Evaluation of the Quality of Ink-Jet Printed Paper by Planar Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - Paper chromatography and thin-layer chromatography (TLC) are two efficient analytical methods that can be used to characterize...     

Microchip capillary electrophoresis with a boron-doped diamond electrochemical detector for analysis of aromatic amines

The attractive features of a boron-doped diamond (BDD) thin-film detector for microchip capillary electrophoretic (CE) separations of dye-related amino-substituted aromatic compounds are described. The diamond electrode was employed in the end-column amperometric detection of 4-aminophenol (4-AP), 1,2-phenylenediamine (1,2-PDA), 2-aminonaphthalene (2-AN), 2-chloroaniline (2-CA), and o-aminobenzoic acid (o-ABA), and its attractive behavior was compared to commonly used screen-printed carbon and glassy-carbon electrodes. These conventional electrode materials exhibit a significant degree of passivation and low sensitivity to the above-mentioned environmental pollutants. The diamond-based electrochemical detection system displayed a favorable analytical performance, including lower noise levels, higher peak resolution with enhanced sensitivity, and improved resistance against electrode passivation. Factors influencing the on-chip analysis were assessed and optimized. The diamond detector displayed detection limits of 2.0 and 1.3 microM for 4-AP and 2-AN, respectively, and a wide linear response for these compounds over the 2-50 microM range. The enhanced stability was demonstrated by relative standard deviation (RSD) values of 1.4% and 4.7% for 100 microM 1,2-PDA and 200 microM 2-CA, respectively, for repetitive detections (n = 7). Besides, the simultaneously observed current decrease was 2.4 and 9.1% for 1,2-PDA and 2-CA, respectively (compared to 21.8 and 41.0% at the screen-printed carbon electrode and 28.3 and 34.1% at the glassy carbon electrode, respectively). The favorable properties of the diamond electrode indicate great promise for environmental applications in CE and other microchip devices.     

Glaspincette

Ohne Zusammenfassung(Briefliche Mittheilung.)     

Zu A. Sauer's Schwefelbestimmungsmethode

Ohne ZusammenfassungChemische Aphorismen über Steinkohlen von Dr. F. Muck. Bochum 1873. Diese Zeitschrift Bd.12, 32 und 178.     

Ueber Beseitigung grosser Mengen von Chlornatrium (und Chlorkalium) bei Mineralanalysen

Ohne Zusammenfassung     

Constant temperature hot-wire anemometer practice in supersonic flows

The performance of a constant-temperature inclined hot-wire in a supersonic flow is critically examined. It is shown that empirical heat transfer correlations commonly used for calibrating hot wires in subsonic flow cannot be used when the flow is supersonic. Calibration and measurement procedures appropriate to supersonic flow are suggested, together with the possible limits on their validity. The instrument was used to measure the mass-weighted Reynolds shear stress in a zero pressure gradient Mach 2.9 turbulent boundary layer. A comparison with the available data suggests good agreement, as long as the normal Mach number remains supersonic under all conditions.     

Design and synthesis of bombykol analogues for probing pheromone-binding protein-ligand interactions

Mono-, difluorinated, and thioanalogues of Bombyx mori female sex pheromones (bombykol, 1) were designed according to the ab initio calculations. These rationally designated analogues were synthesized using hydroboration and Sonogashira coupling strategy via (5E,7Z)-undecadien-1-ol (10) as a common intermediate. A new simplified binding assay based on nanoLC-linear ion trap ESI-MS for quantifying complexation of the B. mori pheromone-binding protein (BmPBP) with native (1) and prepared analogues was developed. The binding properties of native 1 and thioanalogue 4 with PBP were studied in detail. The dissociation constant (K_D) of 1 and 4 was determined to be 2.1×10⁻⁶ M and 2.4×10⁻⁶ M, respectively. The similar values for both ligands correlated with ab initio calculations. The new binding assay could be used to determine the K_D of other PBPs.     

Ueber quantitative Bestimmung des Antimons, gegrundet auf die Leichtl?slichkeit des hydratischen Antimonsulfids in schwefelreicherem Ammoniumsulfid

Ohne Zusammenfassung