Graduation Year


Document Type




Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department


Major Professor

Theresa Evans-Nguyen, Ph.D.

Committee Member

Bill Baker, Ph.D.

Committee Member

Jim Leahy, Ph.D.

Committee Member

Chuanhai Cao, Ph.D.


toxicology, screening, drugs, mass spectrometry, mass defect


Forensic science has long used mass spectrometry for the analysis of drugsand metabolites. Traditionally, screening methods consisted of color tests or immunoassay and confirmation methods used gas chromatography with mass spectrometry, which was considered the gold standard for identification. In the last several decades, advances in liquid chromatography with mass spectrometry (LCMS) have brought this technology to the forefront of forensic drug identification. Drug identification in forensic drug chemistry and forensic toxicology has become increasingly challenging due to the rapid increase in illicit drug analogs including novel opioids such as fentanyl analogs. Traditional screening methodologies are often unable to identify these new drugs. This research uses LCMS as a screening method for both traditional analytes as well as novel fentanyl analogs. First, a targeted triple quadrupole method was developed and validated to replace a traditional immunoassay screen which improved accuracy and specificity. Second, an untargeted high resolution screening method for the identification of potential fentanyl analogs using mass defect and common product ions was implemented. This method was able to identify ~200 fentanyl analogs. Finally, sample preparation was investigated to help overcome some of the matrix challenges involved with LCMS.