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Detection Of Trehalose In Porphyra Extracts Using Mass Spectrometry And Gas Chromatography-Mass Spectrometry, Ying Huo

Master's Theses and Capstones

It is known that trehalose helps many plants to survive under desiccated environment26. This property of trehalose has also been proposed to explain why Porphyra could survive desiccation when left on dry land for a long period of time25. However, after extensive study25, effort at identifying trehalose in Porphyra has been unsuccessful, leaving the question of whether trehalose really exists in Porphyra unanswered. In my thesis research, in collaboration with Dr. Anita Klein, I set out to use ion-trap mass spectrometry and gas chromatography coupled with mass spectrometry to identify and quantify the amount of trehalose in Porphyra extracts. Using …

Building And Deployment Of An Automated, In Situ Greenhouse Gas Gas Chromatographic System, Andrew H. Hart

Master's Theses and Capstones

High-precision, continuous monitoring of greenhouse gases, such as carbon dioxide (CO2), methane (CH4), nitrous oxide (N 2O), sulfur hexafluoride (SF6), and the criteria pollutant carbon monoxide (CO), is important for characterizing their regional sources and sinks and understanding how their ambient levels are changing with time and associated anthropogenic activities. For monitoring this suite of gases, a fully automated gas chromatographic based analytical system was built and deployed in the field at the UNH AIRMAP Observing Station at Thompson Farm in Durham, NH. The instrument consists of a Shimadzu 17A gas chromatograph (GC), equipped with a Flame Ionization Detector and …

Measuring Paralytic Shellfish Toxins In Mussels From New Hampshire Coastal Waters Using Zwitterionic Hydrophilic Liquid Chromatography/Electrospray Mass Spectrometry, Lee Lee Chung

Master's Theses and Capstones

A liquid chromatography/mass spectrometry method (LC/MS) has been adapted from the literature to provide a rapid, direct and highly sensitive routine assays for several Paralytic Shellfish Poisoning (PSP) toxins, with detection limits in the ppb range for STX and its analog neosaxitoxin (NEO) and decarbamoyl saxitoxin (dcSTX). A high throughput sample clean-up aided in reducing the effects of the matrix. Method validation and stability studies have been performed to show that reliable results are produced by this LC/MS method. The LC/MS method was found to supplement the mouse bioassay with the ability to determine the levels and specific types of …

N-Linked Glycans Characterization And Biomarker Discovery By Sequential Mass Spectrometry, Hongqin (Jenny) Jiao

Master's Theses and Capstones

N-linked glycans from a well-studied glycoprotein, (hen albumin) were characterized using ion trap MS (MSn) without chromatographic separation. From the spectral profile, ten major ion compositions were selected for study, which resulted in the characterization of 37 isomeric structures, 16 of which were previously unreported. These findings were compared with previously reported studies using different analytical strategies: IMMS, MS/MS. MSn not only identifies but also structurally characterizes components in the absence of any adjunct instrumentation. Selected examples have been detailed.

A major challenge for adult stem cell (ASC) research is the lack of specific biomarkers for their identification and isolation. …

The Measurement Of Volatile Organic Compounds During Icartt 2004 And Experimental Studies Of Chlorine Atom Reactions With Alpha- And Beta-Pinene, Leif Carsten Nielsen

Master's Theses and Capstones

Proton transfer reaction mass spectrometry (PTR-MS) has been shown to be a reliable and efficient method for determining atmospheric mixing ratios of volatile organic compounds (VOCs). As a part of AIRMAP, two PTR-MS instruments were used in field and laboratory studies. A high sensitivity instrument showed improved limits of detection by 3-5 times when compared to a standard sensitivity instrument. Agreement for quantification of VOCs by PTR-MS to other methods was good. Average atmospheric mixing ratios, diurnal profiles, and deposition velocities of methanol, acetone, acetaldehyde, acetic acid, isoprene, alpha-pinene, beta-pinene, methylethyl ketone, methylvinyl ketone and methacrolein were determined at two …

Design And Construction Of A Chemical Ionization Mass Spectrometer For Ambient Nitryl Chloride Analysis, Leanna Conway

Master's Theses and Capstones

Ambient measurements of trace gas phase species in the Earth's troposphere continue to present an interesting analytical challenge. Instruments must have sufficient sensitivity to monitor low concentrations without compromising the specificity necessary to distinguish the analyte of interest from a complex matrix. A chemical ionization mass spectrometer (CIMS) has been designed and constructed to satisfy these criteria.

Upon validation, the CIMS will assist in the elucidation of the complex chemistry in the troposphere resulting from the influence of urban pollution and marine environment. The CIMS is currently configured to operate in the negative ion mode and employs I- as the …

Development Of Microwave-Assisted Methods To Aid In Carbohydrate Analysis, Stephanie Maniatis

Master's Theses and Capstones

This study involved development of three high-throughput chemical techniques to assist in carbohydrate analysis. The methods utilized both microwave radiation and a volatile organic base to achieve short reaction times and high product yield. Two methods, one reductive and one non-reductive, released intact O-glycans for structural analysis, and one method aided in determination of the site of O-glycosylation on the peptide.

Optimal reaction conditions for each method were determined on standard glycoproteins. In comparison to common release methods, microwave-assisted reductive O-glycan release provided higher yields of O-glycans in every case. O-glycans were released rapidly and were able to be subsequently …

Fungal Glycosphingolipids: Characterization Of Structures And Interactions With Plant Defensins, Jis Joe

Master's Theses and Capstones

Glycosphingolipids (GSLs) play important roles in many fundamental biological processes like activation of signal transduction pathways, immune responses, and cell-cell interactions. Recent reports imply that fungal GSLs are important targets for the antifungal action of plant defensins. In order to study intermolecular interactions of GSLs, it is crucial to know their structures in detail. This thesis consists of two projects in which fungal GSLs of biological and biomedical significance are studied. In the first project, we have completed the structural characterization of acidic GSLs from S. cerevisiae using NMR spectroscopy and electrospray ionization mass spectrometry (ESI-MS). The second project of …

Studies Of The Structures, Biosynthesis And Function Of Fungal Glycosphingolipids, Elizabeth A. Owuor

Master's Theses and Capstones

Glycosphingolipids (GSLs) are ubiquitously distributed among all eukaryotes. In fungi, GSLs have also been implicated in a variety of cellular processes, including growth, cell signaling, differentiation and morphogenesis. Detailed knowledge of fungal GSL structure and biosynthesis is therefore expected to yield valuable insights into both their functions within the organism and their interactions with other organisms, such as with the immune system, of an infected host as well as to provide targets for diagnostic and therapeutic agents.

Research described in this thesis focused on fungal GSL structure and biosynthesis. Two projects are described. The first was aimed at elucidating the …