Biolumineszenz und Chemolumineszenz
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Journal of Bioluminescence and Chemiluminescence - published by
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Aktuelle wissenschaftliche Fachartikel der
genannten Journale:
Analysis of 2-propanol in exhaled breath using in situ enrichment and cataluminescence detection
We report a simple gaseous sensor for the sensitive detection of trace 2-propanol in exhaled breath using in situ enrichment and cataluminescence detection method on the surface of nanomaterials. The influences of heating voltage and absorption time on the CTL intensity were discussed, respectively. In the selected conditions, the linear range of 2-propanol concentration is 60-600 ppbv and the detection of limit is 11 ppbv. Moreover, the lifetime and selectivity of the sensor were also investigated. It has the potential to diagnostic volatile organic compounds in human breath. Copyright © 2010 John Wiley & Sons, Ltd
A stopped-flow study of the dual chemiluminescence for the luminol-KIO4-Mn2+ system in strong alkaline solutions
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 [bull]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.
Fluorescence probe enhanced spectrofluorimetric method for the determination of sparfloxacin in tablets and biological fluids
Yttrium-sensitized fluorescence was used to develop a sensitive and simple spectrofluorimetric method for the determination of sparfloxacin. The method is based on the strong fluorescence of sparfloxacin after adding the fluorescence probe yttrium in buffer solution (pH = 8), and various factors influencing fluorescence were investigated. Under optimum conditions, the enhanced fluorescence intensity of the system showed a good linear relationship with the concentration of sparfloxacin over the range 8 × 10-7 to 1.4 × 10-5 mol L-1 with a correlation coefficient of 0.9997. The detection limit (S/N = 3) was determined as 9.01 × 10-8 mol L-1. The mechanism of the sensitizing effect of probe was discussed. This method has been successfully applied for the determination of sparfloxacin in pharmaceuticals, human urine and serum samples; the result obtained was satisfactory. Copyright © 2010 John Wiley & Sons, Ltd.
Spectrofluorimetric determination of folic acid in tablets and urine samples using 1,10-phenanthroline-terbium probe
A new spectrofluorimetric method was reported for the determination of folic acid (FA), based on its quenching effect on the fluorescence intensity of Tb3+-1,10-phenanthroline complex as a fluorescent probe. The quenched fluorescence intensity at an emission wavelength of 545 nm was proportional to the concentration of FA in Tris-HCl buffer solution of pH 6.2. The effects of pH, time, order of addition of reagents, temperature and concentrations of Tb3+, buffer and 1,10-phenanthroline were investigated and optimized. The linear range for the determination of FA was 0.01-1.1 mg/L. The detection limit was 0.003 mg/L and the relative standard deviation for replicated determination of 1 mg/L of folic acid was 1.2%. This method was simple, practical and relatively free from interference effects. It was successfully applied to assess FA in pharmaceutical tablets and urine samples. Copyright © 2010 John Wiley & Sons, Ltd.
Spectrofluorimetric determination of bilirubin in serum samples
A new spectrofluorimetric method was developed for determination of trace amount of bilirubin. Using oxytetracycline-Eu3+ as a fluorescent probe, in the buffer solution of pH = 7.3, bilirubin can reduce remarkably the fluorescence intensity of the oxytetracycline-Eu3+ complex at [lgr] = 612 nm and the reduced fluorescence intensity was in proportion to the concentration of bilirubin. Optimum conditions for the determination of bilirubin were also investigated. The linear range and limit of detection for the determination of bilirubin were 5.0 × 10-7, 3.0 × 10-5 and 7.7 × 10-8 mol L-1, respectively. This method is simple, practical and relatively free of interference from coexisting substances and can be successfully applied to assess bilirubin in serum samples and compared with the modified Jendrassik-Grof method in clinical analysis. The quenching mechanism of the fluorescence intensity in the system is also discussed. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis and luminescence properties of Zn(Cu0.01Cd0.02Mg0.02)S phosphor
To improve the luminescence properties of ZnS?:?Cu, a multi-doped method was used to prepare Zn(Cu0.01Cd0.02Mg0.02)S in this paper. As a new designed semiconductor compound, particular properties of Zn(Cu0.01Cd0.02Mg0.02)S were investigated, especially luminescence intensity and lifetime. Structure and compositions of Zn(Cu0.01Cd0.02Mg0.02)S phosphor were analyzed by XRD and TEM respectively. Luminescence intensity and luminescence lifetime of the prepared Zn(Cu0.01Cd0.02Mg0.02)S phosphor were investigated by luminescence spectrometry. As a result, compared with pure ZnS or doped ZnS phosphors, Zn(Cu0.01Cd0.02Mg0.02)S showed remarkably improved luminescence properties. The optimum ratio of three dopants was obtained for solving luminescence problems. Copyright © 2009 John Wiley & Sons, Ltd.
L-Cysteine capped CdTe-CdS core-shell quantum dots: preparation, characterization and immuno-labeling of HeLa cells
Functionalized CdTe-CdS core-shell quantum dots (QDs) were synthesized in aqueous solution via water-bathing combined hydrothermal method using L-cysteine (L-Cys) as a stabilizer. This method possesses both the advantages of water-bathing and hydrothermal methods for preparing high-quality QDs with markedly reduced synthesis time, and better stability than a lone hydrothermal method. The QDs were characterized by transmission electronic microscopy and powder X-ray diffraction and X-ray photoelectron spectroscopy. The CdTe-CdS QDs with core-shell structure showed both enhanced fluorescence and better photo stability than nude CdTe QDs. After conjugating with antibody rabbit anti-CEACAM8 (CD67), the as-prepared L-Cys capped CdTe-CdS QDs were successfully used as fluorescent probes for the direct immuno-labeling and imaging of HeLa cells. It was indicated that this kind of QD would have application potential in bio-labeling and cell imaging. Copyright © 2009 John Wiley & Sons, Ltd.
A rapid and simple chemiluminescence method for screening levels of inosine and hypoxanthine in non-traumatic chest pain patients
A rapid and simple chemiluminescence method was developed for detection of inosine and hypoxanthine in human plasma. The method utilized a microplate luminometer with direct injectors to automatically dispense reagents during sample analysis. Enzymatic conversions of inosine to hypoxanthine, followed by hypoxanthine to xanthine to uric acid, generated superoxide anion radicals as a useful metabolic by-product. The free radicals react with Pholasin®, a sensitive photoprotein used for chemiluminescence detection, to produce measurable blue-green light. The use of Pholasin® and a chemiluminescence signal enhancer, Adjuvant-KTM, eliminated the need for plasma clean-up steps prior to analysis. The method used 20 [mgr]L of heparinized plasma, with complete analysis of total hypoxanthine levels (inosine is metabolized to hypoxanthine using purine nucleoside phosphorylase) in approximately 3.7 min. The rapid chemiluminescence method demonstrated the capability of differentiating total hypoxanthine levels between healthy individuals, and patients presenting with non-traumatic chest pain and potential acute cardiac ischemia. The results support the potential use of chemiluminescence methodology as a diagnostic tool to rapidly screen for elevated levels of inosine and hypoxanthine in human plasma, potential biomarkers of acute cardiac ischemia.Copyright ©2009 John Wiley & Sons, Ltd.
Sensitive determination of epinephrine in pharmaceutical preparation by flow injection coupled with chemiluminescence detection and mechanism study
A novel, rapid and sensitive method was described for the determination of epinephrine (EP) using flow injection analysis coupled with chemiluminescence (CL) detection, which based on EP enhanced the weak CL emission of luminol-KIO4 system in NaOH solution. Parameters affecting the CL intensity and reproducibility were optimized systematically. Under the optimized experiment conditions, the net CL intensity was proportional to the concentration of EP in the range of 5.0 × 10-8 to 1.5 × 10-6 mol/L with a detection limit of 1.9 × 10-9 mol/L. The relative standard deviation (RSD) was found to be 0.7% for 13 replicate determinations of 3.0 × 10-7 mol/L EP. The applicability of the proposed method was illustrated in the determination of EP in pharmaceutical preparation. The recoveries of EP at different levels in EP hydrochloride injection were between 95.4 and 104.7%. One assay procedure takes only 27 s, and the sampling rate was calculated about to be 130 samples/h. The possible mechanism of the enhanced CL intensity was studied by examining CL spectra and UV-vis spectra. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of concentrating and exposing the bioluminescent bacteria to the non-luminescent allo-bacterial extracellular products on their luminescence
Bioluminescence is a biochemical process occurring in many organisms. Bacterial bioluminescence has been investigated extensively that lead to many applications of such knowledge. Quorum sensing in the bioluminescent bacteria is a chemical signal process to recognize the strength of its own population to start luminescence in harmony. There is a mechanism in these bacteria to also recognize inter-species strength. When there is a higher number of these bacteria, the possibility and frequency of cell-cell physical contact will be high. In this study, the physical proximity was artificially enhanced between cells and the effect on luminescence in the concentrated cells in the normal culture medium and in the presence of other non-bacterial cell-free supernatants was investigated. The role of such physical contact in the quorum sensing in the bioluminescence is not known. Increase in the luminescence of V. fischeri when concentrated shows that the presence of physical proximity facilitates the quorum sensing for their bioluminescence. Copyright © 2009 John Wiley & Sons, Ltd.
Analysis of phenolic compounds in health care products by low-pressure liquid-chromatography with monolithic column and chemiluminescent detection
This paper presents a new application for monolithic columns with low-pressure chromatographic separation using an flow injection analysis configuration with chemiluminescent detection for the determination of a mixture of phenolic compounds: phloroglucinol, 2,4-dihydroxybenzoic acid, salicylic acid, methyl paraben and n-propyl gallate. The procedure consists of the separation of these compounds on a reverse-phase ultra-short monolithic column with pH 3.0 acetate buffer and 5% acetonitrile as carrier phase. The detection is based on a chemiluminescence measurement coming from Ce(IV)-Rhodamine 6G chemistry with the incorporation of two different chemiluminescent chemical conditions in the chromatographic setup in order to enhance the sensitivity for the different phenolic compounds. All separation and detection variables were optimized to propose a determination method. The analysis is performed in 280?s, with the sampling frequency being some 13 h-1. The calibration function is a double reciprocal function obtaining good results within two orders of magnitude. The limits of detection were 8.8 × 10 -8 m (phloroglucinol), 2.7 × 10 -8 m (2,4-dihydroxybenzoic acid); 2.3 × 10 -8 m (salicylic acid); 5.2 × 10 -8 m (methyl paraben) and 4.1 × 10 -6 m (n-propyl gallate), and the relative standard deviations at a medium level of the linear range were 4.4% (phloroglucinol), 2.8% (2,4-dihydroxybenzoic acid), 5.2% (salicylic acid), 3.6% (methyl paraben) and 6.8% (n-propyl gallate). The method was applied and validated satisfactorily for the determination of these compounds in healthcare products, comparing the results against an HPLC reference method. Copyright © 2009 John Wiley & Sons, Ltd.
A dissolved oxygen sensor based on composite fluorinated xerogel doped with platinum porphyrin dye
A new functional fluorinated material taking n-propyltrimethoxysilicane (n-propyl-TriMOS) and 3,3,3-trifluoropropyltrimethoxysilicane (TFP-TriMOS) as precursors was applied to construct a novel dissolved oxygen sensing film. The sensing film was fabricated by dip-coating the functional fluorinated material-doped [meso-tetrakis(pentafluorophenyl) porphyinato] platinum(II) (PtF20TPP) onto a glass slide. The oxygen sensing film exhibited a good linear relationship, fast response time, long stability and high sensitivity to dissolved oxygen. In the developed optical oxygen sensor, an LED and a photodiode were composed to construct a back-detection optical system not needing an optical fiber based on fluorescence intensity detection. The smart optical oxygen sensor based on the PtF20TPP fluorescence quenching possesses the advantages of portability and low cost and can be applied to the dissolved oxygen in situ monitoring in seawater. Copyright © 2009 John Wiley & Sons, Ltd.
Highly sensitive and selective spectrofluorimetric approach for the rapid determination of trace benzo[[agr]]pyrene in drinking water and in solutions leached from disposable paper cups
Based on the excellent band narrowing and background suppressing features of second-derivative constant-energy synchronous spectrofluorimetry with a [Delta] value of 1400 cm-1, the strong fluorescence intensity for benzo[[agr]]pyrene (BaP) obtained in dichloromethane and the use of standard addition method, a highly sensitive and selective approach for the quantitative determination of trace amount of BaP in drinking water has been established in this study. The detection and quantification limits were 0.11 and 0.37 ng L-1, respectively, and the recoveries obtained from spiked Milli-Q water, bottled natural spring water, tank-purified water and tap water at different concentrations, ranged from 86.0 to 104.0%. This method has been applied for the determination of trace BaP in solution leached from disposable paper cups. The experimental results indicated that BaP was leached from paper cups when filled with hot water, but it was not detected when cool (unheated) water was used. Copyright © 2009 John Wiley & Sons, Ltd.
Development of a novel fluorometric assay for nitric oxide utilizing sesamol and its application to analysis of nitric oxide-releasing drugs
Nitric oxide (NO) is related to various physiological effects as well as to numerous diseases caused by accentuation of NO production. Measurement of NO in cells and tissues is difficult as NO readily reacts with other molecules; furthermore, its half-life as a radical is fleeting. Currently, many NO pharmaceuticals are marketed as therapeutic agents for ischemic disease. Consequently, the identification of NO radicals and determination of generation rate from pharmaceuticals is very important when the effect of the medicinal supply is estimated. In this study, we developed a fluorometric assay for NO employing sesamol (3,4-methylenedioxyphenol) as a fluorometric substrate. Sesamol is converted to a fluorescent derivative (ex. 365 nm, em. 447 nm), which is dimmer in the presence of NO. The detection limit of NO with this method is 400 fmol; moreover, NO generated from drugs can be measured. Copyright © 2009 John Wiley & Sons, Ltd.
Spectral study of interaction between poly [acrylamide-(2-methyl acryloxyethyl) dimethyl buthylammonium bromide] and nucleic acids
A polycation, poly[acrylamide-(2-methylacryloxyethyl) dimethyl buthylammonium bromide] [P (AM-DMB)], was synthesized. The interaction between P (AM-DMB) and DNA was studied by spectral methods. Resonance light scattering spectra, FTIR-spectra and UV-spectra were used to study the mechanisms of the interaction. The results indicate that the conformation of the DNA alters during the interaction because the microenvironment of DNA changes. The binding constant K between P (AM-DMB) and DNA is 8.0 × 103 L mol-1. Copyright © 2009 John Wiley & Sons, Ltd.
Free radical scavenging abilities of flavonyl-thiazolidine-2,4-dione compounds
Free radical scavenging activity of flavonyl-thiazolidine-2,4-dione compounds has been evaluated using chemiluminescence, electron spin resonance spectroscopy with 5,5-dimethyl-1-pyrroline-1-oxide as spin trap and DPPH (2,2[prime]-diphenyl-1-picrylhydrazyl) method. The examined compounds exhibited 28-50% scavenging superoxide anion radical (), 16.7-76.7% hydroxyl radical (HO[bull]) and 9-40% DPPH radical. Compounds containing carbonyl group in their structure can be considered as antioxidants with high relevance and great biological importance. Copyright © 2009 John Wiley & Sons, Ltd.
Photo-mechanical effect in luminescent polymeric materials
The photomechanical effect was found for the first time in a polymer composition on the basis of polymethylmethacrylate with embedded molecules of the luminophor dibenzoylmethanate of boron difluoride incapable of undergoing photochemical isomerization, unlike other compounds. A thermal mechanism of photochemical displacement was suggested. Copyright © 2009 John Wiley & Sons, Ltd.
Quantum-dots-based fluoroimmunoassay for the rapid and sensitive detection of avian influenza virus subtype H5N1
The continuous spread of highly pathogenic avian influenza virus (AIV) subtype H5N1 is threatening the poultry industry and human health worldwide. Rapid and sensitive diagnostic methods are required for the H5N1 surveillance. In this study, the fluorescent (FL) probe of CdTe quantum dots (QDs) was designed using covalently linked rabbit anti-AIV H5N1 antibody. Based on these QD-antibody conjugates, a novel sandwich FL-linked immunosorbent assay (sFLISA) was developed for H5N1 viral antigen detection. The sFLISA allowed for H5N1 viral antigen determination in a linear range of 8.0 × 10-3 to 5.1 × 10-1 [mgr]g mL-1 with the limit of detection (LOD) of 1.5 × 10-4 [mgr]g mL-1. In comparison with virus isolation for 103 clinic samples, the sensitivity and specificity of sFLISA were found to be 93.6 and 91.1% respectively. The sFLISA supplied a novel approach to rapid and sensitive detection of AIV subtype H5N1 and showed great potential for biological applications in immunoassays. Copyright © 2009 John Wiley & Sons, Ltd.
Fluorescent salicylaldehyde hydrazone as selective chemosensor for Zn2+ in aqueous ethanol: a ratiometric approach
4-N,N-diethylaminosalicylaldehyde hydrazone Schiff base (1) and its analogues (2-6) were synthesized and characterized by NMR, MS and elemental analysis. Compound 1 exhibited ratiometric fluorescent response to Zn2+ over other metal ions in aqueous ethanol solution with neutral buffer. The complexation ratio, site and constant and the effect of pH value and water fraction on its fluorescent response to Zn2+ were investigated. Copyright © 2009 John Wiley & Sons, Ltd.
An ethyl acetate sensor utilizing cataluminescence on Y2O3 nanoparticles
A cataluminescence (CTL) sensor using Y2O3 nanoparticles as the sensing materials was proposed for the determination of ethyl acetate. This ethyl acetate sensor showed high sensitivity and specificity at the optimal temperature of 264°C. Quantitative analysis was performed at a wavelength of 425 nm. The linear ranges of CTL intensity vs ethyl acetate concentrations were 2.0-250 ppm (r = 0.9965) and 250-6500 ppm (r = 0.9997) with a detection limit (3[sgr]) of 0.5 ppm. There was no response or weak response when foreign substances such as formic acid, n-hexane, toluene, acetic acid, benzene, and formaldehyde passing through the surface of Y2O3 nanoparticles. The sensor had a long lifetime more than 80 h with 3600 ppm ethyl acetate. It had been applied successfully to determine ethyl acetate in artificial air samples. Copyright © 2009 John Wiley & Sons, Ltd.
Chemiluminescence-based detection of gastrointestinal malignancies
Chemiluminescence is an established method for the in vitro serum monitoring of human tumors. Chemiluminescence may have additional utility for the in vivo detection of tumors. During carcinogenesis, tumors change their phenotype and the proteins they express. Specifically, in carcinogenesis of the esophagus and stomach, enzymes that are normally only expressed in the small intestine brush border become ectopically expressed in precancerous and cancerous lesions. Intestinal alkaline phosphatase and lactase are among the small intestine brush border enzymes that are ectopically expressed. We have found that specific chemiluminescent substrates for alkaline phosphatase and lactase may be used for the in situ detection of intestinal alkaline phosphatase and lactase in unprocessed tissue. In this study, we demonstrate that chemiluminescent 1,2-dioxetane substrates may be used for the detection of precancerous and cancerous lesions from the esophagus and stomach. Copyright © 2009 John Wiley & Sons, Ltd.
Determination of rutin by flow injection chemiluminescence method using the reaction of luminol and potassium hexacyanoferrate(III) with the aid of response surface methodology
A novel flow injection chemiluminescence (CL) method for the determination of rutin was reported. The proposed method was based on the enhanced effect of rutin on the chemiluminescence intensity of luminol and potassium hexacyanoferrate(III) reaction in NaOH medium. The variables of reaction system, such as luminol concentration, potassium hexacyanoferrate(III) concentration and NaOH concentration, were optimized with the aid of response surface methodology. For the responses prediction, a second-order polynomial model (SOPM) was applied. The optimal conditions for determination of rutin estimated by the model equation were as follows: NaOH concentration of 0.13 mol/L luminol concentration of 0.94 × 10-6 mol/L, and K3Fe(CN)6 concentration of 1.09 × 10-4 mol/L. The theoretical increased ratio of CL intensity (IRI) predicted and actual IRI for 0.05 mg/L rutin under the above conditions were 99.40 and 99.74%, respectively. The SOPM model proved to be powerful for navigating the design space. Under the above optimum conditions, the increased IRI was linearly related to the concentration of rutin in the range from 0.008 to 0.100 mg/L with the regression equation IRI = 1948.20c + 5.24 (r = 0.9994) and in the range from 0.100 to 1.000 mg/L with the regression equation IRI = 1362.50 c + 61.94 (r = 0.9996). The detection limit (3[sgr]) was of 1.95 × 10-3 mg/L. The sampling frequency of this method was 72/h. The method was used directly to determine rutin in tablets. Copyright © 2009 John Wiley & Sons, Ltd.
Electrochemiluminescence detection of methamphetamine based on a Ru(bpy)32+-doped silica nanoparticles/Nafion composite film modified electrode
An electrochemiluminescence (ECL) approach for methamphetamine determination was developed based on a glassy carbon electrode modified with a Ru(bpy)32+-doped silica nanoparticles/Nafion composite film. The monodispersed nanoparticles, which were about 50 nm in size, were synthesized using the water-in-oil microemulsion method. The ECL results revealed that Ru(bpy)32+ doped in silica nanoparticles retained its original photo- and electrochemical properties. The ECL intensity was found to be proportional to methamphetamine concentration over the range from 1.0 × 10-7 to 1.0 × 10-5 mol L-1, and the detection limit was found to be 2.6 × 10-8 mol L-1. The proposed ECL approach was used to analyze the methamphetamine content in drugs. Copyright © 2009 John Wiley & Sons, Ltd.
Flow injection chemiluminescence determination of 6-mercaptopurine based on a new system of potassium permanganate-thioacetamide-sodium hexametaphosphate
A novel chemiluminescence method for the determination of 6-mercaptopurine was established based on 6-mercaptopurine inhibition of the chemiluminescence emission of potassium permanganate-thioacetamide-sodium hexametaphosphate system. The peak height was proportional to log 6-mercaptopurine concentration in the range 7.0 × 10-10 to 1.0 × 10-7 g/mL and the detection limit was 1.9 × 10-11 g/mL (S/N = 3). The relative standard deviation was 1.5% for the determination of 8.0 × 10-8 g/mL 6-mercaptopurine (n = 11). The proposed sensor was successfully applied to the analysis of 6-mercaptopurine in human serum samples. Copyright © 2009 John Wiley & Sons, Ltd.
Resonance Rayleigh-scattering spectral method for the determination of some aminoglycoside antibiotics using CdTe quantum dots as a probe
A novel method is used for the determination of some aminoglycoside antibiotics (AGs) such as etimicin (ETM), isepamicin (ISP) and amikacin (AMK). It is based on the resonance Rayleigh scattering (RRS) intensities enhanced by AGs-induced CdTe quantum dots aggregation. Under the optimum conditions, the increments in RRS intensity were directly proportional to the concentration of AGs in certain ranges. At the same time, the second-order scattering, the frequency-doubling scattering and the frequency-trebling scattering intensities were also enhanced and their increments were proportional to the concentration of AGs. Among them, the RRS method had the highest sensitivity; the linear ranges and detection limits for ETM, ISP and AMK were 0.085-7.2, 0.0067-1.2, 0.017-6.0 and 0.025, 0.0051, 0.0020 [mgr]g mL-1. This method was applied to the measurement of AGs in human serum and urine with satisfactory results. In addition, the reaction mechanism and the reasons for the enhancement of RRS are discussed using fluorescence, RRS, transmission electron microscope technology and quantum chemistry method. Copyright © 2009 John Wiley & Sons, Ltd.
Determination of protoberberine alkaloids in medicinal plants based on acidic potassium permanganate chemiluminescence system
A simple method was established to determine protoberberine alkaloids in Cortex Phellodendri and Rhizoma Coptidis based on an acidic potassium permanganate chemiluminescence (CL) system. The optimum conditions for the CL reaction between protoberberine alkaloids and potassium permanganate were studied in detail. Under the optimum conditions, the linear response ranges for berberine, palmatine and jatrorrhizine were 0.038-7.27, 0.031-18.1 and 0.012-3.61 [mgr]g/mL with detection limits of 0.005, 0.004 and 0.0007 [mgr]g/mL, respectively. This method was successfully applied to determine the content of protoberberine alkaloids (calculated using berberine as an index) in Cortex Phellodendri and Rhizoma Coptidis. In addition, a possible mechanism of this CL reaction was proposed on the basis of the investigation of CL, UV and fluorescent spectra of protoberberine alkaloids in acidic solution containing potassium permanganate. Copyright © 2009 John Wiley & Sons, Ltd.
Luminescence studies on Ba2ZnSi2O7 : Eu2+ phosphors crystals
A novel blue green-emitting phosphor Ba2ZnSi2O7 : Eu2+ was prepared by combustion synthesis method and an efficient bluish green emission under from ultraviolet to visible light was observed. The emission spectrum shows a single intensive band centered at 503 nm, which corresponds to the 4f65d1 [rarr] 4f7 transition of Eu2+. The excitation spectrum is a broad band extending from 260 to 465 nm, which matches the emission of ultraviolet light-emitting diodes (UV-LEDs). The effect of doped Eu2+ concentration on the emission intensity of Ba2ZnSi2O7 : Eu2+ was also investigated. The result indicates that Ba2ZnSi2O7 : Eu2+ can be potentially useful as a UV radiation-converting phosphor for white light-emitting diodes. Copyright © 2009 John Wiley & Sons, Ltd.
Sensitive determination of gentiopicroside in medicine and bio-fluids using luminol-myoglobin chemiluminescence combined with flow injection technique
A novel chemiluminescence method for the determination of gentiopicroside is presented, which was based on the inhibitory effect of gentiopicroside on the chemiluminescence reaction between luminol and myoglobin in a flow-injection system. The decrement of chemiluminescence intensity was linear with the logarithm of gentiopicroside concentration over the range from 10.0 pg mL-1 to 500.0 ng mL-1 (r2 = 0.9992), with a detection limit of 3.0 pg mL-1 (3[sgr]). At a flow rate of 2.0 mL min-1, a complete analytical process could be performed within 0.5 min, including sampling and washing, with a relative standard deviation of less than 3.0% (n = 5). The proposed procedure was applied successfully in the determination of gentiopicroside in pharmaceutical preparations, human urine and serum without any pretreatment procedure. The possible mechanism of the reaction was also discussed. Copyright © 2009 John Wiley & Sons, Ltd.
G-rich sequence-functionalized polystyrene microsphere-based instantaneous derivatization for the chemiluminescent amplified detection of DNA
Herein, we develop a novel chemiluminescence (CL) approach with high sensitivity and excellent selectivity, by taking advantage of magnetic beads as preconcentration carriers and polystyrene microspheres as an amplification platform. Briefly, a 'sandwich-type' detection strategy is employed in our design, which involves capture probe DNA immobilized on the surface of carboxyl-terminated magnetic beads and multiple biotinylated reporter DNA self-assembled on the surface of streptavidin-modified polystyrene microspheres. The reporter DNA includes a guanine nucleobase-rich (G-rich) sequence domain for the generation of light and an additional tethered nucleic acid domain complementary with the target DNA. The CL signal is obtained via a novel instantaneous derivatization reaction between a specific CL reagent and the guanine nucleobases rich in the target and reporter DNA. As a result, we demonstrate that this DNA assay is reproducible, stable, easy to use, and can sensitively detect femtomolar target DNA related to anthrax lethal factors with excellent differentiation ability for single-base mismatched sequences. Overall, this new CL protocol couples the high sensitivity of CL analysis with effective magnetic separation for discriminating against unwanted constituents such as mismatched sequences, and hence, offers great promise for DNA hybridization analysis. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and luminescence properties of lanthanide complexes with a new tripodal ligands featuring salicylamide arms
A series of luminescent lanthanide complexes with a new tripodal ligand featuring salicylamide arms, 2,2[prime],2[Prime]-nitrilotris(2-furfurylaminoformylphenoxy)triethylamine (L), were synthesized and characterized by elemental analysis, IR and molar conductivity measurements. Photophysical properties of the complexes were studied by means of UV-vis absorption and steady-state luminescence spectroscopy. Excited-state luminescence lifetimes and quantum yield of the complexes were determined. Luminescence studies demonstrated that the tripodal ligand featuring salicylamide arms exhibits a good antennae effect with respect to the Tb(III) and Dy(III) ion due to efficient intersystem crossing and ligand to metal energy transfer. From a more general perspective, this work offers interesting perspectives for the development of efficient luminescent stains and enlarges the arsenal for developing novel luminescent lanthanide complexes of salicylamide derivatives. Copyright © 2009 John Wiley & Sons, Ltd.
Intense visible multicolored luminescence from lanthanide ion-pair codoped NaGdF4 nanocrystals
Lanthanide ion-pair (Eu3+/Tb3+, Dy3+/Tb3+, Sm3+/Tb3+ and Eu3+/Dy3+) codoped NaGdF4 nanocrystals using Ce3+ as the sensitizer were prepared via the polyol method. The nanocrystals with different codoped lanthanide ion-pairs retain their individual optical properties and the combined spectra can be detected using single-wavelength excitation at about 251 nm. The combined spectra intensity ratios can be adjusted through control of the doping ions molar ratios. Excited with a UV lamp at 254 nm, the as-prepared nanocrystals in aqueous solution emit intense visible emissions of different colors. The nanocrystals were coated with SiO2, to make them biocompatible. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis, characterization and fluorescent properties of cerium(III) glutathione complex
The cerium (III) glutathione complex was synthesized by the redox reaction of cerium (IV) with glutathione reduced (GSH) in aqueous solution. The Job-plots indicate an ML (L = GSSG) stoichiometry of the complex. The fluorescent properties of the compound were investigated. The as-prepared complex showed the characteristic maximum emission spectra of Ce(III) at 350 nm ([lgr]ex = 255 nm). The fluorescence results show that the Ce(IV) ions are first reduced to Ce(III), and then form Ce(III) complex after reacting with GSH. The complex was characterized by element analysis and FT-IR spectra; the stability of the complex was analyzed by cyclic voltammeters and DSC-TG as well. Finally, Ce(IV) was successfully employed to determine the concentrations of GSH in the presence of GSSG, in which the fluorescence intensities are proportional to the concentrations of GSH in the range of 1-100 nM with the detection limit of 0.05 nM of GSH, without interference from the presence of GSSG. Copyright © 2009 John Wiley & Sons, Ltd.
Significant improvement in photoluminescence of ZnSe(S) alloyed quantum dots prepared in high pH solution
In this paper, we described a simple approach for aqueous synthesis of highly luminescent ZnSe(S) alloyed quantum dots (QDs) in the presence of 3-mercaptopropionic acid as stabilizers using zinc chloride and NaHSe as precursors. The synthesis conditions were systematically investigated. We observed that the pH value of the Zn precursor solution had significant influence on the optical properties and the structure of the as-prepared ZnSe(S) QDs. The optimal pH value and molar ratio of Zn2+ to HSe- were 12.0 and 25 : 1 respectively. Under the optimal conditions, we prepared highly photoluminescent ZnSe(S) QDs at up to 31% quantum yield (compared with Rhodamine 6G). The characterization of HRTEM and XRD showed that the ZnSe(S) QDs had good monodispersity and nice crystal structure. The fluorescence life time spectra demonstrated that ZnSe(S) QDs had a long lifetime in contrast to fluorescent dyes. Compared with the currently used organometallic approach, our method was 'green', the reaction condition was mild and the as-prepared ZnSe(S) QDs were water-soluble. More importantly, our method was low cost, and was very suitable for large-scale synthesis of highly luminescent ZnSe(S) QDs for the future applications. Copyright © 2009 John Wiley & Sons, Ltd.
Electrochemiluminescence of an electrocatalytic action of etimicin on Tris(2,2[prime]-bipyridyl)ruthenium(II) immobilized in Nafion modified carbon paste electrode
A sensitive electrochemiluminescence (ECL) detection of etimicin at Tris(2,2[prime]-bipyridyl)ruthenium(II) [Ru(bpy)32+]-Nafion modified carbon paste electrodes was developed. The immobilized Ru(bpy)32+ shows good electrochemical and photochemical activities. Electrochemical and electrochemiluminescence characterizations of the modified carbon electrodes were made by means of cyclic voltammetry and electrochemical impendence spectroscopy. The modified electrode showed an electrocatalytic response to the oxidation of etimicin, producing a sensitized ECL signal. The ECL sensor showed a linear response to etimicin in the range of 8.0-160.0 ng mL-1 with a detection limit of 6.7 ng mL-1. This method for etimicin determination possessed good sensitivity and reproducibility with a coefficient of variation of 5.1% (n = 7) at 100 ng mL-1. The ECL sensor showed good selectivity and long-term stability. Its surface could be renewed quickly and reproducibly by a simple polish step. Copyright © 2009 John Wiley & Sons, Ltd.
Resonance scattering spectral detection of ultratrace Hg(II) using herring sperm DNA modified nanogold probe as catalyst
Herring sperm DNA (hsDNA) was used to modify 10 nm nanogold to obtain a resonance scattering (RS) probe (AuhsDNA) for detection of Hg2+. In the presence of salt, Hg2+ interacts with AuhsDNA to form stable Hg2+-hsDNA complexes, and releases nanogold particles to form larger nanogold clusters that can be removed by membrane filtration. The excess AuhsDNA in the filtrate solution exhibits a catalytic effect on the reaction between hydroxylamine (NH2OH) and Cu(II). The excess AuhsDNA decreased with the addition of Hg2+, which led the RS intensity at 602 nm to decrease. The decreased RS intensity ([Dgr]l602 nm) had a linear response to Hg2+ concentration in the range of 0.4-400 nM, with a detection limit of 0.2 nM Hg2+. This RS method was applied for the detection of Hg2+ in water samples, with sensitivity, selectivity and simplicity. Copyright © 2009 John Wiley & Sons, Ltd.
Chemiluminescence and energy transfer mechanism of lanthanide ions in different media based on peroxomonosulfate system
The chemiluminescence (CL) phenomena of lanthanide (Ln) ions and their coordinate complexes in peroxomonosulfate system and the energy transfer mechanism during the process were investigated in this work. A strong and sharp CL signal was yielded when the Eu(III) or Tb(III) solution was added to the peroxymonosulfate solution. The CL intensity was greatly enhanced by 2,6-pyridinedicarboxylic acid (DPA) ligand [maximum enhancement reached when Ln(III):DPA was 1:1] and hexadecyltrimethylammonium chloride micelles. The degree of enhancement of DPA and micelles on Ln(III) CL was related to the fluorescence lifetimes of Ln(III) in different media. According to the ESR spin-trapping experiments of 2,2,6,6-tetramethyl-4-piperidone and the specific quenching experiments of 1,4-diazabicyclo[2.2.2]octane and sodium azide, singlet oxygen was generated though the Ln(III) ion-catalyzed decomposition of peroxymonosulfate. From the comparisons of the fluorescence and CL spectra, lanthanide ions were the luminescence emitter and the ligand DPA absorbed the energy from singlet oxygen and transferred it to Ln(III) ions in the coordinate complexes. Micelles can enhance the CL intensity by improving intermolecular energy transfer efficiencies, removing the quenching effect of water and prolonging the lifetime of singlet oxygen. Copyright © 2009 John Wiley & Sons, Ltd.
Enhancement of chemiluminescence of the KIO4-luminol system by gallic acid, acetaldehyde and Mn2+: application for the determination of catecholamines
Chemiluminescence (CL) from the oxidation of luminol with potassium periodate in strong alkaline solutions was greatly enhanced by the combined effect of gallic acid, acetaldehyde and Mn2+. The CL spectra exhibited only one emission band at 425 nm, indicating 3-aminophthalate as the emitting species. Various scavengers for superoxide anion, hydroxyl radical and singlet oxygen quenched the CL emission very efficiently (74-100%), suggesting the possible involvement of these reactive oxygen species (ROS) in the CL reactions. It is postulated that oxidation of gallic acid and acetaldehyde by periodate catalyzed by Mn2+ generates these ROS, which then react with luminol to enhance the CL emission. We also found that the enhanced CL emission was strongly inhibited by catecholamines, probably because of their effective scavenging of ROS. Based on this observation, a simple, rapid and sensitive new CL method was developed for the determination of catecholamines. The detection limits (3[sigma]) for dopamine, l-dopa, norepinephrine and epinephrine were 0.63, 1.37, 0.56 and 14.3 nmol/L, respectively. The linear range was 1-10 nmol/L; relative standard deviations were 0.71-1.34% for 0.1 µmol/mL catecholamines. This CL method was applied to the determination of catecholamines in pharmaceutical injections with satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd.
The determination of glutamine with flow-injection chemiluminescence detection and mechanism study
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.
Determination of folic acid by high-performance liquid chromatography with direct electrogenerated chemiluminescence reaction
In our present work, it was found that the electrooxidation of folic acid (FA) was accompanied by electrogenerated chemiluminescence (ECL) emission. Out of the four inorganic salts, NaNO3 solution was found to be a suitable supporting electrolyte for the ECL emission of FA. Coupled with high-performance liquid chromatography separation, this simple ECL method was used for post-column determination of FA. Under the optimal conditions, the ECL intensity has a linear relationship with the concentration of FA in the range of 1.0 × 10-7 to 1.0 × 10-5 g/mL and the detection limit was 5 × 10-8 g/mL (signal-to-noise ratio = 3). Application of the present method to the analysis of FA in human urine proved feasible. Copyright © 2009 John Wiley & Sons, Ltd.
Local-field effect on the fluorescence relaxation of Tm3+:LaF3 nanocrystals immersed in liquid medium
Tm3+:LaF3 nanocrystals were synthesized with hydrothermal technique. Local-field effect on the radiative relaxation rate was studied in the system of Tm3+:LaF3 nanocrystals immersed in several liquid media. The fluorescence lifetime was measured. It was found that the fluorescence decay presented the characteristics of second-order exponential decay, for which the contribution from the ions inside the nanocrystal and ions at the interface of the nanocrystal were distinguished. Investigating the experimental results with proposed models, we found that the surface effect had to be eliminated. For rare earth doped LaF3 nanocrystals, real-cavity model well explains the influence of surrounding medium on the fluorescence relaxation rate. Copyright © 2009 John Wiley & Sons, Ltd.
Determination of thiram in natural waters using flow-injection with cerium(IV)-quinine chemiluminescence system
A simple and rapid flow-injection chemiluminescence method has been developed for the determination of dithiocarbamate fungicide thiram based on the chemiluminescence reaction of thiram with ceric sulfate and quinine in aqueous sulfuric acid. The present method allowed the determination of thiram in the concentration range of 7.5-2500 ng/mL and the detection limit (signal-to-noise ratio = 3) was 7.5 ng/mL with sample throughput of 120/h. The relative standard deviation was 2.5% for 10 replicate analyses of 500 ng/mL thiram. The effects of foreign species including various anions and cations present in water at environmentally relevant concentrations and some pesticides were also investigated. The proposed method was applied to determine thiram in spiked natural waters using octadecyl bonded phase silica (C18) cartridges for solid-phase extraction. The recoveries were in the range 99 ± 1 to 104 ± 1%. Copyright © 2009 John Wiley & Sons, Ltd.
Chemiluminescence determination of naproxen based on europium(III)-sensitized KIO4-H2O2 reaction
A simple and sensitive chemiluminescence (CL) method combined with flow injection technique was developed for the determination of naproxen. It was based upon the weak CL signal arising from the reaction of KIO4 with H2O2 being significantly increased by naproxen in the presence of europium(III) ion. The experimental conditions that affected the CL signal were carefully optimized and the CL reaction mechanism was briefly discussed. Under the optimum conditions, the increment of CL intensity was proportional to the concentration of naproxen ranging from 5.0 × 10-8 to 5.0 × 10-6 g/mL. The detection limit was 1 × 10-8 g/mL naproxen and the relative standard deviation for 5.0 × 10-7 g/mL naproxen solution was 2.1% (n = 11). The proposed method was applied to the determination of naproxen in tablets and in spiked human urine samples with satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and luminescent properties of Eu(TTA)3·3H2O nanocrystallines
Nanocrystallines of rare earth complex, Eu(TTA)3·3H2O, were synthesized by the chemical precipitation method and were characterized by elemental analysis, ultraviolet visible absorption spectroscopy (UV-vis), infrared spectroscopy (IR), differential thermal analysis-thermogravimetry (TG-DTA), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The size of the nanocrystallines was tunable by selecting the proper buffer system, which was used to control the pH of the solution. A small polydispersity in particle size ranging from 70 to 250 nm was obtained when ammonia was used. The nanocrystallines showed the characteristic fluorescence of europium ions and energy transfer from the organic ligand to central ions was observed by fluorescence excitation and emission spectroscopy. These nanoparticles of rare earth complexes have potential application in luminescent materials due to their excellent fluorescence properties. Copyright © 2009 John Wiley & Sons, Ltd.
Label-free DNA sensor based on fluorescent cationic polythiophene for the sensitive detection of hepatitis B virus oligonucleotides
Water-soluble fluorescent conjugated polymers can be used as an optical platform in highly sensitive DNA sensors. Here we report a simple label-free DNA sensor using poly(3-alkoxy-4-methylthiophene) to recognize and detect different oligonucleotide targets related to the YMDD gene mutation of hepatitis B virus. The concentration of surfactant Triton X-100, NaCl, the oligonucleotide capture probe and the oligonucleotide hybridization conditions have a great impact on fluorescence intensity. Under the optimum conditions, two types of oligonucleotide targets involving YMDD gene mutation of hepatitis B virus were successfully recognized. Moreover, there was a linear relationship between fluorescence intensity and the concentration of oligonucleotide target. The detection limit of the wild-type hepatitis B virus target is 88 pmol L-1. Copyright © 2009 John Wiley & Sons, Ltd.
Comparison of chemiluminescence from luminol solution and luminol-TiO2 suspension after illumination of a 355 nm pulse laser
Chemiluminescence (CL) from luminol solution and luminol-TiO2 suspension after illumination of a 355 nm pulse laser is compared. Both the CL systems showed the CL spectra with maximum wavelength of 430 nm, suggesting that the emission was from the excite state of 3-aminophthalate ion. The TiO2 photocatalytically induced luminol CL could be separately detected either when the pulse laser power was smaller than 0.15 mJ/pulse or a slit was placed beyond -2-2 mm in the vertical direction of the laser beam. The TiO2 photocatalytically induced luminol CL intensity was linear to the laser power, while that of the 355 nm pulse laser-induced was nonlinear. A log-log plot between the 355 nm pulse laser-induced luminol CL intensity and laser power showed a near-linear regression fit with a slope of 2.11, suggesting that a two-photon absorption process of luminol was present in the 355 nm pulse laser-induced luminol CL. Adsorbed oxygen on the surface of TiO2 seemed to greatly contribute to the photocatalytically induced CL. Copyright © 2009 John Wiley & Sons, Ltd.
Flow injection determination of benzhexol based on its sensitizing effect on the chemiluminescent reaction of Ce(IV)-sulfite
In this paper, a novel chemiluminescent (CL) method for the determination of benzhexol has been developed by combining the flow injection technique and its sensitizing effect on the weak CL reaction between sulfite and acidic cerium(IV). A mechanism for the CL reaction has been proposed on the basis of CL spectra. Under the optimized conditions, the proposed method allows the measurement of benzhexol hydrochloride over the range 0.1-10 µg/mL with a correlation coefficient of 0.9992 (n = 8), a detection limit of 0.02 µg/mL (3[sigma]), and a relative standard deviation for 2.0 µg/mL benzhexol (n = 11) of 1.65%. The utility of this method was demonstrated by determining benzhexol hydrochloride in tablets. Copyright © 2009 John Wiley & Sons, Ltd.
Chemiluminescence enhancement of 1,2-di[3,4,5-tri(3,4,5-trihydroxybenzoyloxy)benzoyloxy] benzene in the presence of quaternary ammonium ions
The chemiluminescence intensity of 1,2-di[3,4,5-tri(3,4,5-trihydroxybenzoyloxy)benzoyloxy] benzene increased in the presence of quaternary ammonium ions, such as acetylcholine chloride, choline chloride or benzyltrimethylammonium chloride. The complex of 1,2-di[3,4,5-tri(3,4,5-trihydroxybenzoyloxy)benzoyloxy] benzene with acetylcholine chloride, choline chloride or benzyltrimethylammonium chloride was investigated by 1H-NMR spectroscopy. The structure of the complex formed from 1,2-di[3,4,5-tri(3,4,5-trihydroxybenzoyloxy)benzoyloxy] benzene with choline chloride was described by an ab initio quantum chemical calculation. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and luminescence properties of a novel blue emitting phosphor NaMgPO4:Eu2+
A novel blue-emitting phosphor of Eu2+-activated NaMgPO4 was prepared by combustion-assisted synthesis. Sodium dihydrogen phosphate and magnesium nitrate were used as the source of Na, P and Mg, respectively. The ratios of magnesium and phosphorus components that were dissolved into the combustion solution were changed from 1:1 to 1:1.3. Their effect on the crystallinities and photoluminescence spectra of the phosphor particles were investigated. The post-heated phosphor particles had a broad excitation wavelength that ranged from 240 to 410 nm. The phosphor particles prepared from the combustion solution with a 1:1.2 ratio of magnesium to phosphorus had maximum emission intensity under ultraviolet excitation. The effect of doped Eu2+ concentration on the emission intensity of NaMgPO4:Eu2+ was also investigated. Copyright © 2009 John Wiley & Sons, Ltd.
Labeling of BSA and imaging of mouse T-lymphocyte as well as mouse spleen tissue by l-glutathione capped CdTe quantum dots
l-glutathione capped highly fluorescent CdTe quantum dots (QDs) were prepared by an aqueous approach and used as fluorescent labels to link albumin bovine serum (BSA) and rat anti-mouse CD4, which was expressed on mouse T-lymphocyte and mouse spleen tissue. The sharp and narrow emission peaks showed that the as-prepared QDs have desirable dispersibility, uniformity and good fluorescence properties. Both CdTe-BSA and CdTe-CD4 conjugates showed an enhancement of fluorescence intensity over that of bare CdTe QDs. The experimental result of gel electrophoresis confirmed the successful conjugation of CdTe-BSA and CdTe-CD4. The fluorescent microscopic images of CdTe-CD4 labeled mouse T-lymphocyte cells and mouse spleen tissue were compared with that obtained from fluorescein isothiocyanate labeling. It was demonstrated that the CdTe QDs-based probe exhibited much better photostability and fluorescence intensity than fluorescein isothiocyanate, showing a good application potential in the immuno-labeling of cells and tissues. Copyright © 2009 John Wiley & Sons, Ltd.
New luminol chemiluminescence reaction using diperiodatoargentate as oxidate for the determination of amikacin sulfate
A new chemiluminescence (CL) reaction between luminol and diperiodatoargentate {K2 [Ag (H2IO6) (OH) 2]} was observed in alkaline medium. The CL intensity could be greatly enhanced by amikacin sulfate. Therefore a new CL method for the determination of amikacin sulfate was built by combining with flow injection technology. A possible mechanism of the CL reaction was proposed via the investigation of the CL kinetic characteristics, the CL spectrum and the UV absorption spectra of some related substance. The concentration range of linear response was 5.1 × 10-8 to 5.1 × 10-6 mol L-1 with a detection limit of 1.9 × 10-8 mol L-1 (3[sigma]). The proposed method had good reproducibility with a relative standard deviation of 2.8% (n = 7) for 5.1 × 10-7 mol L-1 of amikacin sulfate. It was successfully applied to determine amikacin sulfate in serum. Copyright © 2009 John Wiley & Sons, Ltd.
A cataluminescence gas sensor for ammonium sulfide based on Fe3O4-carbon nanotubes composite
In the present work, Fe3O4-carbon nanotubes (CNTs) composite was explored as a sensing material candidate for ammonium sulfide. Intense chemiluminescence emission can be observed during the catalytic oxidation of ammonium sulfide on the surface of Fe3O4-CNTs composite. Based on this phenomenon, a selective and sensitive gas sensor for the determination of ammonium sulfide was demonstrated. Under the optimized conditions, the linear range of cataluminescence intensity vs concentration of ammonium sulfide gas was 1.4-115 µg mL-1 (R = 0.998) with a limit of detection (S/N = 3) of 0.05 µg mL-1. The relative standard deviation (n = 5) for 14.3 µg mL-1 ammonium sulfide was 1.9%. There was no response to common foreign substances, such as sulfur dioxide, toluene, aether, ethanol, acetone, hydrogen sulfide, carbon bisulfide, benzene and ammonia. The proposed sensor was successfully applied for the determination of ammonium sulfide in artificial air samples. Copyright © 2009 John Wiley & Sons, Ltd.
Resonance light scattering study on the interaction between quinidine sulfate and congo red and its analytical application
The interaction between quinidine sulfate (QDS) and congo red (CR) was studied using resonance light scattering (RLS) technique, ultraviolet-visual spectrophotometry and fluorimetry. In weak acidic medium, QDS reacts with CR to form a supermolecular complex which results in the enhanced RLS intensity. Some important interacting parameters, such as the solution acidity and CR concentration, salt effect and addition order of the reagents, were investigated and optimized. Under the optimum conditions, it was found that the enhanced RLS intensity was in proportion to the concentration of QDS in the range 0.2-8.4 µg mL-1. The corresponding detection limit was 12.0 ng mL-1. The results showed that this new method enabled simple, sensitive and rapid determination of QDS and was used for the determination of QDS in urine and simulated huamn serum samples. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis of the long-persistence phosphor CaAl2O4:Eu2+, Dy3+, Nd3+ by combustion method and its luminescent properties
Calcium aluminate phosphor co-doped Eu2+, Dy3+, Nd3+ is prepared by the combustion method. We study systemically the influences of the quantity of mixed Dy3+ ion, the quantity of flux H3BO3, the differences in dispersing methods between magnetic stirring and ultrasonic dispersing and the combustion temperature on the long-persistence phosphor. The analytical results indicate that Dy3+ ion improves the properties of the phosphors CaAl2O4:Eu2+, Nd3+. The appropriate quantity of flux H3BO3 to reduce the forming temperature of the sample was determined. The monoclinic single phase of CaAl2O4 formed at 500°C and remained steady. The calcium aluminate co-doped Eu2+, Dy3+, Nd3+ was synthesized by dispersal of the raw material using the ultrasonic method, and it had better optical properties. Copyright © 2009 John Wiley & Sons, Ltd.
Determination of tannic acid in industrial wastewater based on chemiluminescence system of KIO4-H2O2-Tween40
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(1[Delta]g)O2(1[sum]-g) in the KIO4-H2O2-Tween40 reaction. Tween40 played an important role in enhancing stabilization of the excited oxygen molecular pair O2(1[Delta]g)O2(1[sum]-g) and in increasing CL intensity. Copyright © 2009 John Wiley & Sons, Ltd.
A flow-injection chemiluminescent method for the evaluation of the antioxidant activity of 5[prime]-nucleotides
In the present work, a simple chemiluminescence (CL) method coupled with flow-injection analysis for the evaluation of antioxidant activity of 5[prime]-nucleotides (5[prime]-AMP, 5[prime]-CMP, 5[prime]-GMP, 5[prime]-UMP) was proposed. It is based on inhibition effect of the studied substances on CL emission of luminol-potassium ferricyanide-pyrogallol. Experiments were performed to evaluate the nature of the inhibition by 5[prime]-nucleotides of the CL reaction and their antioxidant activities. Based on the experimental results, it was observed that 5[prime]-nucleotides are available antioxidants that could effectively scavenge superoxide anion free radicals in a concentration-dependent way. This will provide a basis for further development of the use of nucleotides. Copyright © 2009 John Wiley & Sons, Ltd.
NIR fluorescent ytterbium compound for in vivo fluorescence molecular imaging
We have developed a new NIR fluorescent probe based on an ytterbium(III) (E)-1-(pyridin-2-yl-diazenyl)naphthalen-2-ol (PAN) complex. This probe emits near-infrared luminescence derived from the Yb ion through excitation of the PAN moiety with visible light ([lambda]ex = 530 nm, [lambda]em = 975 nm). The results support the possible utility of the probe for in vivo fluorescence molecular imaging. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis of CdSe quantum dots with luminescence in the violet region of the solar spectrum
We have designed a simple, one-step synthesis of CdSe quantum dots with photoluminescence frequencies ranging from the red through to the violet region of the solar spectrum. The photoluminescence peaks have FWHM of 30 nm indicating absorption over a narrow range of wavelengths. The effect of solvent type and solvent boiling point on the physical and photoluminescence properties of the quantum dots has been studied. High boiling point, non-polar solvents shift the photoluminescence peak to longer wavelengths and low boiling point, polar solvents shift the photoluminescence peak to shorter wavelengths. Copyright © 2009 John Wiley & Sons, Ltd.
Combustion synthesis of Na2Sr(PO4)F:Dy3+ white light emitting phosphor
The synthesis, X-ray diffraction, photoluminescence, TGA/DTA and FTIR techniques in Dy3+ activated Na2Sr(PO4)F phosphor are reported in this paper. The prepared phosphor gave blue, yellow and red emission in the visible region of the spectrum at 348 nm excitation. CIE color co-ordinates of Na2Sr(PO4)F:Dy3+ are suitable as white light-emitting phosphors. Copyright © 2009 John Wiley & Sons, Ltd.
Interaction between felodipine and bovine serum albumin: fluorescence quenching study
The fluorescence quenching spectrum of bovine serum albumin (BSA) was investigated in the presence of felodipine (FLD) by spectroscopic methods including fluorescence spectroscopy and UV-Vis absorption spectroscopy. Stern-Volmer quenching was successfully applied and the corresponding thermodynamic parameters, namely enthalpy change ([Delta]H), free energy change ([Delta]G) and entropy change ([Delta]S) at different temperatures (304, 314 and 324 K) were calculated according to the Van't Hoff relation. This revealed that the hydrophobic interaction plays a major role in stabilizing the complex. The fluorescence spectrum of BSA was studied in presence of various concentrations of SDS surfactant. The distance (r) between donor (BSA) and acceptor (FLD) was obtained according to fluorescence resonance energy transfer (FRET). The synchronous fluorescence spectroscopy was used to investigate the effect of FLD on BSA molecule. The result shows that the conformation of BSA was changed in the presence of felodipine. Copyright © 2009 John Wiley & Sons, Ltd.
