Date of Award

Spring 5-16-2026

Degree Type

Dissertation

Degree Name

PhD. Chemistry

Department

Chemistry and Biochemistry

Advisor

Nicholas H. Snow, Ph.D.

Committee Member

Wyatt R. Murphy, Ph.D.

Committee Member

Yuri V. Kazakevich, Ph.D.

Keywords

Limits of Detection, Gas Chromatography, LOD, MRM, Green Chemistry, API

Abstract

While considerable attention is paid to the analysis of pesticides in food and other consumables, little to no attention is placed on exposure through other commercially available products, such as cut flowers. The cut floral industry is a sector where regulation is not so much protecting the consumer, but is geared toward the prevention of pests traveling from other areas of the world, typically Colombia and Ecuador, to the United States. In the US, only one study has been performed on cut flowers, in the late 1970’s. As instrumentation has become more sensitive the typical detection limits for pesticides have decreased from parts per million to parts per trillion with some even as low as part per quadrillion (ppq). Often, the reported Limits of Detection (LOD) will vary greatly for pesticide analyses even though the sample preparation methodologies, and instrumentation used were similar. Chapter 2 provides the necessary limit of detection theory and chromatography theory. Chapter 3 dives into System Linearity using GC-FID as Model System and the effect of chromatography on Limit of Detection calculations. Chapter 4 focuses on Gas Chromatography for “Greening” Active Pharmaceutical Ingredients (APIs) Analysis Since the 1970s High-performance Liquid Chromatography (HPLC) has been the analysis method of choice for active pharmaceutical ingredients (APIs). Capillary GC has evolved to make GC a potential greener replacement. Methods for the analysis of APIs were developed using GC and compared to traditional HPLC methods based on traditional analytical figures of merit including reproducibility and linear range. The Analytical Method Greenness Score (AMGS) and RGB approaches are presented for evaluating the greenness of GC in pharmaceutical analysis. Chapter 5 looks at the practical application of Trace Pesticide Analysis in GC-MS/MS and Calculated vs. Experimentally Determined LODs in context of Chapter 3’s findings, along with an initial look at Sample Preparation Effects of QuEChERS. Conclusions and future work presented in Chapter 6.

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