Development of Improved Extraction/Purification Methods and Comprehensive Screening/Confirmation by Lc-QqQ-Ms Analysis for Novel Psychoactive Substances
Abstract
The presence of novel psychoactive substances (NPS) in forensic casework poses major difficulties for detection, since there are many structural variations of NPS circulating in the street market. There are currently no comprehensive screening/confirmatory/quantitation methods available that encompass the majority of NPS encountered in forensic toxicology. A major issue faced with developing such a method is that full validation is extremely time consuming. The use of a liquid chromatography triple quadrupole tandem mass spectrometry (LC-QqQ-MS/MS) method makes the detection of a large number of NPS possible because of high selectivity and sensitivity. This research included four main tasks: 1) development of a dynamic multiple reaction monitoring (dMRM) LC-QqQ-MS method for 800+ NPS, 2) validation of the dMRM method for screening and confirmation of 800+ NPS using a series of mixtures of non-coeluting standards, 3) comparison and optimization of NPS extraction methods for urine and whole blood, and 4) screening of spiked and authentic specimens to determine the real-world potential of the dMRM method. Validation was completed for the parameters of selectivity, limit of detection (LOD), limit of quantitation (LOQ), carry over, linearity, bias, precision, freeze-thaw stability, and matrix effects. A method that ultimately included a total of 729 compounds was validated with LOD and LOQ in the pg/mL range. The research presented here implements the largest validated method of its kind for NPS with capabilities as a screening method for NPS in urine and whole blood and as a confirmatory method in urine. Several extraction methods were also compared to determine their efficacy for the extraction of NPS from urine and whole blood. These included dilute- and crash-and-shoot, online and classical solid phase extraction, and QuEChERS. Techniques were compared for elimination of matrix effects, recovery, process efficiency, time, and cost. Through the analysis of blind spiked and authentic specimens, the applicability of the validated method as a screening and confirmatory method was successfully demonstrated. The method developed in this project will aid in reliable identification of NPS in clinical and forensic toxicological samples. Additionally, this work provided data to improve the reliability of extraction of NPS from biological matrices.
Subject Area
Analytical chemistry|Chemistry|Mathematics
Recommended Citation
Kimble, Ashley Nicole, "Development of Improved Extraction/Purification Methods and Comprehensive Screening/Confirmation by Lc-QqQ-Ms Analysis for Novel Psychoactive Substances" (2019). ProQuest ETD Collection for FIU. AAI28315892.
https://digitalcommons.fiu.edu/dissertations/AAI28315892