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Although there is increasing concern about residues from personal care products entering the aquatic environment and their
potential to accumulate to levels that pose a health threat to humans and wildlife, we still know little about the extent
and magnitude of their presence in the aquatic environment. In this study we describe a procedure for isolation, and subsequent
determination, of compounds commonly added to personal care products. The compounds of interest include UV filters with the
commercial name Eusolex (homosalate, 4-methylbenzylidenecamphor, benzophenone-3, octocrylene, butylmethoxydibenzoylmethane,
ethylhexyl methoxycinnamate) and two common anti-microbial agents, clorophene and triclosan. Water samples were filtered,
acidified, and extracted by use of solid-phase extraction. Extracted compounds were then derivatised before analysis by gas
chromatography–mass spectroscopy. By use of our method we obtained limits of detection of 13–266 ng L−1 for UV filters, and 10–186 ng L−1 for triclosan and clorophene. Recoveries were 82–98% for deionised water and 50–98% for natural water (seawater, pool water,
lake water, and river water). Samples collected in Slovenia included seventeen recreational waters (seawater, pool water,
lake water, and river water; August 2004) and four wastewaters (January 2005). The most abundant UV filter was benzophenone-3
(11–400 ng L−1). Of the two anti-microbial agents studied, trace amounts, only, of triclosan were present in the river Kolpa (68 ng L−1) and in an hospital effluent (122 ng L−1). 相似文献
4.
In this study, a method for the determination of organic micro-pollutants, i.e. personal care products such as synthetic musk
fragrances, household bactericides, organophosphate flame retardants and plasticizers, as well as phthalates in sludge, has
been developed. This method is based on lyophilisation and accelerated solvent extraction followed by clean-up steps, i.e.
solid phase extraction and size exclusion chromatography. The determination is performed by gas chromatography coupled to
mass spectrometry. Stable isotope-labelled compounds such as musk xylene (MX D15), tri-n-butylphosphate (TnBP D27) and triphenylphosphate (TPP D15) were used as internal standards. Recovery rates were determined to be 36–114% (with typical relative standard deviation
of 5% to 23%) for the target compounds. The limit of detection was 3–30 ng g−1, and the limit of quantification was 10–100 ng g−1 dry matter. 相似文献
5.
Graziele P. Ramos Paula M. B. Dias Cláudia B. Morais Pedro E. Fröehlich Miguel Dall’Agnol José A. S. Zuanazzi 《Chromatographia》2008,67(1-2):125-129
Red clover (Trifolium pratense L.) is an important forage plant that contains the isoflavones daidzein, genistein, formononetin, and biochanin A. These
compounds have been studied lately due to their human health benefits. The aim of this study was to develop and validate an
HPLC method with simplified sample preparation to quantify daidzein, genistein, formononetin and biochanin A simultaneously
in red clover leaves. The validation showed that the method is specific, accurate, precise and robust, not to mention that
the sample preparation is easier and faster than those described earlier. The response was linear over a range of 0.01–0.2 μg mL−1 for daidzein, 0.05–0.5 μg mL−1 for genistein, 4–40 μg mL−1 for formononetin and 2–20 μg mL−1 for biochanin A. The range of recoveries was 85.6–101.0%. The RSD for intra- and inter-day precision were <2.54 and <7.22%,
respectively. Five populations of red clover, from the National Plant Germplasm System-USDA were analyzed and the content
of daidzein, genistein, formononetin and biochanin A ranged from 7.87–91.31, 51.60–131.30, 6568.33–23461.82, to 2499.55–10337.33 μg g−1 of dried material, respectively. 相似文献
6.
N. V. Podberezskaya S. A. Magarill N. V. Pervukhina I. G. Vasilieva S. V. Borisov 《Journal of Structural Chemistry》1996,37(6):963-985
The structures of rare earth dichalcogenides are investigated. The symmetry and unit cell parameters are considered, and their
relationship with those of the PbFCl and anti-Cu2Sb structural prototypes is analyzed. The interatomic distances in the Ln3+, X2−, and (X2)2− layers and the compatibility factors are examined. It is discussed how the degree of polymerization of the chalcogen ions
in the (X2)2− layers and the compatibility of the latter with the Ln3+ and X2− layers affect the symmetry and the twinning and polymorhism abilities of the compounds.
Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 6, pp. 1140–1170, November–December, 1996.
Translated by L. Smolina 相似文献
7.
Abu B. Kanu Bharath S. Kumar Herbert H. Hill 《International Journal for Ion Mobility Spectrometry》2012,15(1):9-20
The comparison of nanospray and microspray ionizations for detecting mixtures of compounds by ion mobility spectrometry has
been investigated for sensitivity, ion transmission through a drift tube, and ion suppression effects when used as an ionization
source for ambient pressure ion mobility spectrometry (IMS). Several articles have demonstrated that nano-electrospray ionization
mass spectrometry (n-ESI-MS) has improved sensitivity, provides less background noise, and lower limits of detection than
micro-electrospray ionization (μ-ESI) for IMS. Most importantly, data from n-ESI-MS is concentration-sensitive. Our laboratory
previously published an article that observed a striking result when μ-ESI-IMS was investigated for a single compound in the
positive ion mode. The data reported was mass-sensitive. In this new investigation, we have investigated mixtures, and experiments
were designed to evaluate the effect of sensitivity, ion transmission and ion suppressions in μ-ESI-IMS and n-ESI-IMS. At
an electrospray flow rate in the μL min−1 range, compounds with higher proton affinities responded best while at the nanospray flow rates of nL min−1, relative responses were more equal. This study observed that a decreased ESI flow rate resulted in a decreased ion signal.
These trends demonstrated less sensitivity for ESI-IMS at reduced flow rates but suggest better quantification. At higher
flow rates, relative ionization efficiencies were still uniform for all the components studied individually and in mixtures
and sensitivity improved by about 78%. Concentration studies showed that at high concentrations, ion detection efficiencies
were uniform at about 33% for all compounds studied individually and in mixtures. At low concentrations, the detection efficiency
varied from 31% to 86%, depending on the proton affinity of the component in the mixture. Ion transmission through the IMS
tube measured with a segmented Faraday detector that was incorporated into the IMS design indicated that most of the ion current
for mixtures was transported through the IMS tube with a radius of less than 18 mm for both positive and negative ion modes. 相似文献
8.
L. S. Khaikin O. E. Grikina B. V. Lokshin K. P. Dyugaev A. M. Astakhov 《Russian Chemical Bulletin》2008,57(3):499-505
The IR (4000–50 cm−1) and Raman (3500–170 cm−1) spectra of solid 1,1,3,3-tetramethyl-2-nitroguanidine (TMNG) were obtained. The spectra were interpreted using the scaling
of the TMNG quantum-chemical force field in the B3LYP/6-311G(d,p) approximation. Transferable scale factors necessary for
the interpretation of spectra of more complex related compounds were determined. The scaled harmonic force field is supposed
to be used in the analysis of the available gas-phase electron diffraction data for TMNG.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 495–498, March, 2008. 相似文献
9.
Thermogravimetric characteristics and kinetic of co-pyrolysis of olive residue with high density polyethylene 总被引:1,自引:1,他引:0
A. Aboulkas K. El Harfi M. Nadifiyine A. El Bouadili 《Journal of Thermal Analysis and Calorimetry》2008,91(3):737-743
The co-pyrolytic behaviour of olive residue/high-desity polyethylene mixture was examined with a thermogravimetric analyser.
The experiments were done over the temperature range of room temperature to 1273 K at various heating rates (2, 10, 20 and
50 K min−1) and in a nitrogen atmosphere.
The results indicated that mass loss process of mixture consists of three distinct stages and the increase of the heating
rate shifts in the maximum rate loss to higher temperature. The difference of mass loss (Δm) between experimental and theoretical, calculated as algebraic sums of the mixture for different heating rates of 2, 10,
20 and 50 K min−1, is about 7–11% at 740–900 K. These experimental results indicate a significant synergistic effect during co-pyrolysis of
olive residue with high-density polyethylene. In addition, a kinetic analysis was performed to fit thermogravimetric data,
the mixture is considered as multi-stage process. A reasonable fit to the experimental data was obtained for all materials
and their mixture by isoconversional Friedman method. 相似文献
10.
Du F Luo X Jiang G Hou S Liu G Ren L Zhang L Huang Q Jie N 《Analytical and bioanalytical chemistry》2007,388(2):489-493
Analysis of triadimenol was carried out using deoxyribonucleic acids (DNA) via the resonance light scattering (RLS) technique.
After adding triadimenol into aqueous medium of pH 1.72, the RLS of DNA was remarkably quenched. A resonance light scattering
peak at 310 nm was found, and the quenched intensity of RLS at this wavelength was proportional to the concentration of triadimenol.
The linear range of the calibration curve was approximately 0–3 μg mL−1 with a detection limit (S/N = 3) of 0.07 μg mL−1. The triadimenol in samples of water, cucumber and human serum was determined. The results were satisfactory, and the recovery
rates were in the range of 96.3–106.0%, 94.8–105.9% and 92.3–100.5%, respectively. The interaction mechanism was also studied. 相似文献
11.
R. F. Vasil’ev V. D. Kancheva G. F. Fedorova D. I. Batovska A. V. Trofimov 《Kinetics and Catalysis》2010,51(4):507-515
Six antioxidants from the class of chalcones (ArOH), compounds from which flavonoids are obtained in nature, were studied.
The antiradical activity of chalcones and a number of related compounds was determined by a chemiluminescence method using
the scavenging of peroxide radicals ROO· + ArOH → ROOH + OAr· (with the rate constant k
7) in a model reaction of diphenylmethane (RH) oxidation. The structures and energies of the reagents and intermediates were
determined by semiempirical quantum chemical (PM3, PM6) calculations. 3,4-Dihydroxychalcone and caffeic acid, which have a
catechol structure, that is, two neighboring OH groups in phenyl ring B, exhibited high antioxidant activity (k
7 ≈ 107 l mol−1 s−1); this is consistent with the lowest bond strengths D(ArO-H) of 79.2 and 76.6 kcal/mol, respectively. The abstraction of a hydrogen atom by the ROO· radical is the main reaction path of these compounds; however, the low stoichiometric coefficients of inhibition (f = 0.3–0.7) suggest a contribution of secondary and/or side reactions of ArOH and OAr·. In the other chalcones, the ArO-H bond is stronger (D(ArO-H) = 83–88 kcal/mol) and the antioxidant activity is lower (k
7 = 104–105 l mol−1 s−1). 相似文献
12.
Hanbing Rao Zerong Li Xiangyuan Li Xiaohua Ma Choongyong Ung Hu Li Xianghui Liu Yuzong Chen 《Journal of computational chemistry》2010,31(4):752-763
Small molecule aggregators non‐specifically inhibit multiple unrelated proteins, rendering them therapeutically useless. They frequently appear as false hits and thus need to be eliminated in high‐throughput screening campaigns. Computational methods have been explored for identifying aggregators, which have not been tested in screening large compound libraries. We used 1319 aggregators and 128,325 non‐aggregators to develop a support vector machines (SVM) aggregator identification model, which was tested by four methods. The first is five fold cross‐validation, which showed comparable aggregator and significantly improved non‐aggregator identification rates against earlier studies. The second is the independent test of 17 aggregators discovered independently from the training aggregators, 71% of which were correctly identified. The third is retrospective screening of 13M PUBCHEM and 168K MDDR compounds, which predicted 97.9% and 98.7% of the PUBCHEM and MDDR compounds as non‐aggregators. The fourth is retrospective screening of 5527 MDDR compounds similar to the known aggregators, 1.14% of which were predicted as aggregators. SVM showed slightly better overall performance against two other machine learning methods based on five fold cross‐validation studies of the same settings. Molecular features of aggregation, extracted by a feature selection method, are consistent with published profiles. SVM showed substantial capability in identifying aggregators from large libraries at low false‐hit rates. © 2009 Wiley Periodicals, Inc.J Comput Chem, 2010 相似文献
13.
B. A. Trofimov T. A. Skotheim A. G. Mal'kina L. V. Sokolyanskaya G. F. Myachina S. A. Korzhova E. S. Stoyanov I. P. Kovalev 《Russian Chemical Bulletin》2000,49(5):863-869
Polyethylene is exhaustively sulfurized by elemental sulfur at 160–365 °C to release hydrogen sulfide and form black lustrous
powders (sulfur content ≈80%) that possess electric conductivity (10−6–10−8 S cm−1 when doped with I2). Elemental analysis data, IR spectra, X-ray patterns, DSC-TGA. derivatographic data, electric conductivity, and mass spectrometric
characteristics of the polymers synthesized suggest the presence of fused polythienothiophene and polynaphthothienothiophene
blocks in the polymers.
For Part 1, see Ref. 1
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 865–871, May, 2000. 相似文献
14.
Jozef Šima 《Foundations of Chemistry》2009,11(3):135-143
The paper is aimed at the issues of oxidation state determination and limiting values. The possibility of existence of compounds
containing an atom with the oxidation number beyond the current common values, i.e., below −IV and above +VIII are discussed.
Three principal modes of preparation of compounds with the oxidation number exceeding VIII, electrochemical anodic oxidation,
photoionization, and nuclear β-decay, are evaluated. Failure to prepare compounds containing an atom with the oxidation number
below −IV is rationalized. The paper provides an opinion on uncertainties in oxidation state determination in three kinds
of compounds: binary compounds, nitrosyl complexes, and compounds containing mutually bonded atoms of the same element. The
questions are discussed from the viewpoint of correlation of “man-made” quantities and objective, experimentally obtainable
data. 相似文献
15.
An ideal toxicity assay should utilize multiple indexes obtained from transient changes of metabolic activities. Here, we
demonstrate the possibility for a novel toxicity bioassay using the damped glycolytic oscillation phenomenon occurring in
starved yeast cells. In a previous study, the phenomenon was characterized in detail. Under optimum conditions to induce the
phenomenon, the wave shapes of the damped glycolytic oscillations were changed by the instantaneous addition of both glucose
and chemicals and by changing the chemical concentration. We estimated the changes in the oscillation wave shapes as six indexes,
i.e., the number of wave cycles, maximum amplitude, oscillation frequency, attenuation coefficient, initial peak height, and
non-steady-state time. These index changes were obtained from several kinds of chemicals. The chemicals, especially those
for acids (0.01–100 mM HCl and 0.01–50 mM citric acid), bases (0.001–50 mM KOH), heavy metal ions (1–1,000 mg L−1; Cu2+, Pb2+, Cd2+, Hg2+), respiratory inhibitors (3–500 mg L−1 NaN3), dissolved oxygen removers (10–300 mg L−1 NaSO3), surfactants (10–200 mg L−1 benzalkonium chloride), and aldehyde (10–1,000 mg L−1 acetaldehyde), showed characteristic patterns depending on each chemical and its concentration. These significant results
demonstrate the possibilities of new methods for both toxicity qualification and quantification.
Figure Influences of surfactant on the oscillation wave shape
Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
16.
Tahra Ayed Nathalie Guihéry Bahoueddine Tangour Jean-Claude Barthelat 《Theoretical chemistry accounts》2006,116(4-5):497-504
Correlated ab initio calculations have been performed on three dipalladium(I) complexes. These compounds differ both by the metal–metal interaction and by the metal–ligand interaction. The [Pd2Cl2(μ −H2PCH2PH2)2] complex exhibits a σ overlap between the two binding metallic orbitals and has no bridging ligand. In [Pd2Cl4(μ −CO)2]2−, the leading interaction between the two palladium involves a π overlap between the metallic orbitals and goes through the two bridging CO ligands. In [Pd2Cl2(μ −CO)(μ −H2PCH2 PH2)2], a single CO ligand bridges the two palladium atoms which interact through a hybrid σ–δ overlap. The three compounds also differ by the metal–metal distances. Surprisingly enough, while the palladium atoms are formally d
9 in all these complexes, none of them is paramagnetic. We propose here a detailed analysis of the electronic structures of these compounds and rationalize their chemical structures as well as the role of back-donation in the CO bridged compounds. Finally, since highly correlated treatments are used to describe these complexes, a detailed study of the role of both non-dynamical and dynamical correlations is performed. Concerning the [Pd2Cl4(μ −CO)2]2− complex, this analysis has revealed that the complex is not bound at the lowest correlated levels of calculation and therefore dynamical correlation is alone responsible for its binding energy. 相似文献
17.
S. Sekimoto T. Kobayashi K. Takamiya M. Ebihara S. Shibata 《Journal of Radioanalytical and Nuclear Chemistry》2007,272(3):447-450
Chemical compositions of spherules separated from deep sea sediment dredged off Hawaiian islands and from Antarctic ice were
measured by instrumental neutron activation analysis (INAA) using Kyoto University Reactor (KUR). Iron, cobalt, nickel, iridium,
scandium and manganese contents in those spherules were determined to be 19.3–97.7%, 23–4370 mg·kg−1, 0.08–7.04%, 0.84–35.4 mg·kg−1, 1.4–44.3 mg·kg−1 and 93.4 mg·kg−1–7.2 %, respectively, and compared with each other. Particularly, iridium was detected in seven spherules among fourteen from
Hawaii, but only one spherule among twenty-two from Antarctic, and those spherules turned out to be extraterrestrial in origin.
However, it was shown that there was little difference in characteristics of elemental contents between both kinds of spherules,
except for Ir-detected spherules. 相似文献
18.
The quantitative study of the equilibrium Pu4++Cl−⇋Pu3++1/2 Cl2 in LiCl−KCl (70–30% mol) at 455, 500, 550 and 600°C by visible and near I.R. absorption spectrophotometry allows the calculation
of the reaction's equilibrium constant, the mean thermodynamic data ΔH=27±14 kJ·mol−1 and ΔS=37±17 J·mol−1·K−1 and the standard potential of the couple
.
相似文献
19.
Continuous disposal of endocrine-disrupting compounds (EDCs) into the environment can lead to serious human health problems
and can affect plants and aquatic organisms. The determination of EDCs in water has become an increasingly important activity
due to our increased knowledge about their toxicities, even at low concentration. The EDCs in water samples from the reclaimed
water plant of Tianjin, northern China, were identified by gas chromatography (GC)–mass spectrometry (MS). Important and contrasting
EDCs including estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), 4-tert-octylphenol (OP), 4-nonylphenol (NP),
bisphenol A (BPA), di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl)phthalate (DEHP) were selected as the target compounds.
Concentrations of steroid hormones, alkylphenolic compounds and phthalates ranged from below the limit of detection (LOD)
to 8.1 ng L−1, from <LOD to 14.2 ng L−1, and from 1.00 μg L−1 to 23.8 μg L−1, respectively. The average removal efficiencies for target EDCs varied from 30% to 82%. These results indicate that environmental
endocrine disrupting compounds are not completely removed during reclaimed water treatment and may be carried over into the
general aquatic environment. 相似文献
20.
Zhang Fang Jiang Jianwei Yuan Changzhou Hao Liang Shen Laifa Zhang Luojiang Zhang Xiaogang 《Journal of Solid State Electrochemistry》2012,16(5):1933-1940
Nanostructured Co
x
Ni1−x
–Al layered triple hydroxides (Co
x
Ni1−x
–Al LTHs) have been successfully synthesized by a facile hydrothermal method using glycine as chelating agent. The samples
were characterized by X-ray diffraction, thermogravimetry, Fourier transform infrared spectroscopy and scanning electron microscopy.
The morphologies of Co
x
Ni1−x
–Al LTHs varied with the Co content and its effect on the electrochemical behavior was studied by cyclic voltammetry and galvanostatic
charge–discharge techniques. Electrochemical data demonstrated that the Co
x
Ni1−x
–Al LTHs with Co/Ni molar ratio of 3:2 owned the best performance and delivered a maximum specific capacitance of 1,375 F g−1 at a current density of 0.5 A g−1 and a good high-rate capability. The capacitance retained 93.3% of the initial value after 1,000 continuous charge–discharge
cycles at a current density of 2 A g−1. 相似文献