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Virgilio X G Oliveira, Anderson A Dias, Leandro L Carvalho, Thiago M G Cardoso, Flavio Colmati, Wendell K T Coltro
This study describes the use of electrochemical paper-based analytical devices (ePADs) drawn with graphite pencil for the determination of ascorbic acid (AA) in commercial tablets. ePADs were fabricated using vegetal paper and graphite pencil. First, the three-electrode electrochemical cell drawn using a graphical software and toner lines were laser printed on the vegetal paper surface to delimit the electrode areas. Then, the electrode regions were manually painted with graphite pencil. Afterwards, the pseudo-reference electrode was defined with the deposition of silver ink over the graphite surface...
2018: Analytical Sciences: the International Journal of the Japan Society for Analytical Chemistry
Felipe Fantinato Hudari, João Carlos Souza, Maria Valnice Boldrin Zanoni
Hemodialysis is the most commonly used method for the treatment of chronic kidney disease. In this procedure, some patients use diuretics to control weight gain and blood pressure. In this work, a voltammetric sensor based on a glassy carbon electrode modified with carbon nanotubes (GCE/MWCNT) is described for the simultaneous determination of the diuretics hydrochlorothiazide (HCT) and triamterene (TRT). The oxidation of the diuretics on the GCE/MWCNT surface was observed at 1.01 and 1.17V for HCT and TRT, respectively, allowing simultaneous determination, which was not possible with the unmodified glassy carbon electrode...
March 1, 2018: Talanta
Patrícia B Deroco, Romeu C Rocha-Filho, Orlando Fatibello-Filho
The first electroanalytical method for the simultaneous determination of an important antibiotic (amoxicillin - AMX) and an anti-inflammatory drug (nimesulide -NIM), widely used in combination, is here proposed. In this method, a glassy carbon (GC) substrate modified with carbon black (CB) immobilized within a dihexadecylphosphate (DHP) film is used as electrochemical sensor (CB-DHP/GC). The electrochemical activity of this sensor was assessed (comparatively to that of GC) by electrochemical impedance spectroscopy, using the [Fe(CN)6]3-/4- redox couple, when two different active electron transfer regions were clearly characterized...
March 1, 2018: Talanta
Dale A C Brownson, Graham C Smith, Craig E Banks
The modification of electrode surfaces is widely implemented in order to try and improve electron transfer kinetics and surface interactions, most recently using graphene related materials. Currently, the use of 'as is' graphene oxide (GO) has been largely overlooked, with the vast majority of researchers choosing to reduce GO to graphene or use it as part of a composite electrode. In this paper, 'as is' GO is explored and electrochemically characterized using a range of electrochemical redox probes, namely potassium ferrocyanide(II), N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), dopamine hydrochloride and epinephrine...
November 2017: Royal Society Open Science
Patrícia B Deroco, Roberta A Medeiros, Romeu C Rocha-Filho, Orlando Fatibello-Filho
A novel, unique electroanalytical method was developed for the simultaneous quantification of the dyes indigo carmine (IC) and allura red (AR) in candies by coupling flow injection analysis and multiple pulse amperometry with a cathodically pretreated boron-doped diamond electrode, using 0.30 mol L-1 H2SO4 as supporting electrolyte. A dual-potential waveform was employed, causing the electrooxidation of either IC solely or IC and AR simultaneously. Thence, subtraction of current signals was used to quantify IC and AR in the concentration ranges of 70...
May 1, 2018: Food Chemistry
Adriane F Brito, Patrícia C C S Braga, Lorrane K S Moreira, Dayane M Silva, Daiany P B Silva, Germán Sanz, Boniek G Vaz, Flávio S de Carvalho, Luciano M Lião, Rafaela R Silva, François Noël, Hiasmin F S Neri, Paulo C Ghedini, Murilo F de Carvalho, Eric de S Gil, Elson A Costa, Ricardo Menegatti
In the scope of a research program aimed at developing new drugs for the treatment of central nervous system diseases, we describe herein the synthesis and pharmacological evaluation of 1-(4-(3,5-di-tert-butyl-4-hydroxybenzyl) piperazin-1-yl)-2-methoxyethan-1-one (LQFM180). This compound showed antioxidant activity in two models, electroanalytical assays, and DPPH activity. Moreover, in behavioral tests as the open field test LQFM180 (9.4, 18.8, and 37.6 mg/kg, per oral (p.o.)), we detected anxiolytic-like activity...
December 19, 2017: Naunyn-Schmiedeberg's Archives of Pharmacology
Chuhong Lin, Lifu Chen, Eden E L Tanner, Richard G Compton
The oxidation of dopamine in strongly acidic (pH = 0) solution is investigated using microdisc, microcylinder and macro-electrodes together with a range of voltage scan rates. Kinetic and mechanistic analysis over the full range of mass transport conditions show a behaviour consistent with an ECE process with a fast chemical step and in which the second electron transfer is thermodynamically more favourable than the first step. Accordingly the reaction effectively behaves as an EE process.
December 8, 2017: Physical Chemistry Chemical Physics: PCCP
Javier Izquierdo, Peter Knittel, Christine Kranz
Scanning electrochemical microscopy (SECM) has evolved from an electrochemical specialist tool to a broadly used electroanalytical surface technique, which has experienced exciting developments for nanoscale electrochemical studies in recent years. Several companies now offer commercial instruments, and SECM has been used in a broad range of applications. SECM research is frequently interdisciplinary, bridging areas ranging from electrochemistry, nanotechnology, and materials science to biomedical research...
December 6, 2017: Analytical and Bioanalytical Chemistry
Shunbi Xie, Ying Tang, Dianyong Tang
Traditionally, genomic DNA detection is relay on a rigorous DNA amplification process, which always accompanied with complicated gel electrophoresis or expensive fluorescence detection methods. In this work, we have translated genomic DNA detection into adenosine triphosphate (ATP) test based on a split aptamer-based electrochemical sandwich assay. The key characteristic of our method are list as follows: first, nucleic acid amplification of the target gene was performed by the use of a loop mediated isothermal amplification (LAMP) process...
December 1, 2017: Biosensors & Bioelectronics
James G Roberts, Leslie A Sombers
In this review we will describe the electroanalytical method known as fast-scan cyclic voltammetry (FSCV), how it has advanced over the years, and in what way(s) it is impacting other sciences. To begin, a brief history will be discussed. The various means to enhance chemical selectivity by manipulating the applied potential will be covered. Some limitations of this electroanalytical method will be highlighted to inform and provide clarity to the scientific community. The intent is to seek out effective solutions to the difficult problems associated with the technique, so that the field will continue to flourish...
November 28, 2017: Analytical Chemistry
Jadranka Milikić, Ivan Stoševski, Jelena Krstić, Zorica Kačarević-Popović, Šćepan Miljanić, Biljana Šljukić
Monitoring bromides (Br-) is of crucial importance since bromates, potential human carcinogens, are formed during ozonation of water containing bromides in concentrations >100 μg L-1. Within this study, silver (Ag) and four carbon-supported Ag catalysts were synthesized by the γ-radiation method and their morphology and structure examined using transmission electron microscopy, X-ray diffraction, and UV-Vis analysis. The nanocatalysts were tested for Br- sensing in aqueous media using cyclic voltammetry...
2017: Journal of Analytical Methods in Chemistry
Yaw-Jen Chang, Ching-Yuan Ho, Xin-Miao Zhou, Hsiu-Rong Yen
Blood typing assay is a critical test to ensure the serological compatibility of a donor and an intended recipient prior to a blood transfusion. This paper presents a microfluidic blood typing system using a small quantity of blood sample to determine the degree of agglutination of red blood cell (RBC). Two measuring methods were proposed: impedimetric measurement and electroanalytical measurement. The charge transfer resistance in the impedimetric measurement and the power parameter in the electroanalytical measurement were used for the analysis of agglutination level...
November 15, 2017: Biosensors & Bioelectronics
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
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