Indiana University-Purdue University Indianapolis (IUPUI) / In Headspace Solid-Phase Microextraction (Headspace SPME), a sample is heated to encourage a portion of the analyte into the headspace of a vial. A coated fiber is introduced into the sample headspace and the analyte is adsorbed onto the fiber coating. Total Vaporization Solid-Phase Microextraction (TV-SPME) is a technique that is derived from this technique. In TV-SPME, liquid samples are completely vaporized allowing for better adsorption and fewer matrix effects. This method does not require any sample preparation, utilizes minimal supplies and can be automated, making it both an efficient and cost-effective method. Chapter 1 will discuss the theory of SPME and TV-SPME. In Chapter 2, the detection of ɣ-hydroxybutyric acid (GHB) and ɣ-butyrolactone (GBL) in beverages is discussed. The detection of these compounds in beverages is of importance because these drugs may be used to facilitate sexual assault. This crime utilizes substances that cause sedation and memory loss. The derivatization of GHB as well as the properties that make GHB difficult to detect will be discussed. Chapter 3 will discuss the detection of methamphetamine and amphetamine (as their trifluoroacetyl derivatives), GBL, and the trimethylsilyl derivative of GHB in human urine. Amphetamine is a metabolite of methamphetamine, therefore, both drugs should be identified within biological samples. GHB and GBL are metabolites of one another and interconvert when in aqueous solution. This interconversion will be discussed. Chapter 4 will cover method optimization of the Total Vaporization Solid-Phase Microextraction method. Analytes of interest for these analyses were methamphetamine, amphetamine, GHB, and GBL. The optimal extraction temperature ranging from 60-160°C of each drug will be discussed as well as why higher temperatures may not be suitable for this method. A limit of detection study for methamphetamine and amphetamine will also be covered. Chapter 5, the future work chapter, will discuss future analyses using the Total Vaporization Solid-Phase Microextraction method including the analysis of powder materials, plant material, and toxicological samples. Powder material will include the analysis of individual powdered drugs as well as realistic drug mixtures. Some analyses on individual powder samples has already been completed and will be shown. Plant material will include the analysis of naturally occurring compounds found in marijuana plants as well as synthetic cannabinoids. Toxicological samples will expand on previously mentioned urine samples to include drugs such as benzoylecgonine and THC-COOH.

Our study focuses on the application of volatile metabolomics and chemometrics in plant pathology. Specifically, volatile metabolites or volatile organic compounds (VOCs) from the American chestnut tree (Castanea dentata) and its pathogenic fungus Cryphonectria parasitica have been investigated. The American chestnut was once a dominant tree species in the eastern forests of the United States. However, it was nearly devastated by the fungal pathogen C. parasitica. The loss of this tree species has significantly impacted the ecosystem. Therefore, preservation and restoration of American chestnut are crucial. Chapter one provides an overview of mass spectrometry based volatile metabolomics and their implementation in the investigation of plant pathology. The study of volatile metabolites profiles from virulent and hypovirulent strains of C. parasitica are presented in chapter two. The microbial volatile organic compounds (MVOCs) profiles were analyzed via nondestructive sampling method, headspace solid phase microextraction (HS-SPME), combined with gas chromatography (GC)-mass spectrometry (MS). The results indicate that the MVOCs profiles emitted from these two strains are significantly different. In general, compared with its hypovirulent strains, high emissions of sesquiterpenes were observed in the virulent strains. Furthermore, the study explored MVOCs differences associated with hypovirulence processes. The study found that both hypovirulence and aging can alter the virulent strains' MVOCs, and the process can be observed via their volatile metabolites. Chapter three describes the effects of aging, cultivation medium, and pH on fungal volatile metabolite profiles, all of which can change the strength of MVOCs emission and their composition. An acidic environment favors fungal bioactivity and therefore enhanced MVOCs emission. However, due to the inherently low MVOCs production from hypovirulent strains, the pH effect was less apparent in the hypovirulent isolates. The strength of MVOCs emission was highly correlated to the fungal expansion in virulent strains for the first 14 days. The overall emission from hypovirulent strains was relatively steady during the 28-day observation. Finally, the cultivation media are critical to the fungal MVOCs production. Among the tested media, cornmeal was least favorable for MVOCs production for both strains. Finally, Chapter Four presents a study of the total constitutive phenolic content estimation and volatile organic compounds identification from four species of chestnut tree leaf tissues. Folin Ciocalteu reagent assay with UV/Vis spectrophotometry was applied to estimate the total phenolic content in leaf tissues of American chestnut (Castanea dentata), Chinese chestnut (Castanea mollissima), and their backcross breeding generations (B3F2 and B3F3). The results from leaf tissue extraction in methanol/water (95:5 v/v), pH 2, and analyzed under the UV/Vis at 765 nm show that the variations among these tree species are significant (ANOVA, p < 0.05). The kinetics of phenolic compound solid-liquid extraction was elaborated using Peleg, second order, and power law models. Moreover, the analysis of VOCs collected from these species indicated that the distinction of American and Chinese chestnut could be archived via their VOCs, while the hybrids’ leaf VOCs are different from their parents’.

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In 2013, the wooden breast defect in broiler breast meat was characterized by hardened and pale areas at both the caudal and cranial regions of the breast. The objective of this study was to determine the flavor differences between severe woody and normal breast meat in both breast and patties using gas chromatography-mass spectrometry, gas chromatography-olfactometry, and sensory descriptive analysis. Forty-eight individual volatile flavor compounds were identified in both the ground and whole breast chicken samples including aldehydes, ketones, and other functional groups. Minimal differences existed in the volatile fraction of normal and severe woody breast meat. In contrast, woody breast patties had greater concentrations of many oxidation products, including aldehydes, alcohols, and hydrocarbons. The most intense aroma compounds were hexanal, 1-octen-3-ol, 2-pentylfuran, 2-ethylhexyl acetate, and 1-nonanol. The descriptive and volatile results indicated that in patties, woody breast meat was more susceptible to oxidation and off-flavors than normal breast meat.

Based on results of its Aquatic Species Program (1978-1996), which sought to develop algae-to-liquid fuel technology, the U.S. Department of Energy has suggested that algal wastewater treatment may be incorporated into biodiesel production schemes to reduce the operating costs of both processes. the purpose of the current research was to evaluate the triglycerides produced by wastewater-grown algae for their suitability as a fuel feedstock and to investigate the effectiveness of several solvent mixtures and extraction procedures at recovering lipids from fresh algae. The research involved two separate experiments. The first determined the quantity and quality of lipids produced over the lifetime of a batch culture of algae grown in a small outdoor high-rate pond. Transesterification of the algal triglycerides yielded mostly saturated and monounsaturated 16 and 18-carbon fatty acid methyl esters, together comprising approximately 8 to 30% of the biomass in the pond. The average triglyceride production rate during the grwoth phase of the culture was 0.97 grams per square meter of pond surface per day. The second experiment compared several industrially practicable extraction procedures to the Bligh and Dyer laboratory extraction method. The Bligh and Dyer laboratory extraction procedure provides excellent lipid recovery efficiency, but several factors limit its potential on an industrial scale. The Bligh and Dyer method requires a larger volume of solvents than other methods, uses the probable carcinogenic chemical chloroform, and involves a complex series of steps that are difficult to automate. A simple, low-energy extraction process using relatively non-toxic solvents was found to have an extraction efficiency comparable to that of the laboratory method.

Tracer gas surveys are a powerful means of assessing air quantity in underground mine ventilation circuits.  The execution of a tracer gas style ventilation survey allows for the direct measurement of air quantity in locations where this information is otherwise unattainable.  Such instances include inaccessible regions of the mine or locations of irregular flow.  However, this method of completing a mine ventilation survey is an underused tool in the industry.  This is largely due to the amount of training required to analyze survey results. As well, the survey is relatively slow because of the time required to perform analysis of results and the time required to allow for the total elution of tracer compounds from the ventilation circuit before subsequent tracer releases can be made.  These limitations can be mitigated with the development of a protocol for a novel tracer gas which can be readily implemented with existing technology.  Enhanced tracer gas techniques will significantly improve the flexibility of ventilation surveys.  The most powerful means to improve tracer gas techniques applied to mine ventilation surveys is to alter existing protocols into a method that can be readily applied where tracer surveys already take place. One effective method of enhancing existing tracer gas survey protocols is to simply add a second tracer gas that can be detected on a gas chromatograph -- electron capture detector (GC-ECD) using the same method as with the existing industry standard tracer, sulfur hexafluoride (SF6).  Novel tracer gases that have been successfully implemented in the past called for complex analysis methods requiring special equipment, or were designed for inactive workings.  Experimentation with perfluoromethylcyclohexane (PMCH) and SF6 allowed for ideal chromatographic results.  PMCH is a favorable selection for a novel tracer to work in tandem with SF6 due to its chemical stability, similar physical properties and detection limits to SF6, and its ability to be applied and integrated into an existing system.  Additionally, PMCH has been successfully utilized in other large-scale tracer gas studies. Introduction of a novel tracer gas will make great strides in improving the versatility of underground tracer gas ventilation surveys, but further improvement to the tracer gas technique can be made in simplifying individual steps.  One such step which would benefit from improvement is in sampling.  Solid phase microextraction (SPME) is a sampling method that is designed for rapid sampling at low concentrations which provides precise results with minimal training.  A SPME extracting phase ideal for trace analysis of mine gases was selected and a GC-ECD protocol was established.  The protocol for fiber selection and method optimization when performing trace analysis with SPME is described in detail in this thesis.  Furthermore, the impact of sampling with SPME under varying turbulent conditions is explored, and the ability of SPME to sample multiple trace analytes simultaneously is observed. / Master of Science

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