scholarly journals Methodology for Studying Oxidation of Organic Species in Solution

2000 ◽  
Vol 83 (3) ◽  
pp. 584-587 ◽  
Author(s):  
Susan M Grimes ◽  
Helen C Ngwang

Abstract A photoreactor was developed to study products of photochemical oxidation in a wide range of organic compounds. Analysis of the products from the reactor were used to determine the extent of mineralization of the organic material, to characterize any intermediate compounds formed, and to obtain information on the decomposition mechanism. Appropriate methods for separation and characterization include LC, UV spectrophotometry, gas chromatography/mass spectrometry, total organic carbon, and total inorganic carbon. The uses of the reactor are described for the photocatalytic decomposition of phenol and of its major decomposition intermediates 1,2- and 1,4-dihydroxybenzene.

1966 ◽  
Vol 101 (3) ◽  
pp. 792-810 ◽  
Author(s):  
CE Dalgliesh ◽  
EC Horning ◽  
MG Horning ◽  
KL Knox ◽  
K Yarger

1. A gas-liquid-chromatographic procedure is described which permits separation and identification on the same chromatogram of a wide range of substances occurring in urine or tissue extracts. The method uses hydrogen flame ionization, which detects organic compounds whether free or conjugated with no requirement for specific reactive groups. 2. For chromatography, carboxyl groups are quantitatively converted into methyl esters or trimethylsilyl esters. Phenolic, alcoholic and potential enolic groups are converted into trimethylsilyl ethers. Separations are carried out on a 6ft. column of either 10% F-60 (a polysiloxane) or 1% F-60, temperature programming at 2 degrees /min. being used over such part of the temperature range 30 degrees -260 degrees as is required. Propionyl derivatives of hydroxy compounds can also be used, but only on a non-quantitative basis. Derivatives and columns have been selected for optimum range of usefulness when large numbers of samples are examined by using automated gas chromatography. 3. The method is applicable to: fatty acids above butyric acid; di- and tri-carboxylic acids; hydroxy acids and keto acids; polyhydroxy and alicyclic compounds such as glycerol, inositol, quinic acid, shikimic acid, ascorbic acid and sugar alcohols; aromatic hydroxy and acidic compounds, both benzenoid and indolic; sesquiterpenes; steroids; glycine conjugates; mercapturic acids; glucuronides. It is not satisfactory for sulphate conjugates, iminazoles or polypeptides. 4. Methylene units provide an accurate and reproducible parameter for characterizing peak position. Methylene unit values are reported for a large variety of substances occurring in, or related to those occurring in, urine and tissue extracts. 5. The nature of derivatives was confirmed by combining gas chromatography with mass spectrometry. Combined gas chromatography-mass spectrometry gives a diagnostic tool of great power in the evaluation of metabolic patterns, and various uses are discussed.


Author(s):  
Sharmila S ◽  
Ramya E K

Objective: The objective of this study is to analyze the bioactive compounds of the ethanolic leaf extract of Acacia caesia using gas chromatography-mass spectrometry (GC-MS) method and also screen the in vitro cytotoxic activity against HeLa-E 72 cancer cell line.Methods: The present research was carried out using GC-MS analysis, while mass spectra of the compounds found in the extract were matched with the National Institute of Standards and Technology and Wiley library. Cytotoxicity was assessed with 3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide assay, and cellular morphological alterations were studied using phase contrast inverted light microscope of 400×. The ethanol extract of A. caesia was screened for their cytotoxicity at different concentrations (12.5–200 μg/ml), to determine the mean percentage (%) cell viability.Results: The results of GC/MS analysis showed the presence of 41 major compounds. In terms of percentage amounts, 1,8-diphenyl-3,4,10,11- tetrahydro[1,4]dioxino[2,3-g:5,6-g’]diisoquinoline, 6-(chloromethyl)-4-(3,4-dimethoxy-2-(phenylmethoxy)-phenyl)-3-methyl-2-yridinecarboxylate, and 2’,4’,6’-Trinitro-5’-phenyl-1,1’:3’,1”-terphenyl were predominant in the extract and have the property of antioxidant, antidepressant potential, antibacterial activity, cytotoxic, diabetic, and induced brain activity. The results of cytotoxicity at highest concentration (200 μg/ml) of the cells became rounder, shrunken and showed signs of detachment from the surface of the wells denoting cell death.Conclusions: From this study, it is obvious that A. caesia leaf extracts contain various bioactive constituents with a wide range of medicinal properties which is used to treat multiple disorders and it also gives a detailed insight about the phytochemical profile which could be exploited for the development of plant-based drugs. Further, the ethanolic extract of A. caesia exhibits potent cytotoxic activity against HeLa-E 72 cell line.


2019 ◽  
Vol 5 (1) ◽  
Author(s):  
M. Katie Martin ◽  
Dale J. LeCaptain ◽  
Alice Delia

Abstract Each year thousands of wildland fires blaze across the United States causing secondary (“smoke”) damage to numerous businesses and personal property. Currently there are no specific industry standards or guidelines for determining wildfire combustion residues. Remediation decisions often rely on anecdotal evidence from occupants. A variety of particulate methods are used to assess surface contamination but there are few methods for evaluating organic chemical residues that encompass the wide range of chemical classes produced during wildland fires. A new method was developed employing a thermal desorption gas chromatography mass spectrometry (TD-GCMS). TD-GCMS using novel sorbent beds decreases the sample preparation substantially and enables sampling of bulk materials by off-gassing. Furthermore, the method developed is specific to wildland fire events. Results from a simulated wildland fire event are also provided.


2017 ◽  
Vol 142 (3) ◽  
pp. 175-183 ◽  
Author(s):  
Ying Kong ◽  
Jinrong Bai ◽  
Lixin Lang ◽  
Fang Bao ◽  
Xiaoying Dou ◽  
...  

Lilium cultivars have a wide range of variation in floral scent phenotypes. Using gas chromatography–mass spectrometry (GC/MS) analyses of volatile emissions during the night, the floral scent compositions of 35 lily cultivars from seven different hybrid groups were studied. The results showed that there was a positive correlation between volatile emission levels and scent intensities. Nonscented lily cultivars belonging to Asiatic hybrids hardly emitted volatiles, light-scented Longiflorum × Asiatic hybrids emitted low levels of volatiles, and scented lily cultivars (belonging to Oriental, Trumpet, Longiflorum, Longiflorum × Oriental, and Oriental × Trumpet hybrids) emitted significantly high levels of volatiles. In general, the scent compositions of lily cultivars were similar within the same hybrid group, and the differences among hybrid groups reflect their pedigree. Monoterpenoids and benzenoids dominated the floral scents of most volatile-emitting lily cultivars, whereas monoterpenoids alone dominated the floral scents of some volatile-emitting lilies. Although various scent compounds were released from volatile-emitting lily cultivars, the dominant scent compounds were focused on three monoterpenoids [1.8-cineole, linalool, and (E)-β-ocimene] and one benzenoid (methyl benzoate). The scent traits of lily cultivars could be traced back to their parents.


Author(s):  
Sharmila S ◽  
Ramya E K

Objective: The objective of this study is to analyze the bioactive compounds of the ethanolic leaf extract of Acacia caesia using gas chromatography-mass spectrometry (GC-MS) method and also screen the in vitro cytotoxic activity against HeLa-E 72 cancer cell line.Methods: The present research was carried out using GC-MS analysis, while mass spectra of the compounds found in the extract were matched with the National Institute of Standards and Technology and Wiley library. Cytotoxicity was assessed with 3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide assay, and cellular morphological alterations were studied using phase contrast inverted light microscope of 400×. The ethanol extract of A. caesia was screened for their cytotoxicity at different concentrations (12.5–200 μg/ml), to determine the mean percentage (%) cell viability.Results: The results of GC/MS analysis showed the presence of 41 major compounds. In terms of percentage amounts, 1,8-diphenyl-3,4,10,11- tetrahydro[1,4]dioxino[2,3-g:5,6-g’]diisoquinoline, 6-(chloromethyl)-4-(3,4-dimethoxy-2-(phenylmethoxy)-phenyl)-3-methyl-2-yridinecarboxylate, and 2’,4’,6’-Trinitro-5’-phenyl-1,1’:3’,1”-terphenyl were predominant in the extract and have the property of antioxidant, antidepressant potential, antibacterial activity, cytotoxic, diabetic, and induced brain activity. The results of cytotoxicity at highest concentration (200 μg/ml) of the cells became rounder, shrunken and showed signs of detachment from the surface of the wells denoting cell death.Conclusions: From this study, it is obvious that A. caesia leaf extracts contain various bioactive constituents with a wide range of medicinal properties which is used to treat multiple disorders and it also gives a detailed insight about the phytochemical profile which could be exploited for the development of plant-based drugs. Further, the ethanolic extract of A. caesia exhibits potent cytotoxic activity against HeLa-E 72 cell line.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaorong Fu ◽  
Stanisław Deja ◽  
Justin A. Fletcher ◽  
Norma N. Anderson ◽  
Monika Mizerska ◽  
...  

AbstractDe novo lipogenesis (DNL) is disrupted in a wide range of human disease. Thus, quantification of DNL may provide insight into mechanisms and guide interventions if it can be performed rapidly and noninvasively. DNL flux is commonly measured by 2H incorporation into fatty acids following deuterated water (2H2O) administration. However, the sensitivity of this approach is limited by the natural abundance of 13C, which masks detection of 2H by mass spectrometry. Here we report that high-resolution Orbitrap gas-chromatography mass-spectrometry resolves 2H and 13C fatty acid mass isotopomers, allowing DNL to be quantified using lower 2H2O doses and shorter experimental periods than previously possible. Serial measurements over 24-hrs in mice detects the nocturnal activation of DNL and matches a 3H-water method in mice with genetic activation of DNL. Most importantly, DNL is detected in overnight-fasted humans in less than an hour and is responsive to feeding during a 4-h study. Thus, 2H specific MS provides the ability to study DNL in settings that are currently impractical.


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