This work compares the composition at different temperatures of gaseous phase of bergamot essential oil at equilibrium with the liquid phase. A new GC-MS methodology to determine quantitatively the volatile aroma compounds was developed. The adopted methodology involved the direct injection of headspace gas into injection port of GC-MS system and of known amounts of the corresponding authentic volatile compounds. The methodology was validated. This study showed that gaseous phase composition is different from that of the liquid phase at equilibrium with it.
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http://dx.doi.org/10.1186/s13065-017-0340-y | DOI Listing |
Molecules
January 2025
Centro de Investigação em Química (CIQUP), Institute of Molecular Sciences (IMS), Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
An extensive thermochemical study of γ-undecanolactone and δ-undecanolactone has been developed using two complementary calorimetric techniques. The combustion energy of each compound was determined by static-bomb combustion calorimetry, and the corresponding enthalpy of vaporization was determined by high-temperature Calvet microcalorimetry, in which both properties of each compound are reported at = 298.15 K.
View Article and Find Full Text PDFMaterials (Basel)
January 2025
Faculty of Safety Engineering and Civil Protection, Fire University, 52/54 Slowackiego Street, 01-629 Warsaw, Poland.
The main purpose of this article was to determine the smoke-generating and thermal properties of selected types of natural leather. Differences in the amount of smoke generated from the type of finish used in the technological processing of leather were observed. Research has shown that the burnt nubuck (367) sample with exposure at the heat flux intensity of 25 kW/m without the presence of a pilot burner flame achieved the highest value of the specific optical density D.
View Article and Find Full Text PDFSci Total Environ
January 2025
CNR-Institute of Atmospheric Pollution Research, Rende Division, UNICAL Polifuzionale, Rende 87036, CS, Italy.
This study provides a review of 13 oceanographic campaigns between 2000 and 2017 to measure Hg in the Mediterranean, highlighting major findings from measurement and modelling activities during the Med-Oceanor program. The initial campaigns showed that high concentrations of RGM could be found far from industrial source regions and the observed daily variation in concentration, with peaks at midday and lower concentrations during darkness gave the first indications that photochemically mediated oxidation reactions were producing RGM in the MBL. Later atmospheric chemistry modelling studies showed the feasibility of Hg oxidation by bromine containing oxidants, which are released as a result of the acidification of sea salt aerosols in the Marine Boundary Layer (MBL).
View Article and Find Full Text PDFMetabolites
January 2025
Institute of Toxicology, Core Unit Proteomics, Hannover Medical School, 30623 Hannover, Germany.
Charge-free gaseous molecules labeled with deuterium H (D) atoms elute earlier than their protium-analogs H (H) from most stationary GC phases. This effect is known as the chromatographic H/D isotope effect (IE) and can be calculated by dividing the retention times () of the protiated ( ) to those of the deuterated () analytes: IE = /. Analytes labeled with C, N or O have almost identical retention times and lack a chromatographic isotope effect.
View Article and Find Full Text PDFMembranes (Basel)
January 2025
Godo Shigen Co., Ltd., 1545-1 Nanaido, Chosei-mura, Chiba 299-4333, Japan.
Iodine, being an important resource, must be recovered and reused. Iodine is not only attracted to the hydrophobic silicone membrane but also easily vaporized. In this study, we explored the use of five types of silicone hollow fiber membrane modules (SFMMs) for separating iodine in the gaseous phase.
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