Three-dimensional reduced graphene oxide aerogel modified electrode for the sensitive quercetin sensing and its application

Graphene oxide supported MOFs-nanofiber carbon aerogel/SPCE for simultaneous detection of Cd2+ and Pb2+ in seafood

A novel electrochemical sensor for detecting heavy metal ions in seafood was developed to address food safety concerns. The sensor integrates graphene oxide into NH2-UiO-66 loaded nanofiber carbon aerogel, enhanced its three-dimensional conductive network and effective active surface area (0.34 cm2), which improved ion enrichment and oxidation-reduction reaction rates. Using the Box-Behnken design, the sensor was optimized to detect cadmium and lead with LODs of 0.16 μg·L-1 and 0.07 μg·L-1 in the 1 to 150 μg·L-1 linear range. Applied to real seafood samples, the sensor showed results consistent with ICP-OES, confirmed its reliability in complex substrates. This approach offered a promising, low-cost solution for real-time monitoring of heavy metal contamination in seafood, ensuring public food safety.

An electrochemical sensor based on porous heterojunction hollow NiCo-LDH/Ti3C2Tx MXenes composites for the detection of quercetin in natural plants

Cubic hollow-structured NiCo-LDH was synthesized using a solvothermal method. Subsequently, clay-like Ti3C2Tx MXenes were electrostatically self-assembled with NiCo layered double hydroxides (NiCo-LDH) to form composites featuring three-dimensional porous heterostructures. The composites were characterized using SEM, TEM, XRD, XPS, and FT-IR spectroscopy. Ti3C2Tx MXenes exhibit excellent electrical conductivity and hydrophilicity, providing abundant binding sites for NiCo-LDH, thereby promoting an increase in ion diffusion channels. The formation of three-dimensional porous heterostructural composites enhances charge transport, significantly improving sensor sensitivity and response speed. Consequently, the sensor demonstrates excellent electrochemical detection capability for quercetin (Qu), with a detection range of 0.1-20 µM and a detection limit of 23 nM. Additionally, it has been applied to the detection of Qu in natural plants such as onion, golden cypress, and chrysanthemum. The recovery ranged from 97.6 to 102.28%.

Trends on Aerogel-Based Biosensors for Medical Applications: An Overview

Aerogels are unique solid-state materials composed of interconnected 3D solid networks and a large number of air-filled pores. This structure leads to extended structural characteristics as well as physicochemical properties of the nanoscale building blocks to macroscale, and integrated typical features of aerogels, such as high porosity, large surface area, and low density, with specific properties of the various constituents. Due to their combination of excellent properties, aerogels attract much interest in various applications, ranging from medicine to construction. In recent decades, their potential was exploited in many aerogels' materials, either organic, inorganic or hybrid. Considerable research efforts in recent years have been devoted to the development of aerogel-based biosensors and encouraging accomplishments have been achieved. In this work, recent (2018-2023) and ground-breaking advances in the preparation, classification, and physicochemical properties of aerogels and their sensing applications are presented. Different types of biosensors in which aerogels play a fundamental role are being explored and are collected in this manuscript. Moreover, the current challenges and some perspectives for the development of high-performance aerogel-based biosensors are summarized.

Electrochemical Characterization of the Antioxidant Properties of Medicinal Plants and Products: A Review

Medicinal plants are an important source of bioactive compounds with a wide spectrum of practically useful properties. Various types of antioxidants synthesized in plants are the reasons for their application in medicine, phytotherapy, and aromatherapy. Therefore, reliable, simple, cost-effective, eco-friendly, and rapid methods for the evaluation of antioxidant properties of medicinal plants and products on their basis are required. Electrochemical methods based on electron transfer reactions are promising tools to solve this problem. Total antioxidant parameters and individual antioxidant quantification can be achieved using suitable electrochemical techniques. The analytical capabilities of constant-current coulometry, potentiometry, various types of voltammetry, and chrono methods in the evaluation of total antioxidant parameters of medicinal plants and plant-derived products are presented. The advantages and limitations of methods in comparison to each other and traditional spectroscopic methods are discussed. The possibility to use electrochemical detection of the antioxidants via reactions with oxidants or radicals (N- and O-centered) in solution, with stable radicals immobilized on the electrode surface, via oxidation of antioxidants on a suitable electrode, allows the study of various mechanisms of antioxidant actions occurring in living systems. Attention is also paid to the individual or simultaneous electrochemical determination of antioxidants in medicinal plants using chemically modified electrodes.

N-doped graphene aerogel cathode with internal aeration for enhanced degradation of p-nitrophenol by electro-Fenton process

A columnar N-doped graphene aerogel (NGA) was successfully fabricated by one-step hydrothermal synthesis using L-hydroxyproline as reductant, N-doping, and swelling agent, and it was used as the cathode with internal aeration mode for the electro-Fenton degradation of p-nitrophenol. Owing to the stable solid-liquid-gas three-phase interface, more active defects, and modulated nitrogen dopants, the NGA cathode exhibited enhanced electrocatalytic activity. H₂O₂ could be continuously electro-generated via a two-electron oxygen reduction, and the yield of H₂O₂ was 153.3 mg·L^-1·h^-1 with the low electric energy consumption of 15.3 kWh kg^-1. Simultaneously, the NGA cathode had better charge transfer capability with N-doping, which was conducive to the conversion of Fe³⁺/Fe²⁺. Under the optimal condition, nearly 100% removal of p-nitrophenol and 84% removal of TOC were obtained within 60 and 120 min, respectively. The NGA cathode also presented good stability and versatile applicability in different water matrices. Therefore, the NGA is a cost-effective cathode material in electro-Fenton system with adequate activity and reuse stabilization.

A 3D flower-like Co/Ni bimetallic organic framework as an excellent material for electrochemical determination of quercetin

A scheme of the fabrication of 3D flower-like CoNi-MOF nanosheets and their application in electrocatalytic oxidation of quercetin.

Three-dimensional MoS2-graphene aerogel nanocomposites for electrochemical sensing of quercetin

A facile and novel electrochemical sensing platform is reported for quercetin determination with MoS₂ nanoflowers-3D graphene aerogel (3D MoS₂-GA) nanocomposite as signal amplified material. The 3D MoS₂-GA nanocomposite was synthesized through a two-step hydrothermal method, in which MoS₂ nanoflowers were prepared in advance. Characterizations of 3D MoS₂-GA were performed by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The 3D MoS₂-GA-modified glassy carbon electrode (3D MoS₂-GA/GCE) was used to investigate the electrochemical behaviors of quercetin with electrochemical parameters calculated, reaction mechanism discussed, and experimental conditions optimized. Notably, the redox peak current densities of quercetin on 3D MoS₂-GA/GCE raised 5.14 and 6.40 times compared with those on a bare GCE. Furthermore, a novel electroanalytical approach was proposed for the sensitive determination of quercetin within the concentration range 0.01 ~ 5.0 μmol/L, accompanied by a low detection limit of 0.0026 μmol/L (at a working potential of 0.38 V vs. Ag/AgCl). The recovery for practical sample analysis ranges from 97.0 to 105%, and the relative standard deviation is less than 4.2%. This established method shows reliable performance in determination of quercetin in tablets and urine samples.

Two-dimensional material-based functional aerogels for treating hazards in the environment: synthesis, functional tailoring, applications, and sustainability analysis

Environmental pollution is a global problem that endangers human health and ecological balance. As a new type of functional material, two-dimensional material (2DM)-based aerogel is one of the most promising candidates for pollutant detection and environmental remediation. The porous, network-like, interconnected three-dimensional (3D) structure of 2DM-based aerogels can not only preserve the characteristics of the original 2DMs, but also bring many distinct physical and chemical properties to offer abundant active sites for adsorbing and combining pollutants, thereby facilitating highly efficient monitoring and treatment of hazardous pollutants. In this review, the synthesis methods of 2DM aerogels and their broad environmental applications, including various sensors, adsorbents, and photocatalysts for the detection and treatment of pollutants, are summarized and discussed. In addition, the sustainability of 2DM aerogels compared to other water purification materials, such as activated carbon, 2DMs, and other aerogels are analyzed by the Sustainability Footprint method. According to the characteristics of different 2DMs, special focuses and perspectives are given on the adsorption properties of graphene, MXene, and boron nitride aerogels, as well as the sensing and photocatalytic properties of transition metal dichalcogenide/oxide and carbon nitride aerogels. This comprehensive work introduces the synthesis, modification, and functional tailoring strategies of different 2DM aerogels, as well as their unique characteristics of adsorption, photocatalysis, and recovery, which will be useful for the readers in various fields of materials science, nanotechnology, environmental science, bioanalysis, and others.

Carbon-based aerogels for biomedical sensing: Advances toward designing the ideal sensor

Carbon based aerogels are special solid-state materials comprised of interconnected networks of 3D nanostructures with high amount of air-filled nanoporous. They expand the structural properties along with physicochemical characteristics of nanoscale construction blocks to macroscale, and incorporate distinctive attributes of aerogels, like large surface area, high porosity, and low density, with particular features of the different constituents. These features impart aerogels with rapid response signal, high selectivity, and ultra-sensitivity for sensing diverse targets in biomedical media. This has prompted researchers to develop a variety of aerogel-based sensors with encouraging achievements. Hence, this work outlines sensing applications of aerogel-based sensors with a comprehensive overview on the carbon aerogel hybrid materials and their analytical performances. Authors tried to list advantages and limitations of the developed approach and introduced more potent research for possible devices designing. We also point out some challenges and future perspectives related to the improvement of high-efficiency aerogel-based sensors.

Investigation of the spectroelectrochemical behavior of quercetin isolated from Zanthoxylum bungeanum

Flavonoids are common bioactive components in plants. Quercetin is the most abundant flavonoid in the human diet, accounting for more than half of the total daily consumption of flavonoids. In this study, adsorption and electrocatalytic activities of quercetin isolated from Zanthoxylum bungeanum on an electrode was studied via homemade electrodes. An in situ UV-Visible thin-layer spectroelectrochemical method was used to study the electrochemical behavior of quercetin in detail and to explore its electrochemical reaction mechanism. This experiment proves that UV-Vis thin-layer spectroelectrochemistry is a feasible way for studying the electrochemical reaction mechanism of flavonoids in plants.

Fabrication of a Ti3C2Tx modified glassy carbon electrode for the sensitive electrochemical detection of quercetin

Fabrication of MXene/GCE for the electrochemical determination of quercetin.

Application of Electrochemical Sensors Based on Carbon Nanomaterials for Detection of Flavonoids

Flavonoids have a variety of physiological activities such as anti-free radicals, regulating hormone levels, antibacterial factors, and anti-cancer factors, which are widely present in edible and medicinal plants. Real-time detection of flavonoids is a key step in the quality control of diverse matrices closely related to social, economic, and health issues. Traditional detection methods are time-consuming and require expensive equipment and complicated working conditions. Therefore, electrochemical sensors with high sensitivity and fast detection speed have aroused extensive research interest. Carbon nanomaterials are preferred material in improving the performance of electrochemical sensing. In this paper, we review the progress of electrochemical sensors based on carbon nanomaterials including carbon nanotubes, graphene, carbon and graphene quantum dots, mesoporous carbon, and carbon black for detecting flavonoids in food and drug homologous substances in the last four years. In addition, we look forward to the prospects and challenges of this research field.

Au-Co nanoparticles-embedded N-doped carbon nanotube hollow polyhedron modified electrode for electrochemical determination of quercetin

A core-shell ZIF-8@ZIF-67 was synthesized and pyrolyzed to get a Co nanoparticles-embedded N-doped carbon nanotube hollow polyhedron (Co@NCNHP). Then Au nanoparticles were formed on the surface and core of Co@NCNHP to obtain an Au-Co bimetal decorated NCNHP (Au-Co@NCNHP). The resultant nanocomposite was characterized by various methods including transmission electron microscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The Au-Co@NCNHP-based electrochemical sensor displayed an obviously high electrocatalytic response to the oxidation of quercetin, which was attributed to the synergistic effects of Au-Co bimetal nanoparticles and N-doped carbon nanotube with hollow polyhedron. Under the optimal conditions, the oxidation peak currents exhibited a wide linear dynamic range for quercetin concentration from 0.050 to 35.00 μmol/L, and the detection limit was 0.023 ± 0.002 μmol/L (S/N = 3). The analytical applications of the proposed electrochemical sensor were checked by determining the content of quercetin in medical and onion samples with satisfactory results. Grapical abstract.

Development of Aloe vera-titanium oxide-based ultrasensitive sensor for the quantification of quercetin

In the present work, a novel sensor developed for the quantification of quercetin (QRC) is being reported. Due to synergistic effects of Aloe vera and titanium oxide, voltammetric performance of the developed sensor (ALV-TiO2/glassy carbon electrode) was greatly enhanced. The fabricated sensor was characterized by scanning electron microscopy, X-ray diffraction, energy dispersive X-ray, and electrochemical impedance spectroscopy. The sensor was applied to study electrochemical behavior of QRC using square wave voltammetry. Under optimal condition, the developed sensor exhibited a linear response in the range of 3.3 × 10-7 to 2.31 × 10-6 µM with a detection limit of 0.8 nM. The analytical utility of the proposed sensor was justified by applying it for the analysis of QRC in real samples.

Development of an electrochemical biosensor for impedimetric detection of tetracycline in milk

Abstract

This study dealt with the fabrication of an impedimetric biosensor based on nanomaterial modified with pencil graphite electrode for the detection of tetracycline (TET) in milk samples. For response of the impedimetric aptasensor to be improved, the influence of different parameters (immobilization time of reduced grapheme oxide, time of aptamer, and TET binding, and concentration of aptamer) was optimized. In optimum conditions, the aptasensor provided a concentration range within 1 × 10^-16 - 1 × 10^-6 M and with a limit of detection of 3 × 10^-17 M TET. The proposed impedimetric aptasensor was then used in milk samples analysis, and the acceptable recovery was achieved ranging from 92.8 to 102.1%. According to this study, the combination of an aptamer and electrochemical impedance spectroscopy is a promising method for detection of TET in milk samples with high reproducibility and stability.

Graphic abstract

An electrochemical sensing platform amplified with a Au@Ag nanoparticle-decorated three-dimensional N-doped graphene aerogel for ultrasensitive determination of baicalein

A novel electrochemical method for highly sensitive determination of baicalein was developed with Au@Ag/3DNGA as signal amplifier.

Preparation of RGO/TiO2/Ag Aerogel and Its Photodegradation Performance in Gas Phase Formaldehyde

To increase the utilization ratio and catalytic efficiency of the nano TiO2, The RGO/TiO2/(Ag) powders and RGO/TiO2/Ag aerogel photocatalyst were designed and prepared. The composition and microstructure of RGO/TiO2/(Ag) powders and RGO/TiO2/Ag aerogel were studied, in addition, the photocatalytic activity of RGO/TiO2/(Ag) powders and RGO/TiO2/Ag aerogel was researched by the photocatalytic degradation behavior of formaldehyde solution and formaldehyde gas respectively. The result indicate that TiO2 is uniformly loaded on the surface of RGO with a particle size of 10 nm to 20 nm. When the amount of graphene oxide added is 1 wt%, RGO/TiO2 powder has the highest degradation effect on formaldehyde solution, in addition, the introduction of Ag can greatly improve the photocatalytic effect of the sample. The results also show that the pore size of RGO/TiO2/Ag aerogel is between 7.6 nm and 12.1 nm, and the degradation rate of formaldehyde gas is 77.08% within 2 hours.

Recent Advances of Porous Graphene: Synthesis, Functionalization, and Electrochemical Applications

Graphene is a 2D sheet of sp² bonded carbon atoms and tends to aggregate together, due to the strong π-π stacking and van der Waals attraction between different layers. Its unique properties such as a high specific surface area and a fast mass transport rate are severely blocked. To address these issues, various kinds of 2D holey graphene and 3D porous graphene are either self-assembled from graphene layers or fabricated using graphene related materials such as graphene oxide and reduced graphene oxide. Porous graphene not only possesses unique pore structures, but also introduces abundant exposed edges and accelerates mass transfer. The properties and applications of these porous graphenes and their composites/hybrids have been extensively studied in recent years. Herein, recent progress and achievements in synthesis and functionalization of various 2D holey graphene and 3D porous graphene are reviewed. Of special interest, electrochemical applications of porous graphene and its hybrids in the fields of electrochemical sensing, electrocatalysis, and electrochemical energy storage, are highlighted. As the closing remarks, the challenges and opportunities for the future research of porous graphene and its composites are discussed and outlined.

Synthesis and utilization of Co3O4 doped carbon nanofiber for fabrication of hemoglobin-based electrochemical sensor

In this paper cobalt oxide (Co₃O₄) nanoparticles were mixed with polyacrylonitrile to prepare Co₃O₄ doped carbon nanofiber (CNF) composite by electrospinning and carbonization, which was further used to modify on carbon ionic liquid electrode (CILE). Hemoglobin (Hb) was immobilized on Co₃O₄-CNF/CILE surface with Nafion acted as the protective film to fabricate an electrochemical biosensor (Nafion/Hb/Co₃O₄-CNF/CILE). Electrochemical behavior of Hb on the electrode was investigated with a pair of quasi-reversible redox peak appeared on cyclic voltammogram and electrochemical parameters were calculated. Moreover, this biosensor had good analytical capabilities for electrocatalytic reduction of different substrates including trichloroacetic acid, potassium bromate and sodium nitrite with wider detection range from 40.0 to 260.0 mmol L^-1, 0.1 to 48.0 mmol L^-1 and 1.0 to 12.0 mmol L^-1 by cyclic voltammetry, respectively. The proposed method showed excellent anti-interferences ability with good selectivity and was successful used for quantitative detection of real samples, which displayed the potential applications to develop into a new analytical device.

Versatile Aerogels for Sensors

Aerogels are unique solid-state materials composed of interconnected 3D solid networks and a large number of air-filled pores. They extend the structural characteristics as well as physicochemical properties of nanoscale building blocks to macroscale, and integrate typical characteristics of aerogels, such as high porosity, large surface area, and low density, with specific properties of the various constituents. These features endow aerogels with high sensitivity, high selectivity, and fast response and recovery for sensing materials in sensors such as gas sensors, biosensors and strain and pressure sensors, among others. Considerable research efforts in recent years have been devoted to the development of aerogel-based sensors and encouraging accomplishments have been achieved. Herein, groundbreaking advances in the preparation, classification, and physicochemical properties of aerogels and their sensing applications are presented. Moreover, the current challenges and some perspectives for the development of high-performance aerogel-based sensors are summarized.

Ultrasensitive electrochemical detection of ochratoxin A based on signal amplification by one-pot synthesized flower-like PEDOT-AuNFs supported on a graphene oxide sponge

To enhance the sensitivity of an aptasensor, a novel strategy was designed to develop an electrochemical aptasensor based on poly(3,4-ethylenedioxy thiophene)-gold nanoflower (PEDOT-AuNF) composites supported on a three-dimensional graphene oxide sponge (GOS). GOS with a three-dimensional sponge-like porous structure, exhibiting excellent electrical conductivity and a large surface area, provided the first amplification of the electrochemical signal for ochratoxin A (OTA) detection. PEDOT-AuNFs, synthesized by an ionic liquid-assisted one-pot method, presented a peculiar hierarchical flower-like structure, a high electroactive surface area, and more binding sites for immobilizing the aptamer molecules by the Au-S bonds. When PEDOT-AuNFs were supported on the surface of GOS by the interaction of the π-π packing between PEDOT and graphene oxide, a synergistic effect was produced to provide the second amplification for the aptasensor. PEDOT-AuNFs/GOS provided an ultrasensitive detection technique by multiple signal amplification for the electrochemical sensing of OTA. Consequently, this strategy not only endowed the aptasensor with high sensitivity but also needed no complicated signal amplification. The electrochemical sensor was fabricated successfully on a glassy carbon electrode to detect OTA with a linear response in the range of 0.01-20 ng L^-1 and a limit of detection of 4.9 pg L^-1. Moreover, it displayed good specificity, reproducibility and stability. The utilization of the proposed aptasensor for the quantitative determination of OTA in wine indicates that it can find promising applications in detecting OTA and even other mycotoxins in foodstuffs.

A Review: New Trends in Electrode Systems for Sensitive Drug and Biomolecule Analysis

Drug and biomolecule analysis with high precision, fast response, not expensive, and user-friendly methods have been very important for developing technology and clinical applications. Electrochemical methods are highly capable for assaying the concentration of electroactive drug or biomolecule and supply excellent knowledge concerning its physical and chemical properties such as electron transfer rates, diffusion coefficients, electron transfer number, and oxidation potential. Electrochemical methods have been widely applied because of their accuracy, sensitivity, cheapness, and can applied on-site determinations of various substances. The progress on electronics has allowed developing reliable, more sensitive and less expensive instrumentations, which have significant contribution in the area of drug development, drug and biomolecule analysis. The developing new sensors for electrochemical analysis of these compounds have growing interest in recent years. Screen-printed based electrodes have a great interest in electrochemical analysis of various drugs and biomolecules due to their easy manufacturing procedure of the electrode allow the transfer of electrochemical laboratory experiments for disposable on-site analysis of some compounds. Paper based electrodes are also fabricated by new technology. They can be preferred due to their easy, cheap, portable, disposable, and offering high sensitivity properties for many application field such as environmental monitoring, food quality control, clinical diagnosis, drug, and biomolecules analysis. In this review, the recent electrochemical drug and biomolecule (DNA, RNA, µRNA, Biomarkers, etc.) studies will be presented that involve new trend disposable electrodes.

Organized cryogel composites with 3D hierarchical porosity as an extraction adsorbent for nucleosides

Macroscopic monoliths are highly desirable in many fields of application. Herein, well organized organic-inorganic cryogel composite with a three-dimensional hierarchical meso- and macroporous structure are presented, which were produced by in situ copolymerization of mesoporous multifunctional silica (size: 1-20 μm; pore: 2-20 nm mostly) and monomers (hydroxyethyl methacrylate and diallyldimethylammonium chloride) in water below the freezing point. This copolymerization method effectively adjusted the macropores of the basic cryogel, and the nanosilica was more homogeneously dispersed in the basic cryogel. The specific surface area of the cryogel composite was increased 17 times versus than that of the basic cryogel. The abundant meso- and macroporous pores on the cryogel composite provided sufficient reactive sites favorable for the efficient mass transport of target compounds. When the cryogel composite, as solid phase extraction adsorbent, was coupled with high-performance liquid chromatography, an analytical tool, the nucleosides were quantified with good selectivity, lower detection limits (0.9-1.3 ng/mL) and satisfactory recoveries of greater than 80% from spiked human serum.

Sensitive determination of nitrite by using an electrode modified with hierarchical three-dimensional tungsten disulfide and reduced graphene oxide aerogel

Nanosheets of tungsten disulfide (WS₂) were used to improve the physicochemical properties of reduced graphene oxide aerogel (rGA). The nanosheets were directly integrated into 3D hybrid architecture of rGA by a solvothermal mixing method by which the WS₂ sheets were assembled onto the conductive graphene network. WS₂ with highly exfoliated and defect-rich structure made the WS₂/rGA composite possess plentiful active sites, and this enhanced the electrocatalytic capability of the composite. The introduction of poorly conductive WS₂ into 3D rGA system decreases the background current of rGA when used as electrode material. This is advantageous in terms of signal to-noise ratio and analytical performance in general. The WS₂/rGA electrode, best operated at a potential of 0.68 V (vs. SCE) has a linear response in the 0.01 to 130 μM nitrite concentration range with a low detection limit of 3 nM (at S/N = 3). It is selective, reproducible, stable and is successfully applied to the determination of nitrite in spiked bacon samples. Graphical Abstract Schematic presentation of an electrochemically modified electrode for the detection of nitrite based on 3D tungsten disulfide/reduced graphene oxide aerogel (WS₂/rGA).

Platinum nanoparticles decorating a biomass porous carbon nanocomposite-modified electrode for the electrocatalytic sensing of luteolin and application

A sensitive electrochemical method was proposed for the determination of luteolin based on platinum (Pt) nanoparticles decorating a biomass porous carbon (BPC) composite-modified carbon ionic liquid electrode (CILE). For Pt–BPC/CILE, a pair of well-defined redox peaks of luteolin appeared with enhanced peak currents and the positive movement of peak potentials, proving the electrocatalytic activity of the Pt–BPC nanocomposite for redox reaction. The results can be ascribed to the porous structure of BPC, the catalytic activity of Pt nanoparticles and their synergistic effects. Electrochemical parameters were calculated via cyclic voltammetry and differential pulse voltammetry. The results showed that the oxidation peak currents increased linearly with the concentration of luteolin in the range from 0.008 to 100.0 μmol L⁻¹, with a detection limit of 2.6 ± 0.054 nmol L⁻¹. The analytical performance of this sensor was checked by the detection of luteolin contents in a real Duyiwei capsule sample with satisfactory results.

A Pt–BPC nanocomposite-modified electrode was fabricated for luteolin detection.

A novel aptasensor based on 3D-reduced graphene oxide modified gold nanoparticles for determination of arsenite

In this study, a sensitive aptasensor based on three-dimensional reduced graphene oxide-modified gold nanoparticles (3D-rGO/AuNPs) was fabricated for the determination of arsenite (As(III)). The 3D-rGO/AuNPs was fully characterized with various techniques. The 5'-thiolate aptamer was first self-assembled on a glassy carbon electrode (GCE) that it's modified with 3D-rGO/AuNPs via Au-S covalent bonding. In the presence of As(III), the G-quadruplex interaction was formed between a single-stranded DNA and the target, which produced a hindrance for electron transfer. Consequently, the electrochemical impedance spectroscopy signals of a GCE modified with 3D-rGO/AuNPs was increased. In order to improve the response of the designing aptasensor, the effect of the various parameters was optimized. Under the optimal conditions, the aptasensor has an extraordinarily low detection limit of 1.4 × 10^-7 ng mL^-1 toward As(III) with a dynamic range of 3.8 × 10^-7 3.0 × 10^-4 ng mL^-1. The 3D-rGO/AuNPs aptasensor displayed superior selectivity and reproducibility with an acceptable recovery for determination of As(III) in real water samples.