Thiol-ene chemistry as an effective tool for hydrophobization of cotton fabrics

In this paper, several methods of hydrophobization of cotton fabrics using the thio-ene click reaction were compared. Durable, superhydrophobic textiles were obtained in an easy way. Various variants of functionalized silsesquioxanes were used for the hydrophobization of fabrics. The synthesis of bifunctional silsesquioxanes (RSiMe₂O)₄(ViSiMe₂O)₄Si₈O₁₂ and (RSiMe₂O)₄(R’SiMe₂O)₄Si₈O₁₂ were performed via hydrothiolation of silsesquioxane derivative (ViSiMe₂O)₈Si₈O₁₂. Alkoxysilyl, alkyl and fluoroalkyl moieties were introduced as functional groups. Samples were prepared using four methods, differing in the modification method and the number of stages. During the research, fabrics were modified via (a) the dip-coating process, (b) carrying out thiol-ene click reactions directly on the surface of the fabric and (c) using both of these methods. The hydrophobicity of the fabric was evaluated by measuring the Water contact angle (WCA). The obtained samples were also examined using infrared analysis (FT-IR), Scanning electron microscope (SEM), and Elemental analysis (SEM–EDS). All analyses were performed before and after the washing process in order to verify the stability of the performed modifications.

Graphical abstract

     

Aqueous two-phase extraction as an effective tool for isolation of geniposide from gardenia fruit

Natural products are normally obtained by organic solvent extraction and many subsequent chromatographic separations. Compounds of interest are often isolated with very low yield and limited purity. An aqueous two-phase extraction process combined with a simple ethanol treatment, for removing excess inorganic salt, has been developed for preparation of geniposide from gardenia. The system was comprised of PE62, a random copolymer composed of 20% ethylene oxide and 80% propylene oxide, KH2PO4 and ethanol. To find optimal conditions, the partition behavior of geniposide under an aqueous two-phase system was investigated. Various factors were considered, including the concentration of salt, the concentration of polymer, the sample loading, and the addition of ethanol. The experimental results demonstrated that increasing salt concentration or decreasing PE62 concentration results in enhancement of the geniposide partition in the salt-rich phase. The addition of ethanol and higher sample loading also promoted the partition efficiency of geniposide. Based on this study, an optimized system containing 5% PE62, 7.5% KH2PO4, and 10% ethanol was tested on a large-scale extraction. A 39.0-g aliquot of final product (in powder form) with 77% purity of geniposide can be effectively extracted from 500 g of gardenia fruit. This process is proved to be useful for industrial application of geniposide preparation.     

Organotypic raft cultures as an effective in vitro tool for understanding Raman spectral analysis of tissue

There is a growing body of evidence showing that optical spectroscopy has the potential to be a useful in vivo diagnostic tool. Yet, so far there is no definitive cellular and biochemical understanding for the differences seen in the spectra from different tissue categories and disease states. In this study, we examine the use of organotypic raft cultures as an in vitro model of in vivo tissue conditions in an attempt to overcome some of the limitations of previously used methods. Organotypic raft cultures resembling normal and dysplastic epithelial cervical tissue were constructed and grown at an air-liquid interface for 2 weeks. Raman spectra of normal as well as dysplastic raft cultures were measured and compared with in vivo spectra from the corresponding tissue type. Histologic comparisons ensured that the raft cultures had similar structure and morphology to the corresponding intact tissue types. Raman spectra were also acquired from different layers of tissue. Spectral comparisons show that the Raman spectra of the raft cultures are similar to the spectra acquired from the cervix in vivo for both normal and dysplastic tissues. These results show that organotypic raft cultures are an effective and useful tool for the cellular and biochemical analysis of tissue spectroscopy.     

Near-infrared spectroscopy as an effective tool for monitoring the conformation of alkylammonium surfactants in montmorillonite interlayers

Application of near-infrared (NIR) spectroscopy to probing the arrangement of trimethylalkylammonium cations in montmorillonite interlayers has been demonstrated. Detailed analysis of the mid-IR (MIR) and NIR spectra of montmorillonite from Jelšový Potok (JP, Slovakia) saturated with surfactants with varying alkyl chain length (even numbers of carbon atoms from C6 to C18) was performed to show the advantages of the NIR region in characterizing surfactant conformations. The position of the ν_as(CH₂), (∼2930–2920 cm⁻¹), ν_s(CH₂) (∼2860–2850 cm⁻¹), 2ν_as(CH₂) (∼5810–5785 cm⁻¹), (ν + δ)_as(CH₂) (∼4340–4330 cm⁻¹) and (ν + δ)_s(CH₂) (∼4270–4250 cm⁻¹) signals was used as an indicator of the gauche/trans conformer ratio. For all bands, a shift toward lower wavenumber on increasing the alkyl chain length from 6 to 18 carbons suggests a transition from disordered liquid-like to more ordered solid-like structures of the surfactants. The magnitude of the shift was significantly higher for 2ν_as(CH₂) (28 cm⁻¹) than for ν_as(CH₂) (8 cm⁻¹) or ν_s(CH₂) (10 cm⁻¹), showing the NIR region to be a useful tool for examining this issue. Comparison of the IR spectra of crystalline alkylammonium salts and the corresponding organo-montmorillonites demonstrated a confining effect of montmorillonite layers on surfactant ordering. For each alkyl chain length the CH₂ bands of the organo-montmorillonites appeared at higher wavenumbers than for the unconfined surfactant, thus indicating a higher disorder of the alkyl chains. The wavenumber difference between corresponding samples was always higher in the NIR than in the MIR region. All these findings show NIR spectroscopy to be useful for conformational studies.     

Conformational switching in bis(zinc porphyrin) Langmuir-Schaefer film as an effective tool for selectively sensing aromatic amines

A conformational switching of bis(zinc octaethylporphyrin) was observed, for the first time, in a Langmuir-Schaefer film as a consequence of appropriate host-guest interactions. The spectral changes are completely reversible and the high sensitivity (～20ppb) and specificity for aromatic amines open up interesting prospects of this functional material as a performing sensor for amines.     

Application of micro-thin-layer chromatography as a simple fractionation tool for fast screening of raw extracts derived from complex biological, pharmaceutical and environmental samples

The main goal of present paper is to demonstrate the separation and detection capability of micro-TLC technique involving simple one step liquid extraction protocols of complex materials without multi-steps sample pre-purification. In the present studies target components (cyanobacteria pigments, lipids and fullerenes) were isolated from heavy loading complex matrices including spirulina dried cells, birds’ feathers and fatty oils as well as soot samples derived from biomass fuel and fossils-fired home heating systems. In each case isocratic separation protocol involving less that 1 mL of one component or binary mixture mobile phases can be completed within time of 5–8 min. Sensitive detection of components of interest was performed via fluorescence or staining techniques using iodine or phosphomolybdic acid. Described methodology can be applied for fast fractionation or screening of whole range of target substances as well as chemo-taxonomic studies and fingerprinting of complex mixtures, which are present in raw biological or environmental samples.     

Reprint of: Application of micro-thin-layer chromatography as a simple fractionation tool for fast screening of raw extracts derived from complex biological,pharmaceutical and environmental samples

The main goal of present paper is to demonstrate the separation and detection capability of micro-TLC technique involving simple one step liquid extraction protocols of complex materials without multi-steps sample pre-purification. In the present studies target components (cyanobacteria pigments, lipids and fullerenes) were isolated from heavy loading complex matrices including spirulina dried cells, birds’ feathers and fatty oils as well as soot samples derived from biomass fuel and fossils-fired home heating systems. In each case isocratic separation protocol involving less that 1 mL of one component or binary mixture mobile phases can be completed within time of 5–8 min. Sensitive detection of components of interest was performed via fluorescence or staining techniques using iodine or phosphomolybdic acid. Described methodology can be applied for fast fractionation or screening of whole range of target substances as well as chemo-taxonomic studies and fingerprinting of complex mixtures, which are present in raw biological or environmental samples.     

Use of bioluminescent bacterial sensors as an alternative method for measuring heavy metals in soil extracts

The luminescence based bacterial sensor strains Pseudomonas fluorescens OS8 (pTPT11) for mercury detection and Pseudomonas fluorescens OS8 (pTPT31) for arsenite detection were used in testing their application in detecting heavy metals in soil extracts. Three different soil types (humus, mineral and clay) were spiked with 1, 100 or 500 μg g⁻¹ Hg²⁺ or As³⁺. Samples were taken 1, 14 and 30 days and extracted with water, ammonium acetate, hydrogen peroxide and nitric acid to represent water soluble, bioavailable, organic matter bound and residual fractions, respectively. The lowest mercury-concentration measured using biosensor (0.003 μg kg⁻¹) was considerably lower than by chemical method (0.05 μg kg⁻¹). The sensor strain with pTPT31 appeared to have a useful detection range similar to that of chemical methods. Concentration results with chemical and biosensor analysis were very similar in the case of mercury-spiked samples. Although some of the arsenite samples showed higher variation between methods, it is concluded that the bacteria can be used as an alternative traditional methods for different types of samples.     

Chloride present in biological samples as a tool for enhancement of sensitivity in capillary zone electrophoretic analysis of anionic trace analytes

Effects originating from the variability of the sample matrix can be efficiently eliminated when the separation conditions are selected so that compounds of like charge with high concentration referred to as macrocomponents are embodied into the system of transient isotachophoresis. For stacking and separation of anionic trace analytes in biological samples, the presence of chloride is shown to be important to balance out effects of other macrocomponents that act against isotachophoretic stacking. Having acetoacetate, malate, citrate, and some drug metabolites in untreated human serum samples, the stacking mechanism of these compounds in an electrolyte system comprising 5 mM mandelic acid and epsilon -aminocaproic acid, pH 3.8, is explained. Analytes are monitored by indirect UV-absorption detection. Attention is paid to the minimum chloride concentration required with respect to the concentration ratio of phosphate (stacker) and lactate (destacker) present in the sample so as to ensure both stacking and separation of trace analytes. Insight into the separation process is given both with computer simulations and experiments. For selected analytes, the effect of chloride concentration on quantitative evaluation, sensitivity and limit of detection is demonstrated as well. Moreover, the applicability of the mobility window between phosphate and lactate for an additional group of metabolites is sketched.     

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry as a tool for fast identification of protein binders in color layers of paintings

Identification of materials in color layers of paintings is necessary for correct decisions concerning restoration procedures as well as proving the authenticity of the painting. The proteins are usually important components of the painting layers. In this paper it has been demonstrated that matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) can be used for fast and reliable identification of proteins in color layers even in old, highly aged matrices. The digestion can be easily performed directly on silica wafers which are routinely used for infrared analysis. The amount of material necessary for such an analysis is extremely small. Peptide mass mapping using digestion with trypsin followed by MALDI-TOFMS and identification of the protein was successfully used for determination of the binder from a painting of the 19th century.     

Bicyclo[3.3.0]octenol as an effective tool for the determination of absolute configuration of chiral acids. The absolute configuration of aryl-t-butylacetic acid

(+)-endo-cis-Bicyclo[3.3.0]oct-7-en-2-ol gave good optical yields in the kinetic resolution of aryl-t-butylacetic anhydrice, establishing the absolute configuration of t-butyl-α-naphthylacetic acid as (S) - (+).     

Use of Raman spectroscopy as an in situ tool to obtain kinetic data for organic transformations

Raman spectroscopy has been used as an in situ tool to obtain kinetic data for an organic transformation. The model reaction studied was the synthesis of 3-acetylcoumarin from the condensation between salicylaldehyde and ethyl acetoacetate with piperidine as a catalyst. The study shows that precise kinetic data can be obtained quickly and reproducibly, allowing for the facile determination of both overall reaction order and reaction order with respect to each component of the reaction. Additionally, Arrhenius parameters such as activation energy for a reaction can be readily obtained. In conjunction with computational modeling, this data-rich analysis technique also allows for in-depth probing of mechanistic aspects of reactions. Microwave heating proves to be an ideal tool for aiding in kinetic studies. It offers reproducible noncontact heating as well as precise temperature monitoring and data recording.     

Synthesis of Zr-containing FSM-16 as an effective support for Co catalyst in the Fischer-Tropsch synthesis

Zr⁴⁺ ions have been introduced into the framework of FSM-16 using a sol-gel method at Si/Zr ≥ 200 (molar ratio). Co/Zr-FSM-16 showed high CO conversion and a high selectivity for C₅₊ hydrocarbons in the Fischer-Tropsch synthesis due to the high surface area of FSM-16 and the isomorphously substituted Zr⁴⁺ as a co-catalyst.     

Nitromethane-lithium perchlorate system as an effective stimulator for skeletal rearrangements in AdE reactions of sulfur-containing reagents

Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1194–1195, May, 1988.     

Neutron activation analysis as a tool for checking the reliability of spectrophotometric methods for the determination of molybdenum and tungsten in biological materials

A new method for the simultaneous determination of molybdenum and tungsten in biological materials by neutron activation analysis has been developed. It involves a single step radiochemical separation of both elements by extraction chromatography using -benzoinoxime supported on Bio-Beads SM 2. Good accuracy and precision of the method was demonstrated analyzing Bowen's Kale and IAEA's H-8 /Horse Kidney/ reference materials. The method was applied to check the reliability of the results obtained by one standard and one newly developed spectrophotometric methods for the molybdenum content in some plant materials.     

Alkylation of aryl 3-oxopropanedithioate and 3-amino-1-aryl-3-thioxo-1-propanones as an effective tool for the construction of differently substituted thiophenes and annulated thiophenes

The alkylation of aryl 3-oxopropanedithioate with α-haloketones under different reaction conditions afforded substituted aryl[2-(methylsulfanyl)-4-phenyl-3-thienyl]methanones and [3-aryl-5-(methylsulfanyl)-2-thienyl](phenyl)methanones. The same strategy was extended to 3-amino-1-aryl-3-thioxo-1-propanones to afford aryl[2-amino-4-phenyl-3-thienyl]methanones and ethyl 3-phenyl-5-piperidino-2-thiophene carboxylate.