Showing papers on "Fluorescence spectrometry published in 2018"
TL;DR: In this paper, different photocatalysts based on commercial ZnO modified by silver photodeposition were prepared in order to remove phenol from drinking wastewater containing phenol in which the almost total phenol removal was achieved after 180min of UV irradiation time.
Abstract: Different photocatalysts based on commercial ZnO modified by silver photodeposition were prepared in this work. The samples were characterized by X-ray fluorescence spectrometry (XRF), specific surface area (SSA), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and UV–vis diffuse reflectance (UV–vis DRS). XRD and XPS showed that Ag/ZnO samples are composed of metallic Ag (Ag0) and ZnO structure was identified. Furthermore, TEM analysis evidenced that the number of silver particles increased with the Ag content. At last, UV–vis DRS results revealed a reflectance band for Ag/ZnO samples, ascribed to the surface plasmon resonance (SPR) absorption of metal silver particles. Commercial ZnO and Ag/ZnO samples were evaluated in the phenol removal under UV light irradiation. It was observed an enhancement of photocatalytic phenol removal from aqueous solutions by silver addition in comparison to commercial ZnO. In particular, the phenol removal increased with the silver content from 0.14 to 0.88 wt%, after this content (i.e 1.28 wt%) the phenol degradation significantly decreased indicating that the optimal Ag content was equal to 0.88 wt%. The influence of the best photocatalyst dosage and the change of the initial phenol concentration in solution were also investigated in this work and the best photocatalytic performance was obtained by using 50 mg L−1 of phenol initial concentration and 0.15 g L−1 of photocatalyst dosage. Finally, the optimized Ag/ZnO photocatalyst was employed for the treatment of a real drinking wastewater containing phenol in which the almost total phenol removal was achieved after 180 min of UV irradiation time.
370 citations
TL;DR: New insight is provided into the potential application of Lu'an GuaPian green tea as a functional food ingredient to regulate postprandial hyperglycemia through inhibition of α-glucosidase/α-amylase by FGs, particularly the mono- and di- glycosides of kaempferol.
Abstract: Green tea may favorably modulate blood glucose homeostasis, and regular consumption of green tea can prevent the development of type 2 diabetes mellitus. In this study, α-glucosidase and α-amylase inhibitory effects of the novel acylated flavonol tetraglycoside (camellikaempferoside C, 1) and 14 other flavone and flavone glycosides (FGs) isolated from Lu'an GuaPian (Camellia sinensis L.O. Kuntze) were evaluated. The kaempferol monoglycoside (15) showed inhibitory activity against α-glucosidase with IC50 at 40.02 ± 4.61 μM, and kaempferol diglycoside (13) showed α-amylase inhibition with IC50 at 0.09 ± 0.02 μM. Further, inhibitory mechanisms of FGs 15 and 13 were studied by molecular docking analysis and fluorescence spectrometry. Molecular docking suggested that FG 15 interacted with α-glucosidase mainly by hydrogen bonding, which was the same interaction force between FG 13 and α-amylase. Intrinsic fluorescence of α-glucosidase and α-amylase was quenched by 15 and 13, respectively, through a static quenching mechanism. The spontaneous formation of 15-α-glucosidase and 13-α-amylase complexes was driven by van der Waals forces and hydrogen bonding. The present study provides new insight into the potential application of Lu'an GuaPian green tea as a functional food ingredient to regulate postprandial hyperglycemia through inhibition of α-glucosidase/α-amylase by FGs, particularly the mono− and di− glycosides of kaempferol.
100 citations
TL;DR: The results indicated that the smaller than 63 μm road dust in Xi'an, in comparison to the element background value of local soil, had higher Cu, Pb, Zn, Cr, Y, Hf and Zr concentrations.
86 citations
TL;DR: In this article, the capacity of lignite as a parent source of humic acids for agricultural applications is appreciated mainly on the base of extractability and ash content, and the results of X-ray photoelectron spectroscopy and fluorescence spectrometry are not commonly used for the investigation of Lignite humic acid, although they may provide relevant information.
85 citations
TL;DR: It is confirmed that HL1 could be used to detect Al3+ ions in real sample by fluorescence spectrometry and Al3- ions in cells by bioimaging and Density-functional theory calculations are in agreement with the proposed mechanism.
79 citations
77 citations
TL;DR: Graphene oxide adsorbents modified with various amino silanes are described for the preconcentration and speciation of trace and ultratrace levels of chromium ions and were successfully applied to the determination of Cr(VI) in water samples.
Abstract: Novel adsorbents are described for the preconcentration of chromium(VI). Graphene oxide (GO) was modified with various amino silanes containing one, two, or three nitrogen atoms in the molecule. These include 3-aminopropyltriethoxysilane (APTES), N-(3-trimethoxysilylpropyl)ethylenediamine (TMSPEDA), and N1-(3-trimethoxysilylpropyl)diethylenetriamine (TMSPDETA). The resulting GO derivatives were characterized by scanning electron microscopy, X-ray photoelectron spectroscopy, and energy-dispersive X-ray fluorescence spectrometry (EDXRF). Adsorption studies show that these GO based sorbents are highly selective for Cr(VI) in the presence of Cr(III) at pH 3.5. Although the amino silanes applied in modification of GO contain different numbers of nitrogen atoms, the maximum adsorption capacities of GO derivatives are very similar (13.3–15.1 mg·g−1). Such results are in accordance with spectroscopy studies which show that the amount of amino silanes attached to GO decreases in the order of APTES > TMSPEDA > TMSPDETA. The APTES-modified GO was applied to selective and sensitive extraction of Cr(VI) ions prior to quantitation by low-power EDXRF using the Cr Kα line. The Cr(VI) ions need not be eluted from the solid adsorbent. The method has a 0.17 ng·mL−1 detection limit, and the recovery is 99.7 ± 2.2% at a spiking level of 10 ng·mL−1. The method was successfully applied to the determination of Cr(VI) in water samples.
74 citations
TL;DR: Interaction thermodynamics between warfarin and Sudlow I binding site of human (HSA) or bovine (BSA) serum albumin have been examined in strictly controlled experimental conditions by means of isothermal titration calorimetry, fluorescence spectrometry (FS) and frontal analysis capillary electrophoresis (FA/CE).
62 citations
TL;DR: Lifetime Cancer Risk values at the actual global seafood consumption rate of 54 g day-1 are above 10-4 for whelks, scallops, dogfish, ray and lemon sole, however, cancer risks are non-negligible.
61 citations
TL;DR: The ability to provide a fast and multielemental analytical response directly from a solid sample makes both laser-induced breakdown spectroscopy (LIBS) and X-ray fluorescence spectrometry (XRF) very versatile tools for plant nutrition diagnosis as mentioned in this paper.
Abstract: The ability to provide a fast and multielemental analytical response directly from a solid sample makes both laser-induced breakdown spectroscopy (LIBS) and X-ray fluorescence spectrometry (XRF) very versatile tools for plant nutrition diagnosis. This review focuses on the main developments and advances in LIBS and XRF in the analysis of plant materials over the last ten years. Fundamental aspects and instrumentation are given for both techniques. The developments in the quantitative analysis of plant leaves are discussed, with special emphasis on the key aspects and challenges concerning field sampling protocols, sample preparation, and calibration strategies. Microchemical imaging applications by LIBS and XRF (including synchrotron radiation) are also presented in a broader selection of plant compartments (e.g., leaves, roots, stems, and seeds). Challenges, expectations and complementarities of LIBS and XRF towards plant nutrition diagnosis are thoroughly discussed.
57 citations
TL;DR: In this article, the authors investigated the mineralogy and geochemistry of the Palaeogene No. 19-2 coal, parting, and host rocks (roof and floor strata) in the Baliancheng mine, Hunchun Coalfield, Jilin Province, northeastern China.
TL;DR: A novel, rapid fluorescent nanosensor detection method based on MIP-QDs for successfully analyzing cyfluthrin (CYF) in fish and sediment samples was established.
TL;DR: In this paper, the authors investigated the petrology, mineralogy, and geochemistry of anthracites and their host rocks from two coal deposits (Hongmao and Luocheng) in Guangxi Province, southern China.
TL;DR: The method was successfully applied in ultratrace element determination and to the speciation of selenium in environmental waters of both anionic and cationic forms of selected metals using graphene nanosheets and cerium nanoparticles.
Abstract: A nanocomposite prepared from graphene nanosheets and cerium nanoparticles (G/CeO2) was applied to the extraction of Se(IV), As(V), As(III), Cu(II) and Pb(II). The structure of G/CeO2 was investigated by scanning electron microscopy, X-ray diffraction and Raman spectroscopy. The optimal pH values for extraction are 4.0 for As(V), 3.0 for Se(IV), and 6.0 for both Cu(II) and Pb(II). The maximum adsorption capacity of G/CeO2 (expressed as mg·g−1) were calculated by the Langmuir model and are found to be 8.4 for As(V), 14.1 for Se(IV), 50.0 for Cu(II) and 75.6 for Pb(II). The sorbent was applied to dispersive solid phase microextraction prior to direct quantitation by energy-dispersive X-ray fluorescence spectrometry without the need for prior elution. The limits of detection (in ng·mL−1 units) are 0.10 for As(V), 0.11 for Se(IV), 0.19 for Cu(II) and 0.21 for Pb(II). The precisions (RSDs) are <4.5%. The accuracy of the method (1 - 4%) was verified by analysis of the certified reference material (CRM 1640a - natural water). The method was successfully applied in ultratrace element determination and to the speciation of selenium in environmental waters.
TL;DR: Second-hand plastic toys sourced in the UK have been analyzed by X-ray fluorescence spectrometry for hazardous elements and Br as a proxy for brominated flame retardants and in eight cases, Cd or Pb exceeded their migration limits as stipulated by the current EU Toy Safety Directive.
Abstract: About 200 second-hand plastic toys sourced in the UK have been analyzed by X-ray fluorescence spectrometry for hazardous elements (As, Ba, Cd, Cr, Hg, Pb, Sb, Se) and Br as a proxy for brominated flame retardants. Each element was detected in >20 toys or components thereof with the exception of As, Hg, and Se, with the frequent occurrence of Br, Cd, and Pb and at maximum concentrations of about 16000, 20000, and 5000 μg g–1, respectively, of greatest concern from a potential exposure perspective. Migration was evaluated on components of 26 toys under simulated stomach conditions (0.07 M HCl) with subsequent analysis by inductively coupled plasma spectrometry. In eight cases, Cd or Pb exceeded their migration limits as stipulated by the current EU Toy Safety Directive (17 and 23 μg g–1, respectively), with Cd released from yellow and red Lego bricks exceeding its limit by 1 order of magnitude. Two further cases were potentially noncompliant based on migratable Cr, with one item also containing >250 μg g–1 ...
TL;DR: In this article, six residual plant materials were tested as adsorbents to remove Pb2+ and Ni2+ ions from water, and it was verified that Pb 2+ ions were more adsorbed than the Ni 2+ ion.
Abstract: In this study, six residual plant materials were tested as adsorbents to remove Pb2+ and Ni2+ ions from water. The influence of variables such as PH, contact time and adsorption isotherms parameters in adsorption process was studied. The assessment of compatibility with cement of the used contaminated adsorbents has also been performed. The concentration of the studied metal ions was determined by dispersive energy x-ray fluorescence spectrometry. In the studies of pH and kinetics, it was verified that Pb2+ ions were more adsorbed than the Ni2+ ions. The highest values for adsorption capacity were found at pH equal to 4.5 for Pb2+, and at pH equal to 5 for Ni2+ .The adsorption kinetics were fitted to the pseudo-second order model for the both metals. The Langmuir isotherm allowed to estimate the adsorption capacity of the materials for mono and bicomponent solutions, which were superior to those observed in literature. A new proposal for the final destination of the used adsorbents contaminated with metal ions, proved to be a viable alternative for its immobilization.
TL;DR: A novel separation and preconcentration procedure was developed for trace cadmium using the C-dots@cytopore composites as SPE sorbent, and the procedure was further validated by analyzing Cadmium in certified reference materials and a series of environmental water samples.
TL;DR: Pb is the heavy metal of greatest concern because of its common occurrence at high concentrations in legacy paints, coupled with a relatively high bioaccessibility and well-documented chronic neurotoxicity and public exposure to Pb in residential areas may arise through direct contact with paint or soil or via the intrusion of contaminated geosolids to the household on shoes or as airborne dust.
TL;DR: In this article, the nano-catalysts for the ODS process were used as nano catalysts and the properties of the prepared catalysts were identified using UV, XRD, FTIR, Raman spectroscopy, HR-TEM, TGA and SBET techniques.
TL;DR: In this paper, a review of the application of different analytical techniques for the determination of metals and metalloids in different categories of dietary supplements is presented. But the focus of this review is on the use of separative techniques in combination with specific detectors.
TL;DR: In this paper, the results showed that the leaching efficiencies of Ag, Ga and Pb reached 84.39%, 80.76% and 70.47%, respectively, at a roasting temperature of 900 °C and with the optimized leaching parameters.
TL;DR: It is pointed out that grafting of IONPs with PC is a viable strategy for improving the uptake and transcytosis of nanoparticles.
Abstract: Two major hurdles in nanomedicine are the limited strategies for synthesizing stealth nanoparticles and the poor efficacy of the nanoparticles in translocating across the blood brain barrier (BBB). Here we examined the uptake and transcytosis of iron oxide nanoparticles (IONPs) grafted with biomimetic phosphorylcholine (PC) brushes in an in vitro BBB model system, and compared them with bare, PEG or PC-PEG mixture grafted IONPs. Hyperspectral imaging indicated IONP co-localization with cells. Quantitative analysis with total reflection X-ray fluorescence spectrometry showed that after 24 h, 78% of PC grafted, 68-69% of PEG or PC-PEG grafted, and 30% of bare IONPs were taken up by the BBB. Transcytosis of IONPs was time-dependent and after 24 h, 16-17% of PC or PC-PEG mixture grafted IONPs had passed the BBB model, significantly more than PEG grafted or bare IONPs. These findings point out that grafting of IONPs with PC is a viable strategy for improving the uptake and transcytosis of nanoparticles.
TL;DR: Alumina supported on graphene oxide (Al2O3/GO) nanocomposite as new nanosorbent in dispersive micro-solid phase extraction (DMSPE) for As(V) and Cr(III) preconcentration is described, which demonstrates selectivity toward arsenates in the presence of arsenites at pH 5 and chromium( III) ions in the absence of chromate anions.
TL;DR: The experiments indicate that this Co(II) complex could strongly bind to CT-DNA via minor groove mechanism and fluorescence spectrometry of BSA with the complex showed that the fluorescence quenching mechanism of B SA was of static type.
Abstract: [C20H17N3O2] and cobalt (II) complex [Co(L2)(MeOH)2].ClO4, (L2 = 4-((E)-1-((2-(((E)-pyridin-2-ylmethylene) amino) phenyl) imino) ethyl) benzene-1, 3-diol) novel Schiff base has been synthesiszed and chracterized by Fourier transform infrared, UV–vis, 1H-NMR spectroscopy, and elemental analysis techniques. The interaction of Co(II) complex with DNA and BSA was investigated by electronic absorption spectroscopy, fluorescence spectroscopy, circular dichroism, and thermal denaturation studies. Our experiments indicate that this complex could strongly bind to CT-DNA via minor groove mechanism. In addition, fluorescence spectrometry of BSA with the complex showed that the fluorescence quenching mechanism of BSA was of static type. The complex exhibited significant in vitro cytotoxicity against three human cancer cell lines (JURKAT, SKOV3, and U87). The molecular docking experiment effectively proved the binding of complex to DNA and BSA. Finally, antibacterial assay over gram-positive and gram-negative pathogen...
TL;DR: In this article, four particle sizes of fly ash PM (PM 10) before the electrostatic precipitator (ESP) in a 600 MW coal-fired power plant were sampled by a Dekati low pressure impactor (DLPI).
Abstract: Particle matter (PM) emitted from coal combustion can cause great harm to human health and the environment. The existence of hazardous trace element arsenic (As) in PM intensifies its toxicity. In this work, four particle sizes of fly ash PM (PM 10) before the electrostatic precipitator (ESP) in a 600 MW coal-fired power plant were sampled by a Dekati low pressure impactor (DLPI). The coal sample, bottom ash, and ash from ESP (ESP ash) were collected simultaneously. Concentrations of total and valent As (As3+ and As5+) in the sample were determined by the inductively coupled plasma-mass spectrometry (ICP-MS) and high performance liquid chromatography (HPLC) coupled with ICP-MS, respectively. The morphological structure and chemical components of the PM surface were characterized by scanning electron microscopy (SEM) and X-ray fluorescence spectrometry (XRF). Results show that the coal used for the power plant is low-sulfur and low-chlorine bituminous coal with 3.851 mg/kg of As. T...
TL;DR: This study compared three geostatistical methods for spatial simulation of soil Copper (Cu) in a peri-urban agriculture area of Wuhan city, China that are sequential Gaussian co-simulation with auxiliary in-situ portable X-ray fluorescence (PXRF) data, and CoSGS with auxiliary ex-site PXRF data and concluded that CoS GS_ex-s situ is slightly better than CoSgs_in-Situ in
TL;DR: In this paper, the degradation processes that take place in bricks exposed to marine environments have been studied, taking into account the importance of this building material where the silicates present in the final product act as stabilizer in the porous material itself, it is necessary to understand the decay processes that occur in these aggressive environments.
TL;DR: In this paper, a simple and straightforward method has been developed to prepare carbon quantum dots (CQDs) with ultrahigh absolute fluorescence quantum yields (96.9%) for the detection of water in organic solvents without any modification.
Abstract: In this study, a simple and straightforward method has been developed to prepare carbon quantum dots (CQDs) with ultrahigh absolute fluorescence quantum yields (96.9%). The fluorescence peak of CQDs remains the same (565 nm) due to their homogeneous surface structure, when the excitation wavelength was changed from 300 nm to 500 nm. It was found that the as-prepared CQDs exhibit excellent fluorescent properties in organic solvents, but could be quenched by water. As a result, the as-prepared CQDs are promising fluorescent probes for the detection of water in organic solvents without any modification. To our knowledge, this is the first time that CQDs have been adopted as water-sensitive fluorescent probes in organic solvents (ethanol, tetrahydrofuran, and 1,4-dioxane) with a limit of detection as low as 0.01% (V/V). What is more, the dynamic quenching mechanism of the CQDs–water system was clarified by UV-vis absorption spectrometry and time-resolved fluorescence spectrometry.
TL;DR: The developed photocatalyst showed a much higher MO photodegradation efficiency than the other composites under visible light irradiation and was recoverable and durable; its photocatalytic efficiency in MO removal was consistently higher than 93.1% after five reuses without any evident signs of deactivation.
TL;DR: A feasibility study of different adsorbent materials, namely residual fish scales biosorbent (FS), mineral dolomite (DL) and commercial resin (CR), in the heavy metals removal in multicomponent solution based on the properties of a real effluent from automotive battery recycling industry is presented in this paper.
Abstract: We present a feasibility study of different adsorbent materials, namely residual fish scales biosorbent (FS), mineral dolomite (DL) and commercial resin (CR) in the heavy metals removal in multicomponent solution based on the properties of a real effluent from automotive battery recycling industry. Considering the effluent complex characteristics, the materials were assessed aiming to provide not only the heavy metals removal, but also the effluent neutralization and lower sludge generation. For this, all the studied materials were physicochemically and morphologically characterized with the aim of understanding the mechanisms involved in the process. Further, the elemental compositions of the solid and liquid phases generated from each treatment process were assessed by X-ray fluorescence spectrometry. The effluent presented highly acidic characteristics and heavy metals above the legislated limits for discharge (Fe, Zn and Pb). Each adsorbent material followed different mechanisms which led to dissimilar removal and neutralization capacities. The CR showed remarkable heavy metals removal capacity governed by an ion exchange mechanism; conversely, it did not show a neutralization effect. In contrast, FS and DL presented lower removal capacities by complex simultaneous phenomena (ion exchange, precipitation and/or complexation), but a great neutralization potential related to leaching of alkaline constituents. When sludge generation is considered as a key factor, mitigation and enhancement of treated effluent quality could alternatively be addressed by employing the materials in hybrid processes. Hence, the associated use of such materials could be viable yet very challenging for both neutralization and removal of heavy metals from the battery effluent.