Date of Award

Fall 12-2021

Document Type


Degree Name

Master of Science (MS)


Forensic Science



First Advisor or Mentor

Marta Concheiro-Guisán

Second Reader

Teeshavi Acosta

Third Advisor

Karen Scott


In recent years, new designer benzodiazepines have become a challenge in forensic toxicology. These substances are analogues of the classic benzodiazepines, but their pharmacology is not well known, and many of them have been associated with overdoses and deaths. As a result, there has been a surge in efforts to develop ways to accurately test for these compounds in different biological matrices. This study focused to develop and validate a method for determining 17 new designer benzodiazepines in hair by liquid chromatography tandem mass spectrometry (LC-MS/MS). Hair samples were decontaminated, pulverized, and 20 mg of the sample was incubated in methanol. After centrifugation and evaporation of the solvent, the samples were reconstituted and filtered using nano-filter vials. Once reversed-phase chromatographic separation was conducted, two multiple-reaction monitoring (MRM) transitions were used to identify each analyte. The linearity ranged for the limit of quantification (LOQ) between 5 or 25 pg/mg (depending on the compound), to 100 pg/mg. The imprecision was 50%. All analytes displayed ion suppression between 62.8% and -23.9%, except for nifoxipam, nitrazolam, clobazam, deschloroetizolam, and pyrazolam that showed no matrix effect. A fast, sensitive and specific method for the determination of 17 designer benzodiazepines in hair using the LC-MS/MS was developed and validated.

Available for download on Saturday, December 16, 2023