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CL Reaction (cl + reaction)
Selected AbstractsGold nanoparticle-enhanced capillary electrophoresis-chemiluminescence assay of trace uric acidELECTROPHORESIS, Issue 15 2009Shulin Zhao Abstract A sensitive method based on gold nanoparticle-enhanced CE-chemiluminescence (CL) detection was developed for quantifying uric acid (UA) in serum. In this work, gold nanoparticles were added into the running buffer of CE to catalyze the post-column CL reaction between luminol and hydrogen peroxide, achieving highly efficient CL emission. Negative peaks were produced due to the inhibitory effects on CL emission from UA eluted from the electrophoretic capillary. The decrease in CL intensity was proportional to the concentration of UA in the range of 2.5×10,7,1.0×10,5,M. Detection limit was 4.6×10,8,M UA. Ten human serum samples were analyzed by the presented method. Serum level of UA was found to be in the range from 204 to 324,,M for healthy subjects (n=5), and from 464 to 497,,M for diabetic patients (n=5). The two groups were significantly different (p<0.05). The results suggested a potential application of the proposed assay in rapid primary diagnosis of diseases such as diabetes. [source] Metal ion analysis using microchip CE with chemiluminescence detection based on 1,10-phenanthroline,hydrogen peroxide reactionJOURNAL OF SEPARATION SCIENCE, JSS, Issue 3 2009Takahiro Nogami Abstract We developed a microchip CE method with chemiluminescence (CL) detection using the reaction of 1,10-phenanthroline and hydrogen peroxide for separation and determination of metal ions, where the metal ions acted as catalysts for the CL reaction. The microchip consisted of two microchannels that crossed at the intersection and four reservoirs that accessed the ends of the channels. The metal ions in the sample solution migrated in the channel along with 1,10-phenanthroline included in a running solution, and then mixed with hydrogen peroxide in one of the reservoirs to emit CL. The light was detected with a photomultiplier tube located just above the reservoir. Two metal ion groups, the platinum metal group (Ru(III), Rh(III), Pd(II), Os(VIII), Ir(III), and Pt(IV)) and the fourth periodic transition metal group (Cu(II), Fe(II), Co(II), and Ni(II)) were examined using the present system. The lowest detection limit was observed for Os(VIII); Os(VIII) responded over the range of 7.5×10,12,1.0×10,8 M with the detection limit of 7.5×10,12 M (about 38 zmol) (S/N = 3). The mixed solution of Ru(III), Rh(III), Pd(II), Os(VIII), Ir(III), and Pt(IV) could be analyzed using this system within about 2.5 min. In addition, the system was applied to the determination of Cu(II) concentration in a city water supply. [source] Determination of Sudan IV in hot chilli powder with luminol/dissolved oxygen chemiluminescence systemJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2010Lichuan Niu Abstract BACKGROUND: A green, simple and sensitive flow injection chemiluminescence (CL) procedure is proposed for the determination of Sudan dyes. The method is based on the finding that Sudan I, II, III and IV markedly enhance the CL intensity of the luminol/dissolved oxygen reaction. RESULTS: The increment in CL intensity was proportional to the concentration of Sudan I, II, III and IV, giving calibration graphs linear over the ranges 0.007,1, 0.5,30, 1,10 and 0.7,300 ng mL,1 respectively (R2 , 0.9981), with limits of detection of 0.002, 0.2, 0.3 and 0.2 ng mL,1 respectively. At a flow rate of 2 mL min,1, complete determination of Sudan dyes, including sampling and washing, could be accomplished in 40 s, with relative standard deviations of less than 5% (n = 7). CONCLUSION: The proposed method was successfully applied to the determination of Sudan IV in contaminated hot chilli powder, with recoveries ranging from 89.3 to 108.4%. The possible mechanism of enhancement of the lumininol/dissolved oxygen CL reaction by Sudan IV can be attributed to the acceleration of electron transfer. Compared with other procedures, the proposed CL method offers the highest sensitivity and the least reagent consumption for the determination of Sudan IV. Copyright © 2009 Society of Chemical Industry [source] Determination of serum glucose by horseradish peroxidase-catalysed imidazole chemiluminescence coupled to a micro-flow-injection systemLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 5 2007Osamu Nozaki Abstract The reactivity of flow-injection (FI)-horseradish peroxidase (HRP)-catalysed imidazole chemiluminescence (CL) was studied for continuous determination of hydrogen peroxide (H2O2) and serum glucose with immobilized glucose oxidase. Light emission by the HRP-catalysed imidazole CL was obtained when immobilized HRP, alkaline imidazole (in Tricine solution, pH 9.3) and H2O2 were reacted at room temperature. The optimal pH for the CL reaction was 9.3 and the optimal concentration of imidazole was 100 µmol/L. When no imidazole was added, the light intensity of the same H2O2 specimen decreased to a level that could not be quantitatively determined. The spectrum of the light emitted by imidazole CL was in the range 400,600 nm with a peak at 500 nm. The calibration equation for determination of H2O2 was y = 9860x2 + 3830x + 11 700, where y = light intensity (RLU) and x = concentration of H2O2 (µmol/L). The detection limit of H2O2 was 5 pmol, and the reproducibility of the H2O2 assay was 2.3% of the coefficient of variation (H2O2 48 µmol/L, n = 13). The CL method was successfully applied to assay glucose after on-line generation of H2O2 with the immobilized glucose oxidase column, resulting in good reproducibility (CV = 3.3% and 1.0% for the standard glucose and the control serum, respectively). Copyright © 2007 John Wiley & Sons, Ltd. [source] Determination of tsumacide residues in vegetable samples using a flow-injection chemiluminescence methodLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4 2007Haiyan Liu Abstract A sensitive, simple and rapid flow-injection chemiluminescence (FI,CL) method is described to determine tsumacide pesticide residue based on the CL reaction of the alkaline degradation product of tsumacide with acidic KMnO4 when rhodamine 6G was present. Under the optimum conditions, the relative CL intensity is linear with the concentration of tsumacide in the range of 2.0 × 10,3,0.20 mg/L. The detection limit is 6.6 × 10,4 mg/L (3,) and the relative standard deviation for 2.0 × 10,2 mg/L tsumacide solution was 2.28% (intra-day) and 4.85% (inter-day). The proposed method has been applied to determine the residue of tsumacide in vegetable samples and the recovery test is very satisfactory. Copyright © 2007 John Wiley & Sons, Ltd. [source] Luminol chemiluminescence catalysed by colloidal platinum nanoparticlesLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 2 2007Sheng-Liang Xu Abstract Platinum colloids prepared by the reduction of hexachloroplatinic acid with citrate in the presence of different stabilizers were found to enhance the chemiluminescence (CL) of the luminol,H2O2 system, and the most intensive CL signals were obtained with citrate-protected Pt colloids synthesized with citrate as both a reductant and a stabilizer. Light emission was intense and reproducible. Transmission electron microscopy and X-ray photoelectron spectroscopy studies were conducted before and after the CL reaction to investigate the possible CL enhancement mechanism. It is suggested that this CL enhancement is attributed to the catalysis of platinum nanoparticles, which could accelerate the electron-transfer process and facilitate the CL radical generation in aqueous solution. The effects of Pt colloids prepared by the hydroborate reduction were also investigated. The application of the luminol,H2O2,Pt colloids system was exploited for the determination of compounds such as uric acid, ascorbic acid, phenols and amino acids. Copyright © 2006 John Wiley & Sons, Ltd. [source] Investigation on the interaction between dihydroxybenzene and Fe3+,H2O2,Rh6G system based on enhancing chemiluminescenceLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 1 2006Deyong He Abstract A highly sensitive flow-injection chemiluminescence (FI,CL) method has been developed for the determination of dihydroxybenzene, based on the hydroxyl radical reaction. Hydroxyl radical (·OH) produced by the reaction of Fe3+ and H2O2 oxidize rhodamine 6G to produce weak CL. It was observed that catechol and hydroquinone greatly enhanced the weak CL reaction. However, the proposed CL system is not suitable for determination of resorcinol because the enhancement reaction is very slow. The proposed procedure has a linear range of 0.01,2 mg/L for catechol, with a detection limit of 0.006 mg/L, and 0.008,1 mg/L for hydroquinone, with a detection limit of 0.004 mg/L. The possible mechanism of the CL system is discussed. Copyright © 2005 John Wiley & Sons, Ltd. [source] A novel flow-injection chemiluminescence system for the determination of guanineLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4-5 2005Yang Mei Abstract A novel flow-injection chemiluminescence (CL) method for the determination of guanine was developed. The procedure is based on the CL reaction of guanine with hydrogen peroxide in borax buffer (pH 8.5) with Co2+ as a catalyst. The calibration graph is linear within the range of 3 × 10,7,9 × 10,5 g/mL. A detection limit of 1 × 10,7 g/mL, along with a relative standard deviation of 2.23% (3 × 10,7 g/mL guanine, n = 11), were obtained. The present procedure was applied to the measurement of guanine in urine with recoveries of 97.5,107.5%. A possible CL mechanism of the reaction system is proposed. Copyright © 2005 John Wiley & Sons, Ltd. [source] Flow injection chemiluminescence determination of dihydralazine sulphate based on permanganate oxidation sensitized by rhodamine BLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 6 2004Xiao-Feng Yang Abstract A novel ,ow injection chemiluminescence (CL) method for the determination of dihydralazine sulphate (DHZS) is described. The method is based on the CL produced during the oxidation of DHZS by acidic permanganate solution in the presence of rhodamine B. Rhodamine B is suggested as a ,uorescing compound for the energy-transferred excitation. The CL emission allows quantitation of DHZS concentration in the range 5,800 ng/mL, with a detection limit of 1.9 ng/mL (3,). The experimental conditions for the CL reaction are optimized and the possible reaction mechanism is discussed. The method has been applied to the determination of DHZS in pharmaceutical preparations and compares well with the high performance liquid chromatography (HPLC) method. Copyright © 2004 John Wiley & Sons, Ltd. [source] Hydrazine-induced post-chemiluminescence phenomenon of permanganate,luminol reaction and its applicationsLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 6 2004Jianxiu Du Abstract The post-chemiluminescence phenomenon arising from the permanganate,luminol reaction induced by hydrazine and isoniazid was investigated. When hydrazine or isoniazid was injected into the mixture after the end of the reaction of permanganate with alkaline luminol, a new chemiluminescence (CL) reaction was initiated and strong CL signal was detected. A possible CL mechanism is suggested, based upon the studies of the kinetic characteristics of the CL reaction, the UV-visible spectra, the CL spectra and some other experiments. The present reactions allow the determination of 0.1,10.0 mg/L hydrazine and 0.02,1.0 mg/L isoniazid, with detection limits of 0.03 mg/L and 0.006 mg/L, respectively. The method was applied to the determination of isoniazid in pharmaceutical preparations. Copyright © 2004 John Wiley & Sons, Ltd. [source] A novel [Ag(NH3)2]+ probe for chemiluminescent imaging detection of proteins after polyacrylamide gel electrophoresisPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 15 2007Xin Xiong Abstract The development of a novel [Ag(NH3)2]+ probe chemiluminescence (CL)-based imaging method for the detection of various proteins after PAGE is described. The detection is based upon the probe [Ag(NH3)2]+ catalyzing the CL reaction of the luminol,potassium persulfate system. The proposed method detects various proteins labeled by [Ag(NH3)2]+ and expands the application scope to SDS gels. It also detects proteins directly in polyacrylamide gels, without tedious transferring procedures. Furthermore, successful identification of proteins by peptide mass profiling using ionization MS was easily performed, and no pretreatments of gel prior to digestion are needed. Detection limits for standard marker proteins match CBB-R250 staining and the linear dynamic range is superior to CBB-R250 staining and silver staining. The CL imaging conditions, including luminescent reagents, silver ion concentration, the ammonia-controlled system and the washing reagents parameters have also been optimized. [source] Simultaneous Determination of Epinephrine, Noradrenaline and Dopamine in Human Serum Samples by High Performance Liquid Chromatography with Chemiluminescence DetectionCHINESE JOURNAL OF CHEMISTRY, Issue 7 2007Fu-Nan Chen Abstract A simple, rapid and accurate high performance liquid chromatographic (HPLC) technique coupled with chemiluminescence (CL) detection was developed for the simultaneous determination of epinephrine (E), noradrenaline (NA) and dopamine (DA). It was based on the analyte enhancement effect on the CL reaction between luminol and potassium ferricyanide. The effects of various parameters, such as potassium ferricyanide concentration, luminol concentration, pH value and component of the mobile phase on chromatographic behaviors of the analytes (E, NA and DA) were investigated. The separation was carried out on C18 column using the mobile phase of 0.01 mol/L potassium hydrogen phthalate solution and methanol (92:8, V/V). Under the optimum conditions, E, NA and DA showed good linear relationships in the range of 1×10,8,5×10,6, 5.0×10,9,1.0×10,6 and 5.0×10,9,1.0×10,6 g/mL respectively. The detection limits for E, NA and DA were 4.0×10,9, 1.0×10,9 and 8.0×10,10 g/mL. The proposed method has been applied successfully to the analysis of E, NA and DA in human serum samples. [source] Chemiluminescent picture of diphenyleneiodonium-inhibited NADPH oxidase: a bimodal process and its logistic,exponential model-based descriptionLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 4 2007Bonawentura Kochel Abstract A chemiluminescence (CL) study of diphenyleneiodonium-inhibited NADPH oxidase was performed on a cellular system containing neutrophils stimulated by phorbol myristate acetate, indicating a complex bimodal structure of CL processes corresponding to different stages of the inhibition. The complex structure of these processes was described by a superposition of two logistic,exponential (LE) models, characterizing these processes as bimodal ones. To determine the mechanistic foundation of the LE model-described processes, a generalized form of the second-order dynamic system of CL reactions, the solution to which corresponds to the LE model, was constructed. The diphenyleneiodonium effects on neutrophil NADPH oxidase were separated from the total bimodal CL of the whole measurement system by the use of difference CL processes. These difference processes were also found to be bimodal; thus, inhibitor-induced reduction of CL could be described by a second-order dynamic system. The rate constants and initial concentrations in this dynamic system were determined by the least squares method applied to numerical solutions approximating the difference processes. Using interrelations between the parameters of the dynamic system, cooperative effects in the inhibitor reactions with NADPH oxidase were found and described quantitatively. Other evidences of cooperativity were obtained from integral characteristics of the CL reduction process, i.e. dose,response and progress curves, determined by numerical integration of the LE models constituting the superposition. On this basis, it was also possible to detect a specific binding of the inhibitor to the enzyme. Finally, putative reaction mechanisms suggested by the model obtained were considered and compared with those known at present. Copyright © 2007 John Wiley & Sons, Ltd. [source] Gas-phase reactions of Cl atoms with hydrochloroethers: relative rate constants and their correlation with substituents' electronegativitiesJOURNAL OF PHYSICAL ORGANIC CHEMISTRY, Issue 5 2008Pablo R. Dalmasso Abstract Rate constants for the reactions of Cl atoms with CH3OCHCl2 and CH3OCH2CH2Cl were determined at (296,±,2) K and atmospheric pressure using synthetic air as bath gas. Decay rates of these organic compounds were measured relative to the following reference compounds: CH2ClCH2Cl and n -C5H12. Using rate constants of 1.33,×,10,12 and 2.52,×,10,10,cm3,molecule,1,sec,1 for the reaction of Cl atoms with CH2ClCH2Cl and n -C5H12, respectively, the following rate coefficients were derived: k(Cl,+,CH3OCHCl2),=,(1.05,±,0.11),×,10,12 and k(Cl,+,CH3OCH2CH2Cl),=, (1.14,±,0.10),×,10,10, in units of cm3,molecule,1,s,1. The rate constants obtained were compared with previous literature data and a correlation was found between the rate coefficients of some CH3OCHR1R2,+,Cl reactions and ,Electronegativity of CHR1R2. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||