Thesis
Investigating the effects of ESI parameters on ion signal in ESI-FT-ICRMS and studying the effects of ESD parameters on the morphology of samples and their implications to MALDI MS signal intensity
Master of Science (M.S.), Drexel University
Jul 2017
DOI:
https://doi.org/10.17918/etd-7490
Abstract
This thesis investigates two separate projects. The first project investigated the effect of ESI parameters on ion intensity in an ESI-FT-ICRMS using factorial design experiments. The second project investigated the effect of ESD parameters on the deposition of MALDI samples, the MALDI TOF MS ion signal and AFM morphology. Chapter 1 discusses systematically looking at ESI parameters using two-level factorial design experiments. The ESI factors focused on were the sheath gas, auxiliary gas, sweep gas, and electrospray voltage. The response variables of ion signal, standard deviation and S/N were investigated to look at which variables and interactions between these variables were statistically significant, with the goal of maximizing the sensitivity of the instrument for the eventual analysis of complex mixtures isolated from secondary organic aerosols. Chapter 2 discusses the absorption and fluorescence of the isomers of DHB in various solvents. It investigates the samples in both the solid and solution states. The work presented confirmed that using ESD would provide reproducible results to compare samples in the solid state. Chapter 3 investigates various solution properties that determine the initial droplet size for ESD samples. The properties investigated were the surface tension using the capillary rise method, density and conductivity. Both pure solvent and matrix solutions were measured; the values obtained were then used to estimate the initial solution droplet sizes produced during the ESD process. Chapter 4 explores the use of a research quartz crystal microbalance to measure the residual wetness of the ESD spray, the unexpected difference between the calculated mass and the actual mass deposited, and the initial "bump" found in the deposition sprays. Some of the variables examined were the choice of solvent, flow rate, concentration, spray time and use of different matrices and their different impacts on the factors listed above. Finally, chapter 5 investigates the effect of spray height on the morphology and ion signal of MALDI samples using AFM and MALDI TOF MS. The samples prepared for analysis can be consecutively examined in both the AFM and MALDI instrument since the Si wafer used provides a flat enough surface for AFM, but is also conductive enough to be used in the MALDI instrument.
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Details
- Title
- Investigating the effects of ESI parameters on ion signal in ESI-FT-ICRMS and studying the effects of ESD parameters on the morphology of samples and their implications to MALDI MS signal intensity
- Creators
- Christina A. Emeigh - DU
- Contributors
- Kevin Glenn Owens (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xix, 103 pages
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- College of Arts and Sciences; Chemistry; Drexel University
- Other Identifier
- 7490; 991014632186404721