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 20 for “"GC-MS-MS"”.
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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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A novel GC-MS/MS assay for the measurement of 2-hg enantiomers and the utility of 2-hg enantiomer levels as a biomarker for IDH mutant gliomas
… Furthermore, the current mass spectrometry (MS) methods available for the separation and detection are lacking. Current assays use laborious methods that can result in interconversion of enantiomers during sample preparation, and since low-resolution mass spectrometry instruments have been …
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QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) Extraction – Gas Chromatography for the Analysis of Drugs
… clean sample for analysis by gas chromatography (GC) or liquid chromatography (LC) and is commonly used for samples with complex matrices.</p> <p>The goal of this work was to expand the research that has been previously performed using QuEChERS, particularly in the area of GC analysis by exploring …
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Extending the Limits of Solid Phase Microextraction
… –Mass Spectrometer –Mass Spectrometer (SPME-GC-MS-MS) to achieve lowered detection limits with steroids in water and c) and highly selective detection of fatty acid methyl esters in olive oil.</p> <p>Headspace solid-phase microextraction (HS-SPME) was used in combination with gas …
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Scientific Underpinning of Concepts of Geochemical Inversion: Developing and Improving Methods with Application to Petroleum System Analysis
… processing, and co-elution of components in the GC-MS analysis. A single-step GC–MS/MS method was developed for simultaneous determination of various types of molecular markers in whole crudes without group-type pre-separation and discrete analyses of the diverse fractions. The method was …
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Occurrence, Fate and Transport of the Primary Metabolites of Trenbolone Acetate in CAFO Soils and Surface Water Runoff
… a gas chromatography/tandem mass spectrometry (GC/MS/MS) analytical method was developed and applied to the analysis of solid and aqueous samples. 17α- trenbolone, 17β-trenbolone, and trendione, the three primary metabolites of trenbolone acetate, occurred in both solid and aqueous phase …
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A new method for the routine trace analysis of polychlorinated biphenyls in waste oil and contaminated soil
… contaminated soil is normally expensive in terms of time, instrumentation and uses large volumes of hazardous solvents which further increase cost per sample. Commercial laboratories are constantly under pressure to provide a faster turnaround time per sample at low cost and of an acceptable …
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DETERMINATION OF CONTAMINANTS IN FISHERY PRODUCTS TO SUPPORT FOOD SAFETY
… to High-Resolution Mass Spectrometry (LC-HRMS), Gas Chromatography tandem Mass Spectrometry (GC-MS/MS), Inductively coupled plasma-optical emission spectrometry (ICP-OES) and Fourier-transform infrared spectroscopy (μFT-IR), to investigate the presence and concentrations of PFASs, and other …
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INFLAMMATION INDUCED CYTOSINE DEAMINATION DAMAGE IN CANCER ETIOLOGY
… mispair selective glycosylases and analysis by GC/MS/MS. I then propose and model a hypothesis to elucidate how partially redundant and potentially competing DNA repair pathways could be a critical link between oxidative damage and the widely observed cytosine to thymine transition mutations …
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THE IDENTIFICATION AND QUANTIFICATION OF ORGANOPHOSPHATE FLAME RETARDANTS IN RAW MATERIALS UTILIZED IN POLYURETHANE PRODUCTION
… with triple quadrupole mass spectrometry (GC-MS/MS). The examination of flame retardants containing organophosphates was completed utilizing various methods of analyses including electron ionization techniques along with various modes of detection. For optimal sensitivity, precursor and …
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The Relationship between methylation and genes associated with opioid response in humans.
… or intolerable side effects. Genetic polymorphisms in opioid pharmacodynamic and pharmacokinetic important genes have been investigated however there has been a lack of conclusive results. Epigenetic gene regulation is another study field of interest. DNA methylation is a gene regulatory …
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Bioreactor design for scaleup of Catharanthus roseus hairy root cultures for production of indole alkaloids
… for quantification after analyzing chromatograms at five different wavelengths using PDA detection. Extracts were analyzed using different analytical techniques--GC/MS, MS, HPLC-PDA and TLC--and several alkaloids were identified. The presence of ajmalicine, akuammine, apparicine, catharanthine, …
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Langzeitnachweis anaboler Steroidhormone
… anabole Substanzen in Pferdehaar-Proben mittels GC-HRMS und GC-MS/MS entwickelt (Nachweisgrenzen zwischen 0,1 und 5,0 pg/mg). Dabei können zum einen körperfremde anabole Wirkstoffe (z. B. Steroidester in Depotpräparaten) und zum anderen körper-eigene Steroide analysiert werden (z. B. Testosteron …
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Hair analysis for drugs of abuse
… drugs in hair and also investigated the mechanisms by which drugs may be incorporated into hair. The major areas covered in this study can be summarized as follows: 1. The methods for the identification and quantification of opiates, amphetamines, ketamine, cannabis, cocaine, benzodiazepines, …
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Penetration of Carcinogen Across Porcine Esophagus and Applications of Disposable Pipette Extraction for Forensic Toxicology and Food Safety by Gas and Liquid Chromatography/Mass Spectrometry
… studied using Franze diffusion cells. Using LC/MS/MS, the limit of detection (LOD) and limit of quantification (LOQ) of NNN levels were 0.065 and 0.196 ppb, respectively. Alcohol (20 and30%) and the presence of menthol and acetaldehyde (10, 20, and 30%) significantly increased permeation of NNN …
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Management of wine aroma using biotechnical tools
… Spectrometry/Mass Spectrometry (GC-MS/MS), Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (LC-MS/MS) and High-Performance Liquid Chromatography-Fluorescence (HPLC-FLD). VOCs are nonetheless the consequence of yeast metabolism, and some non-conventional yeast present …
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Combined effects of bioavailable organic contaminants in the aquatic environment.
… of organic contaminants, including PAHs (using GC-MS) and PCBs (using GC-ECD). They were then screened for a wide range of pesticides using GC-MS/MS and LC-MS/MS. The extracts were further evaluated for acute cytotoxicity (i.e. neutral red uptake assay) and EROD induction potential using rainbow …
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Label-free proteomic analysis of Xerophyta schlechteri leaf tissue under dehydration stress
… water loss, except for a small group of angiosperms called resurrection plants. They can survive severe water loss without the loss of viability by employing mechanisms that aid them in desiccation tolerance. Desiccation tolerance in resurrection plants is a complex and multifaceted phenomenon and …
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Using Polar Organic Chemical Integrated Sampler (POCIS) to monitor pesticide fluxes in Alpine streams
… threatening freshwater and riparian ecosystems also include agricultural activities, which are often located near watercourses and lead to increased levels of nutrients and pesticides in rivers due to surface runoff from rainwater or from irrigation. One of the most widely used approaches to …