chemical markers
Recently Published Documents


TOTAL DOCUMENTS

400
(FIVE YEARS 106)

H-INDEX

32
(FIVE YEARS 6)

Author(s):  
Samara de Macêdo Morais ◽  
Mércia de Sousa Galvão ◽  
Lary Souza Olegario ◽  
Leila Moreira de Carvalho ◽  
Giuliano Elias Pereira ◽  
...  

2022 ◽  
Author(s):  
Pavel Serov ◽  
Rune Mattingsdal ◽  
Monica Winsborrow ◽  
Henry Patton ◽  
Karin Andreassen

Abstract Parceling the anthropogenic and natural (geological) sources of fossil methane in the atmosphere remains problematic due to a lack of distinctive chemical markers for their discrimination. In this light, understanding the distribution and contribution of potential geological methane sources is important. We present empirical observations of hitherto undocumented, widespread and extensive methane and oil release from geological reservoirs to the Arctic Ocean. Methane fluxes from >7,000 seeps significantly deplete in seawater, but nevertheless reach the sea surface and may transfer to the air. Oil slick emission spots and gas ebullition are persistent across multi-year observations and correlate to formerly glaciated geological structures, which have experienced km-scale glacial erosion that has left hydrocarbon reservoirs partially uncapped since the last deglaciation ~15,000 years ago. Such persistent, geologically controlled, natural hydrocarbon release may be characteristic of formerly glaciated hydrocarbon-bearing basins which are common across polar continental shelves, and could represent an underestimated source of natural fossil methane within the global carbon cycle.


Beverages ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 3
Author(s):  
Biel Granell ◽  
Anaïs Izquierdo-Llopart ◽  
Àngels Sahuquillo ◽  
José F. López-Sánchez ◽  
Javier Saurina

Samples from the different processing stages in the elaboration of sparkling wine (cava)—including must, base wine, and sparkling wine—of Pinot Noir and Xarel·lo grape varieties from different vineyard qualities (A, B, C, D) have been analyzed by inductively coupled plasma (ICP) techniques to determine their elemental composition. The resulting data has been used to characterize these products according to oenological features and product qualities. For this purpose, box plot diagrams, bar charts, and principal components analysis (PCA) have been used. The study of the behavior of each given species has pointed out the relevance of some elements as markers or descriptors of winemaking processes. Among others, Cu and K are abundant in musts and their concentrations progressively decrease through the cava production process. S levels suddenly increase at the base wine step (and further decay) due to the addition of sulfites as preserving agents. Finally, concentrations of Na, Ca, Fe, and Mg increase from the first fermentation due to the addition of clarifying agents such as bentonite. PCA has been applied to try to extract solid and global conclusions on trends and chemical markers within the groups of samples more easily and efficiently than more conventional approaches.


Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7540
Author(s):  
Kerry Wilkinson ◽  
Renata Ristic ◽  
Imogen McNamara ◽  
Beth Loveys ◽  
WenWen Jiang ◽  
...  

It has been well established that bushfire/wildfire smoke can taint grapes (and therefore wine), depending on the timing and duration of exposure, but the risk of smoke contamination from stubble burning (a practice employed by some grain growers to prepare farmland for sowing) has not yet been established. This study exposed excised bunches of grapes to smoke from combustion of barley straw and pea stubble windrows to investigate the potential for stubble burning to elicit smoke taint. Increased levels of volatile phenols (i.e., chemical markers of smoke taint) were detected in grapes exposed to barley straw smoke (relative to control grapes), with smoke density and the duration of smoke exposure influencing grape volatile phenols. However, the sensory panel did not perceive wine made from grapes exposed to low-density smoke to be tainted, despite the presence of low levels of syringol providing compositional evidence of smoke exposure. During the pea stubble burn, grapes positioned amongst the burning windrows or on the edge of the pea paddock were exposed to smoke for ~15–20 and 30–45 min, respectively, but this only resulted in 1 µg/kg differences in the cresol and/or syringol concentrations of smoke-affected grapes (and 1 µg/L differences for wine), relative to controls. A small, but significant increase in the intensity of smoke aroma and burnt rubber flavor of wine made from the grapes positioned amongst the burning pea stubble windrows provided the only sensory evidence of any smoke taint. As such, had vineyards been located immediately downwind from the pea stubble burn, it is unlikely that there would have been any smoke contamination of unharvested grapes.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Emmanuel Kofi Kumatia ◽  
Francis Ofosu-Koranteng ◽  
Alfred Ampomah Appiah ◽  
Kofi Bobi Barimah

Mist Nibima is an essential herbal medicine used to treat malaria, bacterial, yeast, and COVID-19 infections. However, the drug has not been standardized and its active chemical ingredients are also not known. This study employed physicochemical, organoleptic, qualitative, and quantitate phytochemical analysis to established standards for Mist Nibima. Additionally, UHPLC was used to quantify the alkaloid cryptolepine in the drug using calibration curve. The chemical ingredients in Mist Nibima were thereafter characterized using UHPLC-MS. Organoleptic evaluation shows that Mist Nibima is a very bitter, cloudy, broom yellow decoction with the following physicochemical parameters: pH = 6.10 ± 0.08 (at 28.3°C), total solid residue = 5.34 ± 0.27%w/v, and specific gravity = 1.0099 ± 0.0000. The total alkaloid (23.71 ± 1.311%) content of the drug is 3 times its total saponins (7.993 ± 0.067%) content. Methyl cryptolepinoate (37.10%), cryptolepine (33.56%), quindoline (20.78%), 11-isopropylcryptolepine (5.16%), and hydroxycryptolepine (3.14%) were the active chemical ingredients in the drug with the concentrations of 18.64 ± 0.255, 16.85 ± 0.231, 10.42 ± 0.143, 2.56 ± 0.034, and 1.70 ± 0.023 µg/mL, respectively. Administration of a single oral therapeutic dose (30 mL) of Mist Nibima corresponds to ingestion of 559.2 ± 7.662, 505.5 ± 6.930, 312.6 ± 4.285, 76.8 ± 1.028, and 51.0 ± 0.699 µg of methyl cryptolepinoate, cryptolepine, quindoline, 11-isopropylcryptolepine, and hydroxycryptolepine, respectively. This translates into a corresponding daily dose of 1677.6 ± 22.986, 1516.5 ± 20.790, 937.8 ± 12.855, 230.4 ± 3.084, and 153.0 ± 2.097 µg of methyl cryptolepinoate, cryptolepine, quindoline, 11-isopropylcryptolepine, and hydroxycryptolepine. These results could now serve as tools for authentication, standardization, and quality control of Mist Nibima to ensure its chemical and pharmacological consistency and safety.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Ingrid Vicente Farias ◽  
Eduarda Fratoni ◽  
Lais Cristina Theindl ◽  
Angela Machado de Campos ◽  
Eduardo Monguilhott Dalmarco ◽  
...  

Ilex paraguariensis A. St. Hil. (Aquifoliaceae), popularly known as “yerba mate,” has great economic and social significance for the population of Southern Latin America. This study was conducted (1) to investigate the phytochemical composition of four different standardized extracts, (2) to investigate its free radical scavenging properties, and (3) to investigate the anti-inflammatory action of I. paraguariensis and its major chemical markers. The chemical profile was achieved by Folin-Ciocalteu, by LC/DAD, and by LC/MS assays, while the antioxidant and anti-inflammatory properties were investigated, respectively, by DPPH assay and by inhibition of nitric oxide (Griess reaction) and TNF-α (ELISA). Our results demonstrated that the IA (aqueous infusion extract) showed higher amounts of total phenolic contents ( 266.62 ± 10.85   mg CAE·g-1 DE), the highest amounts of all six chemical markers (theobromine, 5-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 3-O-caffeoylquinic acid, caffeine, and rutin), and stronger antioxidant activity ( E C 50 = 54.4 ± 5.14   μ g · m L − 1 ). The IA extract also showed the lowest inhibition of NOx secretion ( 50.10 ± 8.97 % ) as well as inhibition of TNF-α ( 83.33 ± 4.01 % ). Regarding the chemical markers, all compounds showed strong inhibition of NOx secretion, especially theobromine, which was 200x more potent than dexamethasone. Furthermore, TNF-α secretion was also significantly decreased by THEO at 0.033 μM ( 22.15 ± 6.49 % ), NCA at 1.97 μM ( 27.46 ± 3.98 % ), CCA at 0.35 μM ( 39.76 ± 5.73 % ), CGA at 0.56 μM ( 23.58 ± 5.79 % ), CAF at 0.52 μM ( 26.45 ± 5.34 % ), and RUT at 0.16 μM ( 40.18 ± 3.70 % ). Our results suggest that I. paraguariensis and its major chemical markers have strong free radical scavenging properties as well as showed important anti-inflammatory activity and that these compounds in a plant extract may work based on several different mechanisms synergistically, resulting in moderating the immune system.


2021 ◽  
Vol 15 (5) ◽  
pp. 693-699
Author(s):  
Lulu Geng ◽  
Min Wang ◽  
Mingshi Liu ◽  
Haoyang Sun

In this paper, a novel approach was set up to analyze and discriminate propolis from different regions based on GC-MS and multivariate statistical analysis. A number of Chinese and Brazilian green propolis samples were dealt with based on this method, and a set of data were processed with partial least squares-discriminant analysis (PLS-DA). A clear differences between the two groups were shown in score plot. The chemical markers for the differentiation were selected through loading plot. Based on the comparison between the reference and/or NIST database and mass fragments in the publication, chemical markers were tentatively identified. Lauric acid, 2(3H)-naphthalenone, spathulenol and benzenebutanoic acid were taken as chemical markers based on the above strategy. This research could provide some valuable information to the quality control of propolis from different origins.


Author(s):  
Sultan Alotaibi ◽  
Maria Markoulli ◽  
Jerome Ozkan ◽  
Eric Papas

Sign in / Sign up

Export Citation Format

Share Document