Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 611 for “"GC-MS"”.
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Μελέτη και ποσοτικοποίηση πολυκυκλικών αρωματικών υδρογονανθράκων με GC-MS
… μεθόδου προσδιορισμού αυτών των ενώσεων με GC-MS και αναλύθηκαν 20 δείγματα ελαιολάδων συλλεγμένα από ελαιοτριβείο στην Χαλκίδα. Σύμφωνα με τα αποτελέσματα όλα τα δείγματα ελαιολάδων κρίθηκαν ασφαλή και εντός των ορίων που θέτει η νομοθεσία. Το βένζο(a)ανθρακένιο προσδιορίστηκε σε όλα τα …
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Analysis of Aroma Constituents in Cultivated Strawberries by GC/MS
… were separated by Gas Chromatography (GC), and identified by Mass Spectrometer Detector (MSD). Column and experimental conditions were optimized for this particular separation. Salinas, Orrville and Memphis strawberries have very similar aroma constituents, however, in slightly …
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Analysis of Biogenic Amines by GC/FID and GC/MS
… are difficult to analyze by Gas Chromatography (GC) due to their lack of volatility and their interaction with the GC column, often leading to significant tailing and poor reproducibility. Biogenic amines need to be derivatized before both GC and HPLC analyses. The objective of this research was …
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Determination of ground-water tracer 2,6-difluorobenzoic acid by Gc/Ms
In this study, a GC analytical method for the determination of the ground water tracer, 2,6-difluorobenzoic acid (2,6-DFBA) at the part per billion level was established. Three sample preparation methods, which include two methylation methods and one silylation method, have been evaluated. …
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Determination of Carbon Nanotube Modification by TG-MS and Pyrolysis-GC/MS
… were thermogravi me try-mass spectrometry (TG-MS) and pyrolysis-gas chromatography/mass spectrometry (GC/MS). Samples were heated while the gasses evolved were monitored to determine their identities. The soluble SWNTs were less stable than the non-soluble SWNTS. In addition, they also had much …
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Monitoring a natural autoxidation process of methyl linoleate by using GC-MS
… damage to living cells. The technology of GC-MS was employed to monitor the autoxidation of methyllinoleate.</p> <p>Eight of the autoxidation products separated by GC column were identified by interpreting the corresponding EI ion mass spectra. The products from 9-alkoxy methyl linoleate …
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Characterization of short chain fatty acids in microbial cultures by DART-MS and GC-MS
… of mono- and co-cultures in in vitro systems has led to the conclusion that diverse microbial organisms may each contribute in part to the complete metabolism to produce SCFA. GC- MS and DART- MS were investigated as analytical tools in the present study to evaluate the production of …
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Development of a GC-MS method to determine toxic alcohols and their metabolites in postmortem blood
… a gas chromatography-mass spectroscopy (GC-MS) method for the quantitative determination of ETG, DEG, 1,4-BD, PGL, and the toxic metabolite of ETG, glycolic acid (GCA), in postmortem whole blood samples at the Forensic Toxicology Unit (FTU) in the Western Cape, South Africa. We describe …
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GC-MS Investigation of Metabolic Activity in 4-Hydroxy-2-Oxoglutarate Aldolase Deficiency of Primary Hyperoxaluria Type 3
… After extensive optimization, a successful GC-MS analytical method was established, and preliminary qualitative results were obtained from WT and KO liver and urine. In liver several qualitative metabolic differences were detected, and oxoadipic acid was detected in all of the samples; …
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Development and Application of An Integrated GC-MS/MS and GC-IRMS Analytical Approach in Food Quality Evaluation
… vulnerable category of products in terms of food fraud. These materials are widely used in the food, cosmetic, pharmaceutical, and fragrance industries and often command high prices, especially when derived from natural botanical sources. Chemically, plant extracts and essential oils …
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Detection and analysis of spin trapped radical adducts using thermal desorption gas chromatography mass spectrometry (TD-GC-MS)
… (EPR) spectroscopy or Mass Spectrometry (MS). In the current study, Fenton chemistry has been used to generate hydroxyl radicals. Sincethe hydroxyl radical adduct of the spin-trap N-tert-butyl-α-phenylnitrone (PBN) is shortlivedat room temperature a secondary trapping technique is …
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Sample Preparation/Concentration for Trace Analysis in GC/MS (A study of solid phase microextraction and headspace sampling)
… fatty acids in food samples were analyzed by GC/MS. Since SPME is not directly applicable to solid samples, SPME associated with MAE techniques was studied for solids, primarily food samples. The efficiency of classical solvent extraction and MAE was compared. The parameters which affect SPME, …
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Characterization of a black coating overlying rock paintings found in Little Lost River Cave, Idaho using THM-GC-MS
… to verify that the coating is anthropogenic, THM-GC-MS was performed on various samples collected throughout the cave, including soil samples from inside, outside, and above the cave. Humic and fulvic acids, synthetic and natural melanin, and experimentally created cooking residues were also …
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Profiling and putative aroma biomarker identification for flavor in potatoes using a trained sensory panel and HS-SPME GC-MS
… coupled to mass spectrometry (HS-SPME GC-MS) facilitated identification of 42 unique metabolites with significant variation across samples (ANOVA, α=0.05, n=5 technical replicates x 14-15 clones x 2 cooking methods). Based on Spearman's rank correlations, hierarchical clustering …
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Development of a GC-MS method and analysis of phenolic acids in fruit and spice matrices and evaluation of their antioxidant capacity
… phenolic acids using different assays. A GC/MS method was developed for the quantification of ten commonly present phenolic acids in plant foods. Target analytes were the benzoic acid based phenolic acids - anisic, gallic, p-hydroxy benzoic, o-salicylic, protocatechuic, and vanillic acids, …
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