexible fiber-based lithium sensor was fabricated from low-cost cotton using a simple, repeatable dip-coating technique. This lithium sensor is highly suited for ready-to-use wearable applications and can be used directly with-out the preconditioning steps normally required with traditional ion-selective electrodes. The sensor has a stable, rapid and accurate response over a wide Li+ concentration range that spans over the clinically effective and the toxic concentration limits for lithium in human serum...
August 10, 2018: ACS Sensors
Sara Dehdashtian, Mojtaba Shamsipur
Among the toxic metals, cadmium is a very dangerous pollutant because it can extremely damage organs in humans and animals. This toxic metal is introduced into water from different industries such as metal plating, batteries, and alloys. Cadmium bioaccumulates in vital organs and unlike organic pollutants does not show any biological degradation. In this study, an electroactive self-assembled monolayer (SAM) was developed by covalent attachment of a novel mono aza-crown ether substituted catechol-terminated hexane dithiol onto the gold surface...
July 29, 2018: Colloids and Surfaces. B, Biointerfaces
Kaiyu Fu, Donghoon Han, Seung-Ryong Kwon, Paul W Bohn
Inspired by the functioning of cellular ion channels, pore-based structures with nanoscale openings, have been fabricated and integrated into ionic circuits, e.g. ionic diodes and transistors, for signal processing and detection. In these systems, the nonlinear current responses arise either because asymmetric nanopore geometries break the symmetry of the ion distribution, creating unequal surface charge across the nanopore, or by coupling unidirectional electron transfer within a nanopore electrode. Here, we develop a high-performance redox cycling-based electrochemical diode by coating an asymmetric ion-exchange membrane, i...
August 6, 2018: ACS Nano
Azar Alizadeh, Andrew Burns, Ralf Lenigk, Rachel Gettings, Jeffrey Ashe, Adam Porter, Margaret McCaul, Ruairi Barrett, Dermot Diamond, Paddy White, Perry Skeath, Melanie Tomczak
Implementation of wearable sweat sensors for continuous measurement of fluid based biomarkers (including electrolytes, metabolites and proteins) is an attractive alternative to common, yet intrusive and invasive, practices such as urine or blood analysis. Recent years have witnessed several key demonstrations of sweat based electrochemical sensing in wearable formats, however, there are still significant challenges and opportunities in this space for clinical acceptance, and thus mass implementation of these devices...
July 31, 2018: Lab on a Chip
Chellakannu Rajkumar, Balamurugan Thirumalraj, Shen-Ming Chen, Pitchaimani Veerakumar, King-Chuen Lin
Nitrogen-doped multiwalled carbon nanotubes modified with nickel nanoparticles (Ni/N-MWCNT) were prepared by a thermal reduction process starting from urea and Ni(II) salt in an inert atmosphere. The nanocomposite was deposited on a screen printed electrode and characterized by X-ray diffraction, scanning and transmission electron microscopy, nitrogen adsorption, X-ray photoelectron spectroscopy, and thermogravimetric analyses. The performance of the composite was investigated by cyclic voltammetry, differential pulse voltammetry and chronoamperometry...
July 30, 2018: Mikrochimica Acta
Liang Kuang, Huijuan Liu, Baiwen Ma, William A Jefferson, Gong Zhang, Jiuhui Qu
The current understanding of the particle-water interface relies primarily on the use of electric double layer theory (EDL theory), in which the concentration distribution of ions with distance can be evaluated. However, although EDL theory provides a theoretical and mathematical basis, obtaining direct experimental results is also necessary. In this study, an instrument system set with a designed H+ selective micro-electrode was developed for in situ determination at the particle-water interface, and a preliminary investigation of the H+ concentration distribution at the particle-water interface was enabled using data collection at 1 nm/step...
July 24, 2018: Science of the Total Environment
Eman Yossri Frag, Marwa El Badry Mohamed, Elham M Fahim
The performance characteristics of a new selective and sensitive modified screen printed electrode (MSPE; electrode I) and carbon paste electrode (MCPE; electrode II) based on 2-N, N-dimethylcarbamimidoyl (metformin) as modifier for the potentiometric determination of copper (II) in water sample, serum and urine samples of Wilson disease patients have been optimized. The chemical reaction which happens between Cu (II) and the modifier on the surface of the sensors was investigated with scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX), IR spectra measurement and computational calculations at DFT/B3LYP...
July 27, 2018: Biosensors & Bioelectronics
Aftab Aslam Parwaz Khan, Anish Khan, M A Alam, Mohammad Oves, Abdullah M Asiri, Mohammed M Rahman, Inamuddin
A novel nanostructure of poly(o-anisidine-co-methyl anthranilate) (poly(Ani-Co-MA) copolymer has been synthesized by chemical oxidative in situ polymerization technique with equal molar proportion of monomers in the presence of sodium dodecylbenzene sulfonic acid (SDBS) surfactant. The synthesized copolymers were characterized by scanning electron microscope (SEM) and X-ray crystallography (XRD), Fourier transform infrared (FTIR), UV-Vis, thermo-gravimetric analysis (TGA), and simultaneous X-ray photoelectron spectroscopy (XPS) study...
July 29, 2018: Environmental Science and Pollution Research International
Christopher Dedic, Tin Shing Hung, Alan M Shipley, Akira Maeda, Thomas Gardella, Andrew L Miller, Paola Divieti Pajevic, Joseph G Kunkel, Alessandro Rubinacci
Calcium ion concentration ([Ca2+ ]) in the systemic extracellular fluid, ECF-[Ca2+ ], is maintained around a genetically predetermined set-point, which combines the operational level of the kidney and bone/ECF interfaces. The ECF-[Ca2+ ] is maintained within a narrow oscillation range by the regulatory action of Parathyroid Hormone (PTH), Calcitonin, FGF-23, and 1,25(OH)2 D3 . This model implies two correction mechanisms, i.e. tubular Ca2+ reabsorption and osteoclast Ca2+ resorption. Although their alterations have an effect on the ECF-[Ca2+ ] maintenance, they cannot fully account for rapid correction of the continuing perturbations of plasma [Ca2+ ], which occur daily in life...
July 24, 2018: Bone
Marwa F Mansour, Mona M Abd El-Moety, Ehab F El Kady, N M El Guindi, Ann Van Schepdael, S M El-Moghazy Aly
Background The application of an ion selective technique for the determination of analyte concentrations is considered one of the most economical techniques for quality control purposes. Objective To elaborate and investigate the construction and general performance characteristics of potentiometric PVC membrane sensors for venlafaxine cation (Ven+). Method The sensors are based on the use of the ion association complexes of the venlafaxine cation with phosphotungstate (PT) and silicotungstate (ST) counter anions as ion exchange sites in the plasticized PVC matrix...
July 26, 2018: Current Pharmaceutical Design
Izumi C Mori, Yuichi Nobukiyo, Yoshiki Nakahara, Mineo Shibasaka, Takuya Furuichi, Maki Katsuhara
Cyclic nucleotide-gated channels (CNGCs) have been postulated to contribute significantly in plant development and stress resistance. However, their electrophysiological properties remain poorly understood. Here, we characterized barley CNGC2-3 (HvCNGC2-3) by the two-electrode voltage-clamp technique in the Xenopus laevis oocyte heterologous expression system. Current was not observed in X. laevis oocytes injected with HvCNGC2-3 complementary RNA (cRNA) in a bathing solution containing either Na⁺ or K⁺ solely, even in the presence of 8-bromoadenosine 3',5'-cyclic monophosphate (8Br-cAMP) or 8-bromoguanosine 3',5'-cyclic monophosphate (8Br-cGMP)...
July 26, 2018: Plants (Basel, Switzerland)
Peter Zimmermann, Andreas Weltin, Gerald A Urban, Jochen Kieninger
Potentiometric oxygen monitoring using platinum as the electrode material was enabled by the combination of conventional potentiometry with active prepolarization protocols, what we call active potentiometry . The obtained logarithmic transfer function is well-suited for the measurement of dissolved oxygen in biomedical applications, as the physiological oxygen concentration typically varies over several decades. We describe the application of active potentiometry in phosphate buffered salt solution at different pH and ion strength...
July 24, 2018: Sensors
Kuichang Zuo, Jun Kim, Amit Jain, Tianxiao Wang, Rafael Verduzco, Mingce Long, Qilin Li
Capacitive deionization (CDI) can remove ionic contaminants from water. However, concentrations of background ions in water are usually much higher than target contaminants, and existing CDI electrodes have no designed selectivity toward specific contaminants. In this study, we demonstrate a selective CDI process tailored for removal of SO4 2- using activated carbon electrodes modified with a thin, quaternary amine functionalized poly(vinyl alcohol) (QPVA) coating containing submicron sized sulfate selective ion exchange resin particles...
August 6, 2018: Environmental Science & Technology
Sebastian Schmitz, Andrew Kovalchuk, Alejandro Martín-Rodríguez, Jan van Leusen, Natalya V Izarova, Svenja D M Bourone, Yong Ai, Eliseo Ruiz, Ryan C Chiechi, Paul Kögerler, Kirill Yu Monakhov
A series of isostructural dinuclear 3d-4f complexes, isolated as [CuLn(L·SMe)2 (OOCMe)2 (NO3 )]· xMeOH (Ln = Gd 1, Tb 2, Dy 3, and Y 4; x = 0.75-1) and comprising one acetate and two thioether-Schiff base (L·SMe- ) bridging ligands based on 4-(methylthio)aniline and 2-hydroxy-3-methoxybenzaldehyde (HL·SMe = C15 H15 NO2 S), was synthesized and fully characterized. The magnetic properties of the charge-neutral {CuLn} complexes are dominated by ferromagnetic CuII -LnIII exchange interactions. Large-area electron transport studies reveal that the average conductivity of robust, self-assembled {CuLn} monolayers on a gold substrate is significantly lower than that of common alkanethiolates...
August 6, 2018: Inorganic Chemistry
Ting Zhang, Congwei Gao, Wei Huang, Yuling Chen, Yang Wang, Jianmin Wang
A sensitive and selective TAPB-DMTP-COF (TAPB, 1,3,5-tris(4-aminophenyl)benzene; DMTP, 2,5-dimethoxyterephaldehyde; COF, covalent organic framework) modified carbon paste electrode was evaluated as a novel electrochemical sensor for the determination of lead in an aqueous medium. Lead was accumulated on the TAPB-DMTP-COF surface by the complexation with the amine groups, and detected by differential pulse anodic stripping voltammetry. Due to the distinct structure features of COF, the resulting sensor revealed a fast electron transfer rate and outstanding adsorption capacity for lead...
October 1, 2018: Talanta
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