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  • Analytical Chemistry and Spectroscopy  (6)
  • Tetranychus urticae  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Accumulation and turnover of 2-tridecanone in Tetranychus urticae and its consequences for resistance of wild and cultivated tomatoes (1999)
    Springer
    Experimental and applied acarology 23 (1999), S. 1011-1021 
    Details
    ISSN: 1572-9702
    Schlagwort(e): Tetranychus urticae ; tomato trichomes ; L. hirsutum f. glabratum ; Lycopersicon esculentum ; 2-tridecanone ; bio-accumulation ; toxicity bioassay ; plant defence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In this study we assessed the dynamic changes of 2-tridecanone in a herbivorous mite (Tetranychus urticae) on tomato (Lycopersicon esculentum, cv. ‘Moneymaker’), a plant with methyl ketones in the tetracellular tips of the glandular trichomes (Type VI). We showed that spider mites accumulate 2-tridecanone when foraging on cultivated tomato. Thus, the rate of mite–trichome contact multiplied by the amount of toxin per trichome tip exceeded the relative rate of toxin turnover multiplied by the amount of toxin per mite. The relative rate of toxin turnover was estimated to be 1.1 per day on cucumber, a plant without this toxin. The amount per trichome tip varied from 0.33 ng for middle-leaf trichomes to 1.26 ng for main-stem trichomes. Hence, to achieve a static level of 2-tridecanone equal to 8–17 ng per mite – representing the level we found in mites on middle leaves – the rate of mite–trichome contact should be 26–57 per day. Because methyl ketone apparently accumulates in the spider mites on tomato, the rate of mite–trichome contact is probably higher than that. We expect the accumulation of ketones to occur especially on the stems of cultivated tomato, since this is the area most densely occupied with glandular hairs and because here the hairs have higher levels of the methyl ketones. Using dose–response relationships assessed earlier (Chatzivasileiadis and Sabelis, 1997, 1998), we estimated that the number of mite–trichome contacts causing 50% mortality per day is equal to 88 on a tomato stem, whereas it equals 70 for another strain of spider mites collected from cucumber. On wild tomato, L. hirsutum f. glabratum (PI 134417), just one to two contacts would suffice to cause 50% mortality per day. We suggest that methyl ketones from glandular hairs on tomato are an important mortality factor for spider mites on wild tomato and probably also on cultivated tomato.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1006394109643
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  • 2
    Digitale Medien
    Digitale Medien
    Fast atom bombardment (tandem) mass spectrometric analysis of intact polar ether lipids extractable from the extremely halophilic archaebacterium Halobacterium cutirubrum (1989)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 18 (1989), S. 96-105 
    Details
    ISSN: 0887-6134
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Fast atom bombardment (FAB) mass spectrometric analyses of the three major polar ether lipids extracted from Halobacterium cutirubrum produced simple positive and negative ion mass spectra which contained ions with masses which corresponded to cationized or deprotonated lipid molecules. Structural information was obtained on individual components of polar lipid mixtures by discrete selection of ion masses when the instrument was operated in the tandem mass spectrometric mode. Tandem mass spectra contained abundant ions at masses which indicated collision-induced cleavage of phosphate (di)ester, sulphate ester or glycosidic linkages. This study showed that FAB (tandem) mass spectrometry can be used to analyse intact polar ether lipids present at microgram concentrations in crude lipid mixtures and these analyses can indicate the presence of structural features (i.e. O-methylation and the presence of cyclic isoprenoidyl chains) which are difficult to determine with other analytical methods.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bms.1200180203
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  • 3
    Digitale Medien
    Digitale Medien
    A simple approach to the dynamic headspace analysis of volatile flavours using a gas chromatograph/photoionization mass spectrometer (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 16 (1988), S. 373-375 
    Details
    ISSN: 1052-9306
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Dynamic headspace analysis was performed on several samples of foodstuffs in a special gas chromatographic injection system which is normally used for Curie-point pyrolysis analysis. Photoionization was used in the gas chromatographic/mass spectrometric instrument as a reproducible low-energy ionization method. Mass spectral accumulation of the data yields fingerprints of the samples which are amenable to computer-assisted statistical data analysis.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bms.1200160173
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  • 4
    Digitale Medien
    Digitale Medien
    Endgroup analysis of polyethylene glycol polymers by matrix-assisted laser desorption/ionization Fourier-transform ion cyclotron resonance mass spectrometryPresented at the 13th Informal Meeting on Mass Spectrometry, Budapest, 8-10 May 1995. (1995)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 957-962 
    Details
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: Fourier-transform ion cyclotron resonance mass spectrometry (FTICR-MS) by external injection of matrix-assisted laser desorbed and ionized (MALDI) polymers offers good possibilities for characterization of low molecular weight homopolymers (MW range up to 10 kDa). The molecular masses of the molecular weight distribution (MWD) components of underivatized and derivatized (dimethyl, dipropyl, dibutyl and diacetyl) polyethylene giycol (PEG) 1000 and 4000 were measured by MALDI-FTICR-MS. These measurements have been performed using a commercial FTICR spectrometer with a home-built external ion source. MALDI of the samples with a 2,5-dihydroxybenzoic acid matrix in a 1000: 1 matrix-to-analyte molar ratio produces sodiated molecules in a sufficient yield to trap the ions in the ICR cell. The masses of the molecular weight distribution of PEG components were measured in broad-band mode with a mass accuracy of 〈 5 ppm in the mass range around 1000 u and within 40 ppm accuracy around 4000 u. From these measurements, the endgroup mass of the polymer was determined by correlation of the measured component mass with the degree of polymerization. The masses of the PEG endgroups have been determined within a deviation of 3-10 millimass units for the PEG1000 derivatives and 10-100 millimass units for the PEG4000 derivatives, thus confirming the identity of the distal parts of the model compounds.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/rcm.1290091018
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  • 5
    Digitale Medien
    Digitale Medien
    Loss of oligomer information in pyrolysis-desorption/chemical-ionization mass spectrometry of amylose, due to the influence of potassium hydroxide (1989)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 3 (1989), S. 238-240 
    Details
    ISSN: 0951-4198
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: Pyrolysis-desorption/chemical-ionisation mass spectrometry (PyD/CIMS), using ammonia as ionization gas, was employed to investigate the influence of potassium hydroxide on the pyrolytic behaviour of glucans. The mass spectrum of native amylose, a 1 → 4 linked α-D-glucan, revealed an ion series pointing to desorption of intact 1,6-anhydro-oligosaccharides. Ions indicating oligomers up to the nonamer were observed. Addition of trace amounts of potassium hydroxide to amylose resulted in reduction in the size of the 1,6-anhydro-oligosaccharide ions and a simultaneous increase of ions resulting from ring rearrangements. Larger amounts of potassium hydroxide led to a complete loss of mass spectral information at the oligomer level.Similar mass spectrometric distributions in the PyD/CIMS data of a potassium hydroxide extracted tobacco fraction clearly reveal that alkali remnants must be present in this sample, which severly reduce the mass spectrometric information from polysaccharide oligomers. It is important to evaluate the role of inorganics on the thermal activation and subsequent fragmentation of biopolymers in PyD/CIMS experiments.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/rcm.1290030709
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  • 6
    Digitale Medien
    Digitale Medien
    Ammonia chemical ionization mass spectrometry of substituted phenylpropanoids and phenylalkyl phenyl ethers (1995)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 30 (1995), S. 541-548 
    Details
    ISSN: 1076-5174
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: The ammonia chemical ionization (NH3/CI) spectra of phenylpropanoids and substituted phenylalkyl phenyl ethers containing α-hydroxy or α-carbonyl functional groups are discussed. Fragmentation reactions which occur in the temperature range 180-450°C are examined to model pyrolysis mass spectrometric experiments of lignin. Hydroxycinnamyl alcohols and α-hydroxy phenylalkyl phenyl ethers show abundant [M + H - H2O]+ elimination ions and to a lesser extent [M + NH4 - H2O]+ substitution ions while hydroxycinnamic acids and α-carbonyl phenylalkyl phenyl ethers show predominantly [M + H]+ and [M + NH4]+ ions. The interpretation of functional group information is facilitated by using trideuterioammonia (ND3) and [15N] ammonia (15NH3) as reagent gases. Labile hydrogens undergo essentially complete exchange upon ND3/CI and the number of hydroxyl functional groups is readily determined by comparison of the [M + NH4]+ and [M - nH + nD + ND4]+ adduct ions. Incomplete H—D exchange is observed for enolizable and aromatic protons.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jms.1190300404
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  • 7
    Digitale Medien
    Digitale Medien
    The analytical pyrolysis of carbohydrates. 2 - differentiation of homopolyhexoses according to their linkage type, by pyrolysis-mass spectrometry and pyrolysis-gas chromatography/mass spectrometry (1984)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1984), S. 486-492 
    Details
    ISSN: 0306-042X
    Schlagwort(e): Chemistry ; Analytical Chemistry and Spectroscopy
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Curiepoint pyrolysis (Py)-mass spectrometry (14 eV electron impact) in various modes of operation and Curiepoint pyrolysis-gas chromatograpy/mass spectrometry (Py-GC/MS) afforded discrimination between homopolyhexoses of different glycosidic linkage type and configuration: (1 → 2)-β-, (1 → 3)-β-, (1 → 4)-α-, (1 → 4)-β-, (1 → 6)-α, (1 → 6)-β-glucan and (1 → 2)-α-mannan. Pyrolysis-mass spectrometry in multichannel averaging mode, combined with discriminant analysis data processing, revealed significant discrimination between all polyhexoses, except for the (1→6) linked polymers. By using preheated telescopic glass tube sample holders, additional specificity of the pyrolysis-mass spectral fingerprint for the (1 → 3) linked carbohydrate was obtained. Pyrolysis-mass spectrometry in time-resolved mode yielded ion profiles, especially characteristic for the (1 → 3)-β-glucan. Py-GC/MS was an additional discriminating dimension (retention time), providing structural information about the pyrolysate constituents, in particular concerning the anhydrohexoses.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/bms.1200110910
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