Using Supported Liquid Extraction and LC/QTOF-MS

This event originally occurred on January 19th, 2022 from 1pm  – 2:30pm (EST). All presentations and material have been archived for you to access as On-Demand content.

Immunoassays (IA) have offered sufficient sensitivity in toxicology for many decades. However, it lacks specificity and introduces technical challenges associated with identifying a growing number of new psychoactive substances (NPS). In contrast, mass spectrometry (MS)-based techniques can be used to simultaneously identify a broader scope of compounds with multiple data acquisition modes and retrospective data analysis. Many complex biological matrices are encountered in these investigations, although blood is the most encountered biofluid. The extraction of multiple drugs with different physicochemical properties using a single protocol can be challenging. As such, many MS-based screening methods do not include cannabinoids, and laboratories still rely on IA-based detection.

In this webinar, method validation of a SLE LC/QTOF-MS method is presented that simultaneously isolates >200 drugs, including 11-nor-9-carboxytetrahydrocannabinol (THCA), from whole blood at the recommended cutoff concentrations for DUI investigations. Limits of detection (LOD) for Tier I drugs ranged from 0.5 to 50 ng/mL. All compounds (including challenging analytes, e.g. THCA) were detected at or below the recommended cutoffs. Matrix effects and detectability for all analytes at their specified cutoffs were established using 10 independently sourced samples. Ion suppression and enhancement were observed. Retention time, mass accuracy, and coelution scores were used for identification purposes.

Extraction efficiencies were highly compound dependent, and the SLE protocol was selectively optimized to increase THCA recovery at the expense of other compounds that were more readily detected. The lowest extraction efficiencies using the SLE approach were observed for zwitterions (e.g. benzoylecgonine). Carryover, processed sample stability and interferences were also evaluated, and a total of 10 isotopically labeled internal standards were utilized. The scope and sensitivity of testing met or exceeded current recommendations for impaired driving investigations and included relevant medicolegal death investigations compounds of interest.

Learning Objectives:
  • Learn the advantages of utilizing mass spectrometry-based drug screening
  • Learn supported liquid extraction, an emerging technique in forensic toxicology
  • Understand the challenges involved with comprehensive extraction procedures

Presenter Information:

Jessica Lynn Ayala, M.S., D-ABFT-FT
Ayala Jessica headshot
Jessica Lynn Ayala is a full-time doctoral student in the Department of Forensic Science at Sam Houston State University (SHSU). Ms. Ayala received her bachelor of science in chemistry from Texas A&M University-Corpus Christi in 2006 and her master of science in forensic science from SHSU in 2008. She has approximately ten years’ experience working in public and private sector forensic toxicology laboratories. She began work as a technician for a private toxicology laboratory in Deer Park, TX in June 2009. She spent 2 years with the SHSU Regional Crime Laboratory as a Forensic Scientist and 2 years working for the Houston Forensic Science Center as a Criminalist Specialist. She was then employed by the Harris County Institute of Forensic Sciences (HCIFS) as a Toxicologist II in June 2014. She received her American Board of Forensic Toxicology certification in December 2015. In January 2017, she was promoted to Deputy Chief Toxicologist at HCIFS. She then chose to further her career in August 2018 and pursue her doctoral degree at SHSU. Her current research focuses on the cost benefit analysis of MS-based toxicological screening, a project that is funded by the National Institute of Justice.

Dr. Peter JW Stone
Stone Peter
Dr Peter JW Stone is a Senior LC/MS Applications Scientist at Agilent Technologies. He has 20+ years within HP/Agilent of experience working with many small molecule applications related to the Pharmaceutical, Environmental, Food Safety, Clinical and Forensic application areas among others. Currently, the challenges of analyzing for quality and safety with regards to cannabis products consume his time.

Sponsored by Agilent Technologies


For Forensic Use