Search results for "Electrochemical gas sensor"

Reduced graphene oxide decorated with metals nanoparticles electrode as electrochemical sensor for dopamine

2019

Dopamine (DA) is one of the most important neurotransmitters that influences the processes that involve memory, sleep, mood, learning among others [1]. In fact, in the last years, dopamine concentration in human body fluids has been related to some neurodegenerative diseases, such as Parkinson and Alzheimer's diseases [2]. The possibility to have a bio-marker for these disease is of extreme importance because, disease related with dementia, are diagnosed when they are already developed and their management become almost impossible. The possibility to continuously monitor DA level in fluids, such as blood and urine, could accelerate the early diagnosis of these diseases. The principal analyt…

Nanostructured Based Electrochemical Sensors.

2019

In this work, we present some results concerning the electrochemical behavior of nanostructured-based electrochemical sensors. In particular, the attention has been focused on Pd and Cu nanowires for detection of hydrogen peroxide and NiO thin film or Ni@NiO core–shell nanowires for detection of mercury ions. Ordered array of Pd and Cu nanowires was obtained through displacement deposition reaction in a commercial polycarbonate membrane acting as a template. The method leads to stable nanostructured electrodes of Pd and Cu with high surface area. For the detection of mercury ions, we have fabricated a Ni/NiO electrochemical sensor, obtained by mild thermal oxidation of Ni-foil. Some results…

BODIPY dyes functionalized with 2-(2-dimethylaminophenyl)ethanol moieties as selective OFF–ON fluorescent chemodosimeters for the nerve agent mimics …

2014

[EN] Two OFF-ON fluorescent chemodosimeters based on a BODIPY core for the detection of nerve agent mimics have been synthesized. Their reactivity towards diethylcyanophosphonate (DCNP) and diisopropylfluorophosphate (DFP) has been tested in organic and aqueous phase. These chemodosimeters selectively detect the nerve agent mimics with good LODs. The chemodosimeters hold their sensing properties on solid supports, allowing the preparation of a hand held sensing kit. The sensing in solid-liquid phase has been demonstrated. The X-ray structure of compound 2 has been resolved.

PANI-Based Wearable Electrochemical Sensor for pH Sweat Monitoring

2021

Nowadays, we are assisting in the exceptional growth in research relating to the development of wearable devices for sweat analysis. Sweat is a biofluid that contains useful health information and allows a non-invasive, continuous and comfortable collection. For this reason, it is an excellent biofluid for the detection of different analytes. In this work, electrochemical sensors based on polyaniline thin films deposited on the flexible substrate polyethylene terephthalate coated with indium tin oxide were studied. Polyaniline thin films were abstained by the potentiostatic deposition technique, applying a potential of +2 V vs. SCE for 90 s. To improve the sensor performance, the electronic…

Ascorbic Acid determination using linear sweep voltammetry on flexible electrode modified with gold nanoparticles and reduced graphene oxide

2020

Indium tin oxide (ITO) coated on flexible polyethylene terephthalate (PET) substrate electrode was modified with reduced graphene oxide and gold nanoparticles by simple co-electrodeposition performed at -0.8 V vs SCE for 200 s. All samples were characterized by electron scan microscopy. The as prepared electrode was used as electrochemical sensor to selective detection of ascorbic acid using linear sweep voltammetry. Excellent results were obtained in a linear range from 20 to 150 µM of ascorbic acid with a limit of detection of about 3.1 µM (S/N=3.3). The sensors have a reproducibility of about 5.5% and also show high selectivity towards different interferents such as chlorine, calcium, ma…

An electrochemically synthesized nanoporous copper microsensor for highly sensitive and selective determination of glyphosate

2020

Real-time electrochemical detection of extracellular nitric oxide in tobacco cells exposed to cryptogein, an elicitor of defence responses

2008

International audience; It was previously reported that cryptogein, an elicitor of defence responses, induces an intracellular production of nitric oxide (NO) in tobacco. Here, the possibility was explored that cryptogein might also trigger an increase of NO extracellular content through two distinct approaches, an indirect method using the NO probe 4,5-diaminofluorescein (DAF-2) and an electrochemical method involving a chemically modified microelectrode probing free NO in biological media. While the chemical nature of DAF-2-reactive compound(s) is still uncertain, the electrochemical modified microelectrodes provide real-time evidence that cryptogein induces an increase of extracellular N…

A Comparative Study of Poly(Azure A) Film-Modified Disposable Electrodes for Electrocatalytic Oxidation of H₂O₂: Effect of Doping Anion.

2018

In the present paper, poly(azure A) (PAA) films were electrosynthetized in the presence of different doping anions on disposable screen-printed carbon electrodes (SPCEs). The anions used included inorganic monoatomic (chloride and fluoride), inorganic polyatomic (nitrate and sulfate) and organic polyatomic (dodecyl sulfate, DS) species. The coated electrodes thus obtained were characterized by electrochemical techniques and SEM. They showed improved electrocatalytic activities towards hydrogen peroxide oxidation compared to that of a bare SPCE. In particular, the insertion of DS anions inside PAA films provided a special sensitivity to the electrocatalysis of H2O2, which endowed these elect…

Copper nanowire array as highly selective electrochemical sensor of nitrate ions in water

2020

Contamination of water with nitrate ions is a significant problem that affects many areas of the world. The danger from nitrates is not so much their toxicity, rather low, as their transformation into nitrites and in particular into nitrosamines, substances considered to be a possible carcinogenic risk. For this reason, European legislation has set the maximum permissible concentration of nitrates in drinking water at 44 mg/l. Thus, it is clear that a continuous monitoring of nitrate ions is of high technological interest but it must be rapid, easy to perform and directly performed in situ. Electrochemical detection is certainly among the best techniques to obtain the above requirements. In…

Ion-exchange voltammetry at a surfactant-doped electrode: model of mass transfer kinetics to an anionic surface-charged electrode and its application…

2000

cited By 10; International audience; A theoretical model of mass transfer kinetics was developed for investigating the accumulation of cationic compounds at an anionic surfactant-doped screen-printed electrode. It was extended to an enzyme-generated cationic product for the indirect determination of alkaline phosphatase (AP). The model takes into account the analyte depletion, the kinetics of the ion-exchange reaction-diffusion and the kinetics of the enzymatic reaction. The relationship between the ion-exchange voltammetric anodic peak current and the enzyme incubation/accumulation time for a given concentration of AP was established and the validity of the theoretical model was verified e…