Textile Museum Collections. SIM Method Validation for the Assessment of Pesticides

In time the environmental conditions could damage textiles (materials/ artifacts) causing the need to develop better non-destructive or at least micro-destructive analysis techniques of the samples. There are ethnographic textile artifacts that were treated in the past with various pesticides, that have not been mentioned in any document. These are often re-treated with chemicals by museum staff as a method of preventing pest infestation. Due to the progressive use of many pesticides, this paper was focused on the detection and quantification of three pesticides: malathion, methoxychlor, and permethrin (cis- and trans- isomers). Gas chromatography is one of the most widely used analytical techniques for characterizing volatile organic compounds and therefore was the analytical method of choice for the present study. Because these analytes are found at trace levels, the detection and quantification limits of analytes are very small and it is necessary to optimize and validate a SIM method - that allows the mass spectrometer to detect specific compounds with high sensitivity. In SIM mode, the instrument is set to collect data at selected masses of interest, thus increasing the accuracy and precision of the quantitative results. The present paper is aimed to develop this type of method with specificity and selectivity, high precision (expressed in terms of repeatability and intermediate accuracy), accuracy, suitable working range and linearity, and high degree of series� homogenity.

Identification of Anthocyanin Compounds in Butterfly Pea Flowers (Clitoria ternatea L.) by Ultra Performance Liquid Chromatography/Ultraviolet Coupled to Mass Spectrometry

Butterfly pea flower have great sensory attraction, but they have not yet been used widely in Vietnam. Extracts of butterfly pea flowers can be used conveniently as a natural blue colorant for food products. In this study, the identification of anthocyanin compounds in butterfly pea flowers was performed by UPLC coupled with a UV and Mass spectrometer instrument. Positive and negative ion electrospray MS/MS chromatograms and spectra of the anthocyanin compounds were determined. By analyzing the chromatograms and spectra for each ion, five anthocyanins were identified in the butterfly pea flower extract; these were delphinidin-3-(6”‐p-coumaroyl)-rutinoside, cyanidin 3-(6”-p-coumaroyl)-rutinoside, delphinidin-3-(p-coumaroyl) glucose in both cis- and trans- isomers, cyanidin-3-(p-coumaroyl-glucoside) and delphinidin-3-pyranoside. Additionally, based on their intensity, it was determined that cyanidin-3-(p-coumaroyl-glucoside) was the most abundant anthocyanin, followed by cyanidin 3-(6”-p-coumaroyl)-rutinoside, delphinidin-3-(p-coumaroyl-glucoside), delphinidin-3-(6”-p-coumaroyl)-rutinoside and delphinidin-3-pyranoside. In this study, cyanidin derivatives were discovered in butterfly pea flower extract, where these compounds had not been detected in previous studies.

Nucleophilic Substitution at Tetracoordinate Phosphorus.Stereochemical Course and Mechanisms of Nucleophilic Displacement Reactions at Phosphorus in Diastereomeric cis- and trans-2-Halogeno-4-methyl-1,3,2-dioxaphosphorinan-2-thiones: Experimental and DFT Studies

Geometrical cis- and trans- isomers of 2-chloro-, 2-bromo- and 2-fluoro-4-methyl-1,3,2-dioxaphosphorinan-2-thiones were obtained in a diastereoselective way by (a) sulfurization of corresponding cyclic PIII-halogenides, (b) reaction of cyclic phosphorothioic acids with phosphorus pentachloride and (c) halogen–halogen exchange at PIV-halogenide. Their conformation and configuration at the C4-ring carbon and phosphorus stereocentres were studied by NMR (1H, 31P) methods, X-ray analysis and density functional (DFT) calculations. The stereochemistry of displacement reactions (alkaline hydrolysis, methanolysis, aminolysis) at phosphorus and its mechanism were shown to depend on the nature of halogen. Cyclic cis- and trans-isomers of chlorides and bromides react with nucleophiles (HO−, CH3O−, Me2NH) with inversion of configuration at phosphorus. DFT calculations provided evidence that alkaline hydrolysis of cyclic thiophosphoryl chlorides proceeds according to the SN2-P mechanism with a single transition state according to the potential energy surface (PES) observed. The alkaline hydrolysis reaction of cis- and trans-fluorides afforded the same mixture of the corresponding cyclic thiophosphoric acids with the thermodynamically more stable major product. Similar DFT calculations revealed that substitution at phosphorus in fluorides proceeds stepwise according to the A–E mechanism with formation of a pentacoordinate intermediate since a PES with two transition states was observed.

SYNTHESIS OF ETHYL ESTERS OF PHENYL- AND p-PHENYL SUBSTITUTED CYCLOPROPANECARBOXYLIC ACIDS AND THEIR CONVERSION

The reaction of carboethoxycarbene with styrene and p-substituted styrenes in the conditions of thermocatalytic decomposition of ethyl diazoacetate has been studied. It has been shown that the substituents in the investigated styrenes have an essential effect on the activity of the double bond with respect to carboethoxy¬¬carbene. It has been established as a result of the investigation that the substituents in the para- position of styrene influence essentially on the activity of the double bond with respect to carboethoxycarbene. It has been revealed that carboethoxycarbene is connected to the double bond of styrene and p-styrenes practically without formation of by products. As a result of the reaction, 2-phenyl and 2-p-substituted phenyl-1-ethoxycarbonyl cyclopropane (1–4) as a mixture of cis- and trans- isomers at a ratio of~ (30:70) with the predominant formation of a trans-isomer has been obtained. The composition and structure of the synthesized compounds have been established. It has been revealed that all synthesized cyclopropane-containing compounds show the various biologically active properties. In addition, the compounds 9–12 can be used as a modifier and diluent for epoxy resin ED-20

Volatile and phenolic composition of monovarietal red wines of Valpolicella appellations

The volatile and phenolic compositions of nine monovarietal wines from the following grape varieties allowed in the Valpolicella appellation were investigated: Corvina, Corvinone, Rondinella, Molinara, Oseleta, Raboso, Croatina, Sangiovese and Cabernet-Sauvignon. Different clones were also investigated for Corvina and Corvinone, the two main varieties of the appellation. All grapes were harvested from a single experimental block and vinified following a standard protocol. Wines from different clones of Corvina were characterised by higher monoterpenols content, including linalool, α-terpineol and geraniol, as well as by a peculiar pattern of C6-alcohols. Relatively high levels of monoterpene alcohols were also found in Corvinone wines, while Oseleta showed the highest concentration of terpinen-4-ol and cis- and trans- isomers of linalool oxide. The evaluation of the wine aroma profile by means of different aromatic series indicated higher values for the “floral”, “fruity” and “ripe fruit” series for Corvina and Corvinone wines. Major differences in phenolic composition were found between the different varieties of wine. The total phenolics and total tannins values for Corvina, Corvinone, Rondinella and Molinara wines indicated relatively low phenolic content in comparison with Croatina, Oseleta, Cabernet-Sauvignon. There were also major differences in the content of individual phenolic compounds, in particular anthocyanins, between the monovarietal wines.

Unveiling the Coexistence of Cis and Trans Isomers in the Hydrolysis of ZrO2: A Coupled DFT and High-Resolution Photoelectron Spectroscopy Study

High-resolution anion photoelectron spectroscopy of the ZrO₃H₂^- and ZrO₃D₂^- anions and complementary electronic structure calculations are used to investigate the reaction between zirconium dioxide and a single water molecule, ZrO₂^0/- + H₂O. Experimental spectra of ZrO₃H₂^- and ZrO₃D₂^- were obtained using slow photoelectron velocity-map imaging (cryo-SEVI), revealing the presence of two dissociative adduct conformers and yielding insight into the vibronic structure of the corresponding neutral species. Franck-Condon simulations for both the \textit{cis}-- and \textit{trans}--dihydroxide structures are required to fully reproduce the experimental spectrum. Additionally, it was found that water-splitting is stabilized more by ZrO₂ than TiO₂, suggesting Zr-based catalysts are more reactive toward hydrolysis.

Unveiling the Coexistence of Cis and Trans Isomers in the Hydrolysis of ZrO2: A Coupled DFT and High-Resolution Photoelectron Spectroscopy Study

High-resolution anion photoelectron spectroscopy of the ZrO₃H₂^- and ZrO₃D₂^- anions and complementary electronic structure calculations are used to investigate the reaction between zirconium dioxide and a single water molecule, ZrO₂^0/- + H₂O. Experimental spectra of ZrO₃H₂^- and ZrO₃D₂^- were obtained using slow photoelectron velocity-map imaging (cryo-SEVI), revealing the presence of two dissociative adduct conformers and yielding insight into the vibronic structure of the corresponding neutral species. Franck-Condon simulations for both the \textit{cis}-- and \textit{trans}--dihydroxide structures are required to fully reproduce the experimental spectrum. Additionally, it was found that water-splitting is stabilized more by ZrO₂ than TiO₂, suggesting Zr-based catalysts are more reactive toward hydrolysis.