Evaluation of ionic pollutants of acid fog and rain using a factor analysis and back trajectories.

Fog and rain water samples were collected at the same time in the Akita Hachimantai mountain range in northern Japan from June to September in 1998 and 1999. The various ion concentrations in these samples were analyzed, and the fog droplet sizes were measured for each fog event. As the fog droplet size increased, the ion concentration decreased. The slope of log-log plots of the concentration versus the droplet size differed with the kind of ion. In order to characterize the air pollutant, moreover, these data were quantitatively analyzed by an oblique rotational factor analysis. We found that three factors were extracted as the air pollutant source: (NH4)2SO4, acids (HNO3 + H2SO4) and sea-salt. Combining the factor analysis with the 72 h back-trajectory at 850 hPa level, we found that the contribution of each factor varied with the transport pattern of air masses.     

Aryl C-glycosylation using an ionic liquid containing a protic acid

Aryl C-glycosylation of several glycosyl donors, including unprotected sugars, with phenol and naphthol derivatives in an ionic liquid containing a protic acid proceeded effectively and stereoselectively to give the corresponding aryl C-glycosides in good to high yields. Because the ionic liquid was nonvolatile, the reaction could be carried out under reduced pressure; in addition, the ionic liquid could be reused without loss of effectiveness. These features contribute to the significant advantages of this novel aryl C-glycosylation reaction.     

Determination of water pollutants by direct-immersion solid-phase microextraction using polymeric ionic liquid coatings

The determination of a group of eighteen pollutants in waters, including polycyclic aromatic hydrocarbons and substituted phenols, is conducted in direct-immersion solid-phase microextraction (SPME) using the polymeric ionic liquid (PIL) poly(1-vinyl-3-hexadecylimidazolium) bis[(trifluoromethyl)sulfonyl]imide as a novel coating material. The performance of the PIL fiber coating in the developed IL-SPME-gas chromatography (GC)–mass spectrometry (MS) method is characterized by average relative recoveries of 92.5% for deionized waters and 90.8% for well waters, average precision values (as relative standard deviations, RSD%) of 11% for deionized waters and 12% for well waters, using a spiked level of 5 ng mL⁻¹. The detection limits oscillate from 0.005 ng mL⁻¹ for fluoranthene to 4.4 ng mL⁻¹ for 4-chloro-3-methylphenol, when using an extraction time of 60 min with 20 mL of aqueous sample. The extraction capabilities of the PIL fiber have been compared with the commercial SPME coatings: polydimethylsyloxane (PDMS) 30 μm, PDMS 100 μm and polyacrylate (PA) 85 μm. The PIL fiber is superior to the PDMS 30 μm for all analytes studied. A qualitative study was also carried out to compare among the nature of the coating materials by normalizing the coating thickness. The PIL material was shown to be more efficient than the PDMS material for all analytes studied. The PIL coating was also adequate for nonpolar analytes whereas the PA material was more sensitive for polar compounds.     

Molecular nuclei of condensation. Conditions for observance and physicochemical features

The formation of aerosol particles on molecular nuclei of condensation (MoNC) is considered. An interpretation of this phenomenon, consistent with the physicochemical features of MoNC and with the observed regularities, is proposed. The nucleation is induced by the addition of two or several vapor molecules of a developing agent to MoNC to give clusters that are more stable than spontaneous heterogeneous fluctuations. The physical properties of the supersaturated vapors of empirically selected developing agents conform to the condition of low concentrations of heterogeneous fluctuations, which is needed to observe MoNC. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 208–213, February, 1998.     

Nuclear magnetic relaxation of ionic nuclei moving in an external electric field

We have experimentally investigated nuclear magnetic relaxation of some quadrupolar ionic nuclei (²³Na⁺, ⁸⁷Rb⁺ and ³⁵Cl⁻ ) in electrolyte solutions in non-equilibrium states. The measurements of relaxation rates 1/T₁ in the presence of a direct electric field, and thus also an electric current, revealed that differences can occur in comparison with relaxation in the absence of the field. In some systems no change in the relaxation rate was observed, but in certain other (non-aqueous) systems there was a change in the quadrupolar relaxation rate in the presence of the field.     

Simultaneous extraction of several persistent organic pollutants in sediment using focused ultrasonic solid-liquid extraction

Focused ultrasonic solid-liquid extraction (FUSLE) has been optimised for simultaneous analysis of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), phthalate esters (PEs), and nonylphenols (NPs) in sediment samples. Optimisation was performed using naturally polluted freeze-dried sediment samples. The variables studied during the optimisation process were: percentage of maximum power (10-60%), extraction time (10-300 s), number of cycles (1-9), composition of the extraction solvent (acetone-n-hexane, 10:90-90:10), and sample mass (0.1-1 g). The volume of the extractant was constant (10 mL) and the extraction was performed at 0 degrees C in an ice-bath during the optimisation process. All these variables were studied using an experimental design approach by means of The Unscrambler software. The extraction time and the operational variables (number of cycles and power) had no statistically significant effect in the extraction and they were held at 2 min, 20% power, and seven cycles, respectively. The mass and the addition of non-polar solvent (n-hexane) had a negative effect in the extraction yield and, thus, the mass was held at 0.5 g and pure acetone was used as extraction solvent. After those variables were optimised, the effect of the extraction temperature (0 degrees C or room temperature) was also studied. The validation of the extraction method was performed using NIST-1944 reference material in the case of PAHs and PCBs. Because no certified reference sediment is available for PEs and NPs, the results obtained for FUSLE were compared with those obtained for microwave-assisted extraction (MAE) under conditions optimised elsewhere. In all the cases the analysis were performed by gas chromatography-mass spectrometry (GC-MS). Good accuracy were achieved in all cases. The limits of detection (LODs) obtained were between 0.10 and 1.70 ng g(-1) for PAHs (except for naphthalene 5.33 ng g(-1)), 0.02 and 0.16 ng g(-1) for PCBs, 46 and 188 ng g(-1) for PEs, and 0.6 and 12.4 microg g(-1) for NPs. The precision was around 5-10% for most of the PAHs and PCBs and around 2-10% for most of the PEs and NPs.     

Discrimination of colon cancer stem cells using noncanonical amino acid

Cancer stem cells (CSCs) may be responsible for tumor recurrence. Metabolic labelling of newly synthesized proteins with non-canonical amino acids allows us to discriminate CSCs in mixed populations due to the quiescent nature of these cells.     

The first ionic liquid-promoted Kabbe condensation reaction for an expeditious synthesis of privileged bis-spirochromanone scaffolds

A variety of privileged bis-spirochromanones were synthesized for the first time from 4,6-diacetyl resorcinol in one-pot by carrying out the Kabbe condensation in room temperature ionic liquid [bbim]Br.     

Quantification of amino acid ionic liquids using liquid chromatography-mass spectrometry

Amino acid ionic liquids (AAILs) containing imidazolium cations and amino acid (AA) anions, were synthesized and applied as task-specific ionic liquids. A sensitive and fast liquid chromatography-mass spectrometry (LC-MS) method was established for the quantitative analysis of 20 AAILs. Using ion pairing-reversed phase liquid chromatography technique, heptafluorobutyric acid was used as ion-pairing reagent to increase the retention of AAILs. Based on the zwitterionity of amino acid, this method was proposed to determine both the cation and the anion of AAILs simultaneously. The limit of detection of this method is down to 1-15ng/mL and the analysis time is less than 15min. According to the analytical data of seven selected AAILs, we found that the content of amino acid anion is always lower than that of butyl methyl imidazolium cation in AAILs. Moreover, the molar ratio of imidazolium cation to amino acid anion is dependent on the chemical property of the amino acid. These results supplied useful information on the interaction of imidazolium cation with acidic, basic, neutral and non-polar amino acids in AAILs.     

功能化离子液体催化合成柠檬酸三丁酯的研究

柠檬酸三丁酯(TBC)是一种新型无毒塑料增塑剂,具有相溶性好、增塑效率高、无毒、不易挥发、抗霉性、耐候性强等特点而备受关注,成为首选替代邻苯二甲酸酯类的绿色环保产品.随着人们环保意识的增强及法规的日益完善,开发生产柠檬酸三丁酯具有极好的发展前景.     

Growth of polydisperse aerosol in an adiabatic condensation nuclei counter (CNC) with finite expansion time

The diffusional growth of polydisperse aerosol was calculated as a function of expansion time, i.e.; time in which the temperature drop necessary for supersaturation-induced condensational growth is produced. At high nuclei concentrations and/or long expansion time only fractions of the ideal supersaturation (produced with small concentrations and fast expansion) are obtained. Large nuclei are activated earlier than smaller ones and consume so much vapor that smaller nuclei cannot possibly grow. This may cause a strong influence on the particle size detection limit. Therefore, great care is necessary to interpret condensation nuclei counter (CNC) measurements with concentrated polydisperse aerosols correctly.     

Effect of long-range transport of air mass on the ionic components in radiation fog in northern Japan.

Water samples from radiation and upslope types of fog were collected at Takanosu Basin and Hachimantai mountain range of Akita Prefecture in northern Japan, respectively. The effect of the long-range transport of pollutants from the Asian Continent to the basin and the mountain range on the chemical characteristics of two types of fog was studied using chemical analysis data for the water samples as well as the back-trajectories of the air mass. In particular, non-sea-salt (nss)-SO4(2-) of radiation fog provided a much higher concentration than that of upslope fog, which suggests that nss-SO4(2-) might be transported mainly from the Asian Continent. The transport and uptake mechanism of pollutants in the radiation fog water were explained based on their accumulation in the basin due to anticyclonic subsidence and by the long-lasting fog behavior.     

Selective oxidation and chlorination of trifluoromethylsulfide using trichloroisocyanuric acid in ionic liquid

A route to chemoselective oxidation and chlorination of aryltrifluoromethylsulfide using trichloroisocyanuric acid (TCCA) in ionic liquid, an efficiently O-methylation reaction and a reduction of nitro- to amido- in excellent yields have been developed.     

A novel glycosylation of inactive glycosyl donors using an ionic liquid containing a protic acid under reduced pressure conditions

The glycosylation of inactive glycosyl donors, such as methyl glycosides and 1-hydroxy sugars with nearly stoichiometric amounts of various alcohols (1.1 equiv) in an ionic liquid containing a protic acid (acid-IL) under reduced pressure conditions proceeded effectively to give the corresponding glycosides in good to high yields. Furthermore, the acid-IL could be reused for additional glycosylations without the loss of efficiency.     

Modeling of an ionic liquid electrospray using molecular dynamics with constraints

Molecular dynamics simulations have been performed to investigate the behavior of the EMIM-BF(4) ionic liquid for conditions similar to those of electrospray thrusters. To study the physics of ion extrusion a large system composed of approximately 2160 ion pairs was placed inside a platinum capillary and equilibrated. Diffusion coefficients and electrical conductivity were calculated and compared with literature values, showing good agreement and validating the use of a constrained dynamics model with a coarse-grained potential. An electric field was applied to the system in the longitudinal direction and the fraction of solvated and non-solvated emitted ions was analyzed. The threshold electric field for particle emission was found to be 1.2 V/nm, consistent with other reported work.     

Morphological manipulation of ionic block copolymer micelles using an electric field

We present an electric-field-triggered sphere-to-cylinder transition of negatively charged block copolymer micelles with a radically low electric field of 30 V/cm. The system investigated is dilute solutions of strong polyelectrolyte containing ionic-b-neutral block copolymers (i.e., poly(styrenesulfonate-b-methylbutylene)). We have carried out in situ small-angle X-ray scattering experiments equipped with a dc power supply, combined with electron microscopy and atomic force microscopy. The application of small electrical fields across the solutions of spherical micelles results in the transient morphology of interconnected spheres, which are eventually transformed into a cylindrical shape with time. The E-field-induced cylindrical micelles revert to spherical micelles when the E field is switched off.     

Potential-dependent condensation of Water at the Interface between ionic liquid [BMIM][TFSA] and an Au electrode

Surface-enhanced infrared absorption spectroscopy (SEIRAS) at the interface between humid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([BMIM][TFSA]) and an Au electrode reveals that water molecules strongly interact with the anion and are condensed at the interface at high potentials where the anion is the major adsorbate.