Silver microspheres for application as hydrogen peroxide sensor

In this paper, we synthesized flowerlike silver microspheres with nanostructures by simply reducing silver nitrate by ascorbic acid in the presence of PVP. The structure was investigated by SEM. The chemical composition was determined by EDX, XRD and XPS. Recent studies on hydrogen peroxide sensor based on silver nanoparticles inspired us to examine the electrocatalytic activity of prepared microspheres. This electrochemical sensor exhibited good electrocatalytic activity towards the reduction of H₂O₂ in 0.2 M phosphate buffer solution (pH 7.0), and the detection limit of H₂O₂ was found to be 1.2 μM, which was lower than certain enzyme-based biosensors.     

A highly sensitive hydrogen peroxide amperometric sensor based on MnO2-modified vertically aligned multiwalled carbon nanotubes

In this report, a highly sensitive amperometric sensor based on MnO₂-modified vertically aligned multiwalled carbon nanotubes (MnO₂/VACNTs) for determination of hydrogen peroxide (H₂O₂) was fabricated by electrodeposition. The morphology of the nanocomposite was characterized by scanning electron microscopy, energy-dispersive X-ray spectrometer and X-ray diffraction. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy were applied to investigate the electrochemical properties of the MnO₂/VACNTs nanocomposite electrode. The mechanism for the electrochemical reaction of H₂O₂ at the MnO₂/VACNTs nanocomposite electrode was also discussed. In borate buffer (pH 7.8, 0.20 M), the MnO₂/VACNTs nanocomposite electrode exhibits a linear dependence (R = 0.998) on the concentration of H₂O₂ from 1.2 × 10⁻⁶ M to 1.8 × 10⁻³ M, a high sensitivity of 1.08 × 10⁶ μA M⁻¹ cm⁻² and a detection limit of 8.0 × 10⁻⁷ M (signal/noise = 3). Meanwhile, the MnO₂/VACNTs nanocomposite electrode is also highly resistant towards typical inorganic salts and some biomolecules such as acetic acid, citric acid, uric acid and d-(+)-glucose, etc. In addition, the sensor based on the MnO₂/VACNTs nanocomposite electrode was applied for the determination of trace of H₂O₂ in milk with high accuracy, demonstrating its potential for practical application.     

Non-enzymatic electrochemical CuO nanoflowers sensor for hydrogen peroxide detection

The electrocatalytic activity of a CuO flower-like nanostructured electrode was investigated in terms of its application to enzyme-less amperometric H₂O₂ sensors. The CuO nanoflowers film was directly formed by chemical oxidation of copper foil under hydrothermal condition and then used as active electrode material of non-enzymatic electrochemical sensors for H₂O₂ detection under alkaline conditions. The sensitivity of the sensor with CuO nanoflowers electrode was 88.4 μA/mM cm² with a linear response in the range from 4.25 × 10⁻⁵ to 4 × 10⁻² M and a detection limit of 0.167 μM (S/N = 3). Excellent electrocatalytic activity, large surface-to-volume ratio and efficient electron transport property of CuO nanoflowers electrode have enabled stable and highly sensitive performance for the non-enzymatic H₂O₂ sensor.     

A chemiluminescence sensor for the determination of hydrogen peroxide

A chemiluminescence one-shot sensor for hydrogen peroxide is described. It is prepared by immobilization of cobalt chloride and sodium lauryl sulphate in hydroxyethyl cellulose matrix cast on a microscope cover glass. Luminol, sodium phosphate and the sample are mixed before use and applied on the membrane by a micropipette. The calibration graph is linear in the range 20-1600 μg/L, and the detection limit of the method (3σ) is 9 μg/L. A relative standard deviation of 4.5% was obtained for 100 μg/L H₂O₂ (n = 11). The sensor has been applied successfully to the determination of hydrogen peroxide in rainwater.     

Electrode modified with a composite film of ZnO nanorods and Ag nanoparticles as a sensor for hydrogen peroxide

A conducting fluorine-doped tin oxide (FTO) electrode, first modified with zinc oxide nanorods (ZnONRs) and subsequently attached with photosynthesized silver nanoparticles (AgNPs), designated as AgNPs/ZnONRs/FTO electrode, was used as an amperometric sensor for the determination of hydrogen peroxide. The first layer (ZnONRs) was obtained by chemical bath deposition (CBD), and was utilized simultaneously as the catalyst for the photoreduction of Ag ions under UV irradiation and as the matrix for the immobilization of AgNPs. The aspect ratio of ZnONRs to be deposited was optimized by controlling the number of their CBDs to render enough surface area for Ag deposition, and the amount of AgNPs to be attached was controlled by adjusting the UV-irradiation time. The immobilized AgNPs showed excellent electrocatalytic response to the reduction of hydrogen peroxide. The resultant amperometric sensor showed 10-fold enhanced sensitivity for the detection of H₂O₂, compared to that without AgNPs, i.e., only with a layer of ZnONRs. Amperometric determination of H₂O₂ at −0.55 V gave a limit of detection of 0.9 μM (S/N = 3) and a sensitivity of 152.1 mA M⁻¹ cm⁻² up to 0.983 mM, with a response time (steady-state, t₉₅) of 30-40 s. The selectivity of the sensor was investigated against ascorbic acid (AA) and uric acid (UA). Energy dispersive X-ray (EDX) analysis, transmission electron microscopic (TEM) image, X-ray diffraction (XRD) patterns, cyclic voltammetry (CV), and scanning electron microscopic (SEM) images were utilized to characterize the modified electrode. Sensing properties of the modified electrode were studied both by CV and amperometric analysis.     

Vertical copper oxide nanowire arrays attached three-dimensional macroporous framework as a self-supported sensor for sensitive hydrogen peroxide detection

A hierarchical nanostructure consisting of uniform copper oxide nanowires vertically grown on three-dimensional copper framework (CuO NWs/3D-Cu foam) was prepared by a two-step synthetic process. The uniform CuO NWs anchored onto the 3D foam exhibited outstanding electrocatalytic activity towards hydrogen peroxide reduction due to the unique one‐dimensional direction with its excellent catalytic activity and large surface area of 3D substrate, which enhanced electroactive sites and charge conductivity. As a result, a wide linear detection range of 1 µM–1 mM, good sensitivity of 8.87 µA/(mM ⋅ cm²), low detection limit of 0.98 µM, and rapid response time of 5 s to hydrogen peroxide were achieved under a working potential of −0.4 V in phosphate buffer solution (pH of 7.4). In addition, the CuO NWs/3D-Cu foam material showed excellent selectivity to hydrogen peroxide and good resistance against poisonous interferents, including ascorbic acid, dopamine, urea, uric acid, and potassium chloride. Furthermore, the CuO NWs/3D-Cu foam presented good reproducibility, stability, and accurate detection for hydrogen peroxide in real sample; therefore, it may be considered to be a potential free-standing hydrogen peroxide sensor in practical analysis applications.     

A sensitive amperometric sensor for hydrazine and hydrogen peroxide based on palladium nanoparticles/onion-like mesoporous carbon vesicle

Onion-like mesoporous carbon vesicle (MCV) with multilayer lamellar structure was synthesized by a simply aqueous emulsion co-assembly approach. Palladium (Pd) nanoparticles were deposited on the MCV matrix (Pd/MCV) by chemical reduction of H₂PdCl₄ with NaBH₄ in aqueous media. Pd(X)/MCV (X wt.% indicates the Pd loading amount) nanocomposites with different Pd loading amount were obtained by adjusting the ratio of precursors. The particular structure of the MCV results in efficient mass transport and the onion-like layers of MCV allows for the obtainment of highly dispersed Pd nanoparticles. The introduction of Pd nanoparticles on the MCV matrix facilitates hydrazine oxidation at more negative potential and delivers higher oxidation current in comparison with MCV. A linear range from 2.0 × 10⁻⁸ to 7.1 × 10⁻⁵ M and a low detection limit of 14.9 nM for hydrazine are obtained at Pd(25)/MCV nanocomposite modified glassy carbon (GC) electrode. A nonenzymatic amperometric sensor for hydrogen peroxide based on the Pd(25)/MCV nanocomposite modified GC electrode is also developed. Compared with MCV modified GC electrode, the Pd(25)/MCV nanocomposite modified GC electrode displays enhanced amperometric responses towards hydrogen peroxide and gives a linear range from 1.0 × 10⁻⁷ to 6.1 × 10⁻³ M. The Pd(25)/MCV nanocomposite modified GC electrode achieves 95% of the steady-current for hydrogen peroxide within 1 s. The combination of the unique properties of Pd nanoparticles and the porous mesostructure of MCV matrix guarantees the improved analytical performance for hydrazine and hydrogen peroxide.     

Polyethyleneimine-capped silver nanoclusters as a fluorescence probe for sensitive detection of hydrogen peroxide and glucose

In this work, we utilized polyethyleneimine-capped silver nanoclusters (PEI-Ag nanoclusters) to develop a new fluorometric method for the determination of hydrogen peroxide and glucose with high sensitivity. The PEI-Ag nanoclusters have an average size of 2 nm and show a blue emission at 455 nm. The photostable properties of the PEI-Ag nanoclusters were examined. The fluorescence of the PEI-Ag nanoclusters could be particularly quenched by H₂O₂. The oxidization of glucose by glucose oxidase coupled with the fluorescence quenching of PEI-Ag nanoclusters by H₂O₂ can be used to detect glucose. Under optimum conditions, the fluorescence intensity quenched linearly in the range of 500 nM–100 μM with high sensitivity. The detection limit for H₂O₂ was 400 nM. And a linear correlation was established between fluorescence intensity (F₀ − F) and concentration of glucose in the range of 1.0 × 10⁻⁶ to 1.0 × 10⁻⁵ M and 1.0 × 10⁻⁵ to 1.0 × 10⁻³ M with a detection limit of 8.0 × 10⁻⁷ M. The method was used for the detection of glucose in human serum samples with satisfactory results. Furthermore, the mechanism of sensitive fluorescence quenching response of Ag nanoclusters to glucose and H₂O₂ has been discussed.     

Determination of hydrogen peroxide by utilizing a cobalt(II)hexacyanoferrate-modified glassy carbon electrode as a chemical sensor

A mixed-valence cluster of cobalt(II)hexacyanoferrate possesses an electron transfer property and is suitable for the development of an effective hydrogen peroxide detection scheme. The characteristics of cobalt(II)hexacyanoferrate have been studied using both elemental analysis and infrared spectra, confirming the structure is Co[Fe^II(CN)₆]. The cobalt(II)hexacyanoferrate-modified electrode exhibits a rapid response (t_95% - 6.5 s) to the injection of 5.0 × 10⁻⁵ M hydrogen peroxide. The linearity of the response is up to 1.1 × 10⁻³ M (correlation coefficients is 0.999). The sensitivity of this modified electrode is 11.8 μA/mM-mm². The detection limit of cobalt(II)hexacyanoferrate-modified electrode to hydrogen peroxide is 6.25 × 10⁻⁸ M. The current chemical sensor modified with Co[Fe^II(CN)₆] has better sensitivity than previous ones. The modified glassy carbon electrode shows no interference from ascorbic acid, uric acid, acetaminophen, 1,4-dihydroxyquinone, dopamine at the 2.0 × 10⁻⁴ M level and polyamines at 5.0 × 10⁻⁵ M level.     

A highly sensitive and selective dimethyl ether sensor based on cataluminescence

A sensor for detecting dimethyl ether was designed based on the cataluminescence phenomenon when dimethyl ether vapors were passing through the surface of the ceramic heater. The proposed sensor showed high sensitivity and selectivity to dimethyl ether at an optimal temperature of 279 °C. Quantitative analysis were performed at a wavelength of 425 nm, the flow rate of carrier air is around 300 mL/min. The linear range of the cataluminescence intensity versus concentration of dimethyl ether is 100-6.0 × 10³ ppm with a detection limit of 80 ppm. The sensor response time is 2.5 s. Under the optimized conditions, none or only very low levels of interference were observed while the foreign substances such as benzene, formaldehyde, ammonia, methanol, ethanol, acetaldehyde, acetic acid, acrolein, isopropyl ether, ethyl acetate, glycol ether and 2-methoxyethanol were passing through the sensor. Since the sensor does not need to prepare and fix up the granular catalyst, the simple technology reduces cost, improves stability and extends life span. The method can be applied to facilitate detection of dimethyl ether in the air. The possible mechanism of cataluminescence from the oxidation of dimethyl ether on the surface of ceramic heater was discussed based on the reaction products.     

A glassy carbon electrode modified with FeS nanosheets as a highly sensitive amperometric sensor for hydrogen peroxide

Iron sulfides with different atomic ratios were synthesized by a hydrothermal method and used to modify a glassy carbon electrode. The various sulfides were compared to each other for their amperometric response to H₂O₂. It is found that FeS is the most adequate material. Operated in 0.1 M NaOH solution at 0.4 V (vs. Ag/AgCl), the sensor based on FeS displays a linear response that extends from 0.50 μM to 20.5 mM of H₂O₂, with a sensitivity of 36.4 μA mM^?1 cm^?2 and a detection limit of 0.15 μM (at an S/N ratio of 3). The sensor is selective, stable and reproducible.

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Graphical abstract Schematic of the synthesis of pomegranate flower-like FeS by a hydrothermal route using ferric chloride and thiourea (SC(NH₂)₂) as the precursors, and ethanolamine (EA) as the structure-guiding auxiliary agent. A glassy carbon electrode (GCE) modified with this material allows for amperometric sensing of hydrogen peroxide in 0.1 M NaOH solution with a 0.15 μM detection limit. 

     

The electrochemical behavior of hydrogen peroxide sensor based on new methylene blue as mediator

利用共价键合法,将新亚甲蓝(NMB)与辣根过氧化酶(HRP)修饰于玻碳电极表面,制成一种新型的电流型H2O2传感器。探讨了该传感器在0·1mol/L磷酸缓冲溶液(pH=7·0)中的电化学性质。结果表明,NMB作为介体能够有效地在辣根过氧化酶和电极之间传递电子。测得电子转移系数为0·861,表观反应速率常数为1·27s-1。研究了传感器对H2O2的响应及动力学性质,米氏常数为8·27μmol/L,线性响应范围为2·5~100μmol/L。同时研究了pH、缓冲容量及温度等因素对H2O2传感器的影响。     

A luminescence-based probe for sensitive detection of hydrogen peroxide in seconds

Here, we present a fast and simple hydrogen peroxide assay that is based on time-resolved fluorescence. The emission intensity of a complex consisting of terbium ions (Tb³⁺) and phthalic acid (PA) in HEPES buffer is quenched in the presence of H₂O₂ and this quenching is concentration-dependent. The novel PATb assay detects hydrogen peroxide at a pH range from 7.5 to 8.5 and with a detection limit of 150 nmol L⁻¹ at pH 8.5. The total assay time is less than 1 min. The linear range of the assay can be adapted by a pH adjustment of the aqueous buffer and covers a concentration range from 310 nmol L⁻¹ to 2.56 mmol L⁻¹ in total which encompasses four orders of magnitude. The assay is compatible with high concentrations of all 47 tested inorganic and organic compounds. The PATb assay was applied to quantify H₂O₂ in polluted river water samples. In conclusion, this fast and easy-to-use assay detects H₂O₂ with high sensitivity and precision.     

A novel nonenzymatic hydrogen peroxide sensor based on MnO2/graphene oxide nanocomposite

A new electrocatalyst, MnO₂/graphene oxide hybrid nanostructure was successfully synthesized for the nonenzymatic detection of H₂O₂. The morphological characterization was examined by scanning electron microscopy and transmission electron microscopy. The MnO₂/graphene oxide based electrodes showed high electrochemical activity for the detection of H₂O₂ in alkaline medium. The nonenzymatic biosensors displayed good performance along with low working potential, high sensitivity, low detection limit, and long-term stability, which could be attributed to the high surface area of graphene oxide providing for the deposition of MnO₂ nanoparticles. These results demonstrate that this new nanocomposite with the high surface area and electrocatalytic activity offers great promise for new class of nanostructured electrode for nonenzymatic biosensor and energy conversion applications.     

An ultrasensitive iron(III)-complex based hydrogen peroxide electrochemical sensor based on a nonelectrocatalytic mechanism

In this communication, the first nonelectrocatalysis-type hydrogen peroxide electrochemical sensor is reported. The electroactive iron(III) diethylenetriaminepentaacetic acid (DTPA-Fe^III) complex is immobilized on the cysteamine (cys) modified nanoporous gold (NPG) films by covalent method. The immobilized DTPA-Fe^III complex quickly communicates an electron with the electrode. Upon addition of hydrogen peroxide, however, hydrogen peroxide inhibits the direct electron transfer of the DTPA-Fe^III complex due to the generation of nonelectroactive DTPA-Fe^III–H₂O₂ complex. Based on quenching mechanism, the first hydrogen peroxide electrochemical sensor based on a nonelectrocatalytic mechanism is developed. The novel hydrogen peroxide electrochemical sensor has the ultralow detection limit (1.0 × 10^–14 M) and wide linear range (1.0 × 10^–13 to 1.0 × 10^–8 M) with excellent reproducibility and stability.     

Vitamin B3 as a high acid-alkali tolerant peroxidase mimic for colorimetric detection of hydrogen peroxide and glutathione

Small-molecule enzyme mimics as biocatalysts have been extensively applied in diverse colorimetric sensors fabrication. However, excavating potential organic enzyme mimics with high catalytic activity still remains challenging. In this study, the peroxidase mimicking activity of nicotinic acid (VB3) was demonstrated for the first time through chromogenic substrate 3, 3′, 5, 5′-tetramethylbenzidine (TMB) at the existence of hydrogen peroxide (H₂O₂). The catalytic activity of VB3 kept more than 80% of its optimum activity in a broad pH range of 3.0–9.0. In addition, the kinetic parameter (Michaelis constant, K_m = 0.037 mM) of VB3 catalysis to H₂O₂ is smaller than natural horseradish peroxidase (HRP) and previously reported peroxidase mimics. The catalytic mechanism of VB3 is mainly attributed to the active species of hydroxyl radical (OH) and partially attributed to the superoxide free radicals (O₂^?). A convenient and sensitive colorimetric method based on VB3-H₂O₂-TMB chromogenic system for H₂O₂ and glutathione detection was fabricated with the linear ranges of 5.0–100.0 μM and 5.0–50.0 μM, respectively. In short, this work will not only bring new enlightenment on the physiological functions and practical applications in the analytical field of VB3, but also provide a new type of structural reference for small-molecule enzyme mimics.     

A boronic acid based intramolecular charge transfer probe for colorimetric detection of hydrogen peroxide

Many oxidative stress related diseases and adverse health conditions have been associated with the negative effects of hydrogen peroxide and other similar reactive oxygen species in human body. Therefore, increasing attention has been attracted to the detection and monitoring of hydrogen peroxide in living organisms and food items. In this work, a simple, inexpensive colorimetric method for the quantitative determination of hydrogen peroxide in aqueous sample is described. This method utilizes the de-protection of aryl boronic acid to yield a strongly colored water-soluble dye, which is capable of absorbing and emitting in the red region of the spectrum. The mechanism is faster in alkaline condition and utilizes the intramolecular charge transfer between strong phenolate donor and TCF acceptor, thus allowing a naked eye detection of hydrogen peroxide within seconds. The method is unaffected by the presence of various salts, metal ions, and other interfering species, and it can provide a limit of detection as low as ~1 ppm in aqueous samples. This unique way of generating a fluorogenic donor-acceptor pair holds a potential of this dye and other related derivatives for understanding the role of hydrogen peroxide in physiology and pathology.     

A highly selective fluorescence turn-on detection of hydrogen peroxide and d-glucose based on the aggregation/deaggregation of a modified tetraphenylethylene

A new selective fluorescence turn-on detection of hydrogen peroxide was established by taking advantage of the aggregation induced-emission (AIE) behavior of tetraphenylethylene unit and the reaction of hydrogen peroxide toward the arylboronic ester group in compound 1. Moreover, compound 1 was successfully utilized for the selective detection of d-glucose in aqueous solution.     

A novel bimediator amperometric sensor for electrocatalytic oxidation of gallic acid and reduction of hydrogen peroxide

A novel bimediator amperometric sensor is fabricated for the first time by surface modification of graphite electrode with thionine (TH) and nickel hexacyanoferrate (NiHCF). The electrochemical behavior of the TH/NiHCF bimediator modified electrode was characterized by cyclic voltammetry, differential pulse voltammetry and chronoamperometry. The TH/NiHCF bimediator modified electrode exhibited a pair of distinct redox peaks for NiHCF and TH with formal potentials of 0.33 V and −0.27 V vs. SCE at a scan rate of 50 mV s⁻¹ in 0.1 M NaNO₃ and 0.1 M NH₄NO₃ respectively. The electrocatalytic activity of the bimediator modified electrode towards oxidation of gallic acid with NiHCF and reduction of hydrogen peroxide with TH was evaluated and it was observed that the modified electrode showed an electrocatalytic activity towards the oxidation of gallic acid in the concentration range of 4.99 × 10⁻⁶–1.20 × 10⁻³ M with a detection limit of 1.66 × 10⁻⁶ M (S/N = 3) and reduction of H₂O₂ in the concentration range of 1.67 × 10⁻⁶–1.11 × 10⁻³ M with a detection limit of 5.57 × 10⁻⁷ M (S/N = 3). The bimediator modified electrode was found to exhibit good stability and reproducibility.