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1.
The oxidation reaction of H2O2 with KIO4 can produce chemiluminescence (CL) in the presence of the surfactant Tween40 and the CL intensity of the CL system KIO4–H2O2–Tween40 can be strikingly enhanced after injection of tannic acid. On this basis, a flow injection method with CL detection was established for the determination of tannic acid. The method is simple, rapid and effective to determine tannic acid in the range of 7.0 × 10?9 to 1.0 × 10?5 mol/L with a determination limit of 2.3 × 10?9 mol/L. The relative standard deviation is 2.6% for the determination of 5.0 × 10?6 mol/L tannic acid (n = 11). The method has been applied to determine the content of tannic acid in industrial wastewater with satisfactory results. It is believed that the CL reaction formed singlet oxygen 1O2* and the emission was from an excited oxygen molecular pair O2(1Δg)O2(1∑?g) in the KIO4–H2O2–Tween40 reaction. Tween40 played an important role in enhancing stabilization of the excited oxygen molecular pair O2(1Δg)O2(1∑?g) and in increasing CL intensity. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
2.
Chemiluminescence (CL) of 7-hydroxycoumarin, umbelliferone, a strongly fluorescing compound, the precursor of photoactive furocoumarins widely spread in plant kingdom and used in dye lasers has been examined in four oxidative systems producing active oxygen species: A–horseradish peroxidase + H2O2 + buffers pH = 3–10; B? K3Fe (CN)6 + H2O2 + buffers pH = 4–12; C? NaOCI + buffer pH = 3–10.8; and D? HCHO + H2O2 + K2CO3 (Na2CO3), the so-called Trautz–Schorigin reaction. In all these systems a 10–1000-fold increase of CL intensity and quantum yield and an appearance of the blue emission band (λmax = 460–480 nm), typical of the fluorescence of hydroxycoumarin used have been observed. Spectrophotometric and fluorimetric measurements of the systems A–D indicate that the tested hydroxycoumarins - coumarin, umbelliferone and 6-glucoside umbelliferone or esculin – undergo slow (systems A and B) and fast (systems C and D) consumption, leading to the degradation of coumarins. These findings suggest that efficiently fluorescing hydroxy-coumarins may act both as sensitizers – secondary emitters of CL and/or reactants undergoing oxidative degradation. 相似文献
3.
Ahsan Ullah Khan 《Luminescence》1995,10(6):329-333
Simple acidification of aqueous alkaline peroxynitrite quantitatively generates singlet (1Δg) molecular oxygen, detected and quantitated spectroscopically (1270 nm). This observation provides a chemical basis for physiological cytotoxicity of ONOO? generated in the diffusion - controlled reaction of cellular NO? and O. The experiments consist of (i) chemical generation of ONOO? from NO? gas and KO2 powder in alkaline aqueous solution; (ii) absorption spectral identification of ONOO? in the near-UV with maximum at 302 nm; (iii) spectroscopic identification of 1O2 by its emission band at 1200–1340 nm with maximum at 1275 nm; and (iv) quantitation of 1O2 generated in ONOO?/H+ reaction by comparison of the chemiluminescence intensity at 1270 nm with that from H2O2/OCl? reaction that generates 1O2 with unit efficiency at alkaline pH. 1O2 was generated with unit efficiency with respect to ONOO? concentration by the ONOO?/H+ reaction. 相似文献
4.
The behaviors of 15 kinds of metal ions in the thiol‐capped CdTe quantum dots (QDs)–H2O2 chemiluminescence (CL) reaction were investigated in detail. The results showed that Ag+, Cu2+ and Hg2+ could inhibit CdTe QDs and H2O2 CL reaction. A novel CL method for the selective determination of Ag+, Cu2+ and Hg2+ was developed, based on their inhibition of the reaction of CdTe QDs and H2O2. Under the optimal conditions, good linear relationships were realized between the CL intensity and the logarithm of concentrations of Ag+, Cu2+ and Hg2+. The linear ranges were from 2.0 × 10?6 to 5.0 × 10?8 mol L?1 for Ag+, from 5.0 × 10?6 to 7.0 × 10?8 mol L?1 for Cu2+ and from 2.0 × 10?5 to 1.0 × 10?7 mol L?1 for Hg2+, respectively. The limits of detection (S/N = 3) were 3.0 × 10?8, 4.0 × 10?8 and 6.7 × 10?8 mol L?1 for Ag+, Cu2+ and Hg2+, respectively. A possible mechanism for the inhibition of CdTe QDs and H2O2 CL reaction was also discussed. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
5.
Flow injection chemiluminescence determination of naphazoline hydrochloride in pharmaceuticals
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A simple and sensitive flow injection chemiluminescence (FI‐CL) method was developed for the determination of naphazoline hydrochloride (NPZ). The method is based on the enhancing effect of NPZ on the weak CL signal from the reaction of KIO4 with H2O2. Experimental parameters that affected the CL signal, including the pH of the KIO4 solution, concentrations of KIO4, H2O2 and disodium‐EDTA and flow rate were optimized. Under the optimum conditions, the increment of CL intensity was linearly proportional to the concentration of NPZ in the range 5.0 × 10?6 to 70 × 10?6 mol/L. The detection limit was 1.0 × 10?6 mol/L and the relative standard deviation for 50 × 10?6 mol/L NPZ solution was 2.8% (n = 11). In addition, a high throughput of 120 samples/h was achieved. The utility of this method was demonstrated by determining NPZ in pharmaceuticals. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
6.
Exceptional Visible‐Light‐Driven Cocatalyst‐Free Photocatalytic Activity of g‐C3N4 by Well Designed Nanocomposites with Plasmonic Au and SnO2
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Amir Zada Muhammad Humayun Fazal Raziq Xuliang Zhang Yang Qu Linlu Bai Chuanli Qin Liqiang Jing Honggang Fu 《Liver Transplantation》2016,6(21)
In this work, plasmonic Au/SnO2/g‐C3N4 (Au/SO/CN) nanocomposites have been successfully synthesized and applied in the H2 evolution as photocatalysts, which exhibit superior photocatalytic activities and favorable stability without any cocatalyst under visible‐light irradiation. The amount‐optimized 2Au/6SO/CN nanocomposite capable of producing approximately 770 μmol g?1 h?1 H2 gas under λ > 400 nm light illumination far surpasses the H2 gas output of SO/CN (130 μmol g?1), Au/CN (112 μmol g?1 h?1), and CN (11 μmol g?1 h?1) as a contrast. In addition, the photocatalytic activity of 2Au/6SO/CN maintains unchanged for 5 runs in 5 h. The enhanced photoactivity for H2 evolution is attributed to the prominently promoted photogenerated charge separation via the excited electron transfer from plasmonic Au (≈520 nm) and CN (470 nm > λ > 400 nm) to SO, as indicated by the surface photovoltage spectra, photoelectrochemical I–V curves, electrochemical impedance spectra, examination of formed hydroxyl radicals, and photocurrent action spectra. Moreover, the Kelvin probe test indicates that the newly aligned conduction band of SO in the fabricated 2Au/6SO/CN is indispensable to assist developing a proper energy platform for the photocatalytic H2 evolution. This work distinctly provides a feasible strategy to synthesize highly efficient plasmonic‐assisted CN‐based photocatalysts utilized for solar fuel production. 相似文献
7.
The method is based on the fact that dipyridamole can enhance the chemiluminescence (CL) emission from the redox reaction of bis (2,4,6‐tricholorophenyl) oxalate (TCPO) with H2O2 in the presence of silver nanoparticles (AgNPs). The CL reaction mechanism was discussed. The effect of concentrations of TCPO, H2O2, AgNPs and pH value on the CL reaction were investigated. Under the optimum conditions, the linear dynamic range was 1.0–1000 × 10?9 g/mL and the detection limit (3σ) was 9 × 10?10 g/mL. The relative standard deviation (RSD) was 4.8% for 1.0 × 10?9 g/mL dipyridamole (n = 7). The proposed method has been successfully applied to the determination of dipyridamole tablets and the recovery was 99–103%. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
8.
The oxidation reaction between cerium(IV) and Tween 85 in sulfuric acid medium produced weak chemiluminescence (CL). In this paper, it was found that citrate could strongly enhance the CL of cerium(IV)–Tween 85–polyphenol system. Based on studies of ultraviolet–visible spectra and CL spectra, the CL enhancement mechanism had been proposed. It was surmised that the light emission was from an excited oxygen molecular pair O2(1Δg)O2(1∑g–). The maximum emission wavelength was about 478 nm. The effects of 17 amino acids and 29 organic compounds on cerium(IV)–Tween 85–citrate CL were investigated by a flow injection procedure. This study showed the present system had a wide application for the determination of these compounds. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
9.
A flow injection chemiluminescence (FI–CL) method was developed for the determination of cyanide (CN−) based on the recovered CL signal by Cu2+ inhibiting a glutathione (GSH)‐capped CdTe quantum dot (QD) and hydrogen peroxide system. In an alkaline medium, strong CL signals were observed from the reaction of CdTe QDs and H2O2, and addition of Cu2+ could cause significant CL inhibition of the CdTe QDs–H2O2 system. In the presence of CN−, Cu2+ can be removed from the surface of CdTe QDs via the formation of particularly stable [Cu(CN)n](n‐1)– species, and the CL signal of the CdTe QDs–H2O2 system was efficiently recovered. Thus, the CL signals of CdTe QDs–H2O2 system were turned off and turned on by the addition of Cu2+ and CN−, respectively. Further, the results showed that among the tested ions, only CN− could recover the CL signal, which suggested that the CdTe QDs–H2O2–Cu2+ CL system had highly selectivity for CN−. Under optimum conditions, the CL intensity and the concentration of CN− show a good linear relationship in the range 0.0–650.0 ng/mL (R2 = 0.9996). The limit of detection for CN− was 6.0 ng/mL (3σ). This method has been applied to detect CN− in river water and industrial wastewater with satisfactory results. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
10.
Michal Nowak Wiesaw Tryniszewski Agata Sarniak Anna Wodarczyk Piotr J. Nowak Dariusz Nowak 《Luminescence》2019,34(2):183-192
Oxidative reactions can result in the formation of electronically excited species that undergo radiative decay depending on electronic transition from the excited state to the ground state with subsequent ultra‐weak photon emission (UPE). We investigated the UPE from the Fe2+–EDTA (ethylenediaminetetraacetic acid)–AA (ascorbic acid)–H2O2 (hydrogen peroxide) system with a multitube luminometer (Peltier‐cooled photon counter, spectral range 380–630 nm). The UPE, of 92.6 μmol/L Fe2+, 185.2 μmol/L EDTA, 472 μmol/L AA, 2.6 mmol/L H2O2, reached 1217 ± 118 relative light units during 2 min measurement and was about two times higher (P < 0.001) than the UPE of incomplete systems (Fe2+–AA–H2O2, Fe2+–EDTA–H2O2, AA–H2O2) and medium alone. Substitution of Fe2+ with Cr2+, Co2+, Mn2+ or Cu2+ as well as of EDTA with EGTA (ethylene glycol‐bis(β‐aminoethyl ether)‐N,N,N′,N′‐tetraacetic acid) or citrate powerfully inhibited UPE. Experiments with scavengers of reactive oxygen species (dimethyl sulfoxide, mannitol, sodium azide, superoxide dismutase) revealed the dependence of UPE only on hydroxyl radicals. Dimethyl sulfoxide at the concentration of 0.74 mmol/L inhibited UPE by 79 ± 4%. Plant phenolics (ferulic, chlorogenic and caffec acids) at the concentration of 870 μmol/L strongly enhanced UPE by 5‐, 13.9‐ and 46.8‐times (P < 0.001), respectively. It is suggested that augmentation of UPE from Fe2+–EDTA–AA–H2O2 system can be applied for detection of these phytochemicals. 相似文献
11.
Based on the inhibition effect of methimazole (MMI) on the reaction of luminol–H2O2 catalyzed by gold nanoparticles, a novel chemiluminescence (CL) method was developed for the determination of MMI. Under the optimum conditions, the relative CL intensity was linearly related to MMI concentration in the range from 5.0 × 10?8 to 5.0 × 10?5 mol L?1. The detection limit was 1.6 × 10?8 mol L?1 (S/N = 3), and the RSD for 6.0 × 10?6 mol L?1 MMI was 4.83 (n = 11). This method has high sensitivity, wide linear range, inexpensive instrumentation and has been applied to detect MMI in pharmaceutical tablets and pig serum samples. Furthermore, a possible reaction mechanism is discussed. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
12.
Mohammad H. Sorouraddin Mortaza Iranifam Abdolhossein Naseri Mohammad Fadakar‐Sardroud Hossein Gharari‐Alibabalou 《Luminescence》2011,26(6):622-628
A highly selective and simple chemiluminescence (CL) method for determination of penicillin G potassium (PGK) was developed. In the proposed method, CL was elicited from PGK upon its oxidation with H2O2. The light emission was enhanced in the presence of N‐cetyl‐N,N,N‐trimethylammonium bromide (CTMAB). An experimental design, central composite design (CCD), was used to realize the optimized variables, including pH, surfactant (CTMAB) and H2O2 concentrations. Under optimum condition, the calibration graph was linear in the range 3.3 × 10?3–3.3 × 10?1 mmol/L, with a detection limit of 8.8 × 10?4 mmol/L for PGK. The precision was calculated by analysing samples containing 1.6 × 10?1 mmol/L PGK (n = 5) and the relative standard deviation (RSD) was 1.40%. The utility of this method was demonstrated by determining PGK in pharmaceutical formulations for injection. The proposed method was validated by a reference method. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
13.
The main purpose of this study was to develop an inexpensive, simple, rapid and sensitive chemiluminescence (CL) method for the determination of glutamine (Gln) using a flow‐injection (FI) system. Gln was found to strongly inhibit the CL signal of the luminol–H2O2–CuSO4 system in Na2B4O7 solution. A new FI‐CL method was developed for the determination of Gln. Parameters affecting the reproducibility and CL detection were optimized systematically. Under the optimized conditions, the corresponding linear regression equation was established over the range of 5.0 × 10?7 to 2.5 × 10?6 mol/L with the detection limit of 1.8 × 10?8 mol/L. The relative standard deviation was found to be 1.8% for 11 replicate determinations of 1.5 × 10?6 mol/L Gln. The proposed method has been satisfactorily applied for the determination of Gln in real samples (Marzulene‐s granules) with recoveries in the range of 98.7–108.6%. The minimum sampling rate was about 100 samples/h. The possible mechanism of this inhibitory CL was studied by fluorescence spectrophotometer and UV–vis spectrophotometer. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
14.
The chemiluminescence (CL) of lucigenin (Luc2+) can be enhanced by different alcohols in alkaline solution. The effect of different fatty alcohols on the CL of lucigenin was related to the carbon chain length and the number of hydroxyl groups. Glycerol provides the greatest enhancement. UV/Vis absorption spectra and fluorescence spectra showed that N‐methylacridone (NMA) was produced in the CL reaction in the presence of different alcohols. The peak of the CL spectrum was located at 470 nm in all cases, indicating that the luminophore was always the excited‐state NMA. The quenching of lucigenin CL by superoxide dismutase (SOD) and the electron spin resonance (ESR) results with the spin trap of 5,5‐dimethyl‐1‐pyrroline N‐oxide (DMPO) demonstrated that superoxide anions (O2?–) were generated from dissolved oxygen in the CL reaction and that glycerol and dihydroxyacetone (DHA) can promote O2?? production by the reduction of dissolved oxygen in alkaline solution. It was assumed that the enhancement provided by different alcohols was related to the solvent effect and reducing capacity. Glycerol and DHA can also reduce Luc2+ into lucigenin cation radicals (Luc?+), which react with O2?? to produce CL, and glycerol can slowly transform into DHA, which is oxidized quickly in alkaline solution. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
15.
Uniform molecular imprinting microspheres were prepared using precipitation polymerization with thifensulfuron‐methyl (TFM) as template, acrylamide as functional monomer and ethylene glycol dimethacrylate as cross‐linker. TFM could be selectively adsorbed on the molecularly imprinted polymers (MIPs) matrix through the hydrogen bonding interaction and the adsorbed TFM could be sensed by its strikingly enhancing effect on the weak chemiluminescence (CL) reaction between luminol and hydrogen peroxide. On this basis, a novel CL sensor for the determination of TFM using MIPs as recognition elements was established. The logarithm of net CL intensity (ΔI) is linearly proportional to the logarithm of TFM concentration (C) in the range from 1.0 × 10?9 to 5.0 × 10?5 mol L?1 with a detection limit of 8.3 × 10?10 mol L?1 (3σ). The results demonstrated that the MIP–CL sensor was reversible and reusable and that it could strikingly improve the selectivity and sensitivity of CL analysis. Furthermore, it is suggested that the CL enhancement of luminol–H2O2 by TFM might be ascribed to the enhancement effect of CO2, which came from TFM hydrolysis in basic medium. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
16.
A novel phenomenon of dual chemiluminescence (CL) was observed for the KIO4–luminol–Mn2+ system in strong alkaline solutions using the stopped‐flow technique. Scavenging study of the reactive oxygen species (ROS) suggested that the two CL peaks originated from different CL pathways precipated by distinct ROS (O2? and ?OH for the first peak, mainly 1O2 for the second peak). Generation of these ROS at different time intervals from the reactions involving IO4?, O2, and Mn2+ and their subsequent reactions with luminol induced the intense CL emission. The relative intensity of the two CL peaks can be tuned over a wide range by varying the concentrations of Mn2?, luminol and KIO4. Because of the involvement of different ROS in each pathway, the two CL peaks could respond quite differently to various substances. Moreover, variation of the intensity ratio of the two CL peaks altered the relative proportions of the corresponding ROS, thereby changing their responses to a given substance. The dual CL emission acts like a pair of tunable probes and it is believed that this CL system has great potential in analytical applications. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
17.
Anne Herbst Viraj Ranawakage Takashi Asaeda Hendrik Schubert 《Phycological Research》2022,70(1):57-65
The immediate effect of zinc (Zn) and hydrogen peroxide (H2O2) in Chara braunii was analyzed in short-time exposure experiments. The exposure concentrations were 12.3, 18.4, and 24.5 μmol L?1 H2O2, 12, 60, and 120 mg L?1 Zn, and 12.3 μmol L?1 H2O2 + 12 mg L?1 Zn, 12.3 μmol L?1 H2O2 + 60 mg L?1 Zn, and 18.4 μmol L?1 H2O2 + 12 mg L?1 Zn. The stress response of C. braunii was analyzed by measuring photosynthetic photosystem II activity, chlorophyll a and b and carotenoid contents, the H2O2 concentration, and antioxidant enzyme activities of ascorbic peroxidase, catalase, and guaiacol peroxidase. The short-term addition of Zn reduced pigment contents in C. braunii. Chlorophyll a and b and carotenoid contents in H2O2-exposed C. braunii were as high as in control plants. Photosynthesis was reduced in H2O2-treated C. braunii and the short-term addition of Zn did not affect the electron transport rate. H2O2 concentration and antioxidant enzyme activities in C. braunii were not significantly different between control and exposed plants. Trends of enzymatic adaptation were described: the H2O2-induced stress response was characterized by increased antioxidant enzyme activities, whereas Zn inactivated catalase in C. braunii. 相似文献
18.
Ahsan U. Khan 《Luminescence》1989,4(1):200-207
Singlet oxygen generation is reported from (1) enzymatic reaction and (2) electron transfer reactions of the superoxide anion measured directly with an ultrasensitive near-IR emission spectrophotometer by monitoring the O2(1Δg) → O2 (3Σg?) transition at 1268 nm. Near-IR emission spectra from the myeloperoxidase and lactoperoxidase enzymatic systems show only emission of singlet oxygen at 1268nm. The lipoxygenase/Na–linoleate enzymatic reaction exhibits two emissions, 1268 nm and 1288 nm. The latter emission is identified as originating from a peroxy radical. Spectral and kinetic data giving evidence of singlet oxygen generation is obtained from the reaction of potassium superoxide solubilized by 18-crown-6-ether in acetonitrile with a series of organometallic coordination compounds. 相似文献
19.
In this article, a simple, effective chemiluminescence (CL) method for the detection of methylparaben (MP) in cosmetic samples was developed based on an IO4?–H2O2–carbon nitrogen quantum dots (CNQDs) system without a separation process. The results indicated that the redox reaction between periodate and hydrogen peroxide released hydroxide radicals and superoxide radical anions in the presence of bicarbonate. These two radicals were responsible for the formation of excited luminophor CNQD* with a maximum wavelength at 480 nm. Due to the competitive reaction with hydroxide radicals, CL intensity was markedly diminished in the presence of MP. The relative standard deviation in the intraday assay was below 5.5% (n = 9), and the detection limit was as low as 0.50 μmol/L. The proposed method allowed for the successful, selective determination of MP in cosmetics. 相似文献
20.
《Luminescence》2004,19(1):1-7
Indole‐2 and 3‐carboxamides (IDs) are proposed to be selective cyclooxygenase inhibitors. Since cyclooxygenase‐1 may be involved in reactive oxygen species (ROS) production, we hypothesize that these indole derivatives have antioxidative properties. We have employed chemiluminescence (CL) and electron spin resonance (ESR) spin trapping to examine this hypothesis. We report here the results of a study of reactivity of 10 selected indole derivatives towards ROS. The following generators of ROS were applied: potassium superoxide (KO2) as a source of superoxide radicals (O2·?), the Fenton reaction (Co‐EDTA/H2O2) for hydroxyl radicals (HO·), and a mixture of alkaline aqueous H2O2 and acetonitrile for singlet oxygen (1O2). Hydroxyl radicals were detected as 5,5‐dimethyl‐1‐pyrroline‐N‐oxide (DMPO) spin adduct, whereas 2,2,6,6‐tetramethyl‐piperidine (TEMP) was used as a detector of 1O2. Using the Fenton reaction, 0.5 mmol/L IDs were found to inhibit DMPO‐?H radical formation in the range 7–37%. Furthermore the tested compounds containing the thiazolyl group also inhibited the 1O2‐dependent TEMPO radical, generated in the acetonitrile + H2O2 system. About 20% inhibition was obtained in the presence of 0.5 mmol/L IDs. 1 mmol/L IDs caused an approximately 13–70% decrease in the CL sum from the O2·? generating system (1 mmol/L). The aim of this paper is to evaluate these indole derivatives as antioxidants and their abilities to scavenge ROS. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献