1,720,978 research outputs found
A HS-SPME-GC/MS Method for the Determination of Suspected Allergens in Essential Oils, Flavour, Fragrances and Cosmetics
No full textAn analytical methodology suitable to identify and quantify (as limit test) 24 compounds in vegetable materials (fluid and dry extracts) was developed according to EU Directive 2003/15/EC (suspected allergens). Static headspace solid-phase microextraction (HS-SPME) was directly perfomed. Automated mass spectral deconvolution and identification system (AMDIS) program was applied on GC-MS data through use of a library of mass spectra including RI-values
Approaches Towards the Use of MS/MS Spectral Libraries
No full textA test of NIST05 MS/MS spectral library for evaluating of compound identification was carried out on both quadrupole ion trap and triple quadrupole mass spectrometers in conjunction with electrospray ionization. Data are presented
Characterization of phenolic and secoiridoid aglycons present in virgin olive oil by gas chromatography-chemical ionization mass spectrometry
No full textCharacterization of Phenolic and Secoiridoid Aglycons Present in Virgin Olive Oil by GC-CI-MS
No full textOlive oil phenolic and secoiridoid compound derivatives were detected by mass spectrometry. Chemical ionization (Cl) allowed us to obtain parent ions, that were not detectable in the electron impact mode. CI experiments were performed using either CH4 or NH3 as the reactant gas. Unlike CH4-CI, which fails to give molecular mass information, NH3-CI provided, in all the cases explored, an adduct ion [M+18] + that was sufficiently stable to be detected and recorded. Information about molecular masses was very useful for the complete characterization of aglycons from glycosides occurring in virgin olive
oils. Aglycons of ligstroside, of decarbomethoxyoleuropein and of oleuropein were detected. Each aglycon, because of several tautomeric equilibria involving the ring opening of secoiridoid, showed up as compounds with four main structures after derivatization with bis(trimethylsilyl)trifluoracetamide
Application of an HPLC-MS/MS method for Teicoplanin drug substance and related impurities, part 2: Identity assignment of related impurities
No full textA liquid chromatographic MS-compatible method was applied to the structural elucidation of Teicoplanin for identification CRS components. The method, previously developed by our group, involves the use of LiChrospher 100 RP-18 column with a mobile phase composed of ammonium formate 25 mM at pH 6.00 and acetonitrile (ACN). All the peaks with a 0.10% UV area, largely above the disregard limit of 0.15% as fixed by EMA, were considered and submitted to MS/MS fragmentation experiments. The study of MS/MS spectrum collected for Teicoplanin complex major component (namely A 2-2 ) allowed to elucidate the fragmentation pathway and enabled the successful identity assignment of all the 42 detected species. Elution order was also rationalized. An in house batch sample of Teicoplanin was analyzed and, while the 86% of the detected species were structurally identical to those in Teicoplanin for identification CRS, five new derivatives were revealed and structurally characterized. In both the Teicoplanin samples, all the considered species were found to have a Teicoplanin-like structure that allows their classification as closely related impurities, with a significant implication in their qualification threshold
Nutraceutical Value of Pantelleria Capers (Capparis spinosa L.)
No full textAbstract: Unopened flower buds of Capparis spinosa L. (capers), generally used in the Mediterranean area as food flavoring, are known to be a good source of bioactive compounds. The aim of this work was to evaluate the nutraceutical value of salt-fermented capers collected from different areas of Pantelleria Island (Italy), testing their methylglyoxal and glyoxal trapping capacity and antioxidant activity by 2,2-diphenyl-1-picryl hydrazyl (DPPH), [2,2-azinobis(3-ethylben- zothiazoline-6-sulfonic acid)] diammonium salt (ABTS), and oxygen radical absorbance capacity (ORAC) assays. Hydrophilic extracts were also characterized by high-performance liquid chromatography–electrospray ionization/mass spectrometry. Among 24 detected compounds, several flavonol derivatives and glucosinolates were identified. The levels of kaempferol and quercetin derivatives varied considerably among the five accessions considered (6.46 to 267.93 and 22.39 to 367.14 mg kaempferol and quercetin equivalent /g fresh weight, respectively), with kaempferol derivatives more representative than quercetin ones. Person's coefficient indicated a high correlation between total phenolic content and anti-DPPH radical capacity (R2 = 0.665), as well as between total flavonoid content and antioxidant capacity (by ORAC assay; R2 = 0.888) and between total flavonoid content and glyoxal and methylglyoxal trapping capacity (R2 = 0.918). Results indicate that capers from Pantelleria Island represent a rich source of bioactive compounds with potential nutraceutical relevance. Practical Application: The findings of this study highlight the health benefits of Pantelleria capers consumption due to their composition in antioxidants and their biological properties (antiradical and alpha-dicarbonyls trapping) correlated with the development of a high number of chronic–degenerative diseases. These results are also important for the agricultural and commercial sectors involved in the production of capers from Pantelleria, which received the Protected Geographical Indications recognition
HNO made-easy from photochemical cycloreversion of novel 3,5-heterocyclic disubstituted 1,2,4-oxadiazole-4-oxides
Full text linkA variety of symmetric and asymmetric 3,5-heterocyclic disubstituted 1,2,4-oxadiazole-4-oxides have
been prepared through cycloaddition of aromatic and heteroaromatic nitrile oxides to heteroaromatic
amidoximes. A library of novel, fully characterized, 1,2,4-oxadiazole-4-oxides has been obtained as
valuable precursors, upon photochemical activation, of new nitrosocarbonyl intermediates. The photochemical
cycloreversion of the 1,2,4-oxadiazole-4-oxides was investigated from the computational point
of view and the hydrolysis of the generated nitrosocarbonyl intermediates in water constituted the way
for an easy-made HNO generation process because of the photochemical behavior of the parent
compounds
Patterns of traffic polycyclic aromatic hydrocarbons pollution in mountain areas can be revealed by lichen biomonitoring: a case study in the Dolomites (Eastern Italian Alps)
No full textInmountain areas of touristic interest the evaluation of the impact of human activities is crucial for ensuring longterm conservation of ecosystem biodiversity, functions and services. This study aimed at verifying the biological impact of polycyclic aromatic hydrocarbon (PAH) emissions due to traffic along the roads leading to seven passes of the Dolomites (SE Alps), which were recently declared a UNESCOWorld Heritage Site. Thalli of the epiphytic
lichen Pseudevernia furfuracea, collected at increasing distances from the roads, were used as biomonitors. Our study revealed a gradient of decreasing PAH pollution within 300 m from the roads. Differences among passes were evident mainly for samples collected nearest to the roads, but PAH concentrations at 300 m were almost always higher than those of undisturbed reference sites, indicating that traffic PAH pollution may impact natural
ecosystems and lichen diversity at relatively long distances from the emission source
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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