Surfactant in the gaseous phase II. Influence on stability of foams and thin liquid films

The influence of the vapors ofn-amyl orn-decyl alcohol on the stability of single thin liquid films, single bubbles, and foam columns was determined. It was found that the presence of surfactant vapors lowered the stability of foams and single foam films. The mechanism of the destabilizing action of the surfactant vapors on wet, dynamic foams under dynamic conditions is discussed. It is shown that the destabilizing action of the surfactant vapors is a further indication that surface elasticity forces are the main factor determining stability of wet, dynamic foams.     

The Studies of the Heterogeneous Properties of Solid Surfaces by Means of the Derivatograph Q-1500 D

A simple method has been adopted to obtain an important information on the heterogeneous properties of materials studied, adsorbed liquid films and liquid-solid interactions. The method utilizes Q-TG mass loss and the first derivative Q-DTG mass loss curves with respect to temperature and time obtained during programmed liquid thermodesorption in quasi-isothermal conditions. The values of the adsorption capacity, total porosity of material, the value of active centers, desorption energy distribution and mesopore-size distribution functions obtained by this method are in good agreement with those estimated on the basis of independent methods. The theoretical and experimental results provided novel and unique data on the heterogeneity of solid surfaces, properties of liquid adsorbed films and thermal stability of the liquid/solid interfaces. This paper presents the more important results obtained so far in the studies the liquid/solid systems by means of the Paulik's classical and quasi-isothermal techniques. This revised version was published online in July 2006 with corrections to the Cover Date.     

Single-Stage Extraction and Separation of Co2+ from Ni2+ Using Ionic Liquid of [C4H9NH3][Cyanex 272]

The purpose of this study was to optimize the extraction conditions for separating Co²⁺ from Ni²⁺ using N-butylamine phosphinate ionic liquid of [C₄H₉NH₃][Cyanex 272]. A Box–Behnken design of response surface methodology was used to analyze the effects of the initial pH, extraction time, and extraction temperature on the separation factor of Co²⁺ from sulfuric acid solution containing Ni²⁺. The concentrations of Co²⁺ and Ni²⁺ in an aqueous solution were determined using inductively coupled plasma-optical emission spectrometry. The optimized extraction conditions were as follows: an initial pH of 3.7, an extraction time of 55.8 min, and an extraction temperature of 330.4 K. The separation factor of Co²⁺ from Ni²⁺ under optimized extraction conditions was 66.1, which was very close to the predicted value of 67.2, and the error was 1.7%. The equation for single-stage extraction with high reliability can be used for optimizing the multi-stage extraction process of Co²⁺ from Ni²⁺. The stoichiometry of chemical reaction for ion-exchange extraction was also investigated using the slope method.     

USAEME-GC/MS Method for Easy and Sensitive Determination of Nine Bisphenol Analogues in Water and Wastewater

A new, simple and sensitive method for isolating nine compounds from the bisphenol group (analogues: A, B, C, E, F, G, Cl₂, Z, AP) based on one-step liquid–liquid microextraction with in situ acylation followed by gas chromatography-mass spectrometry was developed and validated using influent and effluent wastewaters. The chemometric approach based on the Taguchi method was used to optimize the main conditions of simultaneous extraction and derivatization. The recoveries of the proposed procedure ranged from 85 to 122%, and the repeatability expressed by the coefficient of variation did not exceed 8%. The method’s limits of detection were in the range of 0.4–64 ng/L, and the method’s limits of quantification ranged from 1.3 to 194 ng/L. The developed method was used to determine the presence of the tested compounds in wastewater from a municipal wastewater treatment plant located in northeastern Poland. From this sample, eight analytes were detected. Concentrations of bisphenol A of 400 ng/L in influent and 100 ng/L in effluent were recorded, whereas other bisphenols reached 67 and 50 ng/L for influent and effluent, respectively. The removal efficiency of bisphenol analogues in the tested wastewater treatment plant ranged from 7 to approximately 88%.     

Gold Nanoparticles as Effective ion Traps in Poly(dimethylsiloxane) Cross-Linked by Metal-Ligand Coordination

At this time, the development of advanced elastic dielectric materials for use in organic devices, particularly in organic field-effect transistors, is of considerable interest to the scientific community. In the present work, flexible poly(dimethylsiloxane) (PDMS) specimens cross-linked by means of ZnCl₂-bipyridine coordination with an addition of 0.001 wt. %, 0.0025 wt. %, 0.005 wt. %, 0.04 wt. %, 0.2 wt. %, and 0.4 wt. % of gold nanoparticles (AuNPs) were prepared in order to understand the effect of AuNPs on the electrical properties of the composite materials formed. The broadband dielectric spectroscopy measurements revealed one order of magnitude decrease in loss tangent, compared to the coordinated system, upon an introduction of 0.001 wt. % of AuNPs into the polymeric matrix. An introduction of AuNPs causes damping of conductivity within the low-temperature range investigated. These effects can be explained as a result of trapping the Cl⁻ counter ions by the nanoparticles. The study has shown that even a very low concentration of AuNPs (0.001 wt. %) still brings about effective trapping of Cl⁻ counter anions, therefore improving the dielectric properties of the investigated systems. The modification proposed reveals new perspectives for using AuNPs in polymers cross-linked by metal-ligand coordination systems.     

Separation of Dihydro-Isocoumarins and Dihydro-Stilbenoids from Hydrangea macrophylla ssp. serrata by Use of Counter-Current Chromatography

Previously, different Hydrangea macrophylla ssp. serrata cultivars were investigated by untargeted LC-MS analysis. From this, a list of tentatively identified and unknown compounds that differ significantly between these cultivars was obtained. Due to the lack of reference compounds, especially for dihydro-isocoumarins, we aimed to isolate and structurally characterise these compounds from the cultivar ‘Yae-no-amacha’ using NMR and LC-MS methods. For purification and isolation, counter-current chromatography was used in combination with reversed-phase preparative HPLC as an orthogonal and enhanced purification workflow. Thirteen dihydro-isocoumarins in combination with other metabolites could be isolated and structurally identified. Particularly interesting was the clarification of dihydrostilbenoid glycosides, which were described for the first time in H. macrophylla ssp. serrata. These results will help us in further studies on the biological interpretation of our data.     

Comparing Efficiency of Lysis Buffer Solutions and Sample Preparation Methods for Liquid Chromatography–Mass Spectrometry Analysis of Human Cells and Plasma

The use of a proper sample processing methodology for maximum proteome coverage and high-quality quantitative data is an important choice to make before initiating a liquid chromatography–mass spectrometry (LC–MS)-based proteomics study. Popular sample processing workflows for proteomics involve in-solution proteome digestion and single-pot, solid-phase-enhanced sample preparation (SP3). We tested them on both HeLa cells and human plasma samples, using lysis buffers containing SDS, or guanidinium hydrochloride. We also studied the effect of using commercially available depletion mini spin columns before SP3, to increase proteome coverage in human plasma samples. Our results show that the SP3 protocol, using either buffer, achieves the highest number of quantified proteins in both the HeLa cells and plasma samples. Moreover, the use of depletion mini spin columns before SP3 results in a two-fold increase of quantified plasma proteins. With additional fractionation, we quantified nearly 1400 proteins, and examined lower-abundance proteins involved in neurodegenerative pathways and mitochondrial metabolism. Therefore, we recommend the use of the SP3 methodology for biological sample processing, including those after depletion of high-abundance plasma proteins.     

Comparison of Volatile Profiles of Meads and Related Unifloral Honeys: Traceability Markers

Volatile profiles of unifloral honeys and meads prepared in different ways (boiled-saturated, not boiled-unsaturated) were investigated by headspace solid-phase micro extraction (HS-SPME) and dehydration homogeneous liquid–liquid extraction (DHLLE) followed by GC-FID/MS analyses. The obtained data were analyzed by principal component analysis (PCA) to evaluate the differences between the investigated products. The volatile profiles of honey as well as the boiled and the not boiled meads prepared from it showed significant discrepancies. The meads contained more aliphatic acids and esters but fewer monoterpenes and aliphatic hydrocarbons than the honey. Significant/substantial differences were found between the boiled (more aliphatic alcohols and acids) and the not boiled meads (more aliphatic hydrocarbons and esters). Some compounds related to yeast metabolism, such as tryptophol, may be considered markers of honey fermentation. This research allowed us to identify chemical markers of botanical origin, retained and detectable in the meads: 4-isopropenylcyclohexa-1,3-diene-1-carboxylic acid and 4-(1-hydroxy-2-propanyl)cyclohexa-1,3-diene-1-carboxylic acid for linden; valeric acid, γ-valerolactone, p-hydroxybenzoic acid for buckwheat; 4-hydroxybenzeneacetic acid, homovanillic acid and trans-coniferyl alcohol for honeydew; and methyl syringate for canola.     

呋喃唑酮在凡纳滨对虾组织中代谢动力学研究

运用液相色谱-串联质谱法研究了呋喃唑酮药饵多次给药后在凡纳滨对虾体内的药物代谢动力学.研究结果表明：呋喃唑酮代谢物在血淋巴、肝胰脏、肌肉组织中的代谢过程均符合二室模型,其动力学方程分别为C血液=414.107×e^-0.092t＋124.451×e^-0.005t,C肝胰腺=1625.563×e^-0.019t＋125.700,C肌肉=120.434×e^-0.019t＋71.579×e^-0.001t.凡纳滨对虾血淋巴和肝胰腺中呋喃唑酮代谢物浓度在4h达到高峰,肌肉中药物浓度在2h达到最大值;最高峰时血淋巴、肝胰腺和肌肉中药物浓度平均为570.6μg·L^-1、1948.6μg·kg-1和210.0μg·kg-1.在血淋巴、肝胰腺和肌肉组织中呋喃唑酮代谢物浓度的吸收半衰期（t1/2α）分别为7.497h、36.206h和36.484h,消除半衰期（t1/2β）分别为132.525 h、1 000 479.217 h和505.637 h,总表观分布容积（V1/F）分别为55.775 L·kg^-1、17.16 L·kg^-1和161.574L·kg^-1.说明给药后呋喃唑酮代谢物在凡纳滨对虾体内消除缓慢,残留严重,尤其以肝胰脏残留最为明显.     

基于孔口出流模型的实验研究及理论分析

基于孔口出流模型对底部有小孔的圆柱体容器中液体液面高度随时间的变化规律进行了实验研究,并通过计入液体表面张力引起的孔口收缩和流体黏滞力导致的能量损失对实验结果进行了理论分析,与实验结果一致.