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1.
In this paper, a sensitive resonance light scattering (RLS) method for the determination of protein is reported. In the Tris–HCl (pH 7.50) buffer, protein enhanced the RLS intensity of the Y3+–2‐thenoyltrifluoroacetone (TTA)–sodium dodecyl sulphate (SLS) system. The enhanced RLS intensities were in proportion to the concentrations of proteins in the range 8.0 × 10?9–1.0 × 10?5 g/mL for BSA, 1.0 × 10–8–1.0 × 10?5 g/mL for HSA and 1.0 × 10–8–1.0 × 10?6 g/mL for EA, and their detection limits were 5.0, 5.4 and 6.7 ng/mL, respectively. Actual samples were satisfactorily determined. The interaction mechanism was also studied. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

2.
The behaviors of 15 kinds of metal ions in the thiol‐capped CdTe quantum dots (QDs)–H2O2 chemiluminescence (CL) reaction were investigated in detail. The results showed that Ag+, Cu2+ and Hg2+ could inhibit CdTe QDs and H2O2 CL reaction. A novel CL method for the selective determination of Ag+, Cu2+ and Hg2+ was developed, based on their inhibition of the reaction of CdTe QDs and H2O2. Under the optimal conditions, good linear relationships were realized between the CL intensity and the logarithm of concentrations of Ag+, Cu2+ and Hg2+. The linear ranges were from 2.0 × 10?6 to 5.0 × 10?8 mol L?1 for Ag+, from 5.0 × 10?6 to 7.0 × 10?8 mol L?1 for Cu2+ and from 2.0 × 10?5 to 1.0 × 10?7 mol L?1 for Hg2+, respectively. The limits of detection (S/N = 3) were 3.0 × 10?8, 4.0 × 10?8 and 6.7 × 10?8 mol L?1 for Ag+, Cu2+ and Hg2+, respectively. A possible mechanism for the inhibition of CdTe QDs and H2O2 CL reaction was also discussed. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

3.
We investigated the effects of zinc or lead on growth and on exudation of fluorescent dissolved organic matter (FDOM) by the marine toxic dinoflagellate Alexandrium catenella (Whedon & Kofoid) Balech. The species was exposed to increasing free zinc (1.34 × 10?7 M–3.98 × 10?6 M) or lead (5.13 × 10?9 M–1.82 × 10?7 M) concentra‐tions. Low metal levels ([Zn2+] = 1.34 × 10?7 M; [Pb2+] = 5.13 × 10?9 M) had no effect on cell growth. Toxic effects were observed from higher metal contamination ([Zn2+] = 3.98 × 10?6 M; [Pb2+] = 6.54 × 10?8 M), as a conversion of vegetative cells into cysts. Analysis of the released FDOM by three‐dimensional (3‐D) fluorescence spectroscopy was achieved, using the parallel factor analysis (PARAFAC). The PARAFAC modeling revealed four components associated with two contributions: one related to the biological activity; the other linked to the organic matter decomposition in the culture medium. The C1 component combined a tryptophan peak and characteristics of humic substances, whereas the C2 component was considered as a tryptophan protein fluorophore. The two others C3 and C4 components were associated with marine organic matter production. Relea‐sed fluorescent substances were induced by low ([Zn2+]= 1.34 × 10?7 M; [Pb2+] = 5.13 × 10?9 M) and moderate ([Zn2+] = 6.21 × 10?7 M; [Pb2+] = 2.64× 10?9 M) metal concentrations, suggesting the activation of cellular mechanisms in response to metal stress, to exudate FDOM that could complex metal cations and reduce their toxicity toward A. catenella cells.  相似文献   

4.
Lili Li  Hui Li  Gang Liu  Shouzhi Pu 《Luminescence》2017,32(8):1473-1481
A new photochromic diarylethene based on benzophenone hydrazone has been synthesized. Its photochromic and fluorescent properties changed upon alternating irradiation with UV /Vis light and adding Cu2+/EDTA in methanol, which showed that the diarylethene could be served as a colorimetric and fluorescent chemosensor for selective detection of Cu2+ based on internal charge transfer processes. The colorimetric and turn‐off fluorescent selective detection of Cu2+ was attributed to the 2:1 complex of the diarylethene and Cu2+. The binding constant (Ka ) was 1.53 × 104 L mol?1 and the limit of detection of the diarylethene for Cu2+ was calculated to be 1.45 × 10?6 mol L?1. In addition, the metal‐responsive photochromic behavior of diarylethene was applied successfully to the construction of a molecular logic circuit.  相似文献   

5.
A chemiluminescent assay composed of TCPO [bis(2,4,6-trichlorophenyl)oxalate] and harmless rhodamine B is proposed to be superior in the determination of menadione-catalyzed hydrogen peroxide (H2O2) production by viable mammalian cells to that composed of TCPO and harmful pyrene [Anal. Biochem. 207 (1992) 255–260]. In tests, the proposed assay showed that the measurable concentration of H2O2 and the viable cell number ranged from 10?9 to 10?3 M and from 2 × 102 to 2 × 106 cells/100 μl/well in the presence of 10% bovine serum, respectively. The measuring time was approximately 10 min. On the other hand, the measurable cell numbers by the colorimetric WST-1 and MTT assays requiring several hours ranged only from 103 to 104 cells/100 μl/well and from 104 to 105 cells/100 μl/well, respectively. The cytotoxicity of sodium dodecyl sulfate was also observed at intervals of 1 min by the proposed assay, but not by the above colorimetric assays.  相似文献   

6.
Based on the strong enhancement effect of procaterol hydrochloride on the electrochemiluminescence (ECL) of Ru(bpy)32+ (bpy = 2,2′‐bipyridine) in an alkaline H3PO4–NaOH buffer solution on a bare Pt electrode, a simple, rapid and sensitive method was developed for the determination of procaterol hydrochloride. The optimum conditions for the enhanced ECL have been developed in detail in this work. Under optimum conditions, the logarithmic ECL enhancement vs. the logarithmic concentration of procaterol hydrochloride is linear over a wide concentration range of 2.0 × 10?7 to 2.0 × 10?4 M (r =  0.9976), with a limit of detection of 1.1 × 10?8 M (S/N =  3), and a relative standard deviation of 2.1% (n =  7, c =  5.0 × 10?6 M). The proposed method was applied to the determination of this drug in tablets with recoveries of 89.7%–98.5%. In addition, a possible mechanism for the enhanced ECL of Ru(bpy)32+, which is caused by ProH, has also been proposed.  相似文献   

7.
This method is based on the enhancing effect of codeine (COD) and paracetamol (PAR) on the chemiluminescence (CL) reaction of Ru(phen)32+ with Ce(IV). In the batch mode, COD gives a relatively sharp peak with the highest CL intensity at 4.0 s, whereas the maximum CL intensity of the PAR appears at ~60 s after injection of Ce(IV) solution. Whole CL time profiles allowed use of the time‐resolved CL data in combination with multiway calibration techniques, as multiway partial least squares (N‐PLS), for the quantitative determination of both COD and PAR in binary mixtures. In this work, we found that the impact of Ce(IV) concentration on the CL intensity was different for COD and PAR. Therefore, a Ce(IV) concentration mode was added to the time and sample modes to obtain 3D data. The percent relative standard deviation (%RSD) values for 10 determinations of 1.0 × 10?5 mol/L of COD and 1.0 × 10?4 mol/L of PAR were 6.1% and 8.7%, respectively. The limit of detection (LOD) values (S/N = 3) were 0.9 × 10?8 mol/L and 1.0 × 10?6 mol/L for COD and PAR, respectively. The proposed method was successfully applied to the determination of PAR and COD in commercial pharmaceutical formulations. Acceptable recoveries (90–110%) were obtained for the quantification of these drugs in the real samples. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

8.
A highly sensitive and selective resonance scattering spectral assay was proposed for the determination of horseradish peroxidase (HRP), based on its catalytic effect on the H2O2 oxidation of KI to form I3?. The I3? combined respectively with rhodamine (Rh) dye such as rhodamine S (RhS), rhodamine 6G (Rh6G), rhodamine B (RhB) and butyl‐rhodamine B (b‐RhB), to form association particles (Rh‐I3)n. The four Rh systems all exhibit a stronger resonance scattering (RS) peak at 424 nm. For the RhS, Rh6G, RhB and b‐RhB systems, HRP concentration in the range of 3.2 × 10?12 to 4.8 × 10?9, 2 × 10?11 to 3.2 × 10?9, 1.6 × 10?11 to 3.2 × 10?9 and 1.6 × 10?11 to 4 × 10?9 g/mL was linear to its RS intensity at 424 nm, with a detection limit of 2.2 × 10?12, 2.5 × 10?12, 4.4 × 10?12 and 2.6 × 10?12 g/mL, respectively. This RhS system was most sensitive and stable, and was applied for the determination of HRP in the hepatitis B surface antibody labeling HRP and water samples, with satisfactory results. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

9.
A new sensitive quaternary photoluminescence enhancement system has been successfully developed to determine trace amounts of Eu3+ and Zn2+. The photoluminescence intensity of Eu ? N‐(o‐vanilin)‐1,8‐diaminonaphthalene systems was greatly increased by the addition of specific concentrations of 1, 10‐phenanthroline and Zn2+. The excitation and emission wavelengths were 274 and 617 nm, respectively. Under optimal system conditions, the photoluminescence intensity showed a linear response toward Eu3+ in the range of 5.0 × 10–6 ~ 2.0 × 10–5 M with a limit of detection (= 2.2 × 10–9 M) and the photoluminescence intensity of the system decreased linearly by increasing the Zn2+ concentration in the range of 5.0 × 10–8 ~ 1.0 × 10–6 M with a limit of detection (= 8.8 × 10–11 M). This system was successfully applied for the determination of trace amounts of Eu3+ in a high purity La2O3 matrix and in the synthetic rare earth oxide mixture, and of Zn2+ in a high purity Mg(NO3)2 · 6H2O matrix and in synthetic coexisting ionic matrixes. The energy transfer mechanism, photoluminescence enhancement of the system and interference of other lanthanide ions and common coexisting ions were also studied in detail. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

10.
A terbium‐sensitized spectrofluorimetric method has been developed for determination of catecholamines such as norepinephrine (NE), epinephrine (EP) and dopamine (DA), using sodium dodecyl benzene sulphonate (SDBS). Fluorescence sensitization of terbium ions (Tb3+) by complexation with catecholamines in the presence of SDBS was observed. The fluorescence intensities of the Tb3+–catecholamine complexes were highly enhanced by introducing SDBS with an emission maximum at 545 nm after excitation at 290 nm. The conditions for the complex formation of Tb3+–catecholamine were investigated systematically and optimized to determine catecholamines in a serum sample. Under the optimum conditions, the fluorescence intensities of the Tb3+–catecholamine complexes were increased linearly with the concentration of NE, EP and DA over the ranges 2.5 × 10–10–1.0 × 10–8, 2.5 × 10–10–1.0 × 10–8 and 2.5 × 10–9–1.0 × 10–7 g/mL with correlation coefficients of 0.999, 0.999 and 0.9996, respectively. The limits of detection (3δ) of NE, EP and DA were found to be 4.6 × 10–11, 7.8 × 10–11 and 8.38 × 10–10 g/mL, respectively. Precision of the method was tested at the concentration level of 1.2 × 10?7 g/mL for five replicate measurements of NE, EP and DA, giving relative standard deviations (RSDs) of 1.41%, 1.23% and 1.89%, respectively. The interaction mechanism of the Tb3+–catecholamine complexes system was investigated and presented with ultraviolet absorption spectra. The proposed method has been applied for the quantitative determination of NE, EP and DA in a spiked serum sample and a pharmaceutical preparation sample. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

11.
Nucleic acid can greatly enhance the fluorescence intensity of quercetin in HMTA‐HCl (pH 5.5) buffer. The enhanced intensity is in proportion to the concentration of nucleic acids in the range 5.0 × 10?9 to 1.0 × 10?6 g/mL for fsDNA, 5.0 × 10?9 to 7.0 × 10?7 g/mL for ctDNA and 5.0 × 10?9 to 1.0 × 10?6 g/mL for yRNA, and their detection limits (S/N = 3) are 3.5 × 10?9, 7.8 × 10?10 and 2.6 × 10?9 g/mL, respectively. In comparison with most reported fluorescent probes for the determination of nucleic acids, the proposed probe has higher sensitivity and lower toxicity. The interaction investigation indicates that quercetin binds with double‐strand DNA in groove binding mode, resulting in fluorescence enhancement of this system. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

12.
In this paper, a novel fluorescent sensor 1 for selective and sensitive detection of cysteine was developed based on a complex between bi‐8‐carboxamidoquinoline derivative ligand ( L ) and Cu2+. The interaction of Cu2+ with the ligand causes a dramatic fluorescence quenching most likely due to its high affinity towards Cu2+ and a ligand–metal charge transfer (LMCT) process. The in situ generated L–Cu 2 complex was utilized as a chemosensing ensemble for cysteine. In the presence of cysteine, the fluorophore, L , was released from L–Cu 2 complex because of the strong affinity of cysteine to Cu2+ via the Cu–S bond, leading to the fluorescence recovery of the ligand. The proposed displacement mechanism was confirmed by the results of mass spectrometry (MS) study. Under optimized conditions, the recovered fluorescence intensity is linear with cysteine concentrations in the range 1 × 10?6 mol/l to 8 × 10?6 mol/l. The detection limit for cysteine is 1.92 × 10?7 mol/l. Furthermore, the established method showed a highly sensitive and selective response to cysteine among the 20 fundamental α‐amino acids used as the building blocks of proteins, after Ni2+ was used as a masking agent to eliminate the interference of His. The proposed sensor is applicable in monitoring cysteine in practical samples with good recovery rate.  相似文献   

13.
The population parameters of stargazer (Uranoscopus scaber Linnaeus, 1758) were studied regarding age composition, sex ratio, growth, survival and mortality rates, and the exploitation rate in the southeastern Black Sea near the coast of Turkey during the 2011–2012 fishing season. According to ageing analysis of the samples, age group 1 is the most abundant (47.76%), followed by age 2 (41.04%), age 3 (9.33%), age 0 (1.12%) and age 4 (0.75%). Mean totals as well as total lengths and weights for males and females were 14.5 ± 0.22 cm and 12.9 ± 0.19 g, 16.6 ± 0.24 cm and 62.1 ± 2.76 g, and 37.2 ± 1.92 cm and 87.1 ± 3.88 g, respectively. The mean condition factor was K = 0.0167, while the sex ratio was 53.98% female, 38.75% male and 7.27% immature. Length‐weight, age‐length and age‐weight equations were W = 0.014 × L3.059, L(t)=44.5*[1?e?0.148*(t +1.242)] and W(t)=1544.4*[1?e?0.148*(t + 1.242)]3.059, respectively. The computed survival rate (S), instantaneous total mortality rate (Z), annual mortality rate (A), natural mortality rate (M) and fishing mortality rate (F) were S = 28.94%, Z = 1.24 year?1, A = 71.06%, M = 0.26 year?1 and F = 0.98 year?1, respectively. The exploitation rate was 0.79, which is above the optimum exploitation levels.  相似文献   

14.
A sensitive and selective fluorimetric sensor for the assay of ascorbic acid (AA) using silver nanoparticles as emission reagent was investigated. In this study, silver nanoparticles were prepared based on aqueous–gaseous phase reaction of silver nitrate solution and ammonia gas. The nanoparticles were water‐soluble, stable and had a narrow emission band. They were used as a fluorescence probe for the assay of ascorbic acid on its quenching effect on the emission of silver nanoparticles. The principal reason for quenching is likely to be a complexation between ascorbic acid and silver nanoparticles. The quenching mechanism was established by Stern–Volmer law. Under the optimum conditions, the quenched fluorescence intensity was linear with the concentration of ascorbic acid in the range of 4.1 × 10?6 to 1.0 ×10?4 m (= 0.9985) with a detection limit of 1.0 × 10?7 m . The RSD for repeatability of the sensor for the assay of ascorbic acid concentration of 3.0 × 10?5 and 4.0 × 10?6 m was found to be 1.5 and 1.3%, respectively. The proposed method was applied to the determination of ascorbic acid in vegetables and vitamin C tablets. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

15.
Dichlorodiphenyltrichloroethane (DDT), hexachlorocyclohexane (HCH), and their isomers’ levels in residential soils were determined for the assessment of health risk in Korba, India. Observed concentrations of total HCH and total DDT in soils were more or less comparable with other parts of India and the world. ΣHCH and ΣDDT concentrations ranged between 0.9–20 μg kg?1 and 2–315 μg kg?1, respectively, which were lower than recommended soil quality guidelines indicating low ecotoxicological risk. Carcinogenic and non-carcinogenic impacts of HCH and DDT on human populations through soil ingestion were evaluated and presented. The incremental lifetime cancer risk (ILCR) for adults and children ranged between 7.8 × 10?10–1.6 × 10?7 and 4.1 × 10?9–8.2 × 10?7, respectively. Non-cancer health hazard quotient (HQ) ranged between 5.9 × 10?7–1.8 × 10?3 and 3.1 × 10?6–9.4 × 10?3, respectively, for adults and children. The estimated ILCR and HQ were within the safe acceptable limits of 10?6–10?4 and ≤1.0, respectively, indicating low risk to human populations from exposure to organochlorine pesticides (HCH and DDT) in the study area.  相似文献   

16.
The viral and bacterioplankton communities of the Barents Sea were investigated using a combination of methods of electron and epifluorescence microscopy for the first time. The quantitative composition of the communities and the nature of their interactions were also determined. Our study showed that during the summer the abundance and biomass of bacterioplankton reached 0.4–4.0 × 106 cells/mL and 25.09–84.21 mg/m3 in offshore waters and 0.4–1.8 × 106 cells/mL and 19.63–100.19 mg/m3 in coastal waters, respectively. In both regions, the number of viruses (1.7–35.8 × 106 and 14.5–32.4 × 106 particles/mL) exceeded the number of bacteria by 2–31 and 13–60 times, respectively; the average viral production was 0.75106 and 1.74 × 106 particles/mL/day, respectively. The proportion of infected cells in the total bacterioplankton (7% on average) and virus-induced mortality of bacteria (8%) were much lower in offshore than in coastal waters (14 and 20%, respectively).  相似文献   

17.
Abstract

Impact of root Cd concentration on production of cysteine, non-protein thiols (NP-SH), glutathione (GSH), reduced glutathione (GSSG), and phytochelatins (PCs) in Eichhornia crassipes exposed to different dilutions of brass and electroplating industry effluent (25%, 50%, and 75%), and synthetic metal solutions of Cd alone (1, 2.5, and 3.5?ppm) and with Cr (1?ppm Cd + 1?ppm Cr, 2.5?ppm Cd + 3?ppm Cr, and 3.5?ppm Cd + 4?ppm Cr) was assessed in a 45?days study. Different treatments were used to understand and compare differential antioxidant defense response of plant under practical drainage (effluent) and experimental synthetic solutions. The production of NP-SH and cysteine was maximum under 2.5?ppm Cd + 3?ppm Cr treatments i.e., 1.78?µmol/g fw and 288?nmol/g fw, respectively. The content of GSH declined whereas that of GSSG increased progressively with exposure duration in all treatments. HPLC chromatograms revealed that the concentrations of PC2, PC3, and PC4 (248, 250, and 288?nmol-SH equiv.g?1 fw, respectively) were maximum under 1?ppm Cd, 1?ppm Cd + 1?ppm Cr, and 2.5?ppm Cd + 3?ppm Cr treatments, respectively. PC2, PC3, and PC4 concentrations increased with Cd accumulation in the range 812–1354?µg/g dry wt, 1354–2032?µg/g dry wt and 2032–3200?µg/g dry wt, respectively. Thus, the study establishes a direct proportionality relationship between concentration/length of phytochelatins and root Cd concentrations, upto threshold limits, in E. crassipes.  相似文献   

18.
Background aimsThe ability of hematopoietic progenitor cells–apheresis (HPC-A) that have been stored for many years after cryopreservation to reconstitute hematopoiesis following high-dose chemo/radiotherapy has not been well-documented.MethodsIn this retrospective study, eight Canadian centers contributed data from 53 autologous stem cell transplants (ASCT) performed using HPC-A that had undergone long-term storage (>2 years, range 2–7 years) and 120 ASCT using HPC-A stored for <6 months (short-term storage).ResultsThe doses of nucleated and CD34+ cells per kilogram recipient weight were similar between the short- (mean ± SD, 4.7 ± 4.9 × 108 and 6.8 ± 4.3 × 106, respectively) and long- (4.0 ± 4.9 × 108 and 6.1 ± 3.4 × 106, respectively) term storage groups. The median days to neutrophils (absolute neutrophil count; ANC) >0.5 × 109/L (median 11 days for both short- and long-term storage) and platelets >20 × 109/L (median 12 and 11 for short- and long-term storage, respectively) post-ASCT were not significantly different between the two groups. When ASCT performed with <5 × 106/kg CD34+ cells was compared there was also no difference in ANC or platelet recovery (median 12 days for both after short-term storage, and 12 and 11 days, respectively, after long-term storage). Fourteen HPC-A products stored for >5 years also showed similar count recoveries as the entire long-term storage group (median 11 days for both ANC and platelets).ConclusionsCryopreserved HPC-A can be stored for at least 5 years with no apparent loss in their ability to support hematopoietic reconstitution after high-dose chemotherapy.  相似文献   

19.
Ultra‐weak chemiluminescence (CL) from the reaction of iodide and KMnO4 was strongly enhanced by carbon nanodots (CNDs) in an acidic medium. The CL intensity was directly proportional to the concentration of iodide in the solution. Therefore, a flow‐injection CL system with high sensitivity, selectivity and reproducibility is proposed for the determination of iodide. The proposed method exhibited advantages over a linear range of 3.0 × 10?6–1.0 × 10?4 mol/L and had a detection limit of 3.5 × 10?7 mol/L. The method was successfully applied to the evaluation of iodide in food samples with recoveries of between 96 and 103%. The relative standard deviations were 2.1 and 4.1% for intra‐ and inter‐assay precision, respectively.  相似文献   

20.
Bicyclic dioxetanes 2a–c bearing a 2′‐alkoxy‐2‐hydroxy‐1,1′‐binaphthyl‐7‐yl moiety were effectively synthesized and their base‐induced chemiluminescent decomposition was investigated by the use of alkaline metal (Na+ and K+) or Mg2+ alkoxide in MeOH. When 2a–c were treated with tetrabutylammonium fluoride (TBAF) in dimethyl sulfoxide (DMSO) as a reference system, they showed chemiluminescence as a flash of orange light (maximum wavelength λmaxCL = 573–577 nm) with efficiency ΦCL = 6–8 × 10–2. On the other hand, for an alkaline metal (Na+ or K+) alkoxide/MeOH system, 2a–c decomposed slowly to emit a glow of chemiluminescence, the spectra of which were shifted slightly toward red from the TBAF/DMSO system, and ΦCL (= 1.4–2.3 × 10–3) was considerably decreased. In addition, Mg(OMe)2 was found to play a characteristic role as a base for the chemiluminescent decomposition of 2a–c through coordination to the intermediary oxidoaryl‐substituted dioxetanes 13. Thus, Mg2+ increased ΦCL to more than twice those with Na+ or K+, while it shifted λmaxCL considerably toward blue (λmaxCL = 550–566 nm). Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

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