Determination of a broad spectrum of endocrine‐disrupting pesticides in fish samples by UHPLC–MS/MS using the pass‐through cleanup approach

We describe a new methodology for the simultaneous determination of the endocrine‐disrupting herbicides (acetochlor, alachlor, amitrole, and atrazine), fungicides (carbendazim, triadimefon, penconazole, and propiconazole), and insecticides (carbaryl and carbofuran) in fish samples followed by high‐performance liquid chromatography with tandem mass spectrometry. Samples were extracted and purified using the pass‐through cleanup approach. The recoveries of the pesticides were in the range 71.8–116.5%, with relative standard deviations lower than 15.28%. Limits of quantitation were in the range of 0.03–2.50 μg/kg. Validation results on linearity, accuracy, and precision, as well as on application to the analysis of the endocrine‐disrupting pesticides in 20 fish samples, demonstrated the applicability to screen the presence of pesticides in fish.     

悬浮态乳液聚合

对一种新的聚合方法－－悬浮态乳液聚合的研究进展进行了综述。通过对比悬浮聚合，乳液聚合和悬浮态乳液聚合方法的异同，突出了悬浮态乳液聚合的优点。讨论了悬浮态微液聚合的机理，以及分散剂，表面活性剂，水油比等对聚合物颗粒形态的影响。     

高效液相色谱法对水果中多菌灵与福美双残留的同时测定

建立了高效液相色谱同时测定水果中多菌灵和福美双残留量的方法。样品经二氯甲烷提取,OasisHLB固相萃取柱净化后,经C18色谱柱分离,甲醇-0.05 mol/L甲酸铵溶液(60∶40,体积比)洗脱,紫外检测器进行检测。结果表明,多菌灵、福美双的的线性范围分别为0.01~10.0、0.05~10.0 mg/kg,相关系数分别为1.0、0.9999,检出限分别为0.005、0.03 mg/kg,平均加标回收率为80%~109%。该方法成功用于市售水果样品的测定。     

Nonionic surfactant enhanced semipermanent coatings for capillary electrophoresis of inorganic anions without use of organic additives

Separation of inorganic anions by capillary electrophoresis (CE) is usually conducted in co-electroosmotic mode due to the large electrophoretic mobilities of inorganic anions. Semipermanent surfactant coatings have been shown to be effective for CE of inorganic anions due to their strong capability of electroosmotic flow (EOF) manipulation. However, semipermanent coatings often suffer from their unsatisfactory stability. In addition, organic solvent additives are usually required to adjust the selectivity, which also aggravate the degradation of coating. In this work, a novel semipermanent coating consisting of cationic Gemini surfactant 18-10-18 and nonionic surfactant Tween 20 was developed to separate inorganic anions in CE. This coating is easy to prepare and more stable than pure Gemini coating. The introduction of nonionic surfactant in the coating not only suppresses the reversed EOF but can also adjust the selectivity of separation. Good separations of six model anions were achieved, the separation efficiency was as high as 65040-169700 plates/m and the RSDs of the migration times were less than 0.5 and 2.5% for run-to-run and day-to-day assays, respectively. Calibration curves were linear in the range of 0.05-5.0 mM; the detection limits ranged from 20 to 50 μM. More importantly, no organic solvents are required in the background buffer to achieve the satisfactory separations. This guarantees the coating stability and makes the method greener than most of other methods for CE of inorganic anions.     

Sulfonation of Liquefied Wood and Suspension Property of Its Product in Seed Coating Agent

For the utilization of product from wood liquefaction by ionic liquid, the liquefied product was sulfonated by chlorosulfonic acid as a sulfonating agent, and the product of wood liquefaction sulfonation (WLS) was obtained. The characterization of WLS is determined using FTIR, and the strong absorption peak of sulfonic group is clear. The suitable reaction conditions are as follows, the mass ratio of chlorosulfonic acid to liquefied wood and formaldehyde to liquefied wood are 0.8:1 and 0.9:1, reaction temperature of sulfonation and condensation are at 85°C and 90°C, reaction time of sulfonation and condensation are for 2.5 and 3.0 hours. When the solution concentration of WLS is 15 g · L^?1, the surface tension is 46.9 mN · m^?1. In the formula of seed coating agent, WLS shows better suspension property and less change of viscosity in impact test than that of conventional surfactants, also, it can generate synergy effects with the other surfactants to make higher suspending rate in binary or ternary mixed system than that in single system.     

Effect of chemical and physical factors to improve the germination rate of Echinacea angustifolia seeds

Seeds of Echinacea angustifolia are known for their deep dormancy. In this paper, we studied the responses of E. angustifolia seeds to some chemical and physical factors, such as scarification, chilling (5 °C) period, light and applied BA (6-benzylaminopurine), GA₃ (gibberellic acid) and sound stimulation. When the seed coat layers were removed, the germination rate grew up from 6 to 20% (incubated in light) and the mean time germination (MTG) was reduced from 18 to 6.6 days. On the basis of layers-removed, chilling and continuous light gave significantly higher germination rate (up to 70%). Compare the data of seeds chilled by 0, 6, 12, 18 and 24 days, the maximum germination rate (up to 70%) achieved at 18-days chilling treatment. Further increases in the chilling period could slightly improve germination. Exogenous application of 0.1, 0.2, 0.3 mg/L GA₃ or BA in the previous pretreatment increased germination to 78, 90 and 84% or 76, 86 and 84%, respectively. Obviously, the best concentration of GA or BA is 0.3 mg/L. And the GA₃ or BA treatment shortened the MTG to about 4 days. The influence of sound stimulation was also tested in the experiment. The result showed that one 100 dB and 1000 Hz sound wave (sine-wave) was beneficial to the germination of E. angustifolia seeds.     

Preparation of highly exfoliated epoxy/clay nanocomposites by "slurry compounding": process and mechanisms

Epoxy/clay nanocomposites with a high degree of exfoliation were achieved using a so-called "slurry-compounding" process with which the dispersed state of clay in water can be successfully transferred to an epoxy matrix. In this process sodium montmorillonite was first exfoliated and suspended in water. This suspension was further treated with acetone to form a clay-acetone slurry followed by chemical modification using silane. The modified slurry was then mixed extensively with epoxy to form epoxy/nanoclay composites. It has been shown that the morphologies of clay before and after curing are quite similar and the exfoliation process is termed "slurry compounding". Furthermore, the amount of organic modifier used is only 5 wt % of clay, in contrast to conventional organoclays which normally contain at least 25-45 wt % of organic surfactant. The resulting epoxy/nanoclay composites exhibit a high degree of clay exfoliation and a better thermal mechanical property.     

Self-assembled Gemini surfactant film-mediated dispersion stability

The force-distance curves of 12-2-12 and 12-4-12 Gemini quaternary ammonium bromide surfactants on mica and silica surfaces obtained by atomic force microscopy (AFM) were correlated with the structure of the adsorption layer. The critical micelle concentration was measured in the presence or absence of electrolyte. The electrolyte effect (the decrease of CMC) is significantly more pronounced for Gemini than for single-chain surfactants. The maximum compressive force, F(max), of the adsorbed surfactant aggregates was determined. On the mica surface in the presence of 0.1 M NaCl, the Gemini micelles and strong repulsive barrier appear at surfactant concentrations 0.02-0.05 mM, which is significantly lower than that for the single C(12)TAB (5-10 mM). This difference between single and Gemini surfactants can be explained by a stronger adsorption energy of Gemini surfactants. The low concentration of Gemini at which this surfactant forms the strong micellar layer on the solid/solution interface proves that Gemini aggregates (micelles) potentially act as dispersing agent in processes such as chemical mechanical polishing or collector in flotation. The AFM force-distance results obtained for the Gemini surfactants were used along with turbidity measurements to determine how adsorption of Gemini surfactants affects dispersion stability. It has been shown that Gemini (or two-chain) surfactants are more effective dispersing agents, and that in the presence of electrolyte, the silica dispersion stability at pH 4.0 can also be achieved at very low surfactant concentrations ( approximately 0.02 mM).     

Preparation and characterization of microcapsules containing particulate phosphorescent agent with suspension polymerization

Microcapsules containing particulate phosphorescent agent (strontium aluminate) were prepared by the suspension polymerization method and characterized about a few items such as the mean diameters, the content, the inner structure and the afterglow luminance property. Furthermore, the fundamental experiments were conducted to investigate how the dispersing feature of particulate phosphorescent agent affects the afterglow luminance property. In the experiment, the concentration of oil soluble surfactant, the crosslinking agent species, the added weight of the phosphorescent agent and the pre‐bulk polymerization time were mainly changed stepwise. Afterglow luminance of particulate phosphorescent agent gradually decreased with the afterglow time and considerably decreased because of soaking them in water. Decline of afterglow luminance because of soaking in water could be prevented by microencapsulation. Afterglow luminance of the multicore type microcapsules was found to be higher than that of the core–shell type microcapsules. The content of particulate phosphorescent agent could be increased by performing pre‐bulk polymerization and increasing the concentration of the oil soluble surfactant. Copyright © 2016 John Wiley & Sons, Ltd.     

有机凹凸棒粘土的制备及复合高吸水性树脂的性能

有机凹凸棒粘土的制备及复合高吸水性树脂的性能;凹凸棒粘土;有机改性;高吸水性树脂     

阴离子孪连表面活性剂的合成及其表/界面活性研究

合成了疏水链长度不同和连接基长度不同的7种系列阴离子孪连表面活性剂,研究了它们的表/界面活性。结果表明,它们有较低的表面张力和临界胶束浓度(CMC),有很好的表面活性。它们的CMC都在10-5~10-6mol/L之间,表面张力在26·5~34mN/m之间。它们有非常好的抗一价、二价盐的能力。除了C16-C2-C16在高于5%的NaCl溶液中会产生析出外,其余孪连表面活性剂都能耐盐20%以上。随着盐浓度的增加,孪连表面活性剂与烷烃间的界面张力逐渐降低,能达到10-3mN/m。与中原油田原油间的界面张力能降低到10-3~10-4mN/m,表明它们可应用于特高矿化度油藏提高采收率。     

Auto-organized nano-structure of collagen on Gemini surfactant monolayer

Two kinds of Gemini surfactant monolayer, which showed different hydrophobic property, were selected as adsorption substrates for collagen. The topographic images of collagen were investigated by using an atomic force microscopy (AFM). Their auto-organized nano-structures were influenced by the property of substrate and the process of sample preparation, such as concentration of collagen solution, adsorption time and drying condition. Network-like structures formed on the both Gemini monolayers. With increasing concentration of collagen solution and adsorption time, the density of the network-like structure increased and their strands became wider and the mesh sizes decreased apparently. Contrary to the reference, the network-like structures of collagen also formed on the less hydrophobic Gemini surfactant monolayer even after very short adsorption time, which was considered to result from the more hydrophobic patch on it.     

The photodimerization of a cinnamoyl moiety derivative in dilute solution based on the intramolecular chain interaction of gemini surfactant

A Gemini surfactant, sodium N, N'-di(4-n-butyloxy cinnamoly)-L-cystine, containing a cinnamoyl moiety in the alkyl chains and disulfide bond in the spacer was designed and synthesized. The incorporation of a cinnamoyl moiety into the alkyl chains of Gemini surfactant makes it easy to probe the conformational information of the amphiphile molecule. The UV/vis absorption spectra and steady-state fluorescence were investigated at a concentration far below the critical micelle concentration (cmc). Both blue-shift of absorption and red-shift of fluorescence emission spectra indicate the existence of intramolecular interaction between the two alkyl chains in Gemini surfactant in the singly dispersed state. Results based on the breakdown of the disulfide bond by dithiotheritol (DTT) further confirmed the conclusion. Moreover, the characteristic of intramolecular chain interaction in Gemini surfactant improves the topochemical geometrical requirements of cinnamoyl moiety and increases the local concentration of reactant in dilute solution. Utilizing the incorporation of cinnamoyl moiety into the alkyl chains of Gemini surfactant, the cinnamoyl moiety upon irradiation undergoes dimerization in dilute aqueous solution with high yield of 78%.     

Photostabilization of an entomopathogenic fungus using composite clay matrices

To provide photostabilization for entomopathogenic fungi by anionic dyes, composite matrices based on clay-biopolymer combinations were prepared. In the first step, the negative surface charge of various clays (montmorillonite, attapulgite, bentonite and kaolinite) was reversed to positive by adsorption to the polycationic biopolymer chitosan. The second step involved adsorption of the toxicologically safe anionic dyes fast green (FG) and naphthol yellow S (NYS) to the clay complexes. Compared with cytotoxic photoprotectants like berberine, palmatine and acriflavine, the anionic dyes have no adverse effects up to a concentration of 1 M. In assays using various clay-chitosan-dye matrices and UV irradiation from a lamp source, it was evident that both FG and NYS provided considerable photostabilization for conidia of the entomopathogenic fungus Aschersonia spp. that served as a model biocontrol agent. Apparently, because of the light-dispersing property, bentonite and attapulgite per se provided significant photoprotection. All clay matrices containing FG provided a substantial photostabilization effect.     

Mechanical properties of polymer‐blend nanocomposites with organoclays: Polystyrene/ABS and high impact polystyrene/ABS

Thirty‐three polystyrene (PS)/acrylonitrile‐butadiene‐styrene (ABS) and high impact PS/ABS polymer blends with organoclay and copolymer additives were prepared by melt processing using different mixing sequences in order to test the putative capability of clay to perform a compatibilizing role in polymer blends. In general, the addition of clay increased the tensile modulus and had little effect on tensile strength. For the blends studied in this work, the addition of organoclays caused a catastrophic reduction in impact strength, a critical property for commercial viability. The polymer‐blend nanocomposites adopted a structure similar to that for ABS/clay nanocomposites as determined by X‐ray diffraction and transmission electron microscopy. It is suggested that clay reinforcement inhibits energy absorption by craze formation and shear yielding at high strain rates. Simultaneous mixing of the three components provided nanocomposites with superior elongation and energy to failure compared to sequential mixing. The clay pre‐treated with a benzyl‐containing surfactant gave the best overall properties among the various organoclays tested and of the two clay contents studied 4 wt % was preferred over 8 wt % addition. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Use of an ionic liquid‐based surfactant as pseudostationary phase in the analysis of carbamates by micellar electrokinetic chromatography

The applicability of an ionic liquid‐based cationic surfactant 1‐dodecyl‐3‐methyl‐imidazolium tetrafluoroborate (C₁₂MImBF₄) as pseudostationary phase in MEKC has been evaluated for the analysis of 11 carbamate pesticides (promecarb, carbofuran, metolcarb, fenobucarb, aldicarb, propoxur, asulam, benomyl, carbendazim, ethiofencarb, isoprocarb) in juice samples. Under optimum conditions (separation buffer, 35 mM NaHCO₃ and 20 mM C₁₂MImBF₄, pH 9.0; capillary temperature 25°C; voltage –22 kV) the analysis was carried out in less than 12 min, using hydrodynamic injection (50 mbar for 7.5 s) and detection at 200 nm. For the extraction of these CRBs from juice samples, a dispersive liquid–liquid microextraction (DLLME) procedure has been proposed, by optimization of variables affecting the efficiency of the extraction. Following this treatment, sample throughput was approximately 12 samples per hour, obtaining a preconcentration factor of 20. Matrix‐matched calibration curves were established using tomato juice as representative matrix (from 5 to 250 μg/L for CBZ, BY, PX, CF, FEN, ETH, ISP, and 25–250 μg/L for ASL, ALD, PRC, MTL), obtaining quantification limits ranging from 1 to 18 μg/L and recoveries from 70 to 96%, with RSDs lower than 9%.     

复方磺胺嘧啶混悬剂的助悬剂筛选

以沉降容积比和再分散性为指标 ,优选出制备复方磺胺嘧啶混悬剂时所用的助悬剂为羧甲基纤维素钠。     

Hexamethyldisiloxane‐modified ZnO‐SiO2‐coated superhydrophobic textiles for antibacterial application

A superhydrophobic cotton textile with high antibacterial properties has been fabricated. The cotton textile was coated through the in situ growth of ZnO‐SiO₂ nanoparticles in presence of chitosan as the template agent via a hydrothermal process at 95 °C. This process was followed by the coating of additional layers of hexadecyltrimethoxysilane (HDTMS). The obtained cotton textile showed antibacterial property against Staphylococcus epidermis and Escherichia coli with inhibition zones up to 18.26 and 8.48 mm, respectively. Scanning electron microscopy (SEM) revealed that the coating had a rough surface, which was attributed to the distribution of ZnO‐SiO₂ nanorods of hexagonal shape. This rough surface creates a superhydrophobic layer that repels the bacteria, as proven by the large water contact angle of approximately 150°. Nevertheless, the HDTMS layers prolong the durability of hydrophobicity for up to 3 h.     

Optimizing conditions to study seed germination by calorimetry using soybean (Glycine max [L.] Merr.) seeds

To establish the best conditions for germination, calorimetric experiments were conducted with individual soybean seeds (Glycine max [L.] Merr.) under different conditions of imbibition at 24.7 °C. The calorimetric curves were analysed for imbibition and metabolic processes and compared with imbibition curves to establish a general methodology that could be used to evaluate inter- and intra-species physical and physiological variability. Measurements of pH were performed during the determination of the imbibition curves. The best experimental method for calorimetric investigations of seed germination is to insert the seed in 1% agar instead of placing the seed over wetted filter paper disks. Correlation of imbibition experiments and pH results with mass specific enthalpy of imbibition (determined in a KCN solution) or mass specific enthalpy of germination when seeds were germinated in 1% agar allowed determination of the water content needed for soybean seeds of the cultivar studied (A7636 RG) to activate their metabolic machinery (74–80% or 2.5–3 h) and the moment in which they are ready for root protrusion (122% or 9 h). The method presented here should be useful for evaluating soybean coat permeability to water and other factors related to seed damage before and during harvest and storage.     

Gemini阴离子表面活性剂水溶液的界面活性

Gemini阴离子表面活性剂水溶液的界面活性;Gemini阴离子表面活性剂;表面张力;CMC;C20;界面张力