Showing papers on "Amperometry published in 2017"
TL;DR: Prepared novel Ni@f-MWCNT/GCE was utilized to detect glucose in real serum species and presents one of the record electrocatalytic activity, stability and response towards glucose under the optimized situations.
141 citations
TL;DR: Electrochemical tests indicate that such copper-nitride nanowires array on copper foam (Cu3 N NA/CF) possesses superior non-enzymatic sensing ability toward rapid glucose and H2 O2 detection with high selectivity.
Abstract: It is highly attractive to develop non-noble-metal nanoarray architecture as a 3D-catalyst electrode for molecular detection due to its large specific surface area and easy accessibility to target molecules. Here, we report the development of a copper-nitride nanowires array on copper foam (Cu3N NA/CF) as a dual-functional catalyst electrode for efficient glucose oxidation in alkaline solutions and hydrogen peroxide (H2O2) reduction in neutral solutions. Electrochemical tests indicate that such Cu3N NA/CF possesses superior non-enzymatic sensing ability toward rapid glucose and H2O2 detection with high selectivity. At 0.40 V, this sensor offers a high sensitivity of 14 180 μA mm cm−2 for glucose detection, with a wide linear range from 1 μm to 2 mm, a low detection limit of 13 nm (S/N=3), and satisfactory stability and reproducibility. Its application in determining glucose in human blood serum is also demonstrated. Amperometric H2O2 sensing can also been realized with a sensitivity of 7600 μA mm cm−2, a linear range from 0.1 μm to 10 mm, and a detection limit of 8.9 nm (S/N=3). This 3D-nanoarray architecture holds great promise as an attractive sensing platform toward electrochemical small molecules detection.
133 citations
TL;DR: The reagentless with fabrication method without binder and adhesive agents for immobilized enzyme and this nanocomposite could be used as a platform for disposable biosensor and biofuel cell applications.
128 citations
TL;DR: Two different DNA (ERBB2c and CD24c) modified gold nanoparticles and graphene oxide loaded on glassy carbon electrodes were prepared for early detection of breast cancer markers by electrochemical detection of HER2.
116 citations
TL;DR: This novel hybrid material-based biosensor can suggest a milestone in the development of a highly sensitive detecting platform for biosensor fabrication with highly sensitive detection of target molecules other than H2O2.
106 citations
TL;DR: An amperometric non-enzymatic glucose sensor was developed based on nitrogen-doped graphene with dispersed copper nanoparticles (Cu-NGr) with high selectivity with excellent reproducibility and recovery in complex food materials and was tested for direct application to detect glucose in food samples.
105 citations
TL;DR: The proposed non-enzymatic electrochemical sensor was used for determining H2O2 in apple juice, and the sensor electrode provided satisfactory results with reliable recovery values, revealing that the novel GC/rGO-Nf@Ag6 sensor electrode could be a potential candidate for the detection of H2 O2.
102 citations
TL;DR: In this paper, a magnetic glassy carbon electrode (MGCE) modified with multilayer nanocomposite (Ag@MWCNT-IL-Fe3O4) was used as an immobilization support to promote electron transfer reactions of glucose oxidase (GOx).
Abstract: We present a method to produce a magnetic glassy carbon electrode (MGCE) modified with multilayer nanocomposite (Ag@MWCNT-IL-Fe3O4) as an immobilization support to promote electron transfer reactions of glucose oxidase (GOx). The nanocomposite verified by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). The direct electron transfer (DET) between GOx and Ag@MWCNT-IL-Fe3O4 nanocomposite was investigated using cyclic voltammetry which showed a pair of well-defined redox peaks corresponding to redox active center of GOx. Utilization of constructed electrode for detection of glucose was studied in N2 and air saturated solutions (pH 7.0). The GOx/Ag@MWCNT-IL-Fe3O4/MGCE showed excellent stability, a detection limit of 2.12 μM, a linear range between 6 μM and 2 mM, and a dynamic range up to 2.7 mM at the air saturated solutions. Also, in N2 saturated solutions (pH 7.0), determination of glucose was carried out by amperometry, and the proposed biosensor showed good reproducibility and stability with a detection limit of 3.8 μM and a linear range between 10 μM and 1 mM. Such analytical performances confirm that the fabricated biosensor used in this work has potential to be applied for development of redox enzyme based biosensors.
100 citations
TL;DR: A sandwich aptamer-based screen-printed carbon electrode (SPCE) using chronoamperometry for the detection of cardiac troponin I (cTnI), one of the promising biomarkers for acute myocardial infarction (AMI), showed high sensitivity over other proteins and is anticipated to become an innovative diagnostic tool for AMI.
94 citations
TL;DR: A glassy carbon electrode was modified with a nanocomposite consisting of molybdenum disulfide nanosheets (MoS2) and graphene that was prepared via a hydrothermal process as discussed by the authors.
Abstract: The authors describe an inexpensive electrode for the sensitive amperometric determination of the pesticide methyl parathion. A glassy carbon electrode was modified with a nanocomposite consisting of molybdenum disulfide nanosheets (MoS2) and graphene that was prepared via a hydrothermal process. Its morphology, elemental composition, diffraction, impedance and voltammetric characteristics were studied. The modified electrode displays excellent electrocatalytic ability towards methyl parathion, and the reduction peak current, measured typically at −0.60 V (vs. Ag/AgCl) is related to the concentration of methyl parathion. The effect of concentration, scan rate and solution pH value were optimized. The calibration plot is linear in the 10 nM to 1.9 mM concentration range, with a 3.2 nM detection limit (at a signal-to-noise ratio of 3). The electrode is selective, stable, adequately repeatable and reproducible. The method was successfully applied to the determination of methyl parathion in spiked samples of homogenized apple, kiwi, tomato and cabbage.
92 citations
TL;DR: A novel poly(β-cyclodextrin) (β-CD)/carbon quantum dots (CQDs) composite based sensor was successfully fabricated on glassy carbon electrode through electrochemical polymerization as discussed by the authors.
Abstract: A novel poly(β-cyclodextrin) (β-CD)/carbon quantum dots (CQDs) composite based sensor was successfully fabricated on glassy carbon electrode through electrochemical polymerization As-prepared β-CD/CQDs modified electrode was used for the simultaneous determination of dopamine (DA), uric acid (UA) and tryptophan (Trp) Electrochemical responses of as-prepared electrode were investigated by cyclic voltammetry, electrochemical impedance spectroscopy and differential pulse voltammetry In co-existence system containing DA, UA and Trp, three oxidation peaks well separated from each other and the potential separations of oxidation peaks of DA-UA and UA-Trp were respectively large up to 150 and 420 mV, owing to the synergistic effect of β-CD and CQDs The linear amperometric responses for DA, UA and Trp were obtained in the concentration range of 4–220, 03–200 and 5–270 μM, respectively, with the limits of detection of 014, 001, 016 μM (S/N = 3) and the limits of quantification of 045, 004, 050 μM (S/N = 10) Moreover, as-prepared β-CD/CQDs modified electrode exhibited prominent selectivity, stability and reproducibility, which had promising application for the simultaneous determination of DA, UA and Trp
TL;DR: The aim of this study was the electrochemical detection of the adenosine-3-phosphate degradation product, xanthine, using a newxanthine biosensor based on a hybrid bio-nanocomposite platform which has been successfully employed in the evaluation of meat freshness.
TL;DR: In this paper, an electrochemical sensing scaffold for hydrazine (HZ) and nitrobenzene (NB) has been developed based on gold nanoparticles decorated mesoporous silica microspheres (Au-MSM) modified glassy carbon (GC) electrode.
Abstract: In this report, an electrochemical sensing scaffold (ESS) for hydrazine (HZ) and nitrobenzene (NB) have been developed based on gold nanoparticles decorated mesoporous silica microspheres (Au-MSM) modified glassy carbon (GC) electrode (represented as GC/Au-MSM). The presence and formation of gold nanoparticles in Au-MSM composite material is verified by X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy and by electrochemical methods. The textural and thermal properties are studied by nitrogen adsorption-desorption and thermogravimetric analysis, respectively. The electrocatalytic sensing behavior of GC/Au-MSM towards HZ and NB are investigated in detail employing various electrochemical techniques. Amperometry measurements as a function of HZ concentration exhibit two linear calibration ranges of 5.0 μM to 0.5 mM and 0.5–18.0 mM. Similarly, the differential pulse voltammetry measurements as a function of NB concentration show a linear calibration range of 0.1 μM to 2.5 mM. The limit of detection is evaluated to be 0.11 μM and 15.0 nM for HZ and NB, respectively. The kinetic parameters for HZ oxidation and NB reduction are discussed using chronoamperometry. The proposed GC/Au-MSM ESS shows good selectivity over potent interferences and applied to determine HZ and NB in various water samples.
TL;DR: In this article, the combined electrocatalytic and synergistic properties of gold nanoparticles (AuNPs) decorated multiwalled carbon nanotubes (MWCNTs) and the large surface area of chitosan (CS) cryogel for the fabrication of a highly sensitive and stable electrochemical nonenzymatic sensor were described.
Abstract: This work describes the combined electrocatalytic and synergistic properties of gold nanoparticles (AuNPs) decorated multiwalled carbon nanotubes (MWCNTs) and the large surface area of chitosan (CS) cryogel for the fabrication of a highly sensitive and stable electrochemical non-enzymatic sensor. MWCNTs were pre-mixed with citrate ions that serve as the substrate for gold deposition along their chains. The AuNPs-MWCNTs nanocomposite and chitosan cryogel were easily modified on a gold electrode in only 1 h by freezing and thawing of the mixture after casting it on the electrode surface. Glucose, as a model analyte, was measured by the developed electrode in a flow-injection amperometric system. A fast response time and excellent sensitivity were obtained. The sensor exhibited a linear range between 0.001 and 1.0 mM with a low detection limit (0.5 μM) and a high operational stability (525 injections). There were no effects from the common interferences found in physiological levels in blood samples. After measuring glucose in human blood plasma using this sensor, the results were in good agreement (P > 0.05) with those obtained from the standard spectrophotometrically-measured hexokinase method employed clinically. These good performances made this sensor a potential alternative tool for the detection of glucose and other oxidizable analytes.
TL;DR: The hybrid nanocomposite-modified electrode consisting of reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) using the one-step electrochemical method shows high selectivity towards the determination of DA, AA, or UA in the presence of potentially active bioelements and exhibits many advantages like fast amperometric response, excellent operational stability, and appropriate practicality.
Abstract: Here, we introduce the preparation of the hybrid nanocomposite-modified electrode consisting of reduced graphene oxide (RGO) and gold nanoparticles (AuNPs) using the one-step electrochemical method, allowing for the simultaneous and individual detection of dopamine (DA), ascorbic acid (AA), and uric acid (UA). RGO/AuNPs nanocomposite was formed on a glassy carbon electrode by the co-reduction of GO and Au3+ using the potentiodynamic method. The RGO/AuNPs nanocomposite-modified electrode was produced by subjecting a mixed solution of GO and Au3+ to cyclic sweeping from -1.5 V to 0.8 V (vs. Ag/AgCl) at a scan rate 10 mV/s for 3 cycles. The modified electrode was characterized by scanning electron microscopy, Raman spectroscopy, contact angle measurement, electrochemical impedance spectroscopy, and cyclic voltammetry. Voltammetry results confirm that the RGO/AuNPs nanocomposite-modified electrode has high catalytic activity and good resolution for the detection of DA, AA, and UA. The RGO/AuNPs nanocomposite-modified electrode exhibits stable amperometric responses for DA, AA, and UA, respectively, and its detection limits were estimated to be 0.14, 9.5, and 25 μM. The modified electrode shows high selectivity towards the determination of DA, AA, or UA in the presence of potentially active bioelements. In addition, the resulting sensor exhibits many advantages such as fast amperometric response, excellent operational stability, and appropriate practicality.
TL;DR: Modification of the proposed biosensor by copolymerization of amine functionalized monomer, which is indispensable to the enzyme immobilization, with palladium complex bearing monomer have provided to give perfect response to different glucose concentrations.
TL;DR: In this paper, a non-enzymatic amperometric sensor is fabricated for glucose detection based on nickel nanoparticles supported on porous silicon flour, which can be used for determination of Gl in human blood serum with good accuracy and reproducibility.
Abstract: Here, a non-enzymatic amperometric sensor is fabricated for glucose detection based on nickel nanoparticles supported on porous silicon flour. A facile procedure was introduced for the in-situ electroless assembling of nickel nanoparticles on porous silicon (PS) flour without using any reducing agent. Briefly, Ni@PSnanocompositewaspreparedthroughthechemicalreductionofNi2(Her)+ ions and oxidation of the surface of Si atoms in ammonium fluoride solution. The formation of the Ni@PS nanocomposite was confirmed by scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), energy dispersive spectroscopy (EDS) and FT-IR spectroscopy as well as cyclic voltammetry (CV). The synthesized nanocomposite was employed as an electrode material for non-enzymatic glucose (Gl) sensing using carbon paste electrode (CPE). The prepared amperometric sensor exhibited a wide linear range of 2.0–5000 μmol L−1 with a low limit of detection (0.2 μmol L−1) as well as high stability and fast response time (<3 s). Also, no significant interference was observed from potentially interference species such as dopamine, ascorbic acid, uric acid and Cl− ions. The excellent applicability of the proposed sensor for determination of Gl in human blood serum with good accuracy and reproducibility made Ni@PS nanocomposite promising for the development of effective electrochemical non-enzymatic Gl sensor.
TL;DR: Graphene quantum dots with chitosan (GQDs-CS) were used for the first time as a suitable nanostructured sensing film for efficient immobilization of methylene blue (MB) through amino-hydroxyl reaction to prepare a novel non-enzymatic hydrogen peroxide sensor using a glassy carbon electrode (GCE) as discussed by the authors.
TL;DR: In this article, a non-enzymatic electrochemical blood-glucose sensor has been fabricated using a nanoporous platinum sensing interface prepared by successive electrochemical formation and reduction of thick hydrous platinum oxide layers.
TL;DR: In this paper, the electropolymerization of dopamine on an electrochemically reduced graphene oxide (ERGO) surface was utilized successfully for the electrocatalytic detection of free chlorine (free-Cl).
Abstract: This paper describes the electropolymerization of dopamine on an electrochemically reduced graphene oxide (ERGO) surface that was utilized successfully for the electrocatalytic detection of free chlorine (free-Cl). ERGO was fabricated on a glassy carbon (GC) electrode by the reduction of graphene oxide (GO) using cyclic voltammetry (CV). Subsequently, the electrode (ERGO/GC) surface was electropolymerized using dopamine for 30 cycles and a polydopamine-modified electrode (PDA@ERGO/GC) was obtained. The PDA@ERGO/GC-modified electrode was characterized by field emission scanning electron microscopy, X-ray photoelectron spectroscopy, electrochemical impedance spectroscopy, and CV. The surface coverage concentration (τ) of the PDA@ERGO/GC electrode was 1.70 × 10−10 mol cm−2. The presence of quinone functional groups on the electrode surface offers excellent electrocatalytic ability for the determination of free-Cl. The calculated kinetic parameters of the fabricated electrode confirmed its facile performance towards the determination of free-Cl with a rate constant (ks) and charge transfer coefficient (α) of 3.38 s−1 and 0.75, respectively. Under the optimal conditions, the reduction current of free-Cl is proportional to its concentration range, 9.9–215.2 μM, with a correlation coefficient of 0.998 and a sensitivity and detection limit (LOD) of 0.0071 μA μM−1 and 44 nM, respectively. Furthermore, PDA@ERGO/GC was used for the real sample determination of free-Cl from swimming pool water with satisfactory recoveries obtained in the range of 102.4% to 103.0%.
TL;DR: In this article, an amperometric aptasensor for mycotoxin ochrotoxin A (OTA) detection is presented. But the method is highly specificity for OTA and has a limit of detection as low as 52 pM.
Abstract: The authors describe an amperometric aptasensor for the mycotoxin ochrotoxin A (OTA). It is based on the use of a modified gold electrode containing aptamer (Apt) as the sensing ligand, Methylene Blue (MB) as the redox indicator, single-walled carbon nanotubes (SWCNTs) as electrochemical signal amplifiers, and complementary strands of aptamer (CSs) as assisting DNA. In the absence of OTA, the duplex formed between Apt and CSs on the electrode remains intact. Thus, a strong electrochemical signal is observed due to the presence of the redox marker MB in the duplex. If OTA is added, the duplex will be disassembled and MB and SWCNTs will be released from the surface of the gold electrode. Hence, the electrochemical signal is weakened. The method is highly specificity for OTA and has a limit of detection as low as 52 pM. The aptasensor was successfully applied to the determination of OTA in (spiked) serum and grape juice samples where it shows LODs of 134 and 58 pM, respectively.
TL;DR: In this article, a glassy carbon electrode was modified with polyethyleneimine-functionalized multi-walled carbon nanotubes, and gold and platinum nanoparticles (AuPt-NPs) were electrodeposited.
Abstract: The family of zearalenones (ZENs) represents a major group of mycotoxins with estrogenic activity. They are produced by Fusarium fungi and cause adverse effects on human health and animal production. The authors describe here a label-free amperometric immunosensor for the direct determination of ZENs. A glassy carbon electrode (GCE) was first modified with polyethyleneimine-functionalized multi-walled carbon nanotubes. Next, gold and platinum nanoparticles (AuPt-NPs) were electro-deposited. This process strongly increased the surface area for capturing a large amount of antibodies and enhanced the electrochemical performance. In a final step, monoclonal antibody against zearalenone was orientedly immobilized on the electrode, this followed by surface blocking with BSA. The resulting biosensor was applied to the voltammetry determination of ZENs, best at a working voltage of 0.18 V (vs SCE). Under optimized conditions, the method displays a wide linear range that extends from 0.005 to 50 ng mL−1, with a limit of detection of 1.5 pg mL−1 (at an S/N ratio of 3). The assay is highly reproducible and selective, and therefore provides a sensitive and convenient tool for determination of such mycotoxins.
TL;DR: In this paper, graphite rod (GR) modified with electrochemicaly deposited gold nanoparticles (AuNPs) and adsorbed glucose oxidase (GOx) was used in amperometric glucose biosensor design.
Abstract: Graphite rod (GR) modified with electrochemicaly deposited gold nanoparticles (AuNPs) and adsorbed glucose oxidase (GOx) was used in amperometric glucose biosensor design. Enzymatic formation of polypyrrole (Ppy) on the surface of GOx/AuNPs/GR electrode was applied in order to improve analytical characteristics and stability of developed biosensor. The linear glucose detection range for Ppy/GOx/AuNPs/GR electrode was dependent on the duration of Ppy-layer formation and the linear interval was extended up to 19.9 mmol L−1 after 21 h lasting synthesis of Ppy. The sensitivity of the developed biosensor was determined as 21.7 μA mM−1 cm−2, the limit of detection – 0.20 mmol L−1. Ppy/GOx/AuNPs/GR electrodes demonstrated advanced good stability (the t1/2 was 9.8 days), quick detection of glucose (within 5 s) in the wide linear interval. Additionally, formed Ppy layer decreased the influence of electroactive species on the analytical signal. Developed biosensor is suitable for the determination of glucose in human serum samples.
TL;DR: In this article, the fabrication of copper oxide (CuO) on glassy carbon (GC) electrode by electrodeposition method using Cu-MOF was described, which was exploited for the determination of glucose and the application of the present method was exhibited by determining glucose in human blood serum sample.
TL;DR: In this article, an in-situ synthesis of copper nanoparticles-polyaniline-graphene oxide (CuNPs-PANI-GO) nanocomposite is demonstrated.
Abstract: In this paper, an in-situ synthesis of copper nanoparticles-polyaniline-graphene oxide (CuNPs-PANI-GO) nanocomposite is demonstrated. The formation of polyaniline (PANI) and copper nanoparticles (CuNPs) takes place simultaneously on the GO surface. The synthesized nanocomposite was characterized by UV–vis, FT-IR, XRD, SEM and HR-TEM analysis. Further, the CuNPs-PANI-GO modified electrode shows an excellent electro catalytic activity towards the ultra-sensitive and selective sensing of carcinogenic hydrazine in the presence of 500-fold excess of various common interfering ions and physiological interference. The amperometric current response exhibits a wide linearity range from 40 to 480 nM for hydrazine and the limit of detection and quantification are found to be 0.0045 and 0.015 μM (S/N = 3 & 10) respectively. In addition, the CuNPs-PANI-GO nanocomposite modified electrode exhibits an outstanding recovery results toward hydrazine in various real water samples. The results obtained from the present method were validated with HPLC method.
TL;DR: In this paper, a novel graphene decorated gold nanocage nanocomposite through thermal modification route as a hydrazine sensor was reported, using the galvanic replacement between silver nanocubes and aqueous gold solution.
Abstract: In this study, we report a novel graphene decorated gold nanocage nanocomposite through thermal modification route as a hydrazine sensor. Gold nanocages were synthesized, using the galvanic replacement between silver nanocubes and aqueous gold solution. Graphene nanosheets were functionalized by reaction with N,N-dimethylformamide (DMF) at relatively high temperature to generate chemically modified graphene (CMG). Surface topography and thickness of CMG nanosheets were obtained by atomic force microscopy (AFM). Ultraviolet visible (UV–vis) spectroscopy, scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), Fourier transformed infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) were used to characterize the physicochemical properties of gold nanocage/CMG nanocomposite. The electrochemical behaviour of sensor was investigated using cyclic voltammetry (CV), amperometry and electrochemical impedance spectroscopy (EIS). It was found that the gold nanocage/CMG modified glassy carbon electrode (GCE) exhibits low oxidation potential (0.17 V) with two linear ranges from 6 μM to 30 μM and 30 μM to 1.7 mM for sensing hydrazine with detection limit of 0.5 μM. The modified electrode exhibits good selectivity for hydrazine amperometric response in the presence of common ions and some biological interfering species and it can be easily prepared which makes it reproducible. Furthermore, the present sensor exhibits high level of stability for the determination of hydrazine.
TL;DR: In this paper, a nanocomposite prepared from reduced graphene oxide (rGO) and silver nanoparticles (AgNPs) was used in an electrochemical aptasensor for the sensitive and selective determination of the antibiotic chloramphenicol (CAP).
Abstract: A nanocomposite prepared from reduced graphene oxide (rGO) and silver nanoparticles (AgNPs) is used in an electrochemical aptasensor for the sensitive and selective determination of the antibiotic chloramphenicol (CAP). The nanocomposite was obtained by electrostatic assembly of AgNPs on the surface of polyelectrolyte-functionalized rGO and then used to modify a glassy carbon electrode. The biosensor is then obtained by immobilizing the aptamer against CAP. When incubated with solutions of CAP, the sensor surface is loaded with CAP due to aptamer recognition. The captured CAP can be electrochemically reduced to yield a current that is strongly enhanced as a result of the excellent electrocatalysis property of the graphene/AgNP-nanocomposite. Under optimum conditions, the calibration plot is linear in the 0.01 to 35 μM concentration range, with a 2 nM detection limit (at 3σ). The sensor is reproducible, stable, selective over homologous interferents, and performs excellently when analyzing CAP in milk samples.
TL;DR: The fabricated H2O2 biosensor was used to perform real-time monitoring of H 2O2 released from SP2/0 cells, indicating the MoS2-Au hybrid is an attractive material for application in the efficient immobilization of biomolecules and construction of high-performance biosensors.
Abstract: MoS2 nanosheet–Au nanorod (MoS2–Au) hybrids were utilized to immobilize catalase (CAT) to construct a sensitive hydrogen peroxide (H2O2) electrochemical biosensor for the reliable determination of H2O2 released from living cells. The fabricated biosensor was characterized by transmission electron microscopy (TEM), UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy, it was observed that the MoS2–Au hybrid provides excellent matrixes for the adsorption of CAT and the entrapped CAT maintains its native structure and bioactivity. The results of direct electrochemical measurements indicate that on the CAT/MoS2–Au modified electrode, CAT exhibits a surface controlled and fast electron transfer process towards H2O2 reduction. The MoS2–Au hybrid has a large surface area and provides a biocompatible microenvironment for accelerating direct electron transfer between the enzyme and the electrode. The detection limit of the constructed H2O2 biosensor is 1 × 10−7 M (signal-to-noise = 3) with a wide linear range from 5 × 10−7 M to 2 × 10−4 M and a high sensitivity of 187.4 mA M−1 cm−2. The fabricated H2O2 biosensor also exhibits excellent selectivity, good reproducibility and long-time stability. Furthermore, the biosensor was used to perform real-time monitoring of H2O2 released from SP2/0 cells, indicating the MoS2–Au hybrid is an attractive material for application in the efficient immobilization of biomolecules and construction of high-performance biosensors.
TL;DR: A planar electrochemical sensor based on flower-like CuO nanostructures growth in situ on a commercial screen printed carbon electrode, was fabricated by an easy and effective technique and employed for the nonenzymatic determination of glucose.
Abstract: A planar electrochemical sensor, based on flower-like CuO nanostructures growth “in situ” on a commercial screen printed carbon electrode, was fabricated by an easy and effective technique and employed for the non-enzymatic determination of glucose. The prepared CuO nanostructures were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The carbon electrode modification with CuO was optimized by investigating the effect of the number of deposition cycles of precursor and their concentration. The electrodes modified by in situ growth of CuO were compared to an electrode prepared by simple deposition of CuO powder previously synthesized by the same technique. Cyclic voltammetric and chronoamperometric tests demonstrated that the in situ growth of CuO leads to excellent electrochemical performance toward glucose oxidation in 0.1 M KOH solution. The best sensor, if operated at an applied potential of 0.6 V, has a sensitivity of 1460 μA·mM−1·cm−2 and a 2.5 μM detection limit (at an S/N ratio of 3). Tests carried out within six months revealed an excellent long-term stability. This suggests that the method applied to modify the carbon electrode represents a useful tool for fabrication of an inexpensive and reliable non-enzymatic glucose sensor.
TL;DR: The designed sensor was successfully applied for the assay of hydrogen peroxide in biological and pharmaceutical samples such as milk, green tea, and hair dye cream and mouthwash solution.