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1Author    Dietmar Kuck, Hans-Friedrich GrützmacherRequires cookie*
 Title    Der Einfluß der Kettenlänge auf die massenspektrometrigche Fragmentierung höherer l.co-Diphenylalkane The Influence of the Chain Length on the Mass Spectrometric Fragmentation of Higher 1, co-Diphenylalkanes  
 Abstract    The mass spectrometric fragmentation of l,co-diphenylalkanes (2 < co < 22) has been studied in order to elucidate the effect of the chain length on the reactions of unstable and metastable molecular ions with respect to the occurrence of internally solvated ions in the gas phase. The unstable molecular ions of all l,co-diphenylalkanes react predominantly by formation of C?H7+ and C7Hg + " ions, the latter ones are also formed by metastable molecular ions. Neither the variation of the relative abundances of these fragment ions with the chain length nor the fragmentation of specifically deuterated molecular ions indicate any internal solvation in the reacting ions. Inspite of the localized activated C-H bonds at the benzylic positions, these "activated" H atoms are not involved in intra-molecular hydrogen exchange reactions or the formation of C7Hs + ' ions (with the exception of co = 3). Especially the higher homologues (co > 12) react very similarly to the molecular ions of 1-phenylalkanes, while the fragmentation of the lower homologues (co < 6) is determined by specific ("vinculoselective") competitive reactions, e.g. loss of CvH?' and CsHs. 
  Reference    Z. Naturforsch. 34b, 1750—1764 (1979); eingegangen am 12. Juli 1979 
  Published    1979 
  Keywords    Mass Spectrometry, 1, co-Diphenylalkanes 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-1750.pdf 
 Identifier    ZNB-1979-34b-1750 
 Volume    34 
2Author    H. Parlar, S. Nitz, A. Michna, F. KörteRequires cookie*
 Title    Ein Beitrag zur Zusammensetzung des Insektizides "Toxaphen®" Gaschromatographisch-massenspektroskopische Charakterisierung eines öligen und eines kristallinen Anteils des technischen Toxaphens und dessen insektizide Wirksamkeit A Contribution to the Composition of the Insecticide "Toxaphene®" Gaschromatographic-Masspectroscopical Characterisation of the Oily and the Crystalline Fraction of Technical Toxaphene and their Insecticidal Activity  
 Abstract    Technical Toxaphene can be separated in two fractions by recrystallisation which are investigated with the help of GC/MS and toxicological methods. Especially the Retro-Diels-Alder-fragmentations give specific informations on the structure of highly chlorinated bornane derivatives representing the main components of the technical mixture. For this study lower chlorinated bornanes are used as model substances. Toxicological investigations show that both fractions have lower activity than technical toxaphene. 
  Reference    Z. Naturforsch. 33b, 915—923 (1978); eingegangen am 10. Mai 1978 
  Published    1978 
  Keywords    Toxaphene, Chlorinated Bornane, Mass Spectrometry, Toxicology 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0915.pdf 
 Identifier    ZNB-1978-33b-0915 
 Volume    33 
3Author    KlausG. Heumann, Paul Roßmann, Anni Schwarz, Alfred WindfelderRequires cookie*
 Title    Abhängigkeit der Chlor-Isotopenseparation vom Vernetzungsgrad eines stark basischen Anionenaustauschers Dependence of Chlorine Isotope Separation on the Degree of Cross Linkage of a Strongly Basic Anion Exchange Resin  
 Abstract    Using ion exchange chromatography, the dependence of the chlorine isotope separation on the degree of cross linkage of a strongly basic anion exchange resin was investigated. With increasing degree of cross linkage the elementary separation effect for the two stable isotopes 35 C1 and 37 C1 increases. In all experiments 35 C1~ is enriched in the resin phase, whereas 37 C1~ is enriched in the solution, using 0.1 M NaNC>3 as an eluant. Within the degree of cross linkage of 2 to 10 per cent investigated, there is a linear correlation of the elementary separation effect of the chlorine isotopes with the selectivity coefficient between the ions NO3"" and Cl -. The results show that the electrolyte behavior of anionic isotope exchange reactions is comparable with that of cations. The 35 C1/ 37 C1 isotope ratio is determined using thermal ionization mass spectrometry. Untersuchungen von Isotopieeffekten bei hetero-genen Ionenaustauschreaktionen sind bereits bei einigen Kationen durchgeführt w T orden, wie z.B. 
  Reference    Z. Naturforsch. 34b, 406—411 (1979); eingegangen am 4. Dezember 1978 
  Published    1979 
  Keywords    Isotope Separation, Chlorine, Ion Exchange Chromatography, Mass Spectrometry 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-0406.pdf 
 Identifier    ZNB-1979-34b-0406 
 Volume    34 
4Author    KlausK. Mayer, Ilona Matolović, Erich Fischer, Carl DjerassiRequires cookie*
 Title    Mass Spectrometric Investigations on Unsaturated Hydrocarbons: Halogen Migration in the Molecular Ions of Acetylenes and Alkenes  
  Reference    Z. Naturforsch. 34b, 1612—1614 (1979); eingegangen am 13. Juni 1979 
  Published    1979 
  Keywords    Mass Spectrometry, Halogen Migration, Simple Alkenes, Alkynes 
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 TEI-XML for    default:Reihe_B/34/ZNB-1979-34b-1612_n.pdf 
 Identifier    ZNB-1979-34b-1612_n 
 Volume    34 
5Author    Eberhard Hohaus, Wolfgang Riepe, Klaus Wessendorf, LaRequires cookie*
 Title    Massenspektrometrische Untersuchungen an Borchelaten, V [1] Fragmentierung borhaltiger aromatischer Azoverbindungen Mass Spectrometric Investigation of Boron Chelates, V [1] Fragmentation of Aromatic Azo Compounds Containing Boron M+ M+-R M+-RH A M+-C6H5N2 C6H5N2+ C6H5 +  
 Abstract    Differing fragmentation of boron chelates of aromatic azo compounds confirms the structural formulae la-7c, presented in [2]. More significant differences are caused by the substituent of the boron R (F instead of C6H5). Although certain rules can be deduced by the substitution of F for CeHs with regard to the change in intensity of the ions M+, M+-R (and others), in some cases the stable aromatic azo system causes a significant change in the fragmentation as compared with that of azomethine chelates. The chelates 7 eliminate "RH" and show no molecular ion. Apparently a second chelate ring is closed before further fragmentation can start. Fragmentation of 7 a and b is analogous to 5. Einführung Die Massenspektrometrie nimmt bei der analyti-schen Überprüfung und der Konstitutionsaufklä-rung von Borchelaten eine besondere Stellung ein, weil umfangreiches Material mit verschiedensten Komplexbildnern vorliegt. Deshalb werden die Er-gebnisse der Azochelate [2] mit denen der früher dargestellten verglichen. Die Numerierung der Che-late erfolgt nach dem Formelschema in [2]. Vergleich der Fragmentierungen Chelate 1 und 2: Das Massenspektrum von la zeigt nur eine geringe relative Intensität für das Tab. I. Nr. 
  Reference    Z. Naturforsch. 35b, 316—318 (1980); eingegangen am 8. Oktober 1979 
  Published    1980 
  Keywords    Mass Spectrometry, Boron Azo Chelates, Fragmentation 
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 TEI-XML for    default:Reihe_B/35/ZNB-1980-35b-0316.pdf 
 Identifier    ZNB-1980-35b-0316 
 Volume    35 
6Author    Hartmut Klein, Wittko Francke, WilfriedA. KönigRequires cookie*
 Title    Studien über Wespengift, I Niedermolekulare Bestandteile des Giftblasenextraktes von Paravespula vulgaris Studies on Wasp Venom, I Low Molecular Weight Constituents of Venom Sac Extracts from Paravespula vulgaris  
 Abstract    Low molecular weight constituents of 3400 venom sacs of Paravespula vulgaris were extracted with water, diluted acetic acid, and methanol. After conversion to volatile derivatives carbohydrates, amino acids, fatty acids, other constituents of phospho lipids, and biogenic amines were identified by gas chromatography and mass spectrometry. Quantitative analysis was achieved for amino acids by amino acid analysis and for glucose by an enzymatic assay. Results are discussed with regard to biosynthesis of wasp toxins and phylogenetic aspects of hymenopteran venoms. 
  Reference    Z. Naturforsch. 36b, 757—762 (1981); eingegangen am 11. Februar 1981 
  Published    1981 
  Keywords    Wasp Venom, Gas Chromatography, Mass Spectrometry 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-0757.pdf 
 Identifier    ZNB-1981-36b-0757 
 Volume    36 
7Author    Bernhard Ciommer, Helmut Schwarz, Azzedine Maaroufi, ManfredT. Reetz, Karsten LevsenRequires cookie*
 Title    Silyl-Assistierte Etherspaltung bei Radikalkationen von Hydroxylaminderivaten [1] Silyl-Assisted Ether Cleavage in Radical Cations of Hydroxylamine Derivatives [1]  
 Abstract    It is demonstrad by means of various mass spectrometric techniques that the dissociative ionization of N.N-bis-silylated hydroxylamine derivatives (5 a) and (5 b), giving rise to the cleavage of the (O-C) bond, is anchimerically assisted by migration of the trimethylsilyl group to the ether oxygen, thus generating ion (7). 
  Reference    Z. Naturforsch. 36b, 771—773 (1981); eingegangen am 11. März 1981 
  Published    1981 
  Keywords    Mass Spectrometry, Collisional Activation, Anchimeric Assistance, Silyl Ether 
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 TEI-XML for    default:Reihe_B/36/ZNB-1981-36b-0771_n.pdf 
 Identifier    ZNB-1981-36b-0771_n 
 Volume    36 
8Author    Hubertus Von Nicolai, Heinz Egge, Fritz ZillikenRequires cookie*
 Title    Gaschromatographisch-massenspektrometrische Analyse neutraler und saurer Oligosaccharide der Frauenmilch als Trimethylsilyläther * Gas Chromatographic Mass Spectrometric Analysis of Neutral and Acid Oligo­ saccharides from Human Milk as Their Trimethylsilyl Derivatives  
 Abstract    Gas chromatography and the 20 eV mass spectra of the human milk oligosaccharides fucosido-galactose, fucosido-lactose, di-fucosido-lactose, 3'-N-acetylneuraminyl-lactose, 6'-N-acetylneuraminyl-lactose and of N-acetyllactosamine as pertrimethylsilyl (TMS) ethers are described. The gas chromatographic separation of the L-fucose containing oligosaccharides was performed on Silicone SE 30. The sialic acid containing sugars were separated on DEXSIL 300. The correlations between oligosaccharide structures and mass spectrometric fragmentation pat­ terns are discussed. 
  Reference    (Z. Naturforsch. 30c, 451—459 [1975]; eingegangen am 17. Januar/14. April 1975) 
  Published    1975 
  Keywords    Human Milk Oligosaccharides, Silylation, Gas Chromatography, Mass Spectrometry 
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 TEI-XML for    default:Reihe_C/30/ZNC-1975-30c-0451.pdf 
 Identifier    ZNC-1975-30c-0451 
 Volume    30 
9Author    K.G R Pachler, P. L. Wessels, V. Christ, K. H. MaurerRequires cookie*
 Title      
 Abstract    The significance of pheromones in olfactory communication in mammals, and the possibility of using synthetic pheromones to influence the behaviour of problem animals, are briefly discussed. The isolation, identification and synthesis of the principal volatile component contained in the pedal gland exudate of the bontebok, Damaliscus dorcas dorcas, viz. (Z)-5-undecen-2-one, are re­ ported. Some of the other major constituents of the secretion have been identified as 2-heptanone, 2 -nonanone, 2 -undecanone and 2,5-undecanedione. 
  Reference    (Z. Naturforsch. 31c, 21—28 [1976]; received July 26 1975) 
  Published    1976 
  Keywords    Olfactory Communication, Pheromones, Mass Spectrometry, Ketones 
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 TEI-XML for    default:Reihe_C/31/ZNC-1976-31c-0021.pdf 
 Identifier    ZNC-1976-31c-0021 
 Volume    31 
10Author    Boris JanistynRequires cookie*
 Title    Gaschromatographic, Mass-and Infrared-Spectrometric Identification of Cyclic Adenosine-3': 5'-monophosphate (c-AMP) in Maize Seedlings (Zea mays)  
 Abstract    Gaschromatographic, mass-and infrared-spectrometric evidence is presented for the iden­ tification of adenosine-3':5'-monophosphate (c-AMP) in maize seedlings (Zea mays). The genuine c-AMP content could be quantitated by GC-detection and refere to authentic c-AMP standards. 
  Reference    Z. Naturforsch. 36c, 193—196 (1981); received November 111980 
  Published    1981 
  Keywords    Maize, c-AMP, Gaschromatography, Mass Spectrometry, Infrared Spectrometry 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0193.pdf 
 Identifier    ZNC-1981-36c-0193 
 Volume    36 
11Author    GeorgH. Schmid, KlausP. Bader, Richard Gerster, Christian Triantaphylides, Marcel AndréRequires cookie*
 Title    Dependence of Photorespiration and Photosynthetic Unit Sizes on Two Interdependent Nuclear Gene Factors in Tobacco  
 Abstract    A new set of tobacco mutants was obtained by selfing a single variegated plant which emerged in a seed lot of Nicotiana tabacum var. Consolation. The seeds obtained from this mutant give rise to four phenotypes: variegated, yellow, yellow-green, and green seedlings. The green, yellow-green and yellow characters are due to two interdependent nuclear gene factors. The yellow-green phenotype is the homozygous (aabb) true breeding condition, whereas the green and the yellow phenotype are heterozygous (AaBb) with respect to both nuclear factors, the difference in the yellow and green phenotype being the addition of a labile gene factor pair, Cc, in the yellow condition. If photorespiration is measured as the Warburg effect or as 180 2-consumption by mass spectrometry it appears that the heterozygous green phenotype is the defective condition with high photorespiration. The three phenotypes differ with respect to chlorophyll content and photosynthetic unit sizes, the photosynthetic unit size in the yellow phenotype being approxi­ mately 1/10 of that of the green type. The gene expression for photorespiration (measured as 180 2-uptake for example) in the heterozygous green type is suppressed by the addition of the labile gene factor pair Cc in heterozygous condition which leads to the yellow phenotype. In the yellow and green phenotype the photosynthetic unit size is different but not the ratio of photosys­ tem I/photosystem II activity. Moreover, from the present studies it appears that the Warburg effect i. e. an increase of photo­ synthetic rate upon anoxia, can only partly be due to an inhibition of ribulose 1,5-biphosphate oxygenase or glycolate oxidase. 
  Reference    Z. Naturforsch. 36c, 662—671 (1981); received March 23 1981 
  Published    1981 
  Keywords    Photorespiration, Mass Spectrometry, Photosynthetic Units, Tobacco Mutants 
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 TEI-XML for    default:Reihe_C/36/ZNC-1981-36c-0662.pdf 
 Identifier    ZNC-1981-36c-0662 
 Volume    36 
12Author    Y. Shiraiwa, K. P. Bader, G. H. SchmidRequires cookie*
 Title    Mass Spectrometry Analysis of Oxygen Gas Exchange in High-and LOW-C0 2 Cells of Chlorella vulgaris  
 Abstract    Oxygen gas exchange was monitored in the unicellular green alga Chlorella vulgaris 211 — 11 h by means of a mass spectrometer equipped with a special membrane gas-inlet-system and a photosynthetic reaction vessel. C02-dependent I8 02-uptake as well as ,6 02-evolution were ana-lyzed in both High-and Low-C02 cells. In High-C02 cells, the 18 Oruptake in the light (UL) decreased by 65% upon addition of 3 mM NaHC03, while l6 02-evolution (E) was increased approx. 1.8 times by the same treatment. 18 02-uptake in the dark (UD) was not affected by the addition of external inorganic carbon (Ci). The addition of 3.3 mM NaHCO, also affected UL and E in Low C02-cells, however, to a minor extent. UL under C02-saturating conditions was light intensity-independent up to 2 klux and 1.2 klux in High-and Low-C02 cells, respectively. Above these light intensities UL increased approx. 4-fold in High-and approx. 6-fold in Low-C02 cells. Under C02-limiting conditions, however, UL increased in High-CO: cells even under very low light intensities, showing that photorespiratory oxygen uptake occurred even in the near vicinity of the light compensation point. Under C02-saturating and strong light conditions UL represented almost half of E in Low-C02 cells and about 30% of E in High-C02 cells. In Low-C02 cells addition of ethoxyzolamide (EZA), an inhibitor of carbonic anhydrase, enhanced UL and suppressed E and NET under C02-limiting conditions, whereas the compound had only a minor effect on High-C02 cells. DCMU (3 |XM) strongly inhibited E and UL under C02-saturating conditions, with the remain-ing UL being smaller than UD. KCN (1 mM) and SHAM (1.5 mM) added to DCMU-treated Low-C02 cells suppressed UL by approx. 50%. The resulting value corresponded to half of UD. KCN also inhibited E under CÓ2-saturating conditions, with UL being strongly enhanced showing a maximal uptake at 0.4 mM KCN. Under these conditions NET was nearly zero. The effect seems to be due to an inhibition of RubisCO and an enhancement of Mehler reactions. At 0.7 mM KCN, DCMU entirely inhibited UL, but oxygen uptake appeared increased after turning the light off. This uptake corresponded to approx. 60% of UD. Whereas KCN and SHAM inhibited approx. 70% of UD, only 16% of UL was suppressed. These results suggest that the contribution of mitochondrial respiration to UL was négligeable, since UL seemed to be suppressed in the light under C02-saturated conditions. Iodoacetamide, which is an inhibitor of the Calvin cycle and thereby diverts carbon into the respiratory pathway, inhibited E and NET under C02-saturating conditions, but did not affect UL. This result also shows that UL is not due to mitochondrial respiration. A hydroxylamine derivative [20, 21] which changes the ratio of the RuBP carboxyla-tion to oxygenation activity in tobacco leaves did not affect this ratio in Chlorella. 
  Reference    Z. Naturforsch. 43c, 709—716 (1988); received May 24 1988 
  Published    1988 
  Keywords    Chlorella, Oxygen Gas Exchange, Carbonic Anhydrase, Mass Spectrometry 
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 TEI-XML for    default:Reihe_C/43/ZNC-1988-43c-0709.pdf 
 Identifier    ZNC-1988-43c-0709 
 Volume    43 
13Author    KlausP. Bader, Anja RöbenRequires cookie*
 Title    Mass Spectrometric Detection and Analysis of Nitrogen Fixation in Oscillatoria chalybea  
 Abstract    By means of mass spectroscopic m easurements in an artifical gas atmosphere containing the stable nitrogen isotope 15N2 we were able to demonstrate nitrogen fixation capacity in the filamentous cyanobacterium Oscillatoria chalybea. Our technique proved to be well-suited also for investigations on the light-induced nitrogen fixation in the purple bacteria Rhodobacter sphaeroides and Rhodobacter capsulatus. Oscillatoria chalybea grown without combined nitrogen showed a substantial 15N2-uptake which could clearly be correlated with nitrogen fixation. Nitrate grown cultures did not show this nitrogen uptake or only to a minimal extent. Addition of ammonium chloride resulted in a rapid deactivation of the nitro-genase system. Similar observations have been made with other so-called switch-off effectors like phenazine methosulfate. The structural integrity of the filaments appeared to be a pre­ requisite for nitrogen fixation also in this organism, as even mild mechanical homogenization strongly inhibited the N2-uptake signals. Illumination of the assays under conditions where the photooxidition of water is not operational (Bader, K. P. (1994), Biochim. Biophys. A cta 1188, 2 1 3 -2 1 9) did not affect the nitrogen fixation in Oscillatoria chalybea. Illumination of cultures with concom itant release of oxygen from the w ater splitting reaction resulted in strong inhibition of 15N2-uptake. 
  Reference    Z. Naturforsch. 50c, 199 (1995); received November 11 1994/January 30 1995 
  Published    1995 
  Keywords    Mass Spectrometry, Nitrogen Fixation, Photosynthesis, Cyanobacterium 
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 TEI-XML for    default:Reihe_C/50/ZNC-1995-50c-0199.pdf 
 Identifier    ZNC-1995-50c-0199 
 Volume    50 
14Author    Refat Abdel-Basset, KlausP. BaderRequires cookie*
 Title    Characterization of Hydrogen Photoevolution in Oscillatoria chalybea Detected by Means of Mass Spectrometry  
 Abstract    The filamentous non-heterocystous cyanobacterium Oscillatoria chalybea is capable to photoevolve molecular hydrogen when the cells are flushed to anaerobiosis with nitrogen or argon and exposed to short light flashes or continuous light. The light-induced hydrogen gas exchange of Oscillatoria chalybea has been investigated by direct determ ination of dynamic changes in the hydrogen partial pressure at m/e=2 in the H/D collector of a mass spectromet-ric set-up. By means of this technique also the time curves of the light-induced hydrogen gas exchange could be directly recorded. Depending on the chlorophyll concentration in the measuring cell we observed an increasing hydrogen content of the aqueous Oscillatoria sus­ pension i.e. a dark evolution of molecular hydrogen. Upon the onset of light an initial rise of the H 2-signal was observed which was increasingly mixed or followed by a hydrogen uptake. The capability to photoevolve molecular hydrogen was maximal with young cultures and decreased with increasing age. The hydrogen evolution signals require relatively short dark adaptation to get pronounced; few seconds suffice for 2/3 of the hydrogen evolution amplitude. Prolonged dark adaptation maximizes the flash amplitudes. The hydrogen evolu­ tion signals do not deactivate by low flash frequency Oscillatoria chalybea evolves molecular hydrogen following growth on nitrogen free or nitrate containing medium. Increase of the oxygen partial pressure of the assays completely abolishes the hydrogen evolution signals with an I50-value of 6 ^im. 
  Reference    Z. Naturforsch. 52c, 775—781 (1997); received September 8/October 17 1997 
  Published    1997 
  Keywords    Photosynthesis, Mass Spectrometry, Hydrogen Photoevolution, Cyanobacterium 
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 TEI-XML for    default:Reihe_C/52/ZNC-1997-52c-0775.pdf 
 Identifier    ZNC-1997-52c-0775 
 Volume    52 
15Author    Helmut Schwarz, Friedeich Borchers, Karsten LevsenRequires cookie*
 Title    Stoßaktivierungsmassenspektrometrie von Monoterpenen und Isomerisierung von C7H9 + -Ionen in der Gasphase Collisional Activation Mass Spectrometry of Monoterpenes and Isomerisation of Gaseous C7H9 + Ions  
  Reference    (Z. Naturforsch. 31b, 935—940 [1976]; eingegangen am 29. März 1976) 
  Published    1976 
  Keywords    Collisional Activation Spectra, Ion Structure, Isomerisation, Mass Spectrometry, Terpenes 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-0935.pdf 
 Identifier    ZNB-1976-31b-0935 
 Volume    31 
16Author    Rupert Herrmann, Helmut SchwarzRequires cookie*
 Title    On the Isomerisation and Fragmentation of Butenoic Acid Methyl Esters under Electron Impact  
 Abstract    Ion On the contrary to the photochemical behavior the title compounds do not isomerise to a common intermediate prior to or during electron impact induced fragmentation. The unusual methyl elimination from the trans (2)-butenoic acid methyl ester probably is ac-companied by a concerted [1.3] methoxy rearrangement from the ester function on to the ß carbon atom. 
  Reference    (Z. Naturforsch. 31b, 1013—1014 [1976]; eingegangen am 22. März 1976) 
  Published    1976 
  Keywords    Structure, Neighbouring Group Participation, Alkoxy Rearrangement, Mass Spectrometry, Unsaturated Esters 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-1013_n.pdf 
 Identifier    ZNB-1976-31b-1013_n 
 Volume    31 
17Author    Rupert Herrmann, Helmut SchwarzRequires cookie*
 Title    On the Mechanism of Substituent Interaction During bhe Electron Impact Induced Ether Cleavage from para-Substituted Methoxymethvl Benzenes  
 Abstract    The unusual methyl elimination from para-substituted methoxy-methyl benzenes has been elucidated. It can be shown that two entirely different mechanisms contribute to the reaction: i) intramolecular hydrogen transfer onto the benzene ring (7r-complex formation) and ii) substituent migration via ring expansion. Alternative mechanisms as for instance transanular protonation of the ester function or substituent migration via valence bond isomers are not involved in the formation of the [M-methyl]+-ions. 
  Reference    (Z. Naturforsch. 31b, 1667—1672 [1976]; eingegangen am 24. September 1976) 
  Published    1976 
  Keywords    Mass Spectrometry, Intramolecular Protonation, t-Complex, Rearrangement, Ring Expansion 
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 TEI-XML for    default:Reihe_B/31/ZNB-1976-31b-1667.pdf 
 Identifier    ZNB-1976-31b-1667 
 Volume    31 
18Author    I. Lüderwald, M. Przybylski, H. Ringsdorf, D. Silberhorn, H. Kaibacher, W. VoelterRequires cookie*
 Title    Untersuchung yon isomeren Tripeptiden und Derivaten des Thyrotropin-,Releasing" Hormons durch Elektronenstoß- und Felddesorptions-Massenspektrometrie Investigation of Isomeric Tripeptides and Thyrotropin-Releasing Hormone Derivatives by Electron Impact and Field Desorption Mass Spectrometry  
 Abstract    The complementary informations from field desorption and electron impact mass spectra of free tripeptides and thyrotropine releasing hormone derivatives can be used to determine primary structure and molecular weight. Characteristic and diagnostic frag-mentation pathways, the formation of diketopiperazines and the temperature-dependent tendency to form amine fragments and diketopiperazines will be discussed. 
  Reference    Z. Naturforsch. 33b, 809—817 (1978); eingegangen am 20. Januar 1978 
  Published    1978 
  Keywords    Mass Spectrometry, Sequence Determination, Isomeric Tripeptides, Thyrotropin-Releasing Hormone 
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 TEI-XML for    default:Reihe_B/33/ZNB-1978-33b-0809.pdf 
 Identifier    ZNB-1978-33b-0809 
 Volume    33 
19Author    H.-R Schulten, R. Ziskoven, W. D. LehmannRequires cookie*
 Title    Cesium Determination in Physiological Fluids and Tissues by Field Desorption Mass Spectrometry+  
 Abstract    Quantitative ultratrace analysis (10 nmol to 10 /cmol/1) of cesium in biological samples such as human body fluids and animal tissues is performed without any prior purification or concentration steps. The normal level of cesium ions in heart cells was determined. After poisoning these cells with high concentrations of the alkali cation much higher levels were found inside the cells then had been suggested previously. It is demonstrated that field desorption mass spectrometry is a unique tool for the qualitative and quantitative investigations of metal cations in biological material. 
  Reference    Z. Naturforsch. 33c, 178 (1978); received February 20/March 8 1978 
  Published    1978 
  Keywords    Cesium, Ultratrace Determination, Biological Samples, Mass Spectrometry, Field Desorption 
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 TEI-XML for    default:Reihe_C/33/ZNC-1978-33c-0178.pdf 
 Identifier    ZNC-1978-33c-0178 
 Volume    33 
20Author    R. Ziskoven, C. Achenbach, U. Bahr, H.-R SchultenRequires cookie*
 Title    Quantitative Investigations on the Diaplacental Transfer of Thallium by Field Desorption Mass Spectrometry  
 Abstract    The placental transfer of thallium cations in pregnant mice was investigated by determining the thallium concentrations in fetal and maternal tissue 0.5 to 24 h after application of thallium. The maternal dose o f thallium was 8 mg/kg body weight throughout. Uterus and fetus were found not to differ from other organs like heart and liver in time course and magnitude of thallium uptake with an initial surge during the first few hours of exposure to thallium and a rapid decrease to steady 12 and 24 h values somewhat lower than those found in the kidney. Diaplacental transfer is therefore assumed comparatively rapid and a specific placental barrier for thallium does not seem to exist. For the determination of thallium concentrations Field Desorption Mass Spectrometry was utilized as a reliable, fast, and sensitive method for the analysis o f metal cations in biological material. This method does not require extensive pretreatment of the tissue and total sample amounts in the range of milligrams and less are sufficient for quantitative analysis. 
  Reference    Z. Naturforsch. 35c, 902 (1980); received August 8 1980 
  Published    1980 
  Keywords    Thallium, Placental Transfer, Ultratrace Determination, Mass Spectrometry, Field Desorption 
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 TEI-XML for    default:Reihe_C/35/ZNC-1980-35c-0902.pdf 
 Identifier    ZNC-1980-35c-0902 
 Volume    35 
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