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1.
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   

2.
Hydrogen peroxide formed during the course of the copper(II)-catalysed oxidation of cysteamine with oxygen was continuously determined by a peroxidase (POD)-catalysed luminol chemiluminescence (CL) method. Horseradish peroxidase (HRP), lactoperoxidase (LPO) and Arthromyces ramosus peroxidase (ARP) were used as a CL catalyst. The respective PODs gave specific CL intensity-time profiles. HRP caused a CL delay, and ARP gave a time-response curve which followed the production rate of H2O2. LPO gave only a weak CL flash which decayed promptly. These differences of CL response curves could be explained in terms of the different reactivities of PODs for superoxide anion and the different formation rate of luminol radicals in the peroxidation of luminol catalysed by POD.  相似文献   

3.
Nanoparticles of cadmium selenide (CdSe) doped with europium, were synthesized as stabilizing agents using thioglycolic acid ligand. This method is based on the enhancing effect of CdSe quantum dots (QDs) doped with europium on chemiluminescence (CL) emission. This emission was generated by mixing CdSe QDs with manganese (II), iron (II) and chrome (II) sulfates as catalysts in the presence of hydrogen peroxide (H2O2). The structural characteristics and morphology of these nanoparticles were investigated by scanning electron microscopy, Fourier transform infrared spectroscopy, ultraviolet–visible absorption spectroscopy, X‐ray pattern and dynamic light scattering methods. The CdSe QDs doped with europium were used as the sensitizer in a luminol?hydrogen peroxide CL system. The sensitized CdSe QDs were analyzed for antibacterial activity against Gram‐positive or Gram‐negative bacteria. The results showed that the CdSe QDs are effective against all the studied bacteria, effectiveness was especially higher for Bacillus subtilis.  相似文献   

4.
Isoenzyme c of horseradish peroxidase (HRP‐C) is widely used in enzyme immunoassay combined with chemiluminescence (CL) detection. For this application, HRP‐C activity measurement is usually based on luminol oxidation in the presence of hydrogen peroxide (H2O2). However, this catalysis reaction was enhancer dependent. In this study, we demonstrated that Jatropha curcas peroxidase (JcGP1) showed high efficiency in catalyzing luminol oxidation in the presence of H2O2. Compared with HRP‐C, the JcGP1‐induced reaction was enhancer independent, which made the enzyme‐linked immunosorbent assay (ELISA) simpler. In addition, the JcGP1 catalyzed reaction showed a long‐term stable CL signal. We optimized the conditions for JcGP1 catalysis and determined the favorable conditions as follows: 50 mM Tris buffer (pH 8.2) containing 10 mM H2O2, 14 mM luminol and 0.75 M NaCl. The optimum catalysis temperature was 30°C. The detection limit of JcGP1 under optimum condition was 0.2 pM. Long‐term stable CL signal combined with enhancer‐independent property indicated that JcGP1 might be a valuable candidate peroxidase for clinical diagnosis and enzyme immunoassay with CL detection. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

5.
Anionic sweet potato peroxidase (SPP; Ipomoea batatas) was shown to efficiently catalyse luminol oxidation by hydrogen peroxide, forming a long-term chemiluminescence (CL) signal. Like other anionic plant peroxidases, SPP is able to catalyse this enzymatic reaction efficiently in the absence of any enhancer. Maximum intensity produced in SPP-catalysed oxidation of luminol was detected at pH 7.8-7.9 to be lower than that characteristic of other peroxidases (8.4-8.6). Varying the concentrations of luminol, hydrogen peroxide and Tris buffer in the reaction medium, we determined favourable conditions for SPP catalysis (100 mmol/L Tris-HCl buffer, pH 7.8, containing 5 mmol/L hydrogen peroxide and 8 mmol/L luminol). The SPP detection limit in luminol oxidation was 1.0 x 10(-14) mol/L. High sensitivity in combination with the long-term CL signal and high stability is indicative of good promise for the application of SPP in CL enzyme immunoassay.  相似文献   

6.
As a consequence of the increasing importance of hydrogen peroxide in plant metabolism, more efficient methods are required for accurate determinations of its concentration in plant tissue and organs. Here we present a highly sensitive chemiluminescence (CL) method based on the Co (II) catalysed oxidation of luminol by H2O2. The replacement of ferricyanide, the traditional catalyst of luminol luminescence by Co (II), enhanced the sensitivity of the reaction towards H2O2 in three orders of magnitude. Thus, plant extracts can be diluted to such a level that quenching effects of phenols and ascorbic acid (ASA), which are normally present at high concentrations in plant tissues is avoided, and therefore, pre-treatments with PVP and ascorbate oxidase to remove these quenchers from plant-extracts become unnecessary. To exemplified the high performance of the method, measurements of H2O2 were carried out in PVP treated and non-treated extracts of grapevine leaf, a plant tissue that contain high levels of phenols and ASA. Moreover, increases in H2O2 levels were detected in disc-leaf treated with aminotriazole, a specific Cat inhibitor, showing the importance of Cat as a H2O2 scavenging enzyme in leaves of grapevine.  相似文献   

7.
Highly sensitive detection of hepatitis C virus (HCV) in serum is a key method for diagnosing and classifying the extent of HCV infection. In this study, a p‐phenol derivative, 4‐(1,2,4‐triazol‐1‐yl)phenol (4‐TRP), was employed as an efficient enhancer of the luminol–hydrogen peroxide (H2O2)–horseradish peroxidase (HRP) chemiluminescence (CL) system for detection of HCV. Compared with a traditional enhancer, 4‐TRP strongly enhanced CL intensity with the effect of prolonging and stabilizing light emission. The developed CL system was applied to detecting HCV core antigen (HCV‐cAg) using a sandwich structure inside microwells. Our experimental results showed that there was good linear relationship between CL intensity and HCV‐cAg concentration in the 0.6–3.6 pg/mL range (R = 0.99). The intra‐ and inter‐assay coefficients of variation were 4.5–5.8% and 5.0–7.3%, respectively. In addition, sensitive determination of HCV‐cAg in serum samples using the luminol–H2O2–HRP–4‐TRP CL system was also feasible in clinical settings. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

8.
The host–guest interaction between sulfobutylether‐β‐cyclodextrin (SBE‐β‐CD) and reserpine (RSP) is described using flow injection‐chemiluminescence (FI‐CL) and site‐directed molecular docking methods. It was found that RSP could inhibit the CL intensity produced by a luminol/SBE‐β‐CD system. The decrease in CL intensity was logarithmic over an RSP concentration range of 0.03 to 700.0 nM, giving a regression equation of ?I = 107.1lgCRES + 186.1 with a detection limit of 10 pM (3σ). The CL assay was successfully applied in the determination of RSP in injection, saliva and urine samples with recoveries in the range 93.5–106.1%. Using the proposed CL model, the binding constant (KCD‐R) and the stoichiometric ratio of SBE‐β‐CD/RSP were calculated to be 7.4 × 106 M‐1 and 1 : 1, respectively. Using molecular docking, it was confirmed that luminol binds to the small cavity of SBE‐β‐CD with a nonpolar interaction, while RSP targeted the larger cavity of SBE‐β‐CD and formed a 1 : 1 complex with hydrogen bonds. The proposed new CL method has the potential to become a powerful tool for revealing the host–guest interaction between CDs and drugs, as well as monitoring drugs with high sensitivity. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

9.
Based on the inhibition effect of transferrin (Tf) on the reaction of the luminol–hydrogen peroxide (H2O2) chemiluminescence (CL) system, catalysed by meso‐tetra‐(3‐methoxyl‐4‐hydroxyl) phenyl manganese porphyrin (MnP) as a mimetic enzyme of peroxides, a sensitive flow‐injection CL method has been developed for the determination of Tf in an alkaline medium. The CL reaction was carefully investigated by examining the variations of reaction conditions. Under optimum conditions, the linear range for the determination of transferrin was 0.04–20.0 μg/mL and the detection limit was 1.62 ng/mL. This proposed method was sensitive, convenient and simple, and has been successfully applied to the determination of transferrin in a serum sample. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

10.
In vitro screening of a Fe2+‐chelating effect using a Fenton's reaction–luminol chemiluminescence (CL) system is described. The luminescence between the reactive oxygen species generated by the Fenton's reaction and luminol was decreased on capturing Fe2+ using a chelator. The proposed method can prevent the consumption of expensive seed compounds (drug discovery candidates) owing to the high sensitivity of CL detection. Therefore, the assay could be performed using small volumes of sample solution (150 μL) at micromolar concentrations. After optimization of the screening conditions, the efficacies of conventional chelators such as ethylenediaminetetraacetic acid (EDTA), diethylentriaminepentaacetic acid (DETAPAC), deferoxamine, deferiprone and 1,10‐phenanthroline were examined. EC50 values for these compounds (except 1,10‐phenanthroline) were in the range 3.20 ± 0.87 to 9.57 ± 0.64 μM (n = 3). Rapid measurement of the Fe2+‐chelating effect with an assay run time of a few minutes could be achieved using the proposed method. In addition, the specificity of the method was discussed. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

11.
Conditions for the enhanced horseradish peroxidase (HRP) catalysed reaction between luminol and hydrogen peroxide were optimized to determine detection limits for HRP conjugated to antibody fragment (HRP-Fab) in solution phase. Light output was linear with respect to HRP-Fab concentration but became nonlinear at low HRP-Fab concentrations when an accelerator (enhancer) of the reaction was used. para-Phenylphenol was a more effective enhancer than p-iodophenol at HRP-Fab concentrations below 20 pmol/l. The detection limit for HRP-Fab was 1.2 femtomoles in the absence of p-phenylphenol and 0.08 femtomole in the presence of p-phenylphenol. The acceleration of peroxidase activity at the lowest HRP-Fab concentrations occurred after an incubation time period of up to five minutes. This lag time limited the sensitivity and the mechanism for it was sought. Preincubation experiment results indicated that the lag time phenomenon may involve a reversible alteration in HRP catalytic activity and that enhancer, peroxide, luminol and HRP-Fab had to be incubated together some time before maximum activation could occur.  相似文献   

12.
Based on the catalytic activity of hemin, an efficient biocatalyst, an indirect capillary electrophoresis–chemiluminescence (CE‐CL) detection method for phenols using a hemin–luminol–hydrogen peroxide system was developed. Through a series of static injection experiments, hemin was found to perform best in a neutral solution rather than an acidic or alkaline medium. Although halide ions such as Br? and F? could further enhance the CL signal catalyzed by hemin, it is difficult to apply these conditions to this CE‐CL detection system because of the self‐polymerization of hemin, as it hinders the CE process. The addition of concentrated ammonium hydroxide to an aqueous/dimethyl sulfoxide solution of hemin–luminol afforded a stable CE‐CL baseline. The indirect CE‐CL detection of five phenols using this method gave the following limits of detections: 4.8 × 10?8 mol/L (o‐sec‐butylphenol), 4.9 × 10?8 mol/L (o‐cresol), 5.4 × 10?8 mol/L (m‐cresol), 5.3 × 10?8 mol/L (2,4‐dichlorophenol) and 7.1 × 10?8 mol/L (phenol). Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

13.
Lu Han  Ying Li  Aiping Fan 《Luminescence》2018,33(4):751-758
Peroxidase is a commonly used catalyst in luminol–H2O2 chemiluminescence (CL) reactions. Natural peroxidase has a sophisticated separation process, short shelf life and unstable activity, therefore it is important to develop peroxidases that have both high catalytic activity and good stability as alternatives to the natural enzyme. Gold nanoclusters (Au NCs) are an alternative peroxidase with catalytic activity in the luminol–H2O2 CL reaction. In the present study, ethanediamine was modified on the surface of Au NCs forming cationic Au NCs. The zeta potential of the cationic Au NCs maintained its positive charge when the pH of the solution was between 4 and 9. The cationic Au NCs showed higher catalytic activity in the luminol–H2O2 CL reaction than did unmodified Au NCs. A mechanism study showed that the better performance of cationic Au NCs may be attributed to the generation of 1O2 on the surface of cationic Au NCs and a positive surface charge, for better affinity to luminol. Cationic Au NC, acting as a peroxidase mimic, has much better stability than horseradish peroxidase over a wide range of temperatures. We believe that cationic Au NCs may be useful as an artificial peroxidase for a wide range of potential applications in CL and bioanalysis.  相似文献   

14.
Iso‐luminol functionalized gold nanomaterials were synthesized in high yield by a simple seeding approach, using the chemiluminescent reagent iso‐luminol as reductant in the presence of HAuCl4, AgNO3 and cetyltrimethylammonium bromide (CTAB). The morphology of as‐prepared gold nanoparticles was characterized by transmission electron microscopy and UV–vis spectroscopy, showing that gold nanotadpoles (AuNTps) were obtained. Subsequent experiments revealed that the amounts of seed colloids and AgNO3 and the concentrations of iso‐luminol and CTAB in the growth solution play critical roles in the formation of well‐shaped AuNTps. The surface state of AuNTps was characterized by UV–vis spectroscopy and fluorescence spectroscopy, indicating that iso‐luminol and its oxidation product, 4‐aminophthalate, coexisted on the surface of AuNTps. The CL behaviour was studied by static injection CL experiments, demonstrating that AuNTps were of CL activity. Finally, the growth mechanism of AuNTps was also discussed. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

15.
Reactive oxygen species (ROS) are presently thought to play important role in an increasing number of the physiological and pathological processes in living organisms. Various chemiluminescent (CL) compounds have been studied in order to find suitable and specific probes for the detection of particular ROS species. The CL of luminol is known to be non‐specific and can be induced by various oxidants. Two Cypridina luciferin analogues, CLA and MCLA, have been used for the detection of ROS in vivo. CLAs are thought to emit light only when reacting with superoxide and singlet oxygen. It is possible to distinguish the particular ROS by using a specific quencher or scavenger, e.g. superoxide dismutase (SOD) or sodium azide (NaN3). The CL reactions of luminol (3‐aminophthalhydrazide), CLA [2‐methyl‐6‐phenyl‐3,7‐dihydroimidazo(1,2α) pyrazin‐3‐one] and MCLA [2‐methyl‐6‐(p‐methoxyphenyl)‐3,7‐dihydroimidazo(1,2α) pyrazin‐3‐one] were studied in three hydrogen peroxide decomposition systems (H2O2–HRP; H2O2–CuSO4; and H2O2–NaOCl). The measurements were carried out in phosphate buffer, pH 7.4, at 25 °C, using a luminometer (Fluoroskan Ascent FL and Sirius C). NaN3 was used as the specific quencher of singlet oxygen. The results demonstrate that the proclaimed specifity of the CL of Cypridina luciferin analogues towards singlet oxygen has to be discussed. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

16.
Hu Y  Li G  Zhang Z 《Luminescence》2011,26(5):313-318
In this paper, the novel trivalent copper–periodate complex {K5[Cu(HIO6)2], DPC} has been applied in a luminol‐based chemiluminescence (CL) reaction. Coupled with flow injection (FI) technology, the FI‐CL method was proposed for the determination of lincomycin hydrochloride. The CL reaction between luminol and DPC occurred in an alkaline medium. The CL intensity could be greatly enhanced by lincomycin hydrochloride. The relative CL intensity was proportional to the concentration of lincomycin hydrochloride in the range of 1 × 10?8 to 5 × 10?6 g mL?1 and the detection limit was at the 3.5 × 10?9 g mL?1 level. The relative standard deviation at 5 × 10?8 g mL?1 was 1.7% (n = 9). The sensitive method was successfully applied to the direct determination of lincomycin hydrochloride (ng mL?1) in serum. A possible mechanism of the lumonol–DPC CL reaction was discussed by the study of the CL kinetic characteristics and the spectra of CL reaction. The oxidability of DPC was studied by means of its electrochemical response. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

17.
A simple and sensitive flow‐injection (FI) method for the determination of nitrate and nitrite in natural waters, based on luminol chemiluminescence (CL) detection, is reported. Nitrate was reduced online to nitrite via a copperized cadmium (Cu–Cd) column and then reacted with acidic hydrogen peroxide to form peroxynitrous acid. CL emission was observed from the oxidation of luminol in an alkaline medium in the presence of the peroxynitrite anion. The limits of detection (S:N = 3) were 0.02 and 0.01 µg N/L, with sample throughputs of 40 and 90 /h for nitrate and nitrite, respectively. Calibration graphs were linear over the range 0.02–50 and 0.01–50 µg N/L [R2 = 0.9984 (n = 8) and R2 = 0.9965 (n = 7)] for nitrate and nitrite, respectively, with relative standard deviations (RSDs; n = 3) in the range 1.8–4.6%. The key chemical and physical variables (reagent concentrations, buffer pH, flow rates, sample volume, Cu–Cd reductor column length) were optimized and potential interferences investigated. The effect of cations [Ca(II), Mg(II), Co(II), Fe(II) and Cu(II)] was masked online with EDTA. Common anions (PO43?, SO42? and HCO3?) did not interfere at their maximum admissible concentrations in freshwaters. The effect of salinity on the luminol CL reaction with and without nitrate and nitrite (2 and 0.5 µg N/L, respectively) was also investigated. The method was successfully applied to freshwaters and the results obtained were in good agreement with those obtained by an automated segmented flow analyser reference method. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

18.
It was found that isoniazid (ISO) or p‐aminosalicylic acid (PAS) could enhance the chemiluminescence (CL) emission from Cu (II)‐luminol‐hydrogen peroxide system, and the increased chemiluminescence signals were proportional to their concentrations, respectively. Based on this phenomenon, a chemiluminescence method coupled to capillary electrophoresis (CE) was established for simultaneous determination of ISO and PAS. The CE conditions including running buffer and running voltage were investigated in detail. The effects of the pH of H2O2 solution and the concentrations of luminol, H2O2 and Cu (II) on the CL signal were also investigated carefully. Under the optimized conditions, the analysis could be accomplished within 10 min, with the limits of detection of 0.3 µg mL–1 for ISO and 1.1 µg mL–1 for PAS, corresponding to 7.2 and 26.4 pg per injection (24 nL), respectively. Finally, the method was validated by determining the two analytes in pharmaceutical preparation and spiked human serum samples. The results of pharmaceutical tablet analysis were in good agreement with the labeled amounts. The recoveries for ISO and PAS in human serum were in the range of 92–104% and 90–113%, respectively. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

19.
The compromised optima for high intensity chemiluminescence (CL), using superoxide generators, were all above pH 9.0 for the CL probes luminol and lucigenin. With luminol the optima were at pH 9.0 and 9.4 for the generators KO2 and hypoxanthine/xanthine oxidase (HX/XO), respectively. Lucigenin, with the same generators, produced optima at pH 9.5 and 10.0, respectively. The probe methyl-Cypridina-luciferin analogue (MCLA) produced optima closer to neutral pH, which is preferred for physiological assessments. MCLA had optima at pH 6.0, 8.7 and 9.5 with KO2 and with HX/XO optima at pH 4.8, 6.0, 7.0 and 8.7. When CL was assessed at physiological pH, MCLA observed superoxide radicals with a sensitivity of 100- and 330-fold more than luminol or luicigenin respectively. For singlet oxygen, the sensitivity of MCLA at this pH was 45- and 5465-fold more than for the said probes respectively. H2O2 did not elicit CL between pH 4 and 9.5 with any of the probes and did not influence the production of superoxide or singlet oxygen when co-assessed. Therefore CL could only be obtained when enzymes were used as converters. The optima for the enzyme-conversion system horseradish peroxidase (HRP)/H2O2, and luminol, were at pH 8.0 and 9.2. Lucigenin and HRP/H2O2 also had a biphasic CL profile with optima at pH 7.4 and 9.6. MCLA and HRP/H2O2 had five optima, with the major ones at pH 6.1 and beyond 10. The optima for the myeloperoxidase/H2O system were at 8.6 and beyond 10.0 when luminol and 0.15 mol/L NaBr were used. © 1997 John Wiley & Sons, Ltd.  相似文献   

20.
It was found that flavonoids could remarkably inhibit the chemiluminescence (CL) intensity of an off‐line gold nanoparticle (AuNP)‐catalyzed luminol–H2O2 CL system. By contrast, flavonoids enhanced the CL intensity of an on‐line AuNP‐catalyzed luminol–H2O2 CL system. In the off‐line system, the AuNPs were prepared beforehand, whereas in the on‐line system, AuNPs were produced by on‐line mixing of luminol prepared in a buffer solution of NaHCO3 ? Na2CO3 and HAuCl4 with no need for the preliminary preparation of AuNPs. The on‐line system had prominent advantages over the off‐line system, namely a lowering of the background noise and improvements in the stability of the CL system. The results show that differences in the signal suppression effect of flavonoids on the off‐line AuNP‐catalyzed CL system are influenced by the combined action of a free radical scavenging effect and occupy‐sites function; the latter was proved to be predominant using controlled experiments. Enhancement of the on‐line system was ascribed to the presence of flavonoids promoting the on‐line formation of AuNPs, which better catalyzed the luminol–H2O2 CL reaction, and the enhancement activity of the six flavonoids increased with the increase in reducibility. This work broadens the scope of practical applications of an AuNP‐catalyzed CL system.  相似文献   

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