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Kamonwad Ngamchuea, Korbua Chaisiwamongkhol, Christopher Batchelor-McAuley, Richard G Compton
Biomarkers refer to analytes that can be used in the diagnosis of diseases or disorders. In saliva, there are many components that are potential biomarkers, and increasing research has focussed on the development of saliva as a diagnostic fluid. This review summarizes the existing uses of salivary biomarkers and highlights the importance of the choice of saliva collection as well as the storage procedures. A case study on the effect of collection tools on the concentrations of one of the potential biomarkers, glutathione, is highlighted...
November 17, 2017: Analyst
Zuzana Lukáčová-Chomisteková, Eva Culková, Renata Bellová, Danica Melicherčíková, Jaroslav Durdiak, Ernest Beinrohr, Miroslav Rievaj, Peter Tomčík
Very simple and fast electroanalytical method for the detection Sb(III) on chemically unmodified boron-doped diamond electrode (BDDE) has been developed. Voltammetric behavior of antimony was investigated in various acidic supporting electrolytes and the most suitable medium for the determination of Sb(III) on bare BDDE has been 6molL(-1) HClO4 solution. The analytical performance was studied with differential pulse anodic stripping voltammetry (DPASV) with optimized conditions (deposition potential -1V vs...
February 1, 2018: Talanta
Alyah Buzid, John H T Luong, F Jerry Reen, Fergal O'Gara, Jeremy D Glennon, Gerard P McGlacken
As the leading cause of morbidity and mortality of cystic fibrosis (CF) patients, early detection of Pseudomonas aeruginosa (PA) is critical in the clinical management of this pathogen. Herein, we describe rapid and sensitive electroanalytical methods using differential pulse voltammetry (DPV) at a boron-doped diamond (BDD) electrode for the detection of PA signaling biomolecules. Monitoring the production of key signaling molecules in bacterial cultures of P. aeruginosa PA14 over 8 h is described, involving sample pretreatment by liquid-liquid and solid-phase extraction...
2018: Methods in Molecular Biology
Biljana Nigovic, Ivona Milanovic
The electrooxidation of xanthine oxidase inhibitor febuxostat was investigated on a boron-doped diamond electrode in aqueous solution. The oxidation of the drug molecule was irreversible and exhibited a diffusion-controlled form. A green electroanalytical method for simple and fast measurements of febuxostat was developed at the unmodified electrode surface. The analyses were performed using square-wave voltammetric peak current at 1.38 V. The linear response was obtained in the range of 7.5 × 10(-7) - 2.0 × 10(-5) M with the detection limit of 9...
2017: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Sanju Gupta, Brendan Evans, Alex Henson, Sara B Carrizosa
Nanodiamond particles form agglomerates in the dry powder state and this poses limitation to the accessibility of their diamond-like core thus dramatically impacting their technological advancement. In this work, we report de-agglomeration of nanodiamond (ND) by using a facile technique namely, salt-assisted ultrasonic de-agglomeration (SAUD). Utilizing ultrasound energy and ionic salts (sodium chloride and sodium acetate), SAUD is expected to break apart thermally treated nanodiamond aggregates (~50-100 nm) and produce an aqueous slurry of de-aggregated stable colloidal nanodiamond dispersions by virtue of ionic interactions and electrostatic stabilization...
November 10, 2017: Materials
Shuyue Guo, Hailong Yan, Fei Wu, Lijun Zhao, Ping Yu, Huibiao Liu, Yuliang Li, Lanqun Mao
Graphdiyne (GDY) is recently synthesized two-dimensional carbon allotrope with hexagonal rings cross-linked by di-acetylene through introducing butadiyne linkages (-C≡C-C≡C-) to form 18-C hexagons and is emerging to be fundamentally interesting and particularly useful in various research fields. In this study, we for the first time find that GDY can be used as an electrode material with reactivity tunable by electronic states and surface chemistry of GDY. To demonstrate this, GDY is oxidized into graphdiyne oxide (GDYO) that is then chemically and electrochemically reduced into chemically reduced GDYO (cr-GDYO) and electrochemically reduced GDYO (er-GDYO), respectively...
November 10, 2017: Analytical Chemistry
Abdulwahab Salah, Mehboob Hassan, Jian Liu, Minghui Li, Xiangjie Bo, Jean Chrysostome Ndamanisha, Liping Guo
Graphene (GR) is one of the most promising candidates for utilization in the electroanalytical field because of its superior electrocatalytic activity, excellent electronic conductivity, and high chemical stability. However, the GR sheets usually tend to stack together with π-π interaction. The spontaneous stacking leads to the aggregation of the GR sheets and imposes a negative feedback in the surface area of the GR, which obviously limits its electrochemical application. In this study, nitrogen-doped porous GR (NPGR) with different pore sizes is prepared by using silica (SiO2) as a template...
October 7, 2017: Journal of Colloid and Interface Science
Romain M Présent, Elise Rotureau, Patrick Billard, Christophe Pagnout, Bénédicte Sohm, Justine Flayac, Renaud Gley, José P Pinheiro, Jérôme F L Duval
Genetically engineered microorganisms are alternatives to physicochemical methods for remediation of metal-contaminated aquifers due to their remarkable bioaccumulation capacities. The design of such biosystems would benefit from the elaboration of a sound quantitative connection between performance in terms of metal removal from aqueous solution and dynamics of the multiscale processes leading to metal biouptake. In this work, this elaboration is reported for Escherichia coli cells modified to overexpress intracellular metallothionein (MTc), a strong proteinaceous metal chelator...
November 8, 2017: Physical Chemistry Chemical Physics: PCCP
Dalibor M Stanković, Miloš Ognjanović, Fabian Martin, Ľubomir Švorc, José F M L Mariano, Bratislav Antić
In the present paper, the electrochemical behavior and the properties of two modified glassy carbon (GC) electrodes used for quantification of gallic acid in sweet wines were compared. A comparative study was conducted between titanium nitride- or wolfram carbide-doped reduced graphene oxide, labeled as TNrGO and WCrGO, respectively, modified GC electrodes, which are promising composite nanomaterials for electroanalytical applications. For the first time, WCrGO was synthesized and its electroanalytical properties compared with those of TNrGO...
October 24, 2017: Analytical Biochemistry
Mona A Mohamed, Dalia M El-Gendy, Nashaat Ahmed, Craig E Banks, Nageh K Allam
Adenine-functionalized spongy graphene (FSG) composite, fabricated via a facile and green synthetic method, has been explored as a potential electrocatalyst toward the electroanalytical sensing of codeine phosphate (COD). The synthesized composite is characterized using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray powder diffraction, UV-vis absorption spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy (HRTEM), and thermogravimetric analysis...
October 11, 2017: Biosensors & Bioelectronics
Hayati Filik, Asiye Aslıhan Avan
In the current study, we introduce magnetic solid phase microextraction coupled with electrochemical detection of caffeine. A commercially available disposable screen-printed carbon electrodes modified with poly Alizarin Red S are employed as electrochemical sensors in the detection stage. However, the suitability of magnetic solid phase microextraction for electroanalytical methods such as square wave voltammetry has not been declared. With our optimised conditions in hand, the system response was linearly proportional to the concentration of caffeine in the range of 0...
March 1, 2018: Food Chemistry
Junping Zhang, Jianjun Liao, Fan Yang, Ming Xu, Shiwei Lin
Three non-metallic elements, sulfur, fluorine, and iodine, were used to dope the ultrathin two-dimensional TiO₂ nanosheets, which would regulate their electroanalytical properties toward heavy metal ions. Among these doped materials, fluorine-doped TiO₂ nanosheets shows the highest electrochemical sensitivity and a superior detection limit toward Pb(II) when the doping concentration is 10%. When compared with the bare TiO₂ nanosheets, the sensitivity increased by 102%, and the detection limit decreased by 36...
October 14, 2017: Nanomaterials
Juanjuan Gao, Jingkun Fang, Xuehai Ju, Weiqing Zhu, Xuezhen Lin, Shupeng Zhang, Chuang Ma, Haiou Song
An electrochemically active sensing nanomaterial (denoted as CD-MPEA-NG) has been successfully constructed by an hierarchical self-assembly of cyclodextrin (CD) and N,N-dimethyl-4-(phenylethynyl)aniline (MPEA) on N-doped graphene (NG) in a low-temperature hydrothermal process. The unique nanostructure of the high-performance CD-MPEA-NG was confirmed by utilizing Fourier transform infrared spectra, an X-ray diffractometer, and differential pulse voltammetry (DPV), etc. In particular, the method of density functional theory with dispersion energy (DFT-D) of wB97XD/LanL2DZ was employed to optimize and describe the face-to-face packing structure of heterodimers of NG and MPEA...
November 8, 2017: ACS Applied Materials & Interfaces
S Muralikrishna, D H Nagaraju, R Geetha Balakrishna, Werasak Surareungchai, T Ramakrishnappa, Avinash B Shivanandareddy
Conducting polymers with graphene/graphene oxide hydrogels represent a unique class of electrode materials for sensors and energy storage applications. In this article, we report a facile in situ method for the polymerisation of aniline resulting in the decoration of 1D conducting polyaniline (PANI) nanofibers onto the surface of 2D graphene oxide (GO) nanosheets followed by hydrogel formation at elevated temperature. The synthesized nanomaterial exhibits significant properties for the highly sensitive electrochemical determination as well as removal of environmentally harmful lead (Pb(2+)) ions...
October 16, 2017: Analytica Chimica Acta
Sujay A Chopade, Evan L Anderson, Peter W Schmidt, Timothy P Lodge, Marc A Hillmyer, Philippe Bühlmann
Interfaces of ionic liquids and aqueous solutions exhibit stable electrical potentials over a wide range of aqueous electrolyte concentrations. This makes ionic liquids suitable as bridge materials that separate in electroanalytical measurements the reference electrode from samples with low and/or unknown ionic strengths. However, methods for the preparation of ionic liquid-based reference electrodes have not been explored widely. We have designed a convenient and reliable synthesis of ionic liquid-based reference electrodes by polymerization-induced microphase separation...
October 27, 2017: ACS Sensors
Safaa M Riad, Mohamed K Abd El-Rahman, Esraa M Fawaz, Mostafa A Shehata
Although the ultimate goal of administering active pharmaceutical ingredients (APIs) is to save countless lives, the presence of impurities and/or degradation products in APIs or formulations may cause harmful physiological effects. Today, impurity profiling (i.e., the identity as well as the quantity of impurity in a pharmaceutical) is receiving critical attention from regulatory authorities. Despite the predominant use of spectroscopic and chromatographic methods over electrochemical methods for impurity profiling of APIs, this work investigates the opportunities offered by electroanalytical methods, particularly, ion-selective electrodes (ISEs), for profiling degradation-related impurities (DRIs) compared with conventional spectroscopic and chromatographic methods...
September 8, 2017: Journal of AOAC International
N Mei, L Belleville, Y Cha, U Olofsson, I Odnevall Wallinder, K-A Persson, Y S Hedberg
Welding fume of stainless steels is potentially health hazardous. The aim of this study was to investigate the manganese (Mn) and chromium (Cr) speciation of welding fume particles and their extent of metal release relevant for an inhalation scenario, as a function of particle size, welding method (manual metal arc welding, metal arc welding using an active shielding gas), different electrodes (solid wires and flux-cored wires) and shielding gases, and base alloy (austenitic AISI 304L and duplex stainless steel LDX2101)...
January 15, 2018: Journal of Hazardous Materials
Aniela Pop, Florica Manea, Adriana Flueras, Joop Schoonman
Monitoring of pesticide residues in food, beverages, and the environment requires fast, versatile, and sensitive analyzing methods. Direct electrochemical detection of pesticides could represent an efficient solution. Adequate electrode material, electrochemical technique, and optimal operation parameters define the detection method for practical application. In this study, cyclic voltammetric and differential pulse voltammetric techniques were used in order to individually and simultaneously detect two pesticides, i...
September 6, 2017: Sensors
Mireia Lao, Encarnació Companys, Liping Weng, Jaume Puy, Josep Galceran
Free concentrations of Zn(2+), Fe(3+), Ca(2+) and Mg(2+) in a red wine (Raimat, Catalonia, Spain) have been determined, with the Donnan Membrane Technique (DMT) for the first time. The required equilibration time benefits from the acceptor solution including major cations. K(+) and Na(+), mainly unbound to any ligand in the sample, have been identified as suitable reference ions. A free Zn concentration of 1.76μmolL(-1) determined with DMT was in excellent agreement with the free Zn concentration independently provided by the electroanalytical technique Absence of Gradients and Nernstian Equilibrium Stripping (AGNES), 1...
January 15, 2018: Food Chemistry
Amera Hassanein, Nehal Salahuddin, Atsunori Matsuda, Go Kawamura, Mona Elfiky
A sensitive conductive nanocomposite sensor consisting of chitosan, zinc oxide nanoparticles, and polypyrrole was developed. The sensor was prepared by oxidative polymerization of pyrrole using (NH4)2S2O8 as the oxidant followed by mixing a Chitosan-Zinc oxide composite with a different content of Chitosan. The morphology and surface area of the nanocomposites were changed by changing the percentage of chitosan. The newly developed nanocomposites also showed a significant improvement in electrical conductivity as mentioned from the cyclic voltammetry measurements of the K3[Fe(CN)6] sample...
November 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
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