scholarly journals Characterization of Volatile Compounds in Four Different Rhododendron Flowers by GC×GC-QTOFMS

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3327 ◽  
Author(s):  
Chen-Yu Qian ◽  
Wen-Xuan Quan ◽  
Zhang-Min Xiang ◽  
Chao-Chan Li
Keyword(s):  
Mass Spectrometry ◽  
Volatile Compounds ◽  
Gas Chromatography Mass Spectrometry ◽  
Comprehensive Understanding ◽  
Phenylethyl Alcohol ◽  
One Dimensional ◽  
Flight Mass Spectrometry ◽  
Different Content ◽  
Methyl Benzene

Volatile compounds in flowers of Rhododendron delavayi, R. agastum, R. annae, and R. irroratum were analyzed using comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC) coupled with high-resolution quadrupole time-of-flight mass spectrometry (QTOFMS). A significantly increased number of compounds was separated by GC×GC compared to conventional one-dimensional GC (1DGC), allowing more comprehensive understanding of the volatile composition of Rhododendron flowers. In total, 129 volatile compounds were detected and quantified. Among them, hexanal, limonene, benzeneacetaldehyde, 2-nonen-1-ol, phenylethyl alcohol, citronellal, isopulegol, 3,5-dimethoxytoluene, and pyridine are the main compounds with different content levels in all flower samples. 1,2,3-trimethoxy-5-methyl-benzene exhibits significantly higher content in R. irroratum compared to in the other three species, while isopulegol is only found in R. irroratum and R. agastum.

scholarly journals Chemical Characterization of Craft Filuferru Spirit from Sardinia, Italy

Beverages ◽  
2018 ◽  
Vol 4 (3) ◽  
pp. 62
Author(s):  
Ilaria Langasco ◽  
Marco Caredda ◽  
Gavino Sanna ◽  
Angelo Panzanelli ◽  
Maria Pilo ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Acetic Acid ◽  
Ethyl Acetate ◽  
Volatile Compounds ◽  
Inductively Coupled Plasma ◽  
Chemical Characterization ◽  
Gas Chromatography Mass Spectrometry ◽  
Qualitative And Quantitative ◽  
Alcoholic Strength

Traditional Filuferru is an ancient spirit from Sardinia, Italy, which is usually obtained from the distillation of wine or grape marc. In this contribution, the results of the first chemical characterization of a wide number of crafts Filuferru samples has been accomplished in terms of an evaluation of the alcoholic strength, qualitative and quantitative gas-chromatography–mass spectrometry (GC-MS) analysis of the volatile composition of the distillate, and its trace element composition by means an inductively coupled plasma–mass spectrometry (ICP-MS) method. Both instrumental methods have been validated and applied on 21 craft samples of Filuferru, whereas one sample of commercial distillate has been analyzed for comparison purposes. Alcoholic strength ranged between 41.0 and 62.4% (v/v). Sixty volatile compounds were identified and ten of them have been quantified. Analogies and differences with Grappa (i.e., the Italian distilled spirit closer to Filuferru) have been highlighted in the qualitative and quantitative profile of this matrix. Often meaningful amounts of acetaldehyde, ethyl acetate, dietyl acetal, and acetic acid were measured. Elemental analysis, performed on toxic, non-toxic elements, and oligoelements, 18 in total, revealed a wide variability of concentrations in both analytes and samples. High concentrations of Cu are sometimes evidenced, which are likely caused by losses from the distillation apparatus. The principal components analysis (PCA) allowed the differentiation of the ten volatile compounds quantified in two groups: the former, as described mainly by PC1, constituted by acetic acid, ethyl acetate, dietyl acetal, and acetaldehyde, and the second, described by PC2, constituted by 1-propanol, 2-methyl-1-propanol, the two coeluiting isomers 2-methyl-1-butanol and 3-methyl-1-butanol,1-hexanol, 2-phenylethanol, and 2,3-butanediol. Data obtained may be useful in order to establish a regulation for the production of high-quality traditional Filuferru from Sardinia.

scholarly journals Identification and Characterization of the Genes Involved in Glycosylation Pathways of Mycobacterial Glycopeptidolipid Biosynthesis

2006 ◽  
Vol 188 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Yuji Miyamoto ◽  
Tetsu Mukai ◽  
Noboru Nakata ◽  
Yumi Maeda ◽  
Masanori Kai ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Fatty Acyl ◽  
Gas Chromatography Mass Spectrometry ◽  
Ionization Time ◽  
Flight Mass Spectrometry ◽  
The Common ◽  
Glycosylation Pathway ◽  
Layer Chromatography ◽  
Identification And Characterization

ABSTRACT Glycopeptidolipids (GPLs) are major components present on the outer layers of the cell walls of several nontuberculous mycobacteria. GPLs are antigenic molecules and have variant oligosaccharides in mycobacteria such as Mycobacterium avium. In this study, we identified four genes (gtf1, gtf2, gtf3, and gtf4) in the genome of Mycobacterium smegmatis. These genes were independently inactivated by homologous recombination in M. smegmatis, and the structures of GPLs from each gene disruptant were analyzed. Thin-layer chromatography, gas chromatography-mass spectrometry, and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analyses revealed that the mutants Δgtf1 and Δgtf2 accumulated the fatty acyl-tetrapeptide core having O-methyl-rhamnose and 6-deoxy-talose as sugar residues, respectively. The mutant Δgtf4 possessed the same GPLs as the wild type, whereas the mutant Δgtf3 lacked two minor GPLs, consisting of 3-O-methyl-rhamnose attached to O-methyl-rhamnose of the fatty acyl-tetrapeptide core. These results indicate that the gtf1 and gtf2 genes are responsible for the early glycosylation steps of GPL biosynthesis and the gtf3 gene is involved in transferring a rhamnose residue not to 6-deoxy-talose but to an O-methyl-rhamnose residue. Moreover, a complementation experiment showed that M. avium gtfA and gtfB, which are deduced glycosyltransferase genes of GPL biosynthesis, restore complete GPL production in the mutants Δgtf1 and Δgtf2, respectively. Our findings propose that both M. smegmatis and M. avium have the common glycosylation pathway in the early steps of GPL biosynthesis but differ at the later stages.

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