Analysis of VOCs in Urine Samples Directed towards of Bladder Cancer Detection

Bladder cancer is one of most common types of cancer diagnosed in the genitourinary tract. Typical tests are costly and characterized by low sensitivity, which contributes to a growing interest in volatile biomarkers. Head space solid phase microextraction (SPME) was applied for the extraction of volatile organic compounds from urine samples, and gas chromatography time of flight mass spectrometry (GC×GC TOF MS) was used for the separation and detection of urinary volatiles. A cohort of 40 adult patients with bladder cancer and 57 healthy persons was recruited. Different VOC profiles were obtained for urine samples taken from each group. Twelvecompounds were found only in the samples from theBC group.The proposed candidate biomarkers are butyrolactone; 2-methoxyphenol; 3-methoxy-5-methylphenol; 1-(2,6,6-trimethylcyclohexa-1,3-dien-1-yl)-2-buten-1-one; nootkatone and 1-(2,6,6-trimethyl-1-cyclohexenyl)-2-buten-1-one.Since most of the studies published in the field are proving the potential of VOCs detected in urine samples for the screening and discrimination of patients with bladder cancer from healthy, but rarely presenting the identity of proposed biomarkers, our study represents a novel approach.     

Effect of ethanol in the organic phase on liquid-liquid extraction in monosegmented flow analysis. Determination of zinc in drugs

In liquid-liquid extraction performed by monosegmented flow analysis (MSFA), the aqueous sample is introduced between two air bubbles and flows, under restricted dispersion, through a glass extraction tube where the analyte is retained, usually at pH higher than 8. The retained analyte is removed to a small volume of an organic phase containing a ligand which is introduced after the second air bubble. In this work, the effect of the organic phase composition on the extraction of Cu(II), Zn(II) and Cd(II) in MSFA systems was investigated by changing the ethanol content (0.1-4% v/v) in toluene, chloroform and carbon tetrachloride. The extracting efficiency of the organic phases containing ethanol was evaluated by using dithizone (DT), 1-2-pyridylazo-2 naphthol (PAN) and sodium diethyldithiocarbamate (DDTC) as ligands for the metals. The MSFA extraction system was improved by introducing a new syringe-based device for organic phase delivery. The presence of ethanol in the organic phase shows a remarkable (up to ten times) effect on the extraction efficiency of the flow system when DT is employed. Its presence is mandatory if DDTC is used, as it accounts for ligand solubility in the organic phase. The extraction efficiency also increases with the pH of the aqueous phase as a consequence of higher ionisation of the glass silanols, where the analytes are adsorbed before extraction. The system has been evaluated for determination of Zn(II) in drugs showing a mean R.S.D. of 2.2% and mean relative accuracy of 4.4%, when compared with atomic absorption spectrometry results. Typical sample frequency, sample and organic phase consumption are 30 samples per hour, 200 and 100 mul, respectively.     

Contributions to the complexometric determination of cation mixtures: Simultaneous titration of iron(iii) and aluminium in the presence of ammonium thiocyanate as indicator

With thiocyanate as indicator iron(III) and aluminium(III) can be titrated simultaneously if [Fe⁺³]/[Al⁺³] ? $\text{1}\text{4}$; iron(III) is titrated directly with EDTA, and aluminium(III) is determined by back-titration of the excess of EDTA with cobalt nitrate solution in an acetone-water medium.     

Kinetic parameters of a cyanate ester resin catalyzed with different proportions of nonylphenol and cobalt acetylacetonate catalyst

The isothermal cure of a dicyanate ester monomer has been investigated by differential scanning calorimetry (DSC) in the presence of different quantities of a catalyst system formed by nonylphenol (NP) and cobalt (II) acetylacetonate (Co(AcAc)₂). Two sets of experiences were studied. Firstly, the NP composition was varied from 0 to 10 per hundred resin (phr) and secondly, the Co(AcAc)₂ loadings were changed at 2 phr of NP. It has been observed that the cyanate conversion increases significantly after the first addition of the metal catalyst and, also, at the same time the thermal stability improves. Moreover, the kinetic data have been fitted with a second-order equation respect to the cyanate conversion in the kinetically conversion regime. Also, both the activation energies and the kinetic order respect to the NP and the Co(AcAc)₂ have been determined.     

Spektrochemische Bestimmung von Spurenelementen in reinem Gold

Zusammenfassung Eine Spektrochemische Methode zur Bestimmung von Spuren der Elemente As, Sb, Fe, Mn, Pb, Ni, Bi, Cu, Pt, Pd, Cd, Rh und Ag in reinem Gold wird beschrieben. Zunächst wird das Gold durch Extraktion aus 3 N HCl mit Methylisobutylketon abgetrennt. Die Verunreinigungselemente werden dann an spektralreinem Graphitpulver mit 4% NaCl und 0,02% Co als Bezugselement adsorbiert und im Wechselstromabreißbogen 3,5 min bei 10 A angeregt. Die Spektren wurden mit einem UV-Spektrograph Q 24 auf ORWO-Spektralplatten Blau Extrahart aufgenommen. Die quantitative Bestimmungsgrenze für Mn, Pt und Ag beträgt 10^–6%, für Fe, Pb, Ni, Bi, Cu, Pd und Rh 10^–5% und für As, Sb und Cd 10^–4%. Die relative Standardabweichung überschreitet nicht 30%.

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Spectrochemical determination of trace elements in pure gold

A spectrochemical method for the determination of traces of As, Sb, Fe, Mn, Pb, Ni, Bi, Cu, Pt, Pd, Cd, Rh and Ag in pure gold is described. The gold is first separated by extraction into methyl isobutyl ketone from 3 N HCl solution and then the trace elements are adsorbed on spectrally pure carbon powder containing 4% NaCl and 0.02% Co as reference standard, and excited in an 10 A a.c. arc for 3.5 min. Emission spectra were recorded on ORWO-Blau Extrahart plates with an UV-spectrograph Q 24. Limits of detection were 10^–6% for Mn, Pt and Ag; 10^–5 % for Fe, Pb, Ni, Bi, Cu, Pd and Rh; 10^–4% for As, Sb and Cd. Relative standard deviation was not exceeding 30%.

     

A Modular Synthetic Approach to Monocyclic 1,4‐Azaborines

A simple and general method for the synthesis of a wide range of monocyclic 1,4‐azaborines, including the first examples containing B heteroatoms is described. Post‐heterocycle‐formation olefin isomerization was employed as a key strategy. This new synthetic method provides fundamental insight into the resonance stabilization and photophysical properties of 1,4‐azaborines.     

The Binary Group 4 Azides [PPh4]2[Zr(N3)6] and [PPh4]2[Hf(N3)6]

The binary zirconium and hafnium polyazides [PPh₄]₂[M(N₃)₆] (M=Zr, Hf) were obtained in near quantitative yields from the corresponding metal fluorides MF₄ by fluoride–azide exchange reactions with Me₃SiN₃ in the presence of two equivalents of [PPh₄][N₃]. The novel polyazido compounds were characterized by their vibrational spectra and their X‐ray crystal structures. Both anion structures provide experimental evidence for near‐linear M‐N‐N coordination of metal azides. The species [M(N₃)₄], [M(N₃)₅]^? and [M(N₃)₆]^2? (M=Ti, Zr, Hf) were studied by quantum chemical calculations at the electronic structure density functional theory and MP2 levels.     

Unsupported palladium nanoparticles for ethanol cyclic voltammetric sensing in alkaline media

Carbon-supported palladium nanostructures have had a recent rise in their use for ethanol oxidation applications. In this work, we present the use of unsupported palladium nanoparticles (PdNPs), synthesized by sodium borohydride chemical reduction method, for ethanol electrochemical sensing. The unsupported PdNPs were studied for ethanol oxidation in alkaline media by cyclic voltammetry, and additionally were characterized using transmission electron microscopy, and x-ray photoelectron spectroscopy. The performance of unsupported PdNP-modified glassy carbon electrodes for the electrochemical ethanol oxidation in 1.0 M potassium hydroxide (KOH) solution was studied by cyclic voltammetry. These electrochemical results demonstrated that the unsupported PdNPs have very promising catalytic activity towards the oxidation of ethanol in alkaline media with good detection performance in the concentration range of 2304 to 288 ppm (i.e., 50.00 to 6.25 mM). The detection limit and linear correlation coefficient were 49.3 ppm (1.10 mM) and 0.9998, respectively. The unsupported PdNP-modified glassy carbon electrodes presented good cyclic voltammetric stability for ethanol sensing application in alkaline media.     

Evaluation of retention and release processes of two antibiotics from the biocompatible core-shell microparticles

By dropwise addition of a chitosan solution into different non-solvent, such as: 1 N and 2 N NaOH as well as 1 N NaOH: C₂H₅OH mixture (2:1, v/v) at temperature of 25 °C and 50 °C under stirring, the spherical pure chitosan microparticles were performed. As solvents for chitosan was used 0.1 N acetic acid or 0.1 N HCl. The immersion of the pure chitosan microparticles in hyaluronan solution led to complex microparticles, namely chitosan microparticles covered by a hyaluronan layer. For all the microparticles performed the behaviours in the retention process of two antibiotics: chloramphenicol succinate sodium salt and cefotaxime sodium salt were analyzed. Also, the study shows the release behaviour of cefotaxime sodium salt by the microparticles loaded with this drug. Among the microparticles performed a type of complex microparticles can be considered a suitable drug delivery system for cefotaxime. These microparticles were performed by dropwise addition of chitosan solution in 0.1 N acetic acid into the 1 N NaOH: C₂H₅OH (2:1, v/v) non-solvent at 20 °C for 3 h, followed by their washing up to alkalinity loss and the immersion in hyaluronan solution of 10 g/L concentration for 24 h.     

Mechanochemically initiated polymerizations—5. Polymerization by vibratory milling of acrylamide and methacrylamide

Mechanochemical polymerization by vibratory milling of acrylamide and methacrylamide is discussed. The influences of duration, nature of medium and temperature are examined. The polymers are characterized by elemental analysis, i.r.-spectroscopy. X-ray and by determination of some properties. An anion-radical mechanism is proposed.