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  • 1
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    Number of double bonds in fatty acids from fats and oils by hplc using pentafluorobenzyl esters (1986)
    Wiley
    Details
    Publication Date: 1986-09-01
    Print ISSN: 0003-021X
    Electronic ISSN: 1558-9331
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Published by Wiley
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  • 2
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    The physico-chemical basis of leaf wettability in wheat (1973)
    Springer
    Details
    Publication Date: 1973-12-01
    Print ISSN: 0032-0935
    Electronic ISSN: 1432-2048
    Topics: Biology
    Published by Springer
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  • 3
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    Esterified alkan-1-ols and alkan-2-ols in barley epicuticular wax (1976)
    Springer
    Details
    Publication Date: 1976-06-01
    Print ISSN: 0024-4201
    Electronic ISSN: 1558-9307
    Topics: Biology , Chemistry and Pharmacology
    Published by Springer
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  • 4
    Electronic Resource
    Electronic Resource
    The physico-chemical basis of leaf wettability in wheat (1973)
    Springer
    Planta 114 (1973), S. 289-309 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Wild type wheat (Triticum aestivum L.) and three mutant lines that have reduced glaucousness on the flag leaf sheath have been examined for variations in glaucousness, contact angles, wax chemistry and wax morphology. On the sheath and culm, organs that are glaucous in the wild type, increasing glaucousness is correlated with increasing contact angles, an increasing proportion of β-diketones plus hydroxy-β-diketones in the was and an increasing proportion of wax tubes. Organs that were non-glaucous in all four lines, namely both surfaces of the vegetative leaves and the adaxial surface of the flag leaf, had high contact angles, a dense covering of wax plates and waxes rich in primary alcohols but devoid of β-diketones and hydroxy-β-diketones. The abaxial surface of the flag leaf was the most complex of the organ surfaces studied. In the wild type the glaucousness of the sheath continued onto this surface for 1–2 cm and this was correlated with the other characters studied as it was on the sheath. In the mutants, however, the tubes were absent. Flat ribbons of varying widths, a new wax structure in wheat, as well as various types of plates were found instead. These structures continued to the flag leaf tip and were also present on the abaxial surface of the wild type flag leaf. Changes in contact angle at the tip could not be correlated with the other measured parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387943
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  • 5
    Electronic Resource
    Electronic Resource
    The isolation and identification of the prosthetic group released from a bound form of abscisic acid (1992)
    Springer
    Plant growth regulation 11 (1992), S. 327-334 
    Details
    ISSN: 1573-5087
    Keywords: Onion ; pea ; barley ; isolation of plant growth regulator ; bound form of abscisic acid ; abscisic acid, methyl abscisate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A bound form of abscisic acid, herein called ‘adduct’, has been isolated from peas and barley and has been shown to release methyl abscisate upon mild acid hydrolysis. Mass spectrometry of the methyl abscisate released by 2H2SO4 in 2H2O showed that the remainder of adduct was linked as an enolate of the ketone of the moiety that releases methyl abscisate. Some evidence is adduced to suggest that adduct is a metabolic precursor of abscisic acid. The implications of the distribution of adduct between roots and shoots for the plant's response to stress is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00024572
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  • 6
    Electronic Resource
    Electronic Resource
    The fragmentation of methyl abscisate and its 2E isomer in methane positive and negative chemical ionization mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 375-387 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fragmentation pathways of methyl abscisate and its 2E isomer in methane positive ion chemical ionization (PICI) and methane negative ion chemical ionization (NICI) mass spectrometry have been elucidated using isotopically labelled analogues. It is shown that in PICI the most abundant ions are formed by the loss of water, methanol, both methanol and water and of methyl formate. The PICI mass spectrum of methyl 2E abscisate differs significantly in that the loss of water is much less important. In NICI, the most abundant ions from methyl abscisate are due to the molecular anion, [M - H2O]- and [M - CH3OH]-. It is shown, however, that the methyl ester methyl is not lost in this last fragmentation. Two other significant ions contain the side chain and the ring of methyl abscisate, respectively. In contrast, the NICI mass spectrum of methyl 2E abscisate differs principally in showing an abundant loss of a hydrogen atom.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150705
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  • 7
    Electronic Resource
    Electronic Resource
    Partition and adsorption in the separation of long chain lipids by normal phase high performance liquid chromatography (1990)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 13 (1990), S. 817-825 
    Details
    ISSN: 0935-6304
    Keywords: Normal Phase HPLC ; Partition ; Adsorption ; Theory ; Inductive effect ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Martin's adaption of Raoult's Law has been shown to describe partition phenomena in normal phase HPLC. Thus, in the separation of fatty acid pentaflorobenzyl esters and of triacylglycerols in dichloromethane or acetonitrile in half-water-saturated hexane, the natural logarithm of the corrected retention volume is proportional to the number of double bonds that these solutes contain. By extending Martin's adaption of Raoult's Law with activity coefficients, evidence was obtained that deviations observed for the homologous series of saturated fatty acid pentafluorobenzyl esters from C2 to C5 could be accounted for by a diminution of adsorption by the inductive effect. For chain lengths longer than C5, it appeared that there were additional field and inductive effects from the methyl end of the hydrocarbon chains.Thus, with these half-water-saturated solvent systems, the silica surface is probably covered with a bilayer of water which, in the dynamic situation in an HPLC column, attracts several layers of the polar organic component of the mobile phase by dispersive interactions. This stationary phase surface may, then, be considered to be immiscible with the predominantly hexane mobile phase due to these dispersive interactions and thus partition can occur between these two phases. Solutes that enter the stationary phase are then free to interact with the underlying aqueous phase by adsorption.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240131205
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  • 8
    Electronic Resource
    Electronic Resource
    Methane chemical ionization mass spectrometry of the pentafluorobenzyl derivatives of abscisic acid, its metabolites and other plant growth regulators (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 17 (1988), S. 281-286 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tetraethyl ammonium hydroxide has been used as a catalyst for the pentafluorobenzylation of abscissic acid and its metabolites, as well as zeatin, gibberellic acid and indole acetic acid. These derivatives, acetylated where necessary, were subjected to methane negative ion chemical ionization mass spectrometry. The spectra were quite simple and are therefore ideally suited for selected ion monitoring at high sensitivity with heavy isotope labelled internal standards. The sensitivity for pentafluorobenzyl abscisate was 20 fg with a signal to noise ratio of greater than 10:1. The other compounds were within an order of magnitude of this. It is thus feasible, at least in principle, to quantify components from all four groups of plant growth regulators from the same tissue.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200170409
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  • 9
    Electronic Resource
    Electronic Resource
    Positive and negative ion methane chemical ionization mass spectrometry of amino acid pentafluorobenzyl derivatives (1985)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1985), S. 668-672 
    Details
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Condensation of pentafluorobenzyl bromide with α-amino acids under basic conditions using a brief reaction time generates amino acid-PFB derivatives. These compounds have satisfactory gas chromatographic properties and their methane positive and negative ion mass spectra have been recorded. These spectra contain few fragment ions and the negative ion mass spectra are dominated by a single anionic species making them suitable for selected ion monitoring experiments for the quantification of amino acids. Using Leu and Tyr as two typical examples we have found that negative ion chemical ionization mass spectrometry generates an increase of 250 to 300 times that observed for the same compounds under positive ion conditions.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200121108
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