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ion-selective electrode

Muxin Lu, Yajuan Deng, Yi Luo, Junping Lv, Tianbao Li, Juan Xu, Shu-Wei Chen, Jinyi Wang
The development of an effective method for detecting heavy metal ions remains a serious task due to their high toxicity to public health and environments. Herein, a new electrochemical method based on a graphene aerogel (GA) and metal-organic framework (MOF) composites was developed for simultaneous detection of multiple heavy metal ions in aqueous solutions. The GA-MOF composites were synthesized via the in situ growth of the MOF UiO-66-NH2 crystal on the GA matrix. GA not only serves as the backbone for UiO-66-NH2 but also enhances the conductivity of the composites by accelerating the electron transfer in the matrix...
October 19, 2018: Analytical Chemistry
Yoonseob Kim, Zhou Lin, Intak Jeon, Troy Van Voorhis, Timothy M Swager
π-Conjugated polyaniline nanofiber networks are an attractive material platform for reversible and selective capture and release of toxic heavy metal ions from water. The nanofiber geometry facilitates fastsorption kinetics, sulfur functionalization of the backbone for improved adsorption, and electrochemical control of the oxidation (charge) state for reversible triggered sorption/desorption of metal ions. These active materials also function as sensors in that the sorption of mercury ions can be detected by analysis of cyclic voltammograms...
October 18, 2018: Journal of the American Chemical Society
Enguang Lv, Jiawang Ding, Wei Qin
Peptide-based sandwich assays are promising tools in molecular detection, but may be restricted by the availability of "pairs" of affinity peptides. Herein, a new potentiometric sandwich assay for bacteria involving peptide pairs derived from an antimicrobial peptide (AMP) ligand is demonstrated. As a model, the original AMP with well-defined structure for Listeria monocytogenes (LM) can be split into two fragments to serve as the peptide pairs for the sandwich assay. The recognition and binding of the short peptide pairs to the target can be verified by circular dichroism, flow cytometry, fluorometry, and optical microscopy...
October 18, 2018: Analytical Chemistry
Rosa M Arán-Ais, Dunfeng Gao, Beatriz Roldan Cuenya
The utilization of fossil fuels (i.e., coal, petroleum, and natural gas) as the main energy source gives rise to serious environmental issues, including global warming caused by the continuously increasing level of atmospheric CO2 . To deal with this challenge, fossil fuels are being partially replaced by renewable energy such as solar and wind. However, such energy sources are usually intermittent and currently constitute a very low portion of the overall energy consumption. Recently, the electrochemical conversion of CO2 to chemicals and fuels with high energy density driven by electricity derived from renewable energy has been recognized as a promising strategy toward sustainable energy...
October 18, 2018: Accounts of Chemical Research
Elena Zdrachek, Eric Bakker
This review describes, with 186 references, progress in the field of potentiometric sensing in the period between January 2016 and August 2018. January 2016 was when the last fundamental review covering the topic of potentiometric sensors appeared in the special issue of Analytical Chemistry and was set as start date. This review starts with a description of progress in the development and improve-ment of reference electrodes, which represent an indispensable part of any electro-chemical cell and has a particularly important influence on the accuracy of potentiometric measurements...
October 17, 2018: Analytical Chemistry
Megha A Deshmukh, Gajanan A Bodkhe, Sumedh Shirsat, Arunas Ramanavicius, Mahendra D Shirsat
Heavy metal ions are considered as one of the major water pollutants, revealing health hazards as well as threat to the ecosystem. Therefore, investigation of most versatile materials for the sensitive and selective detection of heavy metal ions is need of the hour. Proposed work emphasizes the synthesis of conducting polymer and carbon nanotube nanocomposite modified with chelating ligand for the detection of heavy metal ions. Carbon nanotubes are having well known features such as tuneable conductivity, low density, good charge transport ability, and current carrying capacity...
2018: Frontiers in Chemistry
Ashley J Malin, Julia Riddell, Hugh McCague, Christine Till
BACKGROUND: Fluoride exposure has the potential to disrupt thyroid functioning, though adequate iodine intake may mitigate this effect. This is the first population-based study to examine the impact of chronic low-level fluoride exposure on thyroid function, while considering iodine status. The objective of this study was to determine whether urinary iodine status modifies the effect of fluoride exposure on thyroid stimulating hormone (TSH) levels. METHODS: This cross-sectional study utilized weighted population-based data from Cycle 3 (2012-2013) of the Canadian Health Measures Survey (CHMS)...
October 10, 2018: Environment International
Jennifer Taher, Jake Cosme, Brian A Renley, David J Daghfal, Paul M Yip
OBJECTIVES: The Abbott Alinity family of chemistry and immunoassay systems recently launched with early adopters contributing imprecision and bias data, which was consolidated to assess the performance of Alinity assays across multiple sites using the Sigma metric. Multi-site Sigma metrics were determined for 3 ion-selective electrodes, 12 photometric assays, and 3 immunoassays across 11 independent laboratory sites in 9 countries. METHODS: Total allowable error (TEa) goals followed a previously defined hierarchy that used CLIA as the primary goal...
October 9, 2018: Clinical Biochemistry
Nella M Vargas-Barbosa, Bernhard Roling
The potential of zero charge (PZC) is a fundamental property that describes the electrode/electrolyte interface. The determination of the PZC at electrode/ionic liquid interfaces has been challenging due to the lack of models that fully describe these complex interfaces as well as the non-standardized approaches used to characterize them. In this work, we present a method that combines electrode immersion transient and impedance measurements for the determination of the PZC. This combined approach allows the distinction of the potential of zero free charge ( pzfc ), related to fast double layer charging on a millisecond timescale, from a potential of zero charge on a timescale of tens of seconds related to slower ion transport processes at the interface...
May 21, 2018: Journal of Chemical Physics
Wenbin Li, Jianfeng Huang, Liangliang Feng, Liyun Cao, Shuwei He
Surface structure plays a decisive role in the surface capacity and electrochemical kinetics of rechargeable batteries. Tuning the surface structure of building blocks has been considered to be a new effective strategy to promote the electrochemical performance of 3D self-assembled nanoarchitectures. Herein, VS4 microspheres assembled from the nano-units with different crystallinities are synthesized via a facile template-free hydrothermal method. The results show that the electrochemical performance of VS4 microspheres as anode materials for sodium-ion batteries (SIBs) largely depends on their crystallinity, and a VS4 electrode with the lowest crystallinity delivers a high reversible capacity of 412 mA h g-1 at 0...
October 11, 2018: Nanoscale
Nate T Garland, Eric S McLamore, Nicholas D Cavallaro, Deyny Mendivelso-Perez, Emily A Smith, Dapeng Jing, Jonathan C Claussen
Flexible graphene electronics are rapidly gaining interest, but their widespread implementation has been impeded by challenges with ink preparation, ink printing, and post-print annealing processes. Laser-induced graphene (LIG) promises a facile alternative by creating flexible graphene electronics on polyimide substrates through a one-step laser writing fabrication method. Herein we demonstrate the use of LIG, created through a low-cost UV laser, for electrochemical ion selective sensing of plant-available nitrogen (i...
October 4, 2018: ACS Applied Materials & Interfaces
Debmalya Santra, Subhradeep Mandal, Angshuman Santra, Uttam Kumar Ghorai
The quality of drinking water often remains unknown to the people because of the inadequacy of cost-effective testing systems that can be used in field. Major portable instruments for water quality analysis include Ion Selective Electrodes (ISE) or Colorimeters. These are low cost devices but in case of multiple analyte detection like hexavalent Cr, Fluoride (F-) and Iron (Fe) with single instrumentation, no portable systems are available till date as per the authors' knowledge. In this paper, we demonstrate the working of a low cost (approximate price INR 1500 or US $ 20) portable colorimetric system that can be operated with android smartphones wirelessly to estimate the contamination levels of Cr(VI), F-, or Fe in drinking water...
October 3, 2018: Analytical Chemistry
Brunna Xavier Martins, Raul Ferraz Arruda, Gildeíde Aparecida Costa, Hassan Jerdy, Sávio Bastos de Souza, Julianna Maria Santos, William Rodrigues de Freitas, Milton Masahiko Kanashiro, Eulógio Carlos Queiroz de Carvalho, Nadir Francisca Sant'Anna, Fernanda Antunes, Raul Martinez-Zaguilan, Sennoune Souad, Anna Lvovna Okorokova-Façanha, Arnoldo Rocha Façanha
BACKGROUND: Metastatic tumor cells have acidic extracellular pH and differential electrochemical H+ gradients generated across their cell membranes by V-type H+ -ATPases. This study shows that inhibition of the V-ATPases by the plant-derived monoterpene Myrtenal results in tumor cell death and decreased metastatic dissemination in mice. METHODS: The Myrtenal anticancer toxicity was evaluated in vitro using murine (B16F0 and B16F10) and human (SkMel-5) melanoma cell lines, and in in vivo mouse metastatic dissemination model...
September 11, 2018: Biochimica et biophysica acta. General subjects
Bingqing Han, Jie Zeng, Ying Yan, Haijian Zhao, Tianjiao Zhang, Weiyan Zhou, Jiangtao Zhang, Jing Wang, Yufei Wang, Chuanbao Zhang
BACKGROUND: Chloride is the main anion in human body. A simple and accurate method for serum chloride measurement was developed using ion chromatography (IC) in China. METHODS: In the measurement, serum samples were diluted 500 times with water, filtered and injected into ion chromatography column. A mixed eluent (2 mmol/L CO32- + 12 mmol/L OH-) was used and peak area signal was collected. Five calibrators made from Standard Reference Material (SRM) 919b were used in the bracketing method...
September 1, 2018: Clinical Laboratory
Shumaila Razzaque, Kewei Wang, Irshad Hussain, Bien Tan
A very simple and facile methodology has been used to prepare dithiocarbamate functionalized hollow microporous organic capsules (HMOCS-DTC) intriguing with excellent stability, high surface area and appropriate microporous architecture. In this strategy, SiO2 particles are used as template to construct PS-DVB-MAA microspheres and then dithiocarbamate groups are grafted on it. HMOCs-DTC/GC has been used as an electrode material for the detection of Cu(II) ions. Herein the cyclic voltammetry (CV) and electron impedance spectroscopy (EIS) has been exploited to study the electrochemical potentiol of designed material...
September 30, 2018: Chemistry: a European Journal
Jingying Zhai, Liyuan Yang, Xinfeng Du, Xiaojiang Xie
Optical ion sensors normally have a relative narrow sensitive detection window. Here, based on multicolor light-emitting diodes (LEDs), we report on an electrochemical-to-optical signal transduction scheme under chronoamperometry control to convert the potentiometric response of ion-selective electrodes (ISEs) to optical output with tunable sensitivity and much wider response range. The sensing principle was demonstrated on K+, Ca2+ and Pb2+. LED light intensity was found to depend linearly on the concentration of monovalent ions, enabling the standard addition analytical protocol...
September 28, 2018: Analytical Chemistry
Marina Krasovska, Vjaceslavs Gerbreders, Irena Mihailova, Andrejs Ogurcovs, Eriks Sledevskis, Andrejs Gerbreders, Pavels Sarajevs
ZnO nanostructures are promising candidates for use in sensors, especially in electrochemical sensors and biosensors, due to their unique physical and chemical properties, as well as sensitivity and selectivity to several types of contamination, including heavy metal ions. In this work, using the hydrothermal method, nanostructures of ZnO were synthesized in four different morphologies: nanorods, nanoneedles, nanotubes and nanoplates. To determine the peculiarities of adsorption for each morphology, a series of electrochemical measurements were carried out using these nanostructured ZnO coatings on the working electrodes, using aqueous solutions of Pb(NO3 )2 and Cd(NO3 )2 as analytes with different concentrations...
2018: Beilstein Journal of Nanotechnology
Ron Rosenberg, Michael S Bono, Soumya Braganza, Chintan Vaishnav, Rohit Karnik, A John Hart
Small-holding farmers in the developing world suffer from sub-optimal crop yields because they lack a soil diagnostic system that is affordable, usable, and actionable. This paper details the fabrication and characterization of an integrated point-of-use soil-testing system, comprised of disposable ion-selective electrode strips and a handheld electrochemical reader. Together, the strips and reader transduce soil ion concentrations into to an alphanumeric output that can be communicated via text message to a central service provider offering immediate, customized fertilizer advisory...
2018: PloS One
Pavithra Pathirathna, Ryan J Balla, Shigeru Amemiya
Electrochemical measurements with unprecedentedly high sensitivity, selectivity, and kinetic resolution have been enabled by a pair of electrodes separated by a nanometer-wide gap. The fabrication of nanogap electrodes, however, requires extensive nanolithography or nanoscale electrode positioning, thereby preventing the full exploration of this powerful method in electrode design and application. Herein, we report the simple fabrication of double-carbon-fiber ultramicroelectrodes (UMEs) with nanometer-wide gaps not only to facilitate nanogap-based electrochemical measurements but also to gain high time resolution, signal-to-background ratio, and kinetic selectivity for dopamine against ascorbic acid...
September 27, 2018: Analytical Chemistry
F G Zhang, H F Yan, W Zhao
Objective: To optimize the ion selective electrode method of measuring urinary fluorine in WS/T 30-1996. Methods: The volume of 5 mol/L NaOH solution was fixed to confect the TISAB buffer solution. The samples were prepared by mixing 5 ml urine and equal volume of TISAB solution. Fluorine electrode and calomel electrode was used to test. When the potential value changed less than ±0.5 mV in one minute, it could be recorded. The standard curve method was selected as a quantitive method. Results: The linear range of this method was 0...
June 20, 2018: Chinese Journal of Industrial Hygiene and Occupational Diseases
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