Effects of Storage Conditions and GC×GC/FID Parameters on the Composition and Flash Point of Jet a and The Identification and Quantitation of Alkylphenols In Jet A Using PREP-HPLC And GC×GC/(+)EI MS

Jet fuel is mostly comprised of hydrocarbons, but it also contains trace-levels of heteroatom containing compounds. The properties of jet fuel, which must remain within specified ranges for optimal safety and performance, depend on the exact structures and amounts of these hydrocarbons and/or heteroatom containing compounds. Therefore, accurate and precise analytical methods are needed for their identification and quantitation. Two-dimensional gas chromatography with flame ionization detection (GC×GC/FID) is a powerful analytical technique for identifying and quantifying the hydrocarbons in jet fuel. However, GC×GC/FID cannot be used to analyze the heteroatom containing compounds in jet fuel because the FID is nonselective. Also, it is poorly understood how some of the laboratory procedures (e.g., duration of storage, type of storage container used) and GC×GC/FID method parameters (e.g., mass-loading value, S/N threshold value, number of measurements made for each sample vial) affect the accuracy and precision of the hydrocarbon composition measurements. It is also poorly understood how some laboratory procedures (e.g., duration of storage, type of storage container used) affect the accuracy and precision of flash point measurements. This dissertation focuses on the examination of the influence of sample storage conditions on the accuracy and precision of hydrocarbon composition measurements of Jet A made with GC×GC/FID and the accuracy and precision of flash point measurements of Jet A made with a Tag closed cup flash point tester. Areas of focus also include the influence of the column load value used, the S/N threshold value used, and the number of measurements made for a single sample vial on the accuracy and precision of the GC×GC/FID results. This dissertation also describes the development of an analytical method for the identification and quantitation of alkylphenols in Jet A (which are the most abundant heteroatom containing compounds in jet fuel) by using preparative high-performance liquid chromatography (prep-HPLC) and two-dimensional gas chromatography with electron ionization time-of-flight mass spectrometry (GC×GC/(+)EI TOF MS)

Determining the Composition of Carbonate Solvent Systems Used in Lithium-Ion Batteries without Salt Removal

In this work, two methods were investigated for determining the composition of carbonate solvent systems used in lithium-ion (Li-ion) battery electrolytes. One method was based on comprehensive two-dimensional gas chromatography with electron ionization time-of-flight mass spectrometry (GC×GC/EI TOF MS), which often enables unknown compound identification by their electron ionization (EI) mass spectra. The other method was based on comprehensive two-dimensional gas chromatography with flame ionization detection (GC×GC/FID). Both methods were used to determine the concentrations of six different commonly used carbonates in Li-ion battery electrolytes (i.e., ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), and vinylene carbonate (VC) in model compound mixtures (MCMs), single-blind samples (SBS), and a commercially obtained electrolyte solution (COES). Both methods were found to be precise (uncertainty 6) from the sample prior to analysis. Removal of the lithium salt was avoided by diluting the electrolyte solutions prior to analysis (1000-fold dilution) and using minimal sample volumes (0.1 µL) for analysis