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991.
Hermann Meincke 《化学,工程师,技术》1977,49(7):560-562
992.
Hermann Timmen und Jutta Blüthgen 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1973,153(5):283-288
Zummmenfassung Aus Butter bzw. Butterreinfett wird im Kjeldahlkolben ein Salpetersäure-extrakt hergestellt und dieser mit Perehlorsäure aufgeschlossen. Nach Reduktion mit Hydroxylammoniumchlorid und Abpufferung auf pH 4,5 wird zunächst der Cu-Bathocuproin-Farbkomplex gebildet, mit Hexanol extrahiert und bei 479 nm bestimmt. Anschließend erfolgt die Bildung des Fe-Bathophenanthrolin-Komplexes und seine Messung bei 533 nm. Das ausgearbeitete Verfahren gestattet die Bestiimmung des Fe-Gehaltes in Butter (gefundene Werte: 0,11-0,45 ppm) und Butterreinfett (gefundene Werte: 0,05-0,25 ppm, in einem Einzelfall 1,94 ppm) und die Bestimmung des Cu-Gehaltes in Butter (gefundene Werte: 0,02-0,06 ppm) mit guter Sicherheit und Präzision. Eine genaue Bestimmung der äußerst geringen Cu-Konzentrationen, wie sie im Butterreinfett normalerweise vorkommen (unter 0,02 ppm), aus einer Untersuchungsprobe von etwa 20 g ist, wie bei allen photometrischen Verfahren auf der Grundlage der z. Z. verfügbaren Farbreagentien, nicht möglich, jedoch kann eine Überschreitung der heute bei 0,02-0,05 ppm angenommenen Toleranzgrenze für Cu in Butterreinfett guter Haltbarkeit leicht festgestellt werden.
Estimation of copper and iron in butterfat from one digest.I. Photometric method
Summary The sample of butter or anhydrous butterfat is extracted with nitric acid in a Kjeldahi flask and the extract digested by perchloric acid. After reduction with hydroxylamine hydrochloride and buffering to a pH of 4,5 first the Cu-bathocuproine complex is formed, extracted with hexanol and photometrically measured at 479 nm. Then, likewise, the Fe-bathophenantholine complex is formed and estimated at 533 nm. The method allows the estimation of Fe in butter (concentrations found: 0.11-0.45 ppm) and anhydrous butteroil (concentrations found: 0,05-0,25 ppm, in one case: 1.94 ppm) and of Cu in butter (concentrations found: 0.02-0.06 ppm) with good security and precision. As with each photometric method based on the most sensitive Cu reagents now available, an accurate measurement of traces of Cu as usually present in anhydrous butteroil (less than 0.02 ppm) from a sample of about 20 g is not possible; however, exceeding of the tolerance level for butteroil of good keeping quality (at present assumed to be 0.02-0.05 ppm) can easily be detected.相似文献
993.
994.
995.
Michael Petz Hans-Peter Thier und Hermann Vogt 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1980,170(5):329-333
Zusammenfassung Für das Coccidiostatikum Amprolium wird ein einfaches und rasch durchführbares Verfahren zur Rückstandsanalyse beschrieben, bei dem der Wirkstoff zu 2-Picolin gespalten und dieses gaschromatographisch mit dem stickstoffselektiven thermionischen Detektor bestimmt wird. Zusatzversuchezeigen, daß sich Amprolium in Hühnerfleisch und Eiern bis hinunter zu 0,01 mg/kg quantitativ und sehr reproduzierbar wiederfinden läßt. Ergebnisse der Untersuchung von Eiern und Fleisch von Hühnern nacheiner Behandlung mit Amprolium sowie von Ei- und Fleischproben aus dem Handel werden mitgeteilt.
Residues of the coccidiotstat amprolium in meat and eggsGas Chromatographic Method for the Determination and Results of Residue Analyses
Summary A simple and rapid gas chromatographic procedure for the residue analysis of the coccidiostat amprolium in muscle tissue, organs and eggs is described. The quaternary compound is cleaved by an excess of sulphite, yielding 2-methylpyridine which is detected by gas chromatography using the nitrogen-selective thermionic detector. Amprolium added to eggs and poultry meat at levels between 0,01 and 1,0 mg/kg was recovered quantitatively and with very high reproducibility. Results are given for residues found in eggs and meat of laying hens fed with amprolium and for commodities purchased locally.相似文献
996.
997.
Relationship between microstructure and mechanical properties of a spinodally decomposing Cu-15Ni-8Sn alloy prepared by spray deposition 总被引:1,自引:0,他引:1
A spinodally decomposing alloy of composition Cu-15 wt pct Ni-8 wt pct Sn processed by Osprey spray deposition was examined
and the principal factors determining strength and ductility studied. Strengthening contributions are shown to arise from
grain-size reduction by controlled recrystallization, and from the internal stress fields created by spinodal decomposition.
Discontinuous precipitation takes place after the completion of spinodal decomposition and is partly responsible for the decrease
of yield stress after such prolonged aging. At the same time, there is some loss of ductility, but the discontinuous precipitation
is not believed to be the main cause. Instead, it is the appearance of additional phases, such as Ni3Sn, in the matrix that is considered to be the main cause of the brittleness. 相似文献
998.
SJ Mansour WT Matten AS Hermann JM Candia S Rong K Fukasawa GF Vande Woude NG Ahn 《Canadian Metallurgical Quarterly》1994,265(5174):966-970
999.
On a highly dispersed Ag/SiO2 catalyst the reaction of ethylene with hydrogen was studied by means of isotopic exchange. Although hydrogenation does not proceed below 550 K, a latent but intensive interaction between ethylene and hydrogen could be observed already at 480 K. On the investigated catalyst the mechanism of the ethylene hydrogenation is similar to that known for nickel, the catalytic behaviour, however, being distinctly different. 相似文献
1000.
McCartney John E.; Tai Mei-Sheng; Hudziak Robert M.; Adams Gregory P.; Weiner Louis M.; Jin Donald; Stafford Walter F. III; Liu Sen; Bookman Michael A.; Laminet Axel A.; Fand Irwin; Houston L. L.; Oppermann Hermann; Huston James S. 《Protein engineering, design & selection : PEDS》1995,8(3):301-314
Single-chain Fv fusions with C-terminal cysteinyl peptides (sFv')have been engineered using model sFv proteins based upon the26-10 anti-digoxin IgG and 741F8 anti-c-erbB-2 IgG monoclonalantibodies. As part of the 741F8 sFv construction process, thePCR-amplified 741F8 VH gene was modified in an effort to correctpossible primer-induced errors. Genetic replacement of the N-terminalp-strandsequence of 741F8 VH with that from the FR1 of anti-c-erbB-2520C9 VH resulted in a dramatic improvement of sFv folding yields.Folding in urea-glutathione redox buffers produced active sFv'with a protected C-terminal sulfhydryl, presumably as the mixeddisulfide with glutathione. Disulfide-bonded (sFv')2 homodimerswere made by disulfide interchange or oxidation after reductiveelimination of the blocking group. Both 2610 (sFv')2and 741F8 (sFv')2 existed as stable dimers that were well behavedin solution, whereas 741F8 sFv and sFv' exhibited considerableself-association. The 741F8 sFv binds to the extracellular domain(ECD) of the c-erbB-2 oncogene protein, which is often overexpressedin breast cancer and other adenocarcinomas. The recombinantECD was prepared to facilitate the analysis of 741F8 bindingsite properties; the cloned ECD gene, modified to encode a C-terminalSer-Gly-His6 peptide, was transfected into Chinese hamster ovarycells using a vector that also expressed dihydrofolate reductaseto facilitate methotrexate amplification. Optimized cell linesexpressed ECD-His6 at high levels in a cell bioreactor; afterisolation by immobilized metal affinity chromatography, finalECD yields were as high as 47 mg/l. An animal tumor model complementedphysicochemical studies of 741F8 species and indicated increasedtumor localization of the targeted 741F8 (sFv')2 over othermonovalent 741F8 species. 相似文献