Hydrogen Peroxide In Water Samples Research Articles

A novel electrochemiluminescence resonance energy transfer system of luminol-graphene quantum dot composite and its application in H2O2 detection

Luminol-nitrogen doped graphene quantum dot (luminol-NGQDs) nanocomposite was synthesized and a novel electrochemiluminescence resonance energy transfer (ECL-RET) process occurred between luminol as the donor and NGQDs as the acceptor in the composite. This ECL-RET effect helped luminol-NGQDs composite produced an anodic ECL signal without coreactants. The ECL-RET mechanism was also studied based on the fluorescence spectra, the ultraviolet–visible absorption spectra and the electrochemiluminescence (ECL) spectra. Based on the significant sensitization effect of hydrogen peroxide on luminol-NGQDs ECL signal, an ECL method for the sensitive determination of hydrogen peroxide was established and then applied to the detection of hydrogen peroxide in water samples.

A ratiometric fluorescent probe for sensing hydrogen peroxide based on a hemicyanine–naphthol fluorophore

The synthesis, properties and applications of a water-soluble boronate-functioned hemicyanine-naphthol hybrid as a novel ratiometric fluorescent sensor for hydrogen peroxide are presented. The dye displayed remarkable a colour change from pale orange (λ(em) = 590 nm) to pink (λ(em) = 690 nm) in the presence of H2O2, which could be rationalized by the chemoselective H2O2-mediated transformation of arylboronate to phenolate with high selectivity and a fast response (within 2 min). A good linear relationship (R(2) = 0.9951) was obtained with the H2O2 concentration ranging from 0 to 25 μM, with a limit of detection of 0.09 μM according to the signal-to-noise ratio (S/N = 3). The advantages of this fluorophore include easy modification, excellent aqueous solubility and superior photostability, and it has been applied to the detection of trace amounts of hydrogen peroxide in water samples.

Direct chemiluminescence of fluorescent gold nanoclusters with classic oxidants for hydrogen peroxide sensing

Direct chemiluminescence (CL) of fluorescent gold nanoclusters was observed for the first time upon oxidation with classic oxidants. The CL mechanism was investigated by the studies of CL spectrum, UV–vis absorption spectra and X-ray photoelectron spectra before and after the reaction. The excited state Mn(II)∗, originating from the reduction of permanganate with gold nanoclusters, was suggested as the possible luminophor for the reaction. The potential analytical application was demonstrated by using hydrogen peroxide as an example, based upon the fact that hydrogen peroxide decreased the CL signal significantly. The decreased CL intensity was proportional to the concentration of hydrogen peroxide in the range 1.0×10−6–1.0×10−4molL−1. The detection limit was 5×10−7molL−1 and the relative standard deviation was 1.4% for 1.0×10−5molL−1 hydrogen peroxide in 11 replicated measurements. This method was applied to the determination of hydrogen peroxide in water samples with satisfactory results.

Cu(II)‐Based MOF Immobilized on Multiwalled Carbon Nanotubes: Synthesis and Application for Nonenzymatic Detection of Hydrogen Peroxide with High Sensitivity

AbstractCu(II)‐based MOF (Cu‐bipy‐BTC, bipy=2,2′‐bipyridine, BTC=1,3,5‐tricarboxylate) was synthesized and immobilized on multiwalled carbon nanotubes. The prepared composite was characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), X‐ray photoelectron spectra (XPS) and IR spectra. Then the material was modified onto the surface of a glassy carbon electrode, and showed a couple of well‐defined redox peaks in a phosphate buffer solution (pH 6.0), ascribed to the redox process of CuII/I in the Cu‐bipy‐BTC. The modified electrode was then applied to fabricate a non‐enzymatic hydrogen peroxide biosensor. The sensor showed good electrocatalytic activity toward the reduction of hydrogen peroxide with a wide linear range (3–70 µmol L−1 and 70–30000 µmol L−1) and a detection limit of 0.46 µmol L−1, as well as good stability and repeatability. In addition, the sensor has been successfully applied to determine hydrogen peroxide in water samples with good accuracy. Thus, the Cu‐bipy‐BTC/MWCNTs composite has great potential for applications in electrochemical sensors.

The effective peroxidase-like activity of chitosan-functionalized CoFe2O4 nanoparticles for chemiluminescence sensing of hydrogen peroxide and glucose

Here, we report a highly simple and general protocol for functionalization of the CoFe(2)O(4) NPs with chitosan polymers in order to make CoFe(2)O(4) NPs disperse and stable in solution. The functionalized CoFe(2)O(4) NPs (denoted as CF-CoFe(2)O(4) NPs) were characterized by scanning electron microscope (SEM), thermogravimetric (TG), X-ray diffraction (XRD) and FT-IR spectra. It was found that the CoFe(2)O(4) NPs were successfully decorated and uniformly dispersed on the surface of chitosan without agglomeration. The CF-CoFe(2)O(4) NPs were found to increase greatly the radiation emitted during the CL oxidation of luminol by hydrogen peroxide. Results of ESR spin-trapping experiments demonstrated that the CF-CoFe(2)O(4) NPs showed catalytic ability to H(2)O(2) decomposition into ˙OH radicals. On this basis, a highly sensitive and rapid chemiluminescent method was developed for hydrogen peroxide in water samples and glucose in blood samples. Under optimum conditions, the proposed method allowed the detection of H(2)O(2) in the range of 1.0 × 10(-9) to 4.0 × 10(-6) M and glucose in the range of 5.0 × 10(-8) to 1.0 × 10(-5) M with detectable H(2)O(2) as low as 500 pM and glucose as low as 10 nM, respectively. This proposed method has been successfully applied to detect H(2)O(2) in environmental water samples and glucose in serum samples with good accuracy and precision.

β−cyclodextrins-based inclusion complexes of CoFe 2O 4 magnetic nanoparticles as catalyst for the luminol chemiluminescence system and their applications in hydrogen peroxide detection

β−cyclodextrins ( β−CD)-based inclusion complexes of CoFe 2O 4 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 CoFe 2O 4 magnetic nanoparticles and naked CoFe 2O 4 magnetic nanoparticles on the luminol–hydrogen peroxide CL system was investigated. It was found that inclusion complexes between β−CD and CoFe 2O 4 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 CoFe 2O 4 MNPs or inclusion complexes between β−CD and CoFe 2O 4 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 CoFe 2O 4 MNPs or inclusion complexes between β−CD and CoFe 2O 4 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.

Fluorometric Determination of Hydrogen Peroxide in Natural Water Samples by Flow Injection Analysis with a Reaction Column of Peroxidase Immobilized onto Chitosan Beads

It was found that a FIA system with an immobilized enzyme reaction column could be utilized for the determinations of hydrogen peroxide in some water samples, such as rain water and tap water. A column was packed with chitosan beads immobilizing horseradish peroxidase. Under the recommended conditions, it took 5 min for each assay, and the detection limit, which was defined as a signal-to-noise ratio of 3, was 3.0 ng dm−3 of hydrogen peroxide. The relative standard deviation at 1.0 mg dm−3 of hydrogen peroxide was 1.5% (n=20). There was no interference from some coexisting substances having a low oxidation-reduction ability or not; therefore, a standard addition method could be applied to rain water and tap water samples. From such results, it has become clear that the proposed FIA system can be applied to the determination of hydrogen peroxide in water samples, and that the system is suitable for routine analysis in environmental observations.