Gravimetric determination of zirconium with a new azopyrazolone derivative

3-Methyl-5-oxo-1-phenyl-2-pyrazolin-4-ylazo-2'-(6',8'-naphthalenedisulfonic acid) (disodium salt) is proposed as a new reagent for the gravimetric determination of zirconium. The precipitate formed at pH 1–1.5 can be weighed directly and there are few interferences.     

Einwirkung von p-Nitroso-dimethylanilin auf Brenztraubensäure und ihre Derivate, 6. Mitt.: Kondensation der Phenylbrenztraubensäure mit primären aromatischen Aminen

Phenylpyruvic acid reacts with p-nitroaniline to yield the 3-hydroxypyrrolinone2a, and with anilines bearing+M substituents in the p-position to yield the 3-enaminopyrrolinones1b-1e.

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5. Mitt.:M. Ruse, E. Hamburg undM. Petri, Chem. Ber.103, 3727 (1970).     

Gas chromatography-mass spectrometry of carbonyl compounds in cigarette mainstream smoke after derivatization with 2,4-dinitrophenylhydrazine

An improved gas chromatography-mass spectrometry (GC-MS) method was described for the analysis of carbonyl compounds in cigarette mainstream smoke (CMS) after 2,4-dinitrophenylhydrazine (DNPH) derivatization. Besides formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, methyl ethyl ketone, butyraldehyde, and crotonaldehyde that are routinely analyzed in cigarette smoke, this technique separates and allows the analysis of several C4, C5 and C6 isomeric carbonyl compounds. Differentiation could be made between the linear and branched carbon chain components. In cigarette smoke, the branched chain carbonyls are found at higher level than the linear chain carbonyls. Also, several trace carbonyl compounds such as methoxyacetaldehyde were found for the first time in cigarette smoke. For the analysis, cigarette smoke was collected using DNPH-treated pads, which is a simpler procedure compared to conventional impinger collection. Thermal decomposition of DNPH-carbonyl compounds was minimized by the optimization of the GC conditions. The linear range of the method was significantly improved by using a standard mixture of DNPH-carbonyl compounds instead of individual compounds for calibration. The minimum detectable quantity for the carbonyls ranged from 1.4 to 5.6 microg/cigarette.     

On the Effects of UV Radiation on the Release Ability of Glucose Embedded in Hydroxypropyl Cellulose Films

New drug delivery systems based on hydroxypropyl cellulose (HPC) and different percents of glucose were prepared and characterized to check their suitability as UV resistant patches. The spectral absorption properties of the HPC and HPC-glucose blends before and after UV irradiation were analyzed. The surface polarity and hydrophilicity were correlated with the morphology of the films and analyzed with respect to the UV exposure time and the embedded amount of glucose. The effects of UV radiation on in vitro evaluation of glucose release from the HPC films are reported. The mechanism involved in the drug release process, evaluated using the Korsmeyer-Peppas equation, was dependent on the introduced amount of glucose and less on the UV exposure time. A more polar, smoother, and less dense surface releases the glucose over larger periods of time, making the system with lower percents of glucose more adequate for the pursued purpose.     

Results from solvophobic theory applied to methylene selectivity in reversed-phase HPLC

A significant amount of work has been previously dedicated to the understanding of methylene selectivity parameter. The conventional theory applied for this understanding was mostly based on the assumption that the difference in the Gibbs free energy of transfer from the mobile phase to the stationary phase is a constant for any two compounds in a homologous series that differ by a CH₂ group. In the present study, it is shown based on solvophobic theory that this assumption is indeed correct, but it provides a theoretical justification for it. Exemplification of the results of theory was obtained using the values for methylene selectivity (α(CH₂)) measured experimentally for seven different C18 chromatographic columns including two core–shell columns and using water and either methanol or acetonitrile as an organic component. Four different homologous series of compounds were used for evaluation. The study proved the theoretical prediction that the values for α(CH₂) obtained using different homologous series of compounds are only slightly different from those obtained using the toluene–butylbenzene series. Even using different homologous series, the same type of information regarding the columns comparison, and the changes in log α(CH₂) with the solvent composition was obtained.     

Affinity capillary electrophoresis to evaluate the complex formation between poliovirus and nanobodies

It was demonstrated that nanobodies with an in vitro neutralizing activity against poliovirus type 1 interact with native virions. Here, the use of capillary electrophoresis was investigated as an alternative technique for the evaluation of the formation of nanobody–poliovirus complexes, and therefore predicting the in vitro neutralizing activity of the nanobodies. The macromolecules are preincubated offline in a specific nanobody‐to‐virus ratio and analyzed by capillary electrophoresis with UV detection. At low nanobody‐to‐virus ratios, a clear shift in migration time of the viral peak was observed. A broad peak was obtained, indicating the presence of a heterogeneous population of nanobody–virion complexes, caused by the binding of different numbers of nanobodies to the virus particle. At elevated nanobody‐to‐virus ratios, a cluster of peaks appeared, showing an additional increase in migration times. It was shown that, at these high molar excesses, aggregates were formed. The developed capillary electrophoresis method can be used as a rapid, qualitative screening for the affinity between poliovirus and nanobodies, based on a clearly visible and measurable shift in migration time. The advantages of this technique include that there is no need for antigen immobilization as in enzyme‐linked immunosorbent assays or surface plasmon resonance for the use of radiolabeled virus or for the performance of labor‐ and time‐intensive plaque‐forming neutralization assays.     

Wastes from Wood Extraction Used in Composite Materials: Behavior after Accelerated Weathering

New materials were obtained by incorporating in polypropylene (PP) matrix 60% wood wastes resulting after extraction with supercritical carbon dioxide, water, and ethanol. Structural, mechanical, thermal, and rheological characterizations, as well as moisture uptake of the composites, were evaluated before and after accelerated weathering. It was found that the extraction method influenced the composite properties due to the hydrophilic-hydrophobic balance. The addition of extracted fibers results in an increase in hardness and tensile properties and a decrease of impact strength as compared to PP.     

Gold layers on untreated and plasma-treated substrates of quaternized polysulfones

Thin gold layers were sputtered on the quaternized polysulfones (containing different tertiary amines—N,N-dimethylethylamine and N,N-dimethyloctylamine, respectively) surfaces unmodified and modified by low-pressure and high-frequency plasma treatment. Adhesion and morphological aspects of complex structures were studied for different gold sputtering and plasma treatment times. Water contact angle, atomic force microscopy, and surface properties reveal that adhesion increases with gold sputtering and plasma treatment times. Values of the mean adhesion force between cantilever and the studied surfaces, measured from AFM investigation, were correlated with quaternized polysulfone structures, modification of hydrophobicity after plasma treatment, and gold deposition on polymer surfaces.