scholarly journals Heliotropin, Heliotrope Odor and Tahitian Vanilla Flavor: The End of a Saga?

2007 ◽  
Vol 2 (3) ◽  
pp. 1934578X0700200 ◽  
Author(s):  
Daniel Joulain ◽  
Raymond Laurent ◽  
Jerome Masson ◽  
Jean-Claude Beolor ◽  
Hugues Brevard
Keyword(s):  
Thermal Desorption ◽  
Analytical Data ◽  
Dynamic Headspace ◽  
Flower Fragrance ◽  
Wrong Interpretation

A targeted search for heliotropin (or piperonal) in the flower fragrance of heliotrope and in cured vanilla beans of Tahitian origin is reported. Heliotropin is not detected in the fragrance emitted by heliotrope, using dynamic headspace SBSE sampling, followed by thermal desorption and analysis by conventional GC-MS. Main constituents are anisaldehyde and benzaldehyde, which confirms previous findings. Less than one part per million of heliotropin is accurately detected in authentic Tahitian vanilla bean, in using both GC-MS and LC-MS/MS. This confirms previous observations, which had shown that 4-methoxyaromatic compounds are the characteristic elements in the flavor of Tahitian vanilla, with p-anisaldehyde as the the main aroma donator. We suggest that heliotropin was named after the discovery of piperonal by degradation of piperine, the odor of which was reminiscent of the heliotrope flower. Later, its identification in vanilla extracts was the result of either a wrong interpretation of analytical data, or, much more probably, adulterations of these extracts. As a result, heliotropin should not be cited any longer as a characteristic consituent of Tahitian vanilla.

AN INVESTIGATION OF SAMPLING METHODS FOR THE ANALYSIS OF INSECT CUTICULAR HYDROCARBONS

1985 ◽  
Vol 20 (4) ◽  
pp. 435-443 ◽  
Author(s):  
Jeffrey H. Brill ◽  
Wolfgang Bertsch
Keyword(s):  
Cuticular Hydrocarbons ◽  
Thermal Desorption ◽  
Sampling Method ◽  
Sampling Methods ◽  
Headspace Analysis ◽  
Dynamic Headspace ◽  
Quantitative Sampling ◽  
Solvent Washing

Several sampling methods were examined to determine their efficiency at recovering the cuticular hydrocarbons, including solvent washing, extraction, and dynamic headspace analysis. Hexane proved to be an acceptable solvent for obtaining a representative hydrocarbon sample, but is not a good solvent for quantitative recoveries, unless special measures are taken. This appears to be as a result of both limitations in solubility and kinetic problems. Dynamic headspace analysis using a pyroprobe for thermal desorption of the hydrocarbons proved to be a rapid and quantitative sampling method.

QUANTITATIVE ANALYSIS OF FATTY ACIDS IN VULCANIZED STYRENE–BUTADIENE RUBBER BY THERMAL DESORPTION AND THERMALLY ASSISTED HYDROLYSIS AND METHYLATION-GC/MS

2014 ◽  
Vol 87 (3) ◽  
pp. 516-525 ◽  
Author(s):  
Atsushi Watanabe ◽  
Chu Watanabe ◽  
Robert Freeman ◽  
Mari Nakajima ◽  
Norio Teramae ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Thermal Desorption ◽  
Methyl Esters ◽  
Analytical Data ◽  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Relative Standard ◽  
Total Fatty Acids ◽  
Styrene Butadiene

ABSTRACT Determination of stearic acid in rubber is very important from the viewpoint of quality control of products. In place of the conventional liquid-phase extraction procedures for the analysis of additives in rubber, stearic and palmitic acids in vulcanized styrene–butadiene rubber (SBR) samples were directly analyzed in the solid state by thermal desorption (TD)–gas chromatography (GC)/mass spectrometry (MS) and thermally assisted hydrolysis and methylation (THM)–GC/MS. It was found that the precision of analytical data was only fair in the TD-GC/MS analysis, with 7.8% relative standard deviation (RSD), because of the interaction between the polar fatty acids and basic sites in the GC chromatographic system. On the other hand, THM-GC/MS, in which the fatty acids are derivatized to the methyl esters using tetramethylammonium hydroxide, can overcome this problem. Under the optimized measurement conditions of this study for THM-GC/MS, the average determined value (0.62 wt%) of total fatty acids in the SBR samples was found to agree well with the compounded amount (0.64 wt%) used in the preparation stage of the SBR samples, and the RSD was 3.2%.

HREM interface studies in SiC-whisker-reinforced Al2O3 and Si3N4 ceramics

1988 ◽  
Vol 46 ◽  
pp. 734-735
Author(s):  
W. Braue ◽  
R.W. Carpenter ◽  
D.J. Smith
Keyword(s):  
Analytical Data ◽  
Base Material ◽  
High Strength ◽  
Ceramic Composites ◽  
Good Thermal Stability ◽  
All Ceramic ◽  
Sic Whiskers ◽  
Base Composite ◽  
C 30 ◽  
Si3n4 Ceramics

Whisker and fiber reinforcement has been established as an effective toughening concept for monolithic structural ceramics to overcome limited fracture toughness and brittleness. SiC whiskers in particular combine both high strength and elastic moduli with good thermal stability and are compatible with most oxide and nonoxide matrices. As the major toughening mechanisms - crack branching, deflection and bridging - in SiC whiskenreinforced Al2O3 and Si3N41 are critically dependent on interface properties, a detailed TEM investigation was conducted on whisker/matrix interfaces in these all-ceramic- composites.In this study we present HREM images obtained at 400 kV from β-SiC/α-Al2O3 and β-SiC/β-Si3N4 interfaces, as well as preliminary analytical data. The Al2O3- base composite was hotpressed at 1830 °C/60 MPa in vacuum and the Si3N4-base material at 1725 °C/30 MPa in argon atmosphere, respectively, adding a total of 6 vt.% (Y2O3 + Al2O3) to the latter to promote densification.

Developing GIS portal to ensure sanitary and epidemiological surveillance of transferring radio engineering objects

2020 ◽  
Vol 99 (4) ◽  
pp. 344-350
Author(s):  
Evgeny V. Zibarev ◽  
A. S. Afanasev ◽  
O. V. Slusareva ◽  
T. I. Muragimov ◽  
V. A. Stepanets ◽  
...  
Keyword(s):  
Electromagnetic Fields ◽  
Analytical Data ◽  
Base Stations ◽  
Epidemiological Surveillance ◽  
Graphical Form ◽  
Residential Areas ◽  
Information Portal ◽  
Radiofrequency Electromagnetic Fields ◽  
Online Mode ◽  
Automated Processes

In recent years, in the Russian Federation there has been an increase in the levels of radiofrequency electromagnetic fields in residential areas, including due to an increase in the number of base stations (BS). The purpose of sanitary and epidemiological surveillance at the stages of placement and commissioning of base stations (BS) is to prevent their adverse effects on public health. The increase in the number of base stations, together with the advent of new electronic equipment and antennas, provide opportunities for improving the processes of their accounting at the stage of placement and monitoring of the levels of radiofrequency electromagnetic fields at the operation stage. This automation tool can be a geo-information portal for providing sanitary and epidemiological surveillance of cellular base stations. The prototype of the geo-information portal allows both calculating the size of sanitary protection zones (SPZ) and building restriction zones (RZ) from the BS in online mode, displaying the results of calculations in graphical form and issuing sanitary and epidemiological conclusions for the placement and operation of base stations. The geo-information portal has the ability to synchronize with the data of the radio frequency center. Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing will be able to receive up-to-date analytical data. There will be completely automated processes of collecting, processing and storing information on BS.

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