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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)...
August 31, 2017: 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
Nicolò Dossi, Stefano Petrazzi, Rosanna Toniolo, Franco Tubaro, Fabio Terzi, Evandro Piccin, Rossella Svigelj, Gino Bontempelli
A simple, reliable, and low-cost fabrication method is proposed here for assembling paper-based electrochemical devices (PEDs) using a commercial desktop digitally controlled plotter/cutter, together with ordinary writing tools. Permanent markers (tips of 1 mm) were used to create effective hydrophobic barriers on paper, while micromechanical pencils (mounting 4B graphite leads, 0.5 mm in diameter) were adopted for automatically drawn precise reference, counter, and working carbon electrodes. Fabrication parameters, such as writing pressure and speed, were first optimized, and the electrochemical performance of these devices was then evaluated by using potassium hexacyanoferrate(II) as redox probe...
September 13, 2017: Analytical Chemistry
Asma Saljooqi, Tayebeh Shamspur, Ali Mostafavi
This paper describes the synthesis of Ag-4-ATP-MWCNT nanocomposite and its use as a modifier of working electrode. The surface of the electrochemical Ag-4-ATP-MWCNT electrode was modified with a double-stranded DNA (dsDNA) to detect daunorubicin-DNA interactions. Differential pulse voltammetry was applied to develop an electroanalytical procedure for the determination of daunorubicin and evaluate its interaction with dsDNA immobilized on the electrode surface. After the optimization of operational parameters, the linear dependence of the peak current on the daunorubicin concentration was observed in the range of 0...
August 15, 2017: Bioelectrochemistry
Georgina M S Alves, Luciana S Rocha, Helena M V M Soares
Nowadays, water is no longer regarded as an inexhaustible resource and the excessive release and proliferation of toxic metal(loid)s into aquatic environments has become a critical issue. Therefore, fast, accurate, simple, selective, sensitive and portable methodologies to detect multiple elements in natural waters is of paramount importance. Electrochemical stripping analysis is an efficient tool for trace metal(loid)s determinations and bring new prospects for answering the current environmental concerns...
December 1, 2017: Talanta
Shimeles Addisu Kitte, Wenyue Gao, Yuriy T Zholudov, Liming Qi, Anaclet Nsabimana, Zhongyuan Liu, Guobao Xu
The electrogenerated chemiluminescence (ECL) application of stainless steel, a robust and cost-effective material, has been developed for the first time. The type 304 stainless steel electrode shows appealing ECL performance for luminol-H2O2 system. It enables the detection of H2O2 with a linear range from 1 to 1000 nM and a limit of detection of 0.456 nM (S/N = 3). The ECL method based on type 304 stainless steel electrode is more sensitive, more cost-effective, and much simpler than other ECL methods reported before...
August 23, 2017: Analytical Chemistry
Amitava Moulick, Lukas Richtera, Vedran Milosavljevic, Natalia Cernei, Yazan Haddad, Ondrej Zitka, Pavel Kopel, Zbynek Heger, Vojtech Adam
In the last decade, the control of avian influenza virus has experienced many difficulties, which have caused major global agricultural problems that have also led to public health consequences. Conventional biochemical methods are not sufficient to detect and control agricultural pathogens in the field due to the growing demand for food and subsidiary products; thus, studies aiming to develop potent alternatives to conventional biochemical methods are urgently needed. In this review, emerging detection systems, their applicability to diagnostics, and their therapeutic possibilities in view of nanotechnology are discussed...
August 29, 2017: Analytica Chimica Acta
Cristiane Kalinke, Paulo Roberto Oliveira, Geovane Arruda Oliveira, Antonio Sálvio Mangrich, Luiz H Marcolino-Junior, Márcio F Bergamini
This work reports for the first time the use of chemically activated biochar as electrode modifier for nickel determination. The biochar activation was performed by refluxing with HNO3, which promoted a higher nickel preconcentration compared to unmodified and modified biochar precursor electrodes. Morphological and structural characterization revealed the increase of surface acid groups, surface area and porosity of biochar after activation. Nickel determination was investigated adopting an alternative voltammetric methodology based on monitoring the Ni(II)/Ni(III) redox couple...
August 29, 2017: Analytica Chimica Acta
Sean E Goodwin, Daniel E Smith, Joshua S Gibson, Robert G Jones, Darren A Walsh
Protic ionic liquids (PILs) are ionic liquids that are formed by transferring protons from Brønsted acids to Brønsted bases. While they nominally consist entirely of ions, PILs can often behave as though they contain a significant amount of neutral species (either molecules or ion clusters), and there is currently a lot of interest in determining the degree of "ionicity" of PILs. In this contribution, we describe a simple electroanalytical method for detecting and quantifying residual excess acids in a series of ammonium-based PILs (diethylmethylammonium triflate [dema][TfO], dimethylethylammonium triflate [dmea][TfO], triethylammonium trifluoroacetate [tea][TfAc], and dimethylbutylammonium triflate [dmba][TfO])...
August 18, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Jerônimo Raimundo de Oliveira Neto, Stefani Garcia Rezende, Gérman Sanz Lobón, Telma Alves Garcia, Isaac Yves Lopes Macedo, Luane Ferreira Garcia, Virgínia Farias Alves, Ieda Maria Sapateiro Torres, Mariângela Fontes Santiago, Fernando Schmidt, Eric de Souza Gil
Honey is a functional food widely consumed. Thus, the evaluation of honey samples to determine its phenolic content and antioxidant capacity (AOC) is relevant to determine its quality. Usually AOC is performed by spectrophotometric methods, which lacks reproducibility and practicality. In this context, the electroanalytical methods offer higher simplicity and accuracy. Hence, the aim of this work was to use of electroanalytical tools and laccase based biosensor on the evaluation of AOC and total phenol content (TPC) of honey samples from different countries...
December 15, 2017: Food Chemistry
Ricardo A G de Oliveira, Elsa M Materon, Matias E Melendez, André L Carvalho, Ronaldo C Faria
Breast cancer is the most common cancer in women worldwide. The detection of biomarkers has played a significant role in the early diagnosis and prognosis of breast cancer. Herein, we describe the construction of a disposable microfluidic immunoarray device (DμID) for the rapid and low-cost detection of CA15-3 (carbohydrate antigen 15-3), a protein biomarker for breast cancer. The DμID was constructed using a simple and rapid prototyping technique and was applied to detect CA15-3 in cancer patients. The DμID construction was based on the use of a double-sided adhesive card with a microfluidic channel and a screen-printed array with 8 electrodes...
August 8, 2017: ACS Applied Materials & Interfaces
Majid Arvand, Shiva Hemmati
The goal of this study was to develop an electroanalytical method for the simultaneous determination of steroid hormones for the first time. The key factor in the electrochemical methods is the choice of suitable electrode materials. For this purpose, graphene quantum dots (GQDs) doped poly(sulfosalicylic acid) (PSSA) was immobilized on a glassy carbon electrode (GCE). Apart from exhibition strong and stable electrocatalytic response towards estradiol (E2) and progesterone (P4), the proposed sensor was able to distinguish two hormone's oxidation peaks clearly...
November 1, 2017: Talanta
Yang Liu, Meng Cai, Weiping Wu, Yuting Fang, Pei She, Shouming Xu, Jianguo Li, Kang Zhao, Jingjuan Xu, Ning Bao, Anping Deng
Herein, we reported a disposable electroanalytical device for competitive enzyme-linked immunosorbent assay (ELISA) of phenylethanolamine A (PA). Conductive carbon tape coated with gold cluster served as the working electrode, while the counter and reference electrodes were fabricated on the filter paper by the screen-printing technique. Separating fabrication of the working electrode from other electrodes could make it possible for full utilization of the working electrode modification in bulk and no contamination of the immune-reagents on the counter and reference electrodes...
April 11, 2017: Biosensors & Bioelectronics
Xiaojuan Liu, Mengmeng Song, Ting Hou, Feng Li
This study addresses the need for sensitive pesticide assay by reporting a new label-free and immobilization-free homogeneous electroanalytical strategy, which combines acetylcholinesterase (AChE)-catalyzed hydrolysis product-mediated DNA conformational switch and rolling circle amplification (RCA) to detect organophosphorous and carbamate pesticides in a "signal-on" mode. When target pesticides were present, AChE activity was inhibited and could not trigger the following DNA conformational change and the RCA reaction, which results in numerous methylene blue (MB) molecules in a free state, generating a strong electrochemical response...
April 28, 2017: ACS Sensors
Jianzhi Huang, Qiang Zeng, Silan Bai, Lishi Wang
In this work, we first report a new application of coal as a novel modified electrode material in electrochemical sensing, achieving excellent electrochemical performance similar to graphene and making the utilization of coal become more multipurpose and more meaningful. Raw coal was first ball-milled, then centrifugated, and finally annealed, thus obtaining annealed coal that possesses lots of edge-plane-like defective sites, resulting in good electron-transfer efficiency and excellent electrocatalytic activity, which makes it promising when used as signal amplifier material and as a modified matrix in electrochemical sensing...
July 26, 2017: Analytical Chemistry
Fuxian Cai, Qinghua Wang, Xiaoqian Chen, Weiwei Qiu, Fengping Zhan, Fei Gao, Qingxiang Wang
A nanocomposite of flake-shaped manganese-terephthalic acid MOF/single-walled carbon nanotubes (Mn(TPA)-SWCNTs) was synthesized using manganese chloride, terephthalic acid and SWCNTs as raw materials. Theoretical modeling study shows that the Mn(TPA) component has stronger adsorption ability to lead ion (Pb(2+)) than the other common heavy metal ions, which is in good agreement with the result of electrochemical assay. Then, the Mn(TPA)-SWCNTs were used as a sensing matrix for the voltammetric determination of Pb(2+)...
July 6, 2017: Biosensors & Bioelectronics
Daniel Martín-Yerga, Isabel Álvarez-Martos, M Carmen Blanco-López, Charles S Henry, M Teresa Fernández-Abedul
In this work, we report a simple and yet efficient stencil-printed electrochemical platform that can be integrated into the caps of sample containers and thus, allows in-field quantification of Cd(II) and Pb(II) in river water samples. The device exploits the low-cost features of carbon (as electrode material) and paper/polyester transparency sheets (as substrate). Electrochemical analysis of the working electrodes prepared on different substrates (polyester transparency sheets, chromatographic, tracing and office papers) with hexaammineruthenium(III) showed that their electroactive area and electron transfer kinetics are highly affected by the porosity of the material...
August 15, 2017: Analytica Chimica Acta
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