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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 10 of 10 for “"atmospheric pressure chemical ionization"”.
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Evaluating the Utility of an Atmospheric Pressure Chemical Ionization Mass Spectrometer for Detecting Organic Peroxides During Beta-Pinene Ozonolysis Experiments
… intent of this study was to use a positive-ion atmospheric pressure chemical ionization mass spectrometer ((+) APCI-MS/MS) to detect organic peroxide products formed during β-pinene ozonolysis experiments. Detection was based on utilizing the neutral-loss scan (NLS) analysis mode of the …
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Mass Spectrometric Studies on the Primary Products of Fast Pyrolysis of Carbohydrates and the Molecular Structures of Asphaltenes, and the Development of a Rastering Probe for Laser-Induced Acoustic Desorption into an Atmospheric Pressure Chemical Ionization Source
… due to the lack of suitable evaporation/ionization methods for the heavier components. Consequently, very little is known about the structures of molecules in asphaltenes, the heaviest fraction of crude oil and one of the most complex mixtures in nature. Elucidating the structures of the …
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Photochemistry of Polycyclic Aromatic Hydrocarbons with Environmentally Relevant Metals
… and resulting samples are analyzed by high-pressure liquid chromatography (HPLC), UV-Vis, attenuated total reflectance Fourier transformer infrared spectroscopy (ATR-FTIR), solid-phase extraction (SPE), and electrospray ionization/atmospheric pressure chemical ionization mass spectroscopy …
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Method development for analysis of polyamines and metabolites by mass spectrometry
… used flowinjection liquid chromatography (LC)-atmospheric pressure chemical ionization (APCI)selected ion monitoring at low/high resolving power (LR/HR-SIM)-mass spectrometry (MS). Samples were extracted from murine erythroleukemia (MEL) cell culture and were analyzed without chemical …
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Reactivity Studies of Tridhydropyridine Radical Cautions by using Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry and Advancement of Mass Spectrometric Analysis of Asphaltenes and Degradation Products
… not only provides information about the chemical properties of triradicals but also helps us understand better the influence of spin/spin interactions within polyradicals. ^ In addition to fundamental studies, as described above, mass spectrometry can be helpful in structural elucidation …
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Supercritical Fluid Extraction of Nylon 6,6 Fiber Finish and Oligomers
… oligomers from nylon 6,6 fibers. The effects of pressure, extraction temperature, modifier percentage, static extraction time, and dynamic extraction time on the supercritical fluid extraction efficiency of nylon 6,6 oligomers were examined. Results from the SFE methods for both finish and …
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Chemical and Physical Studies of Secondary Organic Aerosol Formed from Beta-pinene Photooxidation
Atmospheric organic aerosols have a significant impact on climate and human health. However, our understanding of the physical and chemical properties of these aerosols is inadequate, thus their climate and health influences are poorly constrained. In this study, we investigated the secondary …
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Development of an LC-MS/MS method for the analysis of triacylglycerols from meat and application in the discrimination of cooked meat products
… (TAGs) has been developed for coupling with atmospheric pressure chemical ionization tandem mass spectrometry using an ion trap mass spectrometer. The method developed offers significant improvements on existing methods for TAG analysis, giving better resolution of TAGs with similar …
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Optimal Analysis of Sulfonamides From Biological Matrices Using Supercritical Fluids
… investigated the effect of temperature and pressure on the supercritical fluid extraction (SFE) of sulfonamides from a spiked sand matrix. Temperature effects were either positive or negative with respect to extraction rate and total recovery, depending on the pressure and extraction fluid …
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Experimental and theoretical investigations of molecular ions by spectroscopy as well as ion mobility and mass spectrometry
… of this thesis was the elucidation of different ionization methods (resonance-enhanced multiphoton ionization – REMPI, electrospray ionization – ESI, atmospheric pressure chemical ionization – APCI) in ion mobility (IM) spectrometry. In order to gain a better understanding of the ionization …