Optimization of extraction procedure and determination by high performance liquid chromatography of flavonols and phenolic acids from Hypericum Perforatum L.

Hypericum perforatum is a medicinal plant which has been known in traditional medicine as an antiinflammatory and healing agent. Nowadays the use of Hypericum extracts is concerned mainly with antidepressive applications. In the present work, HPLC – RP- C18 column chromatography with photodiode array detection was applied for the determination of the derivatives of cinnamic and benzoic acid (e.g., caffeic, chlorogenic, ferulic, sinapic, gallic acids) (Fig.1.) and flavonols - quercetine derivatives (quercetine, rhamnetine, quercitrin, mirycetine, keampferol and rutin) in Hypericum Perforatum. Phenolic compounds were extracted from the sample matrix with ethanol and ethanolwater mixture in different ratios solvent (3:7; 8:2; v/v) at 30°C and 60°C in water-bath shaker and by ultrasonic extraction and then analyzed before and after acid and basic hydrolysis. The total amount of studied flavonols and phenolic acids were compared with the total flavonoids content (TFC) and with total polyphenols content (TPC). UV-Vis spectrometry was used to investigate methods for qualitative and quantitative determination of these compounds

Hexakis(1H-imidazole-κN 3)cobalt(III) tris­(hexa­fluoridophosphate) hexa­hydrate

In the crystal structure of the title compound, [Co(C3H4N2)6](PF6)3·6H2O, the CoIII atom lies on a special position with site-symmetry and the P atom is located on a special position with site symmetry . The CoIII atom has an almost ideal octa­hedral coordination formed by the N atoms of six imidazole ligands. The water mol­ecules form hydrogen-bonded helical chains propagating in [001] by O—H⋯O inter­actions with a distance of 2.913 (2) Å. They simultaneously inter­act as hydrogen-bond acceptors and donors with the cations and anions, respectively, resulting in the formation of a three-dimensional assembly. Weak C—H⋯F inter­actions further stabilize the crystal structure

The influence of pH and selected cations on the spectrofluorometric determination of oxytetracycline hydrochloride

The spectrofluorometric method for the oxytetracycline hydrochloride in pure and in veterinary products Tetrox and Oxymed 50 determination is described. The influence of pH solution and presence selected cations on fluorescence intensity were studied too. It was ascertained that the highest fluorescence intensity take place at pH=9. Moreover, the quenching of fluorescence intensity was observed at presence Ca2+, Al3+ and Fe3+ in contrast to Mg2+ which caused increasing of intensity. The obtained recovery (97.23±0.12% for Tetrox and 95.21±0.10% for Oxymed 50) values meet the European Pharmacopoeia requirement. Moreover, the relative standard deviation (RSD) was below 0.23% confirmed high precise of the method. The statistical test (t-Student and F-Snedecor) used for comparison spectrofluorometric and chromatographic methods pointed that they are comparable in respect of precision but not of accuracy

Facile preparation of copper nitride powders and nanostructured films

The simple fluorinated precursor, copper(II) trifluoroacetate, Cu(CF3COO)2 can be effectively utilised in the synthesis of Copper(I) nitride, Cu3N, powders and films by combinations of wet processing and gas-solid (ammonolysis) techniques. The resulting materials were characterized by powder X-ray diffraction (PXD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), diffuse reflectance UV-visible spectroscopy (DRUV-Vis), Raman spectroscopy, infrared spectroscopy (IR), thermogravimetric-differential thermal analysis-mass spectrometry (TG-DTA-MS) and nitrogen adsorption (BET) analysis. Moreover, variable temperature IR (VT-IR) studies of the solid phase were performed in situ during ammonolysis. Single-phase Cu3N powders composed of sub-micron scale platelets can be produced over relatively short reaction times. Materials prepared in this way are stoichiometric narrow band gap semiconductors. The same trifluoroacetate precursor was used to prepare nanostructured nitride films by dip coating. The surface microstructure was investigated and evaluated relative to films deposited by spin coating and nebulisation using soluble carboxylate precursors

Studies of levels of biogenic amines in meat samples in relation to the content of additives

<p>The impact of meat additives on the concentration of biogenic amines and the quality of meat was studied. Fresh white and red meat samples were fortified with the following food additives: citric and lactic acids, disodium diphosphate, sodium nitrite, sodium metabisulphite, potassium sorbate, sodium chloride, ascorbic acid, α-tocopherol, propyl 3,4,5-trihydroxybenzoate (propyl gallate) and butylated hydroxyanisole. The content of spermine, spermidine, putrescine, cadaverine, histamine, tyramine, tryptamine and 2-phenylethylamine was determined by capillary isotachophoretic methods in meat samples (fresh and fortified) during four days of storage at 4°C. The results were applied to estimate the impact of the tested additives on the formation of biogenic amines in white and red meat. For all tested meats, sodium nitrite, sodium chloride and disodium diphosphate showed the best inhibition. However, cadaverine and putrescine were characterised by the biggest changes in concentration during the storage time of all the additives. Based on the presented data for the content of biogenic amines in meat samples analysed as a function of storage time and additives, we suggest that cadaverine and putrescine have a significant impact on meat quality.</p

Electron interaction with copper(II) carboxylate compounds

In the present study we have performed electron collision experiments with copper carboxylate complexes: [Cu2(t-BuNH2)2(µ-O2CC2F5)4], [Cu2(s-BuNH2)2(µ-O2CC2F5)4], [Cu2(EtNH2)2(µ-O2CC2F5)4], and [Cu2(µ-O2CC2F5)4]. Mass spectrometry was used to identify the fragmentation pattern of the coordination compounds produced in crossed electron – molecular beam experiments and to measure the dependence of ion yields of positive and negative ions on the electron energy. The dissociation pattern of positive ions contains a sequential loss of both the carboxylate ligands and/or the amine ligands from the complexes. Moreover, the fragmentation of the ligands themselves is visible in the mass spectrum below m/z 140. For the studied complexes the metallated ions containing both ligands, e.g., Cu2(O2CC2F5)(RNH2)+, Cu2(O2CC2F5)3(RNH2)2+ confirm the evaporation of whole complex molecules. A significant production of Cu+ ion was observed only for [Cu2(µ-O2CC2F5)4], a weak yield was detected for [Cu2(EtNH2)2(µ-O2CC2F5)4] as well. The dissociative electron attachment processes leading to formation of negative ions are similar for all investigated molecules as the highest unoccupied molecular orbital of the studied complexes has Cu–N and Cu–O antibonding character. For all complexes, formation of the Cu2(O2CC2F5)4−• anion is observed together with mononuclear DEA fragments Cu(O2CC2F5)3−, Cu(O2CC2F5)2− and Cu(O2CC2F5)−•. All dominant DEA fragments of these complexes are formed through single particle resonant processes close to 0 eV

Copper Nitride Nanowire Arrays—Comparison of Synthetic Approaches

Copper nitride nanowire arrays were synthesized by an ammonolysis reaction of copper oxide precursors grown on copper surfaces in an ammonia solution. The starting Cu films were deposited on a silicon substrate using two different methods: thermal evaporation (30 nm thickness) and electroplating (2 μm thickness). The grown CuO or CuO/Cu(OH)2 architectures were studied in regard to morphology and size, using electron microscopy methods (SEM, TEM). The final shape and composition of the structures were mostly affected by the concentration of the ammonia solution and time of the immersion. Needle-shaped 2–3 μm long nanostructures were formed from the electrodeposited copper films placed in a 0.033 M NH3 solution for 48 h, whereas for the copper films obtained by physical vapor deposition (PVD), well-aligned nano-needles were obtained after 3 h. The phase composition of the films was studied by X-ray diffraction (XRD) and selected area electron diffraction (SAED) analysis, indicating a presence of CuO and Cu(OH)2, as well as Cu residues. Therefore, in order to obtain a pure oxide film, the samples were thermally treated at 120–180 °C, after which the morphology of the structures remained unchanged. In the final stage of this study, Cu3N nanostructures were obtained by an ammonolysis reaction at 310 °C and studied by SEM, TEM, XRD, and spectroscopic methods. The fabricated PVD-derived coatings were also analyzed using a spectroscopic ellipsometry method, in order to calculate dielectric function, band gap and film thickness