On reduction of the drug diflunisal in non-aqueous media

Monatshefte für Chemie - Chemical Monthly - The electrochemical reduction of diflunisal was studied in dimethyl sulfoxide on static mercury drop electrode. Diflunisal yields one irreversible...     

Tritium in organic matter around Krško Nuclear Power Plant

The aim of the research was to obtain first results of tritium in the organic matter of environmental samples in the vicinity of Kr?ko NPP. The emphasis was on the layout of suitable sampling network of crops and fruits in nearby agricultural area. Method for determination of tritium in organic matter in the form of Tissue Free Water Tritium (TFWT) and Organically Bound Tritium (OBT) has been implemented. Capabilities of the methods were tested on real environmental samples and its findings were compared to modeled activities of tritium from atmospheric releases and literature based results of TFWT and OBT.     

Determination of the thermal modification degree of beech wood using thermogravimetry

Thermal modification is one of the environmental friendly wood preservation technologies. During this process, changes of the main woody cell wall components occur, which lead to improved dimensional stability, lower hygroscopicity and improvement in biological durability. Several chemical reactions which occur during thermal treatment of wood caused changes in wood properties. During TG measurements, thermal decomposition reactions, which was not completed during previous thermal modification process, continued in wood samples, meaning that more thermally treated samples exhibited lower mass losses in a certain or whole temperature range up to 600 °C. Therefore, mass loss, obtained within selected temperature range, could be used as a marker of previous thermal treatment. The aim of the present work is to evaluate suitability of a thermogravimetric method (TG) for determination of a degree of thermal treatment of beech wood. On the basis of thermally untreated sample and those which were thermally modified at 180, 190, 200, 210, 215 and 220 °C in the absence of oxygen, respectively, and with known values of mass loss during the modification processes, several calibration curves were constructed. They represent mass loss in a certain temperature range during TG measurement versus mass loss during previous thermal modification. In a temperature range from 130 to 300 °C and from 130 to 320 °C under nitrogen atmosphere, a linear dependence was observed; correlation coefficients R ² were 0.87 and 0.91, respectively. In wider temperature range and under air atmosphere, lower correlation coefficients were obtained. High correlation coefficient, higher than 0.95, was observed in a temperature range from 25 to 130 °C under both atmospheres. In this region, dehydration due to rehydration of thermally modified samples occurs. The results of this work were compared with those obtained for Norway spruce.     

Investigation of thermal stability, spectral, magnetic, and antimicrobial behavior for new complexes of Ni(II), Cu(II), and Zn(II) with a bismacrocyclic ligand

Novel complexes of type M₂LCl₄·nH₂O (M: Ni, n = 4; M: Cu, n = 2.5 and M: Zn, n = 1.5; L: ligand resulted from 1,3-phenylenediamine, 3,6-diazaoctane-1,8-diamine, and formaldehyde one-pot condensation) were synthesized and characterized. The ligand was also isolated and characterized. The complexes features have been assigned from microanalytical, electrospray ionization tandem mass spectrometry, IR, UV–vis, ¹H NMR, and EPR spectra as well as magnetic data at room temperature. Simultaneous thermogravimetric/dynamic scanning calorimetry/evolved gas analysis measurements were performed to evidence the nature of the gaseous products formed in each step. Processes as water elimination, fragmentation, and oxidative degradation of the organic ligand as well as chloride elimination were observed during the thermal decomposition. The final product of decomposition was metal(II) oxide except for copper complex where CuCl remained also in the oxide network. The complexes exhibited an improved antibacterial activity in comparison with the ligand concerning both planktonic as well as biofilm-embedded cells.     

Crystal Structure and Solid State 13C Nmr Analysis of Methyl 3,4,6-Tri-O-Acetyl-2-Deoxy-2-(3-Phenylureido)-β-D-Glucopyranoside

ABSTRACT

The X-ray diffraction analysis of methyl 3,4,6-tri-O-acetyl-2-deoxy-(3-phenylureido)-β-D-glucopyranoside was performed and showed that the molecules are associated by two NHz.O=C hydrogen bonds. One molecule with disorder of an acetyl group at C-4 was found in the asymmetric crystal unit. The signals in ¹³C CPMAS NMR spectrum are duplicated indicating that local symmetry is lower than those of the crystal.     

Addition of Al(OH)3 versus AlO(OH) nanoparticles on the optical,thermo-mechanical and heat/oxygen transmission properties of microfibrillated cellulose films

Cellulose - Differently structured aluminum (tri/mono) hydroxide (Al(OH)3 /AlO(OH)) nanoparticles were prepared and used as thermal-management additives to microfibrillated cellulose (MFC),...     

Fast simultaneous LC/MS/MS determination of 10 active compounds in human serum for therapeutic drug monitoring in psychiatric medication

A UPLC/MS/MS method with simple protein precipitation has been validated for the fast simultaneous analysis of agomelatine, asenapine, amisulpride, iloperidone, zotepine, melperone, ziprasidone, vilazodone, aripiprazole and its metabolite dehydro‐aripiprazole in human serum. Alprenolol was applied as an internal standard. A BEH C₁₈ (2.1 × 50 mm, 1.7 µm) column provided chromatographic separation of analytes using a binary mobile phase gradient (A, 2 mmol/L ammonium acetate, 0.1% formic acid in 5% acetonitrile, v/v/v; B, 2 mmol/L ammonium acetate, 0.1% formic acid in 95% acetonitrile, v/v/v). Mass spectrometric detection was performed in the positive electrospray ionization mode and ion suppression owing to matrix effects was evaluated. The validation criteria were determined: linearity, precision, accuracy, recovery, limit of detection, limit of quantification, reproducibility and matrix effect. The concentration range was as follows: 0.25–1000 ng/mL for agomelatine; 0.25–100 ng/mL for asenapine and iloperidone; 2.5–1000 ng/mL for amisulpride, aripiprazole, vilazodone and zotepine; 2.3–924.6 ng/mL for dehydroaripiprazole; 2.2–878.4 ng/mL for melperone; and 2.2–883.5 ng/mL for ziprasidone. Limits of quantitation below a therapeutic reference range were achieved for all analytes. Intra‐run precision of 0.4–5.5 %, inter‐run precision of 0.6–8.2% and overall recovery of 87.9–114.1% were obtained. The validated method was successfully implemented into routine practice for therapeutic drug monitoring in our hospital. Copyright © 2015 John Wiley & Sons, Ltd.     

Modulating the Enantiodiscrimination Features of Inherently Chiral Selectors by Molecular Design: A HPLC and Voltammetry Study Case with Atropisomeric 2,2’-Biindole-Based Monomers and Oligomer Films

A family of inherently chiral electroactive selectors based on the 2,2’-biindole atropisomeric scaffold, of easy synthesis and modulable functional properties, is studied in cascade in two enantioselection contexts. They are at first investigated as probes in enantioselective HPLC, studying molecular structure and temperature effects, and achieving very efficient semipreparative enantioseparation. The enantiomers thus obtained, of remarkable chiroptical features (optical rotation as well as circular dichroism), are successfully applied as selectors in chiral voltammetry in different media for discrimination of the enantiomers of chiral electroactive probes, either by conversion into enantiopure electroactive electrode surfaces by electrooligomerization on glassy carbon substrate (the two monomers with shorter alkyl chains), or as chiral additive in achiral ionic liquid (the monomer with longest alkyl chains). Discrimination is conveniently and reproducibly achieved in terms of significant potential differences for the two enantiomers, specularly inverting either probe or selector configuration. In one case successful discrimination is also observed with the two probe enantiomers concurrently present, either as racemate or with enantiomeric excesses, neatly accounted for by the peak current ratios.     

Synthesis and Structure of 2‐Hydroxy‐2‐Methyl‐1,3‐Bis‐(Methyl 3′,4′,6′‐Tri‐O‐Acetyl‐β‐D‐Glucopyranosid‐2‐yl)‐Imidazolidine‐4,5‐Dione

The title compound was synthesized starting from methyl 3,4,6‐tri‐O‐acetyl‐2‐acetamido‐2‐deoxy‐β‐D‐glucopyranoside, oxalyl chloride, and methyl 3,4,6‐tri‐O‐acetyl‐2‐amino‐2‐deoxy‐β‐D‐glucopyranoside. The crystal and molecular structure of the obtained imidazolidine‐4,5‐dione have been determined by X‐ray analysis as well as ¹H and ¹³C NMR spectroscopy.