Ultrasensitive non-enzymatic electrochemical detection of paraoxon-ethyl in fruit samples using 2D TiCT/MWCNT-OH.

This study reports on the development of a highly sensitive non-enzymatic electrochemical sensor based on a two-dimensional TiCT/MWCNT-OH nanocomposite for the detection of paraoxon-based pesticide. The synergistic effect between the TiCT nanosheet and the functionalized multi-walled carbon nanotubes enhanced the sensor's conductivity and catalytic activity. The nanocomposite demonstrates superior electrochemical and electroanalytical performance compared to the pristine TiCT and MWCNT-OH in detecting paraoxon-ethyl in fruit samples (green and red grapes), with a linear response range from 0.

Electrochemical sensors based on the composite of reduced graphene oxide and a multiwalled carbon nanotube-modified glassy carbon electrode for simultaneous detection of hydroquinone, dopamine, and uric acid.

Using a simple drop-casting technique, we successfully fabricated a sensitive electrochemical sensor based on the composite of reduced graphene oxide (RGO) and multiwalled carbon nanotubes (MWCNT) deposited on the surface of a glassy carbon electrode (GCE) for individual and simultaneous measurements of hydroquinone (HQ), dopamine (DA), and uric acid (UA). The nanocomposite of RGO/MWCNT was further characterized in terms of its structural properties, surface morphology, and topography using Raman, FT-IR spectroscopy, SEM, HRTEM, and AFM. Then, the proposed sensor for simultaneous measurement of HQ, DA, and UA based on RGO/MWCNT-modified GCE was investigated for its electrochemical behavior and electroanalytical performances using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV).

Facet-controlled growth and soft-chemical exfoliation of two-dimensional titanium dioxide nanosheets.

TiO remains one of the most popular materials used in catalysts, photovoltaics, coatings, and electronics due to its abundance, chemical stability, and excellent catalytic properties. The tailoring of the TiO structure into two-dimensional nanosheets prompted the successful isolation of graphene and MXenes. In this review, facet-controlled TiO and monolayer titanate are outlined, covering their synthesis route and formation mechanism.

Comparison of the analytical performance of two different electrochemical sensors based on a composite of gold nanorods with carbon nanomaterials and PEDOT:PSS for the sensitive detection of nitrite in processed meat products.

Herein, two platforms for electrochemical sensors were developed based on a combination of gold nanorods (AuNRs) with electrochemically reduced graphene oxide (ErGO) or with multiwalled carbon nanotubes (MWCNTs) and PEDOT:PSS for nitrite detection. The first and second electrodes were denoted as AuNRs/ErGO/PEDOT:PSS/GCE and AuNRs/MWCNT/PEDOT:PSS/GCE, respectively. Both materials for electrode modifiers were then characterized using UV-Vis and Raman spectroscopy, SEM, and HR-TEM.

Electrochemical Sensors based on Gold-Silver Core-Shell Nanoparticles Combined with a Graphene/PEDOT:PSS Composite Modified Glassy Carbon Electrode for Paraoxon-ethyl Detection.

Herein, a nonenzymatic detection of paraoxon-ethyl was developed by modifying a glassy carbon electrode (GCE) with gold-silver core-shell (Au-Ag) nanoparticles combined with the composite of graphene with poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS). These core-shell nanoparticles (Au-Ag) were synthesized using a seed-growth method and characterized using UV-vis spectroscopy and high-resolution transmission electron microscopy (HR-TEM) techniques. Meanwhile, the structural properties, surface morphology and topography, and electrochemical characterization of the composite of Au-Ag core-shell/graphene/PEDOT:PSS were analyzed using infrared spectroscopy, field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and electrochemical impedance spectroscopy (EIS) techniques.

Effect of Aspect Ratio of a Gold-Nanorod-Modified Screen-Printed Carbon Electrode for Carbaryl Detection in Three Different Samples of Vegetables.

In this study, three different sizes of gold nanorods (AuNRs) were synthesized using the seed-growth method by adding various volumes of AgNO as 400, 600, and 800 μL into the growth solution of gold nanoparticles. Three different sizes of AuNRs were then characterized using UV-vis spectroscopy, high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) patterns, and atomic force microscopy (AFM) to investigate the surface morphology, topography, and aspect ratios of each synthesized AuNR. The aspect ratios from the histogram of size distributions of three AuNRs as 2.

Electrochemical Sensors Based on a Composite of Electrochemically Reduced Graphene Oxide and PEDOT:PSS for Hydrazine Detection.

In this study, hydrazine sensors were developed from a composite of electrochemically reduced graphene oxide (ErGO) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), deposited onto a glassy carbon electrode (GCE). The structural properties, electrochemical characterization, and surface morphologies of this hydrazine sensor were characterized by Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM). In addition, the proposed hydrazine sensor also demonstrates good electrochemical and analytical performance when investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and amperometry techniques under optimal parameters.

Selective non-enzymatic uric acid sensing in the presence of dopamine: electropolymerized poly-pyrrole modified with a reduced graphene oxide/PEDOT:PSS composite.

A highly selective electrochemical sensor based on a molecularly imprinted polymer (MIP) to be developed for uric acid detection in the presence of dopamine as an interference molecule was demonstrated in this study. This non-enzymatic uric acid sensor was developed by electropolymerizing poly-pyrrole onto a composite of electrochemically reduced graphene oxide (ErGO) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) on a glassy carbon electrode (GCE) to give MIP/ErGO/PEDOT:PSS electrodes. The structural properties, surface morphology, and electrochemical interface of this fabricated uric acid sensor was then characterized using infrared spectroscopy, scanning electron microscopy, atomic force microscopy, and electrochemical impedance spectroscopy.

Multifunctional SiC@SiO Nanofiber Aerogel with Ultrabroadband Electromagnetic Wave Absorption.

Traditional ceramic materials are generally brittle and not flexible with high production costs, which seriously hinders their practical applications. Multifunctional nanofiber ceramic aerogels are highly desirable for applications in extreme environments, however, the integration of multiple functions in their preparation is extremely challenging. To tackle these challenges, we fabricated a multifunctional SiC@SiO nanofiber aerogel (SiC@SiO NFA) with a three-dimensional (3D) porous cross-linked structure through a simple chemical vapor deposition method and subsequent heat-treatment process.

A facile electrochemical sensor based on a composite of electrochemically reduced graphene oxide and a PEDOT:PSS modified glassy carbon electrode for uric acid detection.

A glassy carbon electrode modified with electrochemically reduced graphene oxide (ErGO) and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was developed for uric acid determination with dopamine as interference in artificial saliva. The electrochemical performance of the fabricated electrode was studied using both techniques of cyclic voltammetry (CV) and differential pulse voltammetry (DPV), under optimized conditions. Using DPV, the sensor based on ErGO/PEDOT:PSS modified GCE displayed a linear relationship in the concentration ranges of 10-100 µM for uric acid.

Voltammetric detection of vitamin B1 (thiamine) in neutral solution at a glassy carbon electrode via in situ pH modulation.

Voltammetric analysis is often dependent on pH and on the addition of buffer reagents to optimise the analytical procedure. This approach is not always possible for in situ analytical measurements, for example when studying biological fluids or ingredients in food. Therefore, a method is proposed herein, which employs a working electrode to do both, that is, to locally modulate the pH value and to measure the analytical response.

Bacteriophage M13 Aggregation on a Microhole Poly(ethylene terephthalate) Substrate Produces an Anionic Current Rectifier: Sensitivity toward Anionic versus Cationic Guests.

Bacteriophage material (M13, wild-type) deposited as a film onto a poly(ethylene terephthalate) (PET) substrate (6 μm thick with a 20 μm diameter laser-drilled microhole) has been investigated for ion conductivity and ionic current rectification effects for potential applications in membranes. The M13 aggregate membrane forms under acidic conditions (in aqueous 10 mM acids) and behaves like a microporous anion conductor with micropores defined by the packing of cylindrical virus particles. Asymmetric deposition on the PET film substrate in conjunction with semipermeability leads to anionic diode behavior.

Voltammetric characterisation of diferrocenylborinic acid in organic solution and in aqueous media when immobilised into a titanate nanosheet film.

Diferrocenylborinic acid (FcBOH, 1) has been synthesized in good yield via an improved synthetic path. Characterisation by nuclear magnetic resonance (NMR), mass spectrometry (HRMS), infrared spectroscopy (FTIR), X-ray crystallography, and by electrochemical methods reveal two one-electron oxidation processes for the two electronically coupled ferrocenyl moieties. The oxidation of 1 dissolved in organic media is contrasted to the oxidation of 1 in aqueous environments (by incorporation of 1 into a lamellar film of 2D titanate nanosheets on a glassy carbon electrode).

Cationic Rectifier Based on a Graphene Oxide-Covered Microhole: Theory and Experiment.

Cation transport through nanochannels in graphene oxide can be rectified to give ionic diode devices for future applications, for example, in desalination. A film of graphene oxide is applied to a 6 μm thick poly(ethylene terephthalate) substrate with a 20 μm diameter microhole and immersed in aqueous HCl solution. Strong diode effects are observed even at high ionic strength (0.

Extraction of hydrophobic analytes from organic solution into a titanate 2D-nanosheet host: Electroanalytical perspectives.

Titanate nanosheets (single layer, typically 200 nm lateral size) deposited from aqueous colloidal solution onto electrode surfaces form lamellar hosts that bind redox active molecular redox probes. Here, hydrophobic redox systems such as anthraquinone, 1-amino-anthraquinone, deca-methylferrocene, 5,10,15,20-tetraphenyl-21,23-porphine manganese (III) chloride (TPPMnCl), and α-tocopherol are shown to bind directly from cyclopentanone solution (and from other types of organic solvents) into the titanate nanosheet film. For anthraquinone derivatives, stable voltammetric responses are observed in aqueous media consistent with 2-electron 2-proton reduction, however, independent of the pH of the outside solution phase environments.