Graduation Term

Summer 2025

Degree Name

Master of Science (MS)

Department

Department of Chemistry

Committee Chair

Christopher Mulligan

Committee Member

Jeremy Driskell

Committee Member

Christopher Hamaker

Abstract

The widespread presence of environmental and consumer-product contaminants (e.g. trace metals, opium alkaloids) has underscored the need for rapid, reliable, and high-throughput analytical techniques that are capable of handling complex solid samples. While traditional mass spectrometric (MS) methods tend to have high sensitivity and accuracy, they often require labor-intensive and time-consuming sample preparation steps that limit throughput and field applicability. This thesis investigates the use of 3D-Printed Cone Spray Ionization-Mass Spectrometry (3D-PCSI-MS) as an ambient ionization technique for the direct screening of contaminants from solid matrices, eliminating the need for traditional sample preparation and allowing for real-time analysis.

In this work, two primary applications were explored: the screening of heavy metals and metalloids in soil and the detection of opium alkaloids on commercially available poppy seeds. In the first study, ‘reactive’ 3D-PCSI was utilized, which employed the principles of chelation chemistry by using a ligand to react with the metal species in soil. The chelation reagents L2 (C14H14N4S), ethylenediaminetetraacetic acid (EDTA), and nitrilotriacetic acid (NTA) were each tested for performance comparison against L1 (C14H14N4SO), which was the primary chelation reagent in the previous work. Out of the three alternative reagents, L2 exhibited the strongest performance, forming stable, detectable complexes with a wide range of metals, including lead, cadmium, mercury, and lithium. Experimental limits of detection (LODs) reached sub-ppb levels for several metals, demonstrating competitive sensitivity. A user-blinded error rate study further confirmed the method’s robustness and reliability, yielding a 98.4% accuracy with minimal false positives or negatives. This highlights 3D-PCSI-MS as a promising platform for rapid environmental monitoring and field-deployable contaminant screening.

The second study applied 3D-PCSI-MS for the direct screening of opium alkaloids such as morphine, noscapine, papaverine, codeine, and thebaine from unwashed poppy seeds. The results of this study showed successful detection and quantification of target alkaloids at various concentrations. An error rate assessment confirmed the method’s relatively high sensitivity and specificity, which demonstrates its potential as a tool for detecting contamination in consumer food products such as poppy seeds. Importantly, the approach avoids the need for extensive sample preparation, which is often a barrier in traditional LC-MS or GC-MS methodologies.

Together, these two applications demonstrate the value of 3D-PCSI-MS as a powerful tool for high-throughput, solid sample analysis. By combining rapid ambient ionization with high sensitivity detection capabilities, this technique offers an alternative to traditional MS methods, particularly in fields where results may be time-sensitive, such as forensic science, environmental health and safety, and food safety. The findings also support the broader implementation of error rate assessment in method validation, which would help to improve the credibility of analytical results across disciplines. Future work may expand the utility of 3D-PCSI-MS to additional types of analytes, as well as explore further automation of the method via an autosampler which would assist in improving reproducibility and generally streamlining the 3D-PCSI-MS process.

Access Type

Thesis-Open Access

DOI

https://doi.org/10.30707/ETD.1763755359.119222

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Available for download on Tuesday, March 10, 2026

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