Comprehensive Drug Screening of Whole Blood by LC–HRMS–MS in a Forensic Laboratory

Abstract

As the number of prescriptions, over-the-counter medications and drugs of abuse continue to increase, forensic laboratories are faced with the challenge of developing more comprehensive screening methods in order to detect them in whole blood samples. Another challenge faced by forensic laboratories is detecting and identifying novel synthetic compounds as they emerge and change. Traditional drug screening methods include enzyme immunoassay (EIA) and either gas or liquid chromatography paired with mass spectrometry (GC–MS or LC–MS-MS, respectively). While these methods are good, they have their disadvantages. For example, EIA requires special reagents for each drug class, GC–MS requires extensive sample preparation, and LC–MS-MS only detects drugs on a known inclusion lists of compounds of interest. Described below is the development of a robust and comprehensive screening method for drugs in whole blood samples that eliminates the aforementioned disadvantages of the traditional methods. Using a Q Exactive Focus ™ liquid chromatography-high resolution-accurate mass spectrometer (LC–HRMS-MS), a method was developed that is capable of detecting approximately 200 drugs at a concentration of 2 μg/L for most analytes. This method also employs a more automated data processing feature which reduces processing time. Finally, it has the added benefit of retroactive data analysis, which allows it to be used for unknown drug analysis as well. Used as an initial screening method, the comprehensive drug screen using LC–HRMS-MS has the potential to take on two of the most important challenges faced by forensic laboratories today.

Metabolomics‐driven determination of targets for salicylic acid and ibuprofen in positive electrospray ionization using LC‐HRMS

“…Since many toxicologically relevant compounds are basic in nature, screening with LC–HRMS is typically performed using positive electrospray ionization (ESI+), using either data‐dependent 1,5 or data‐independent acquisition modes 6,7 . However, there are a, albeit smaller, number of important compounds which are not sufficiently ionized using ESI+ on most systems 8 . This includes, but is not limited to, acidic and neutral compounds such as valproic acid (VPA), salicylic acid (SA), ibuprofen (IBP), and barbiturates.…”

“…This includes, but is not limited to, acidic and neutral compounds such as valproic acid (VPA), salicylic acid (SA), ibuprofen (IBP), and barbiturates. These compounds are typically analyzed using negative ESI (ESI−) either by performing a separate analysis 7 or by using polarity switching 8 . In the authors' laboratory, the typically employed strategy to accommodate the shortcomings of ESI+ is to include screening, or quantification, of these compounds in existing targeted LC coupled with tandem MS (LC‐MS/MS) methods.…”

“…6,7 However, there are a, albeit smaller, number of important compounds which are not sufficiently ionized using ESI+ on most systems. 8 This includes, but is not limited to, acidic and neutral compounds such as valproic acid (VPA), salicylic acid (SA), ibuprofen (IBP), and barbiturates. These compounds are typically analyzed using negative ESI (ESIÀ) either by performing a separate analysis 7 or by using polarity switching.…”

“…These compounds are typically analyzed using negative ESI (ESIÀ) either by performing a separate analysis 7 or by using polarity switching. 8 In the authors' laboratory, the typically employed strategy to accommodate the shortcomings of ESI+ is to include screening, or quantification, of these compounds in existing targeted LC coupled with tandem MS (LC-MS/MS) methods. However, metabolomics-driven approaches have recently been used to identify targets in ESI+ for compounds typically analyzed in ESIÀ.…”

Novel Evaluation of Submandibular Salivary Gland Tissue for Use as an Alternative Postmortem Toxicology Specimen

“…Unlike the postmortem concentrations of classic drugs/drug classes (eg, amphetamines, cocaine, codeine, morphine, barbiturates), many of the emergent novel substances (eg, MT-45, acetyl fentanyl, etizolam, flubromazolam) are often present in concentrations several magnitudes lower than the concentrations encountered with the classic drugs. [6][7][8][9] There is a dearth of information regarding what are typical concentrations for emerging novel substances and which specimen matrices are best suited for their detection; thus, collection of samples from different sites and of different types, including tissue samples seems prudent. Procuring alternative postmortem samples capable of providing results comparable to postmortem blood results may in some cases, be worth the additional resources necessary to collect and store them particularly when ancillary testing is needed.…”