•Graphene (GR)-based electrochemical sensors and biosensors are reviewed in detail.•We describe the advantages and disadvantages of GR- based sensing technologies.•We compared all the sensing systems ...in terms of their precision, reproducibilities, regeneration capacity, stabilities, and specificities.•More than 150 studies that have used GR are discussed.
Graphene (GR), the thinnest and the lightest sp2 carbon nanomaterial, has exhibited extraordinary properties in terms of fast electron mobility, high current density, high mechanical strength, excellent thermal conductivity, and ultra-larger surface area. These characteristics make GR an ideal nanomaterial for nanoelectronics, nanodevices, and nanocomposites. GR-based biosensors, thus, have attracted great attention toward providing a novel sensor platform for analyzing the target biomolecules with high sensitivity and selectivity. Moreover, GR has been used in chemical sensors because of its excellent electrochemical properties. Using GR and GR derivative-modified electrodes, enzyme and DNA biosensors, immunosensors, and chemical sensors have been developed. In this review, the methods of immobilization involved in developing biosensors and chemical sensors have been summarized in Tables. Moreover, the linear ranges, limits of detection (LODs), reproducibilities, and reusabilities of these reported biosensors and chemical sensors are compared in detail. Future prospects in this rapidly developing field are also discussed.
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•Nanorod-like CoMoO4 at MPC supports were prepared by a simple method.•CoMoO4/MPC hybrids were acted as an effective sensing platform for non-enzymatic glucose detection.•The novel ...CoMoO4/MPC hybrids will hold promise in development of electrode materials.
Glucose is a popular biosensor target due to its closely with diabetes or hypoglycemia in blood. Designing efficiency electrocatalysts for the determination of glucose is vital to develop glucose detection devices. CoMoO4, as a kind of bimetallic oxide material, exhibits unique electrochemical properties. 3D macroporous carbon (MPC) has large specific surface area and excellent electrical conductivity, providing an effective support for loading other nano-entities to form novel composite with good synergetic effects. Herein, nanorod-like CoMoO4 anchored onto MPC support was synthesized for the development of a promising electrochemical sensing platform for glucose. Attributing to the synergic effects between the good electrocatalytic performance of CoMoO4 nanorods and the extraordinary electrical conductivity of 3D layered MPC, the novel CoMoO4/MPC composites non-enzymatic sensor shows excellent electrocatalytic performance for oxidation of glucose. Under the optimum conditions, the proposed CoMoO4/MPC hybrids provided a reliable linear range of 5 × 10−7 to 1.08 × 10−4 M with a low limit of detection (0.13 μM) for the detection of glucose. Meanwhile, the CoMoO4/MPC sensing platform shows fast response time of 1.76 s, good stability and selectivity for detecting glucose. Moreover, this non-enzymatic sensor also has been successfully applied to measure glucose level in human blood samples. Therefore, the developed sensor holds a new promise for the construction of facile and sensitive non-enzymatic glucose analytical platform.
•Screen-printed electrodes modified with nanomaterials provide better analytical features.•Paper based electrochemical devices provide easy and cost effective analyses.•Label-free innovative ...electrochemical immunosensors as screening methods to detect important metabolites.•Novel DNA-based electrochemical disposable sensors: new devices to measure low concentrations of clinical markers.
This review addresses recent advances in the development of screen-printed electrode based biosensors modified with different nanomaterials such as carbon nanotubes, graphene, metallic nanoparticles as gold, silver and magnetic nanoparticles, and mediator nanoparticles (Prussian Blue, Cobalt Phthalocyanine, etc.), coupled with biological recognition elements such as enzymes, antibodies, DNA and aptamers to obtain probes with improved analytical features. Examples of clinical applications are illustrated, together with examples of paper-based electrochemical devices, of multiple detections using arrays of screen printed electrodes, and of the most recent developments in the field of wearable biosensors. Also the use of smartphones as final detectors is briefly depicted.
As an emerging contaminant, per- and polyfluoroalkyl substances (PFASs) make up a large group of persistent anthropogenic chemicals, which are difficult to degrade in the environment. Notwithstanding ...their wide range of applications in consumer products and industrial processes, PFASs have been detected in the environment as well as in human body. Due to their potential adverse human health effects, the U.S. Environmental Protection Agency (EPA) set the combined concentration of PFOA and PFOS in drinking water at 70 ng/L or 70 ppt (parts per trillion) as a lifetime health advisory level. Current standard detection methods for PFASs heavily rely on chromatographic techniques coupled with mass spectrometry. Although these methods provide accurate, specific, and sensitive measurements, their applications are greatly limited in advanced analytical laboratories because it necessitates expensive instrumentations, professional operators, complicated sample pretreatment, and considerable analysis time. Therefore, other detection methods beyond chromatographic based techniques, such as optical and electrochemical techniques, have also been extensively explored for simple, accessible, inexpensive, rapid, and sensitive detection of PFASs, particularly PFOA and PFOS. The purpose of this review is to provide recent progress in alternative detection platforms relying on non-MS based techniques for PFASs analysis. Starting with a brief introduction about the importance of monitoring PFASs, recent advances in various PFASs detection methods are grouped and discussed based on the difference of signals, with an emphasis on the working principles of different techniques, the sensing mechanism, and the sensing performance. The review is closed with the conclusion and discussion of future trends.
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•Urgent needs to develop analytical tools for emerging contaminants PFASs are discussed.•Optical, electrochemical, and chromatographic-based non-MS sensors for PFASs are reviewed.•Working principles, sensing mechanism, and sensing performance of PFASs sensors are presented.•The challenge and future directions in PFASs sensor development are discussed.
Carbon nanomaterials are quite promising to be combined with metal-organic frameworks (MOFs) to enhance the sensing ability of both materials. In this work, a MOF nanoparticle of UiO-66-NH2 is ...integrated with carbon nanotubes (CNTs) (UiO-66-NH2/CNTs) with a facile solvothermal method. The morphology, surface area and properties of this UiO-66-NH2/CNTs nanocomposite was investigated using electron microscopy, XRD, XPS, BET analysis and electrochemical techniques. Catalytic oxidation of dopamine (DA) and acetaminophen (AC) on this nanocomposite was achieved, owing to a 3D hybrid structure or a large electroactive surface area, excellent electrical conductivity, a large number of active sites of this nanocomposite. It was further utilized as a sensing platform to establish an electrochemical sensor for the monitoring of both DA and AC. The enhanced oxidation signals led to the voltametric sensing of DA and AC in a broad linear range from 0.03 to 2.0 μM and low detection limits (S/N = 3) of 15 and 9 nM for DA and AC, respectively. The proposed sensor also possessed good reproducibility, repeatability, long-term stability, selectivity, and satisfactory recovery in serum samples analysis. Therefore, it has the great potential for the accurate quantification of DA and AC in complex matrixes.
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•An electrochemical sensor for simultaneous detection of dopamine and acetaminophen with high sensitivity and selectivity.•The nanocomposite of UiO-66-NH2 and carbon nanotubes shows high electrocatalytic activity toward dopamine and acetaminophen.•The extension of the applications of metal-organic frameworks.
Herein, 5.0 mg of chitosan hydrochloride was accurately weighed and dissolved in 5.0 mL of Milli-Q water. To this solution, 3.0 mg of MoS2 and 2.0 mg of MWCNTs were added. The mixture underwent ...ultrasonic dispersion in a sonicator for 1 h. Then, 6 µL of the nanocomposite was dropwise added onto the GCE surface and dried in a drying oven at 35°C for 50 min. Finally, the dried electrodes were equilibrated at room temperature for 10 min.
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•One-step construction of composite nanomaterial films based on MWCNTs, MoS2 and Chitosan.•The sensors exhibited a wide linear range, with an LOD of 0.16 µmol/L.•The prepared sensors showed good recoveries in several water samples.•The prepared sensors can be used to explore the principles of CIP electrochemical reactions.•The sensor exhibited reliable reproducibility, selectivity and stability.
Ciprofloxacin (CIP), extensively used in medical, agricultural, and forestry sectors as an antibiotic, poses risks of water contamination due to misuse or improper disposal, highlighting the pressing necessity for accelerated detection methods. Hydrophilic multi-walled carbon nanotubes (MWCNTs) and molybdenum disulfide (MoS2) were co-dispersed in a chitosan (CS) solution, which facilitates film formation. The high specific surface area of MWCNTs, coupled with the excellent semiconducting properties of MoS2 and the overall hydrophilicity of the composite nanomaterial film, markedly increases the active sites and reaction contact area. Subsequently, a drop-coating method was used to fabricate a MWCNTs@MoS2@Chitosan film onto the surface of a glassy carbon electrode (GCE) for CIP detection spanning from 0.50 to 1200.00 µmol/L using Differential Pulse Voltammetry (DPV), achieving a limit of detection (LOD) of 0.16 µmol/L. Simultaneously, the sensor demonstrates excellent reproducibility, stability, and selectivity. In several real water samples, the sensor performance was verified using a spiked recovery method. And in three water samples the recoveries ranged from 98.38 to 113.53 %, with a relative standard deviation (RSD) of less than 4.80 %. Meanwhile, the accuracy of these result was verified using UV–visible (UV–vis) spectroscopy. Furthermore, we proposed an electrooxidation mechanism for CIP that involves a reaction with two electrons and two protons.
In this study, molecularly imprinted electrochemical sensors (MIPs/MWCNTs-COOH/SPCE) were prepared by electropolymerization on a substrate electrode modified with carboxylated multi-walled carbon ...nanotubes (MWCNTs-COOH) using pyrrole as the functional monomer and 2,5-DHBA as the template molecule.
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•Development of a molecularly imprinted SPCE sensor based on MWCNTs-COOH modification.•Wide linear range for the detection of 2,5-DHBA.•Achieves highly selective detection of target substances.•The concentration of –OH can be calculated from the detection of 2,5-DHBA.
Hydroxyl radicals (–OH) are reactive substances with high reactivity and extreme oxidizing power that attack all pollutants without selectivity and play a huge role in the environment. In this study, molecularly imprinted electrochemical sensors (MIPs/MWCNTs-COOH/SPCE) were prepared by electropolymerization on a substrate electrode modified with carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) using pyrrole as the functional monomer and 2,5-DHBA as the template molecule. The surface morphology and electrochemical behavior of the sensors were characterized by scanning electron microscopy (SEM) and electrochemical methods of cyclic voltammetry (CV) and electrochemical impedance (EIS). The conditions of functional monomer pyrrole dosage, number of electropolymerization turns, elution time, adsorption time, and pH of detection solution were optimized. Under the optimal experimental conditions, the oxidation peak current of the target 2,5-DHBA by differential pulse voltammetry (DPV) showed a good linear relationship with its concentration between 1 × 10−8 ∼ 1 × 10−4 mol/L. The linear equation was Ip = 0.493lgC2,5-DHBA+4.469 (R=0.997), and the detection limit was 8.50 × 10−9 mol/L. And the experiment results sensor has good repeatability, stability and selectivity, and is a convenient, sensitive and novel method for the detection of –OH.
The unique coupling between B and N atoms as a result of co-doping could result in novel electronic structures in graphene. In this work, role of synergistic coupling effect of boron and nitrogen ...while codoping by systematically varying the concentrations of boron and nitrogen precursors is used to analyse the effects on electrochemical sensing of dopamine and hydrogen peroxide and supercapacitance performance. When compared with single doped samples (B and N), the codoped samples exhibited better supercapacitance and electrochemical sensing. Different boron and nitrogen doped graphene (BNGn (n = 1-5)) samples have been synthesized to modulate the electronic structure and surface states in order to improve the electrochemical performances. BNG5 sample shows a high specific capacitance of 378.7 F/g at 0.145 A/g in 1.0 M H2SO4, a threefold increase over single-doped graphene due to the high boron content that resulted in the highest B–N content. These samples show 92.11% cycling retention after 2000 cycles. Thus, B,N codoped samples can be tailored to be promising supercapacitor electrode materials. Excellent nonenzymatic dopamine and hydrogen peroxide sensing performance shown by BNG2 sample with 0.15 μM and 0.018 μM limit of detection (LOD) in 0–120 μM and 1–12 mM range respectively, was due to the high content of BC2O, BCO2, graphitic and oxidized N dopant species. Thus, this work brings to fore the different moieties which play crucial role in enhancing the supercapacitance (B–N, BC2O) and sensing behavior (oxidized dopants) for B,N codoped graphene. This opens up avenues to tailor doped graphene for specific applications.
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•Study synergic coupling of B,N in graphene with systematic concentration variation.•BN codoped graphene showed better supercapacitance (378.7 F/g) over single doped.•Excellent electrochemical dopamine sensing (0.15 μM) observed in BN codoped samples.•Excellent electrochemical H2O2 detection (0.018 μM) observed in BN codoped samples.•Chemical moieties enhancing supercapacitance and sensing applications are highlighted.
Among the clays, halloysite nanotubes (HNTs) are fabulous hollow tubular type of aluminosilicates due to their interesting properties such as their natural occurrence, high surface area and ...cytocompatibility. Different ways of functionalization for the inner and surface of HNTs have been used to control their properties for specific applications. Moreover, the modified HNTs are considered a precious carrier for nanomaterials for improving their dispersion and can be designated for electrochemical sensing application due to their high surface area. The free lumen that was in HNTs can be utilized for hosting other compounds for obtaining nanostructures with excellent synergistic properties.
The main purpose of this review is for the first time conducting a survey on the reports for engineering the HNTs surface to be used as an electrochemical sensor for identifying various analytes such as hydrogen peroxide, glucose, nitrite, ascorbic acid, surface plasmon resonance, catechol amines, hydrazine, dopamine and uric acid. Moreover, the latest procedures for the modification of HNTs with specified applications have been also described.
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•HNTs are marvelous nanotubular materials which can be utilized for various applications.•The inner and external surface of HNTs could show distinguished surface chemistry.•HNTs can be modified using various for improving their properties for specified uses.•The nanocomposites containing HNTs could be an efficient electrochemical sensor based on their properties.
A 3D hierarchical flowerball-like CoSe2/MnSe nanosheet arrays (CoSe2/MnSe FNSAs) derived from CoMn-LDH and cobalt glycerate spheres precursor acts as an electrode has excellent sensing performance ...for hydrazine with a wide detection range of 0.001–7.45 mM and the low detection limit of 0.4 μM at S/N=3, respectively.
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•Flowerball-like CoSe2/MnSe nanosheet arrays (CoSe2/MnSe FNSAs) was prepared by hydrothermal and selenization method.•The unique “flowerball” heterostructure nanostructure provide abundant active sites.•CoSe2/MnSe FNSAs acts an efficient catalyst electrode for hydrazine oxidation.•CoSe2/MnSe FNSAs displays high sensing performance for hydrazine detection.•CoSe2/MnSe FNSAs operates efficiently for hydrazine in environmental water samples.
Hydrazine (N2H4) is considered to be a highly toxic substance harmful to human body and environment, and has received much attention in the field of electrochemical detection in recent years. In this study, 3D hierarchical flowerball-like CoSe2/MnSe nanosheet arrays (CoSe2/MnSe FNSAs) were obtained using CoMn-LDH as precursor and cobalt glycerate spheres as the sacrificial template by simple hydrothermal reaction and selenization method. Bimetal selenides have more active electrochemical activity and more abundant electrochemical redox reactions. The unique hierarchical flowerball-like nanosheet array heterostructure can accelerate ionic diffusion kinetics and improve electron transfer. As a hydrazine electrochemical sensor, CoSe2/MnSe FNSAs exhibits excellent electrocatalytic performance with a wide detection range of 0.001–7.45 mM and a low detection limit of 0.4 μM. This strategy provides a new choice for the detection of environmental organic pollutants.
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