Organophosphate esters, widely used as flame retardants and plasticizers, are regarded as a class of emerging pollutants. In this work, a novel approach was developed for the fabrication of a solid‐phase microextraction fiber by using hybrid silica‐based materials with immobilized ionic liquids with sol–gel technology, and the prepared solid‐phase microextraction fiber was then coupled with gas chromatography and flame photometric detection for the analysis of six organophosphate esters. The high loading of 1‐hexadecyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide was confined within the hybrid network. The developed solid‐phase microextraction fiber possesses a coating thickness of ~35 μm with good thermal stability and long lifetime. The parameters affecting the extraction efficiency such as extraction time, temperature, pH, and ionic strength of the sample solution were optimized. Under the optimized conditions, the limits of detection were in the range of 0.04?0.95 μg L?1, and the precision of the method assessed with repeatability and reproducibility of (RSD%) ?13 and ?29%, respectively. The proposed method was successfully applied to determine the six organophosphate esters in three real water samples, with recoveries in the range of 64.8?125.4% at two different spiking concentration levels. As a result, the proposed method demonstrated its potential for application in trace determination of organophosphate esters in actual water samples. 相似文献
The title compound (Ph2PO)2 is analyzed by single crystal X-ray diffraction analysis. The crystals are monoclinic, space group P2(1)/n with a = 9.5112(19) Å, b = 11.161(2) Å, c = 9.5487(19) Å, α = 90°, β = 91.65(3)°, γ = 90°, V = 1013.2(3) Å3, Z = 2, F(000) = 420, Dc = 1.319 g cm–3, μ = 0.232 mm?1, the final R = 0.0818, and wR = 0.2259. A total of 7954 reflections were collected, of which 1758 were independent (Rint = 0.0542). In the crystal packing diagram, intermolecular C—H···O hydrogen bonds stabilize the solid state of the title compound. 相似文献
The gelation properties of derivatives of N‐alkylated (R)‐12‐hydroxystearic acid hydrazide (n‐HSAH, n=0, 2, 6, 10; n is the length of an n‐alkyl chain on the terminal nitrogen atom) in a wide variety of liquids is reported. The n‐HSAH compounds were derived from a naturally occurring alkanoic acid, (R)‐12‐hydroxystearic acid (R‐12HSA), and although they differ from the analogous N‐alkyl (R)‐12‐hydroxystearamides (n‐HSAA) only by the presence of one N?H group, their behavior as gelators is very different. For example, the parent molecule (0‐HSAH) is a supergelator in ethylene glycol, in which it forms self‐standing gels that are self‐healing, partially thixotropic, moldable, and load‐bearing; gels of 0‐HSAA are not self‐standing. 0‐HSAH is structurally the simplest molecular gelator of which we are aware that is capable of forming both self‐standing and partially thixotropic gels. Also, diffusion of the cationic dye erythrosine B and the anionic dye methylene blue in 0‐HSAH/ethylene glycol gel blocks is much slower than the self‐diffusion of ethylene glycol. Polarizing optical microscopy, X‐ray diffraction, and FTIR studies revealed that the self‐assembled fibrillar networks (SAFINs) of the gels are crystalline, and that 0‐HSAH molecules may be arranged in a triclinic subcell with bilayer stacking. The SAFINs are stabilized by strong hydrogen‐bonding interactions between the hydrazide groups of adjacent molecules and a perpendicular hydrogen‐bonding network between the pendent hydroxyl groups of 0‐HSAH. The other n‐HSAH (n=2, 6, 10) molecules appear to be arranged in orthorhombic subcells with monolayers and strong hydrogen‐bonding interactions between the hydrazide group of one gelator molecule and the hydroxyl group of a neighboring one. These results show how small structural modifications of structurally simple gelator molecules can be exploited to form gels with novel properties that can lead potentially to valuable applications, such as in drug delivery. 相似文献
In this paper we construct a framework to price the inflation-linked derivatives with the stochastic inflation rate, the stochastic interest rate, and stochastic risky assets with stochastic volatility. Because of the popularity of the guaranteed minimum death benefit (GMDB) in insurance market, we mainly study two types of GMDBs: the inflation guarantee and the combination guarantee. We consider the guaranteed minimum death benefit as an European option with a random maturity date, the closed-form pricing formulas for the GMDBs are derived by Fourier-based method. Moreover, we give an elaborate sensitivity analysis to explain economical behaviors of our models. The numerical results show that the death benefit of inflation guarantee is slightly overpriced in constant volatility of stock situation. 相似文献
In this paper, we first give a classification of the family of 2-geodesic transitive abelian Cayley graphs. Let \(\Gamma \) be such a graph which is not 2-arc transitive. It is shown that one of the following holds: (1) \(\Gamma \cong \mathrm{K}_{m[b]}\) for some \(m\ge 3\) and \(b\ge 2\); (2) \(\Gamma \) is a normal Cayley graph of an elementary abelian group; (3) \(\Gamma \) is a cover of Cayley graph \(\Gamma _K\) of an abelian group T / K, where either \(\Gamma _K\) is complete arc transitive or \(\Gamma _K\) is 2-geodesic transitive of girth 3, and A / K acts primitively on \(V(\Gamma _K)\) of type Affine or Product Action. Second, we completely determine the family of 2-geodesic transitive circulants. 相似文献
A novel FRET-based probe LS3 was designed and synthesized. As expected, it exhibited high selectivity and sensitivity for detecting Cu2+ over other commonly coexistent metal ions. The detection limit was measured to be 0.0423 μM for Cu2+, which can meet the selective requirements for practical application. In addition, the newly synthesized compound 3a/b have potential value of further synthesizing more analogous FRET-based probes. 相似文献
A feasible in operation, labor-saving and low-cost one-step technology to fabricate fullerenol nanoparticles (FNPs) up to 10 g in laboratory was developed by improved alkaline-oxidation approach using moderately concentrated sodium hydroxide solution as the hydroxylation agent and o-dichlorobenzene as the solvent. This strategy paves the avenue for industrial-scale bulk production of FNPs. The resulted product, [C60(OH)22·8H2O]n, were characterized by various measurements including matrix-assisted laser desorption ionization time-of-flight mass spectrometry, high-resolution 1H nuclear magnetic resonance spectrometry, Fourier transform infrared spectroscopy, UV-Visible spectrophotometer, thermogravimetric analysis, differential scanning calorimetry, dynamic light scattering analysis, scanning electron microscopy, and electron spin resonance spectrometer. Radical scavenging assay in vitro confirmed the high efficiency of water-soluble [C60(OH)22·8H2O]n as a novel radical scavenger. Furthermore, [C60(OH)22·8H2O]n as an excellent candidate has the potential to serve as the plant defense stimulation agent in maize.