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1.
In this paper, we utilized the instinct peroxidase-like property of Fe3O4 magnetic nanoparticles (MNPs) to establish a new fluorometric method for determination of hydrogen peroxide and glucose. In the presence of Fe3O4 MNPs as peroxidase mimetic catalyst, H2O2 was decomposed into radical that could quench the fluorescence of CdTe QDs more efficiently and rapidly. Then the oxidization of glucose by glucose oxidase was coupled with the fluorescence quenching of CdTe QDs by H2O2 producer with Fe3O4 MNPs catalyst, which can be used to detect glucose. Under the optimal reaction conditions, a linear correlation was established between fluorescence intensity ratio I0/I and concentration of H2O2 from 1.8 × 10−7 to 9 × 10−4 mol/L with a detection limit of 1.8 × 10−8 mol/L. And a linear correlation was established between fluorescence intensity ratio I0/I and concentration of glucose from 1.6 × 10−6 to 1.6 × 10−4 mol/L with a detection limit of 1.0 × 10−6 mol/L. The proposed method was applied to the determination of glucose in human serum samples with satisfactory results. 相似文献
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3.
A simple and sensitive method for the determination of nanomolar levels of hydrogen peroxide (H2O2) in seawater has been developed and validated. This method is based on the reduction of H2O2 by ferrous iron in acid solution to yield hydroxyl radical (OH) which reacts with benzene to produce phenol. Phenol is separated from the reaction mixture by reversed phase high performance liquid chromatography and its fluorescence intensity signals were measured at excitation and emission of 270 and 298 nm, respectively. Under optimum conditions, the calibration curve exhibited linearity in the range of (0-50) × 103 nmol L−1 H2O2. The relative standard deviations for five replicate measurements of 500 and 50 nmol L−1 H2O2 are 1.9 and 2.4%, respectively. The detection limit for H2O2, defined as three times the standard deviation of the lowest standard solution (5 nmol L−1 H2O2) in seawater is 4 nmol L−1. Interference of nitrite ion (NO2−) on the fluorescence intensity of phenol was also investigated. The result indicated that the addition of 10 μmol L−1 NO2− to seawater samples showed no significant interference, although, the addition of 50 μmol L−1 NO2− to the seawater samples decreases the fluorescence intensity signals of phenol by almost 40%. Intercomparison of this method with well-accepted (p-hydroxyphenyl) acetic acid (POHPAA)-FIA method shows excellent agreement. The proposed method has been applied on-board analysis of H2O2 in Seto Inland seawater samples. 相似文献
4.
In this paper, the electrogenerated chemiluminescence (ECL) from thiol-capped CdTe quantum dots (QDs) was reported. The ECL emission was occurred at −1.1 V and reached a maximum value at −2.4 V when the potential was cycled between 0.0 and −2.5 V. The reduced species of CdTe QDs could react with the coreactants to produce the ECL emission. The CdTe QD concentration (6.64 × 10−7 mol L−1) of ECL is lower than that (1.0 × 10−3 mol L−1) of chemiluminescence (CL). Based on the enhancement of light emission from thiol-capped CdTe QDs by H2O2 in the negative electrode potential, a novel method for the determination of H2O2 was developed. The light intensity was linearly proportional to the concentration of H2O2 between 2.0 × 10−7 and 1.0 × 10−5 mol L−1 with a detection limit of 6.0 × 10−8 mol L−1. Compared with most of previous reports, the proposed method has higher sensitivity for the determination of H2O2. In addition, the ECL spectrum of thiol-capped CdTe QDs exhibited a peak at around 620 nm, which was substantially red shifted from the photoluminescence (PL) spectrum, suggesting the surface states play an important role in this ECL process. 相似文献
5.
In this paper, a polydopamine (PDA) film is electropolymerized on the surface of bilayer lipid membrane (BLM) which is immobilized with horseradish peroxidase (HRP). The coverage of the PDA film on HRP/BLM electrode is monitored by electrochemical impedance spectroscopy (EIS). The electrocatalytic reduction of H2O2 at the PDA/HRP/BLM electrode is studied by means of cyclic voltammetry (CV). The biosensor has a fast response to H2O2 of less than 5 s and an excellent linear relationship is obtained in the concentration range from 2.5 × 10−7 to 3.1 × 10−3 mol L−1, with a detection limit of 1.0 × 10−7 mol L−1 (S/N = 3). The response current of BLM/HRP/PDA biosensor retains 84% of its original response after being stored in 0.1 mol L−1 pH 7.0 PBS at 4 °C for 3 weeks. The selectivity, repeatability, and storage stability of PDA/HRP/BLM biosensor are greatly enhanced by the coverage of polydopamine film on BLM. 相似文献
6.
A new petentiometric method to determine peroxide hydrogen and glucose had been studied. This method had been applied on the petentiometric determination of peroxide hydrogen and glucose in the total ionic strength adjustment buffer (TISAB) (pH 7.5) solution with the glassy electrode modified by the calix[4]arene. The glassy carbon electrode covered with the calix[4]arene depended on the H2O2 concentration in the range of log[H2O2] from −3.3 to −1.2 in the solution of TISAB (pH 7.5) with nearly Nernstian slope of about 65.6 ± 3 mV and the detection limit of peroxide hydrogen was 4.0 × 10−5 mol L−1. The glassy carbon electrode covered with the calix[4]arene depended on the glucose concentration in the range of log[glucose] from −3.6 to −2.8 in the solution of TISAB (pH 7.5) with nearly Nernstian slope of about 50.2 ± 2 mV and the detection limit of glucose was 2.0 × 10−5 mol L−1. The electrode had the good selectivity, sensitivity, stability and repeatability. 相似文献
7.
Magnetic nanoparticles (Fe3O4) were synthesized by a chemical coprecipitation method. X-ray diffraction (XRD) and transmission electron microscope (TEM) were used to confirm the crystallite structure and the particle's radius. The Fe3O4 nanoparticles and chitosan (CS) were mixed to form a matrix in which haemoglobin (Hb) can be immobilized for the fabrication of H2O2 biosensor. The Fe3O4-CS-Hb film exhibited a pair of well-defined and quasi-reversible cyclic voltammetric peaks due to the redox of Hb-heme Fe (III)/Fe (II) in a pH 7.0 phosphate buffer. The formal potential of Hb-heme Fe(III)/Fe(II) couple varied linearly with the increase of pH in the range of 4.0-10.0 with a slope of 46.5 mV pH−1, indicating that electron transfer was accompanied with single proton transportation in the electrochemical reaction. The surface coverage of Hb immobilized on Fe3O4-CS film glassy carbon electrode was about 1.13 × 10−10 mol cm−2. The heterogeneous electron transfer rate constant (ks) was 1.04 s−1, indicating great facilitation of the electron transfer between Hb and magnetic nanoparticles-chitosan modified electrode. The modified electrode showed excellent electrocatalytic activity toward oxygen and hydrogen peroxide reduction. The apparent Michaelis-Menten constant for H2O2 was estimated to be 38.1 μmol L−1. 相似文献
8.
β−cyclodextrins (β−CD)-based inclusion complexes of CoFe2O4 magnetic nanoparticles (MNPs) were prepared and used as catalysts for chemiluminescence (CL) system using the luminol-hydrogen peroxide CL reaction as a model. The as-prepared inclusion complexes were characterized by XRD (X-ray diffraction), TGA (thermal gravimetric analysis) and FT-IR. The oxidation reaction between luminol and hydrogen peroxide in basic media initiated CL. The effect of β−CD-based inclusion complexes of CoFe2O4 magnetic nanoparticles and naked CoFe2O4 magnetic nanoparticles on the luminol-hydrogen peroxide CL system was investigated. It was found that inclusion complexes between β−CD and CoFe2O4 magnetic nanoparticles could greatly enhance the CL of the luminol-hydrogen peroxide system. Investigation on the kinetic curves and the chemiluminescence spectra of the luminol-hydrogen peroxide system demonstrates that addition of CoFe2O4 MNPs or inclusion complexes between β−CD and CoFe2O4 MNPs does not produce a new luminophor of the chemiluminescent reaction. The luminophor for the CL system was still the excited-state 3-aminophthalate anions (3-APA*). The enhanced CL signals were thus ascribed to the possible catalysis from CoFe2O4 MNPs or inclusion complexes between β−CD and CoFe2O4 nanoparticles. The feasibility of employing the proposed system for hydrogen peroxide sensing was also investigated. Experimental results showed that the CL emission intensity was linear with hydrogen peroxide concentration in the range of 1.0 × 10−7 to 4.0 × 10−6 mol L−1 with a detection limit of 2.0 × 10−8 mol L−1 under optimized conditions. The proposed method has been used to determine hydrogen peroxide in water samples successfully. 相似文献
9.
A new kind of near-infrared fluorescence agent, tricarbochlorocyanine dye (Cy.7.Cl), had been synthesized in house and used for near-infrared spectrofluorimetric determination of hydrogen peroxide (H2O2) by flow injection analysis (FIA) for the first time. The oxidation reaction of Cy.7.Cl with H2O2 occurred under the catalysis of horseradish peroxidase (HRP) and it was studied in detail. The possible reaction mechanism was discussed. Under optimal experimental conditions, fluorescence from Cy.7.Cl displayed excitation and emission maxima (ex/em) at 780 and 800 nm, respectively. The two linear working ranges were 1.86 × 10−7 to 4.11 × 10−7 mol L−1 and 4.11 × 10−7 to 7.19 × 10−6 mol L−1, respectively. The detection limit was 5.58 × 10−8 mol L−1 of H2O2. The effect of interferences was studied. The proposed method was successfully applied to the determination of hydrogen peroxide in rainwater, serum and plant samples. 相似文献
10.
A novel disposable third-generation hydrogen peroxide (H2O2) biosensor based on horseradish peroxidase (HRP) immobilized on the gold nanoparticles (AuNPs) electrodeposited indium tin oxide (ITO) electrode is investigated. The AuNPs deposited on ITO electrode were characterized by UV-vis, SEM, and electrochemical methods. The AuNPs attached on the ITO electrode surface with quasi-spherical shape and the average size of diameters was about 25 nm with a quite symmetric distribution. The direct electron chemistry of HRP was realized, and the biosensor exhibited excellent performances for the reduction of H2O2. The amperometric response to H2O2 shows a linear relation in the range from 8.0 μmol L−1 to 3.0 mmol L−1 and a detection limit of 2 μmol L−1 (S/N = 3). The value of HRP immobilized on the electrode surface was found to be 0.4 mmol L−1. The biosensor indicates excellent reproducibility, high selectivity and long-term stability. 相似文献
11.
In this paper, a novel gold nanoparticles based protein immobilization method was designed. Biocomposites of gold nanoparticles and proteins were successfully coated on poly(methyl methacrylate) (PMMA) plates and polystyrene microtiter plates. The proteins could be immobilized on solid materials with high density and better bioactivity. Based on above design, chemiluminescence (CL) imaging assay for determination of H2O2 and recombinant human interleukin-6 (rHu IL-6) was developed. The linear range and the loading capability were greatly improved when compared with imaging assay performed with direct proteins immobilization. Under the selected experimental conditions, a linear relationship was obtained between the CL intensity and the concentration of H2O2 in the range of 1.0 × 10−6 to 1.0 × 10−4 mol L−1, and rHu IL-6 in the range of 2.0-312.0 pg mL−1. The detection limits were 2 × 10−7 mol L−1 (3σ) for H2O2 and 0.5 pg mL−1 for rHu IL-6 with relative standard deviation of 3.8% for 3.0 × 10−5 mol L−1 H2O2, and 4.4% for 39.0 pg mL−1 rHu IL-6. This method has been applied to the determination of rHu IL-6 in human serum with satisfactory results. 相似文献
12.
Fuguang Lu Huaijiang Li Min SunLulu Fan Huamin QiuXiangjun Li Chuannan Luo 《Analytica chimica acta》2012
A novel flow injection chemiluminescence (FI-CL) sensor for determination of sulfadiazine (SDZ) using core–shell magnetic molecularly imprinted polymers (MMIPs) as recognition element is developed. Briefly, a hydrophilic MMIPs layer was produced at the surface of Fe3O4@SiO2 magnetic nanoparticles (MNPs) via combination of molecular imprinting and reversible stimuli responsive hydrogel. And it provided the MMIPs with excellent adsorption capacity and rapid adsorption rate due to the imprinted sites mostly situated on the surface of MMIPs. Then the prepared SDZ-MMIPs were packed into flow cell to establish a novel FI-CL sensor. The sensor provided a wide linear range for SDZ of 4.0 × 10−7 to 1.0 × 10−4 mol L−1 with a detection limit of 1.54 × 10−7 mol L−1. And the relative standard deviation (RSD) for the determination of 1.0 × 10−6 mol L−1 SDZ was 2.56% (n = 11). The proposed method was applied to determine SDZ in urine samples and satisfactory results were obtained. 相似文献
13.
H2O2 is a widely occurring molecule which is also a byproduct of a number of enzymatic reactions. It can therefore be used to quantify the corresponding enzymatic substrates. In this study, the time-resolved fluorescence emission of a previously described complex consisting of phthalic acid and terbium (III) ions (PATb) is used for H2O2 detection. In detail, glucose oxidase and choline oxidase convert glucose and choline, respectively, to generate H2O2 which acts as a quencher for the PATb complex. The response time of the PATb complex toward H2O2 is immediate and the assay time only depends on the conversion rate of the enzymes involved. The PATb assay quantifies glucose in a linear range of 0.02–10 mmol L−1, and choline from 1.56 to 100 μmol L−1 with a detection limit of 20 μmol L−1 for glucose and 1.56 μmol L−1 for choline. Both biomolecules glucose and choline could be detected without pretreatment with good precision and reproducibility in human serum samples and infant formula, respectively. Furthermore, it is shown that the detected glucose concentrations by the PATb system agree with the results of a commercially available assay. In principle, the PATb system is a universal and versatile tool for the quantification of any substrate and enzyme reaction where H2O2 is involved. 相似文献
14.
A simple and reliable one-pot approach was established for the development of a novel hydrogen peroxide (H2O2) biosensor based on in situ covalent immobilization of horseradish peroxidase (HRP) into biocompatible material through polysaccharide-incorporated sol-gel process. Siloxane with epoxide ring and trimethoxy anchor groups was applied as the bifunctional cross-linker and the inorganic resource for organic-inorganic hybridization. The reactivity between amine groups and epoxy groups allowed the covalent incorporation of HRP and the functional biopolymer, chitosan (CS) into the inorganic polysiloxane network. Some experimental variables, such as mass ratio of siloxane to CS, pH of measuring solution and applied potential for detection were optimized. HRP covalently immobilized in the hybrid matrix possessed high electrocatalytic activity to H2O2 and provided a fast amperometric response. The linear response of the as-prepared biosensor for the determination of H2O2 ranged from 2.0 × 10−7 to 4.6 × 10−5 mol l−1 with a detection limit of 8.1 × 10−8 mol l−1. The apparent Michaelis-Menten constant was determined to be 45.18 μmol l−1. Performance of the biosensor was also evaluated with respect to possible interferences. The fabricated biosensor exhibited high reproducibility and storage stability. The ease of the one-pot covalent immobilization and the biocompatible hybrid matrix serve as a versatile platform for enzyme immobilization and biosensor fabricating. 相似文献
15.
Direct electrochemistry of hemoglobin (Hb) is observed at carbon nanotube (CNT) interface. The adsorbing Hb can transfer electron directly at CNT interface compared with common carbon material. The heterogeneous electron transfer rate constant k of Hb can be calculated as 0.062 s−1, the transfer coefficient α is 0.21 and the average surface coverage of Hb on CNT surface is 3.58 × 10−9 ± 2.7 × 10−10 mol/cm2. It is found that the adsorbing Hb still keeps its catalytic activity to H2O2. This sensor was used to detect H2O2. The apparent Michaelis-Menten constant is calculated as 6.75 × 10−4 mol L−1. 相似文献
16.
Nilanjal MisraJayashree Biswal Alka GuptaJ.K. Sainis S. Sabharwal 《Radiation Physics and Chemistry》2012,81(2):195-200
Gold nanoparticles (Au nps) have been synthesized in aqueous solution of polyvinyl pyrrolidone (PVP) by gamma radiolysis from HAuCl4·3H2O precursor and in presence of small concentrations of Ag+, 2-propanol and acetone. The effect of different experimental parameters, such as concentration of reactant, molecular weight of PVP on nanoparticle formation was studied. TEM image confirmed that spherical Au nps were formed when PVP of molecular weight 360,000 Da was used as capping agent. H2O2 is a reactant in the enzyme catalyzed reaction of o-phenylene diamine (o-PDA). The reaction product has a weak absorption in the yellow region of the spectrum. When this product interacts with Au nps, it leads to enhancement of the absorption peak. The nanoparticles synthesized by radiation method were used for estimation of H2O2. The absorbance value of this peak at λmax was observed to change with H2O2 concentration, which was monitored for estimation of H2O2. The response is linear in the range of 2.5×10−6 mol dm−3 to 2×10−4 mol dm−3 and 1×10−7 mol dm−3 to 3×10−6 mol dm−3 H2O2 in two separate sets of experimental parameters with detection limit 1×10−7 mol dm−3. 相似文献
17.
Longzhen Zheng Dan YeLeyan Xiong Jingpeng XuKun Tao Zhijun ZouDanlin Huang Xiaowei KangShaoming Yang Jian Xia 《Analytica chimica acta》2013
A novel cobalt-tetraphenylporphyrin/reduced graphene oxide (CoTPP/RGO) nanocomposite was prepared by a π–π stacking interaction and characterized by ultraviolet–visible absorption spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS). The CoTPP/RGO nanocomposite exhibited high electrocatalytic activity both for oxidation and reduction of H2O2. The current response was linear to H2O2 concentration with the concentration range from 1.0 × 10−7 to 2.4 × 10−3 mol L−1 (R = 0.998) at the reductive potential of −0.20 V and from 1.0 × 10−7 to 4.6 × 10−4 mol L−1 (R = 0.996) at the oxidative potential of +0.50 V. The H2O2 biosensor showed good anti-interfering ability towards oxidative interferences at the oxidative potential of +0.50 V and good anti-interfering ability towards reductive interferences at the reductive potential of −0.20 V. 相似文献
18.
In this paper, a novel electrochemiluminescence (ECL) imaging sensor array was developed for determination of hydrogen peroxide (H2O2), which was based on Cu/Zn alloy galvanic cell generated ECL. In alkaline solution, Cu/Zn galvanic cell was formed because of corrosion effect, the galvanic cell could supply stable potential for ECL generation of luminol, and the weak ECL emission could be enhanced by H2O2. The galvanic cell sensor array was designed by putting Cu/Zn alloy in 96-well microtiter plates separately. The relative ECL intensity was proportional with the concentration of hydrogen peroxide in the range of 1.0 × 10−6 to 1.0 × 10−4 mol l−1 and the detection limit was 3.0 × 10−7 mol l−1 (3σ), the relative standard deviation (R.S.D.) for 11 parallel measurements of 1.0 × 10−5 mol l−1 H2O2 was 4.0%. 相似文献
19.
A compact, reliable and low cost flow injection chemiluminescence system is described. The flow system consists of a set of solenoid micro-pumps that can dispense reproductive micro-volumes of solutions. The luminometer was based on a coiled cell constructed from polyethylene tubing that was sandwiched between two large area photodiodes. The whole equipment costs about US$ 750 and weights ca. 3 kg. Equipment performance was evaluated by measuring low concentrations of hydrogen peroxide by oxidation of luminol and for the determination of ammonium, based on its inhibition of the luminescence provided by the reaction of luminol and sodium hypochlorite. Linear responses were achieved within 1.0-80 μmol L−1 H2O2 and 0.6-60 μmol L−1 NH4+ with detection limits estimated as 400 nmol L−1 H2O2 and 60 nmol L−1 NH4+ at the 99.7% confidence level. Coefficients of variation were 1.0 and 1.8%, estimated for 20 μmol L−1 H2O2 and 15 μmol L−1 NH4+ (n = 20), respectively. Reagent consumption of 55 μg luminol, effluent volume of 950 μL per determination and sampling rate of 120 samples per hour were also achieved. 相似文献
20.
The main purpose of this study is to develop an inexpensive, simple, selective and especially highly selective modified mixed-oxide carbon paste electrode (CPE) for voltammetric determination of Pb(II). For the preliminary screening purpose, the catalyst was prepared by modification of SiO2-Al2O3 mixed-oxide and characterized by TG, CHN elemental analysis and FTIR spectroscopy. Using cyclic voltammetry the electroanalytical characteristics of the catalyst have been determined, and consequently the modified mixed-oxide carbon paste electrode was constructed and applied for determination of Pb(II). The electroanalytical procedure for determination of the Pb(II) comprises two steps: the chemical accumulation of the analyte under open-circuit conditions followed by the electrochemical detection of the preconcentrated species using differential pulse anodic stripping voltammetry. During the preconcentration step, Pb(II) was accumulated on the surface of the modifier by the formation of a complex with the nitrogen atoms of the pyridyl groups in the modifier. The peak currents increases linearly with Pb(II) concentration over the range of 2.0 × 10−9 to 5.2 × 10−5 mol L−1 (r2 = 0.9995).The detection limit (three times signal-to-noise) was found to be 1.07 × 10−9 mol L−1 Pb(II). The chemical and instrumental parameters have been optimized and the effect of the interferences has been determined. The Proposed method was used for determination of lead ion in the real samples. 相似文献