- Detalles de la revista
- Formato
- Revista
- eISSN
- 2719-9509
- Publicado por primera vez
- 01 Jan 1992
- Periodo de publicación
- 4 veces al año
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- Acceso abierto
Specific Structural Analysis of Solanesol and Related Compounds by Fast Atom Bombardment in Combination with Tandem Mass Spectrometry
Páginas: 85 - 93
Resumen
Rapid identification of solanesol even in the presence of a complex matrix can be accomplished using fast atom bombardment (FAB) mass spectrometry in combination with tandem mass spectrometry methods. FAB MS analysis using a nitrobenzyl alcohol matrix doped with lithium yields an abundant (M + Li)+ ion of m/z of 637 which is a very characteristic marker for the presence of solanesol and is quite sufficient for screening for the presence of solanesol in many cases. MS/MS analysis of this ion produces a spectrum which yields specific structural information regarding each isoprene unit of the entire structure. Furthermore, these methods are very useful for characterizing unknowns as demonstrated by the characterization of diol, triol and ester impurities in commercially available solanesol. Application of the MS/MS/MS analysis provides insight into the fragmentation mechanism and can be a useful alternative to conventional labeling methods for confirming spectral interpretations.
- Acceso abierto
Development of Experimental Methods for Study of Gas-Phase Charge-Reversal Charge Transfer Processes of Potential Interest in Smoke Chemistry
Páginas: 95 - 105
Resumen
Gas phase reactions are of fundamental interest in smoke chemistry. Many types of reactions and decompositions have been characterized. However, one type of reaction, the charge transfer process, is very difficult to characterize by conventional means. Methods have been developed using a four sector tandem mass spectrometer for chemical characterization of charge-reversal charge transfer reaction products. This is accomplished by operating two of the sectors of the instrument in the negative ion mode and the other two sectors of the instrument in the positive ion mode with inert gas collision at the interface to facilitate charge transfer. For example if a negatively charged ion generated and selected in MS I is collisionally activated at the interface and the products are analysed with MS II in the positive ion mode, then only chemical species generated in charge-reversal charge transfer processes of the original parent anion are identified. This technique has been applied to fundamental studies of model compounds including fatty acids, solanesol, sugars and humectants.
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Tobacco and the Environment: The Continuous Reduction of Worldwide Energy Source Use for Green Leaf Curing
Páginas: 107 - 117
Resumen
Air-, flue-, fire-, and sun-cured, tobacco types require post-harvest curing of green leaves to produce optimum subjective and objective qualities for storage and subsequent processing and manufacture. Materials for construction of curing barns vary widely between countries. The major use of heating fuels within such structures is for flue-cured tobacco. Choice of energy sources, coal, wood, oil or gas depends on local availability, cost, and relative efficiencies. The vital importance of reducing such materials to a minimum has been recognised for many years by research into improving barn and furnace design and construction. Consumption of wood for curing has been shown to represent a minute proportion of total world wide consumer use. To ensure local availability, the growing of trees by flue cured farmers on a personal, self-sufficient, sustainable basis is well underway in parts of Africa, Asia, and South and Central America. Tobacco production, within an environmental farming system, on an economic basis, is discussed and strongly stressed.
- Acceso abierto
The Biological Degradation of Nicotine by Nicotinophilic Microorganisms
Páginas: 119 - 129
Resumen
Various microorganisms are capable of breaking down tobacco alkaloids by different biochemical processes and possess characteristic enzymatic systems for the catabolism of nicotine. Bacteria of the genus Pseudomonas and the fungus Cunninghamellaechinulata degrade nicotine via N-methylmyosmine and pseudooxynicotine which is linked to the opening of the pyrrolidine ring (pyrrolidine pathway), whereas Arthrobacteroxidanshydroxylates the pyridine ring in the 6-position. 6-hydroxynicotine is produced as a primary product (pyridine pathway). Tobacco plants, and some fungi (e.g. Pelliculariafilamentosa) degrade nicotine via demethylation to nornicotine (methyl pathway). As a result of the microbial degradation of nicotine and other tobacco alkaloids, carbon and nitrogen are made bioavailable. Following metabolic conversion to carboxylic acids, the reaction products are used by unicellular organisms as primary nutrients and a source of energy for the synthesis of new cell compounds.