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31.
US Environmental Protection Agency Method 300.0 specifies the use of an IonPac AS4A anion-exchange column with a carbonate-hydrogencarbonate eluent and suppressed conductivity detection for the determination of inorganic anions in environmental waters by ion chromatography. Hydroxide eluents have not typically been used for the routine analysis of common inorganic anions due to the lack of an appropriate hydroxide selective column and the difficulty in preparing contaminant free hydroxide eluents. The use of ion chromatography with a hydroxide-selective IonPac AS17 column, automated eluent generation and potassium hydroxide gradient represents a new approach to the routine determination of inorganic anions in environmental waters. This new approach, which is a modification of Method 300.0, allows equivalent method performance with improved linearity, precision, and method detection limits. The AS17 column provides superior retention of fluoride from the column void volume and improved resolution from small organic acids, such as formate and acetate, compared to the AS4A column. Quantitative recoveries were obtained for all the common inorganic anions spiked into typical environmental waters using this new approach, and the Performance Based Measurement System Tier 1 method validation quality control acceptance criteria are well within the acceptable ranges defined by Method 300.0. In addition, the EG40 eluent generator eliminates the need to manually prepare eluents, increasing the level of automation and ease-of-use of the ion chromatography system. 相似文献
32.
Annika Pohl Gunnar Westin Kjell Jansson 《Journal of Sol-Gel Science and Technology》2003,26(1-3):257-260
The first purely alkoxide-based sol-gel route to nano-phase powders and thin films of perovskite La0.75Sr0.25MnO3 is described. The phase and microstructure evolution on heat treatment of free gel films to form the target nano-phase oxide were investigated by TGA, IR spectroscopy, powder XRD, SEM and TEM-EDS. The xerogel consisted of a hydrated oxo-carbonate, without remaining alkoxo groups or solvent. Heating at 5°C·min–1 decomposed the carbonate groups and yielded the pure perovskite La0.75Sr0.25MnO3 at 760°C. The cell dimensions were virtually unchanged from the first observation of perovskite at 680°C, to 1000°C, 4 h. The monoclinic cell of La0.75Sr0.25MnO3 obtained at 1000°C, 4 h, had the dimensions a = 5.475(1), b = 5.504(2), c = 7.771(1) Å, = 90.50(2), fitting the literature data quite well. Crack-free, homogenous, 150 nm thick La0.75Sr0.25MnO3 films were prepared by spin-coating Si/SiO2/TiO2/Pt and polycrystalline -Al2O3 substrates with a 0.6 M alkoxide solution, followed by heating at 5°C·min–1 to 800°C, 30 min. 相似文献
33.
S. Pohl 《无机化学与普通化学杂志》1983,498(3):20-24
Crystal Structure of AlI3 · 2 PI3:P2I5+ AlI4? The crystal structure of the title compound was determined from single crystal X-ray data. P2I5+AlI4? crystallizes in the orthorhombic space group Pbca, a = 1 088.3, b = 1 827.3, c = 2 031.6 pm, V = 4040 · 106 pm3, Z = 8. The P2I5+ and AlI4? ions are connected by weak iodine-iodine bonds (I? I distances between 343.5 and 376.3 pm). The mean P? I and Al? I bond lengths were found to be 240.9 and 252.9 pm respectively. 相似文献
34.
Marcela Dvorakova Marie Pribylova Radek Pohl Marie E. Migaud Tomas Vanek 《Tetrahedron》2012,68(33):6701-6711
A migration of methyloxycarbonyl group from secondary to primary hydroxyl was observed in furanosides (ribosides and xylosides) under usual desilylation conditions using tetrabutylammonium fluoride. The migration was studied further on several alkyloxycarbonyl furanosides under either basic or acidic conditions. As follows from 13C labelling experiments and product distribution, the migration in xylosides, proceeds intramolecularly via six-membered cyclic carbonate, whereas in ribosides, the migration is intermolecular. Acidic conditions prevented the migration in ribosides whereas the migration in xylosides was circumvented under neutral conditions. 相似文献
35.
Desaktivierung von Pd‐Katalysatoren zur Acetoxylierung: direkte Beobachtung durch XPS‐Untersuchungen
36.
The first total synthesis of the chlorinated 1‐oxo‐β‐carboline alkaloid bauerine C based on a Japp–Klingemann reaction is reported. An intermediate of this synthesis was converted to the fully aromatic β‐carboline bauerine B, and the related alkaloid bauerine A was prepared in an analogous manner. 相似文献
37.
38.
H. Pohl 《Fresenius' Journal of Analytical Chemistry》1955,146(5):359
Ohne Zusammenfassung 相似文献
39.
Molrefraktion elementorganischer Verbindungen, 1. Mitt.: Enileitung. Die Refraktion der Sn−C-Bindung
Jan J. Pohl 《Monatshefte für Chemie / Chemical Monthly》1968,99(5):1705-1712
Zusammenfassung Die Berechnung der Sn–C-Bindungsrefraktionskonstante anhand der Daten von 287 Verbindungen aus 112 Literaturzitaten ergibt die in Tabelle 5 zusammengefaßten Ergebnisse. Bei der Beteiligung eines aromatisch oder konjugiert mehrfachgebundenen Kohlenstoffatoms an der Sn–C-Bindung sind die gefundenen Sn–C-Bindungsrefraktionskonstaten wesentlich höher als im Falle eines primären oder sekundären Alkyl- oder isoliert mehrfach-gebundenen Kohlenstoffatoms.
Results of the calculation of Sn–C bond refraction constants for 287 compounds, based on data from 112 references, are presented in table 5. Accordingly, Sn–C bond refraction constants appear to be essentially higher for carbon atoms with aromatic or conjugated multiple bonds than for primary or secondary carbon atoms in alkyl groups or carbon atoms with isolated multiple bonds. *** DIRECT SUPPORT *** A3615129 00004相似文献
40.
H. Pohl 《Fresenius' Journal of Analytical Chemistry》1965,212(2):340
Ohne Zusammenfassung 相似文献