Development of a solid phase extraction method for fentanyl analogs in biological matrices for analysis by LC-MS/MS

Abstract

To combat the looming Opioid Crisis, the federal government has allotted funds to local and state law enforcement laboratories to research methods to incorporate emerging opioids into their reporting capabilities. Fentanyl and its analogs (fentalogs) are the most significant threat amongst these compounds, with some having many hundreds to thousands of times the strength of morphine. Because of their immense potency, more and more sensitive methods are needed for their detection. The Oklahoma State Bureau of Investigation (OSBI) has invested in the validation of a more robust solid-phase extraction (SPE) method to improve their current capabilities, as well as expand them. Several fentanyl analogs were chosen from an extensive review of the literature to determine which are most prevalent. In addition to two isotopically labeled internal standards, 14 compounds including parent fentanyl were developed into a new liquid chromatography tandem mass spectrometry (LC-MS/MS) method. This method was validated for whole blood and urine matrices. The validation was performed in compliance with ISO/IEC 17025:2017, ANAB standards and guidelines, and the current OSBI Toxicology Unit Quality Manual. It was overseen by the current Toxicology Technical Manager (TM) and managed by the OSBI Forensic Science Center (FSC) Quality Manager. It was successfully validated following the completion of five studies: interference, carry over, ion suppression/enhancement, limit of detection, and stability. Once brought online, this method will be used in toxicology casework. If a sample screens presumptively positive for fentanyl-related compounds, this method will be used for confirmation testing. Given the success with which this method was validated, more of the current liquid-liquid extractions, such as that for benzodiazepines, will likely be converted to the new SPE paradigm in the future.