Screening procedure for 38 fentanyl analogues and five other new opioids in whole blood by liquid chromatography-tandem mass spectrometry

In recent years, many new opioids, particularly fentanyl analogues, have appeared on the drug market. The extreme potency of even low doses of these compounds leads to numerous fatal poisonings. This also results in the fact that only sophisticated techniques are capable of detecting fentanyl analogues at concentrations that can be expected in blood. In this context, the purpose of this study was to develop a fast liquid chromatography-tandem mass spectrometry screening method for the detection of fentanyl analogues, and other new synthetic opioid receptor agonists in whole blood. Blood samples were extracted with ethyl acetate under basic conditions. The separation was achieved with the gradient of the mobile phase composition and the gradient of the flow rate in 13 minutes. The detection of all compounds was based on dynamic multiple reaction monitoring. Most of the compounds were well differentiated by their retention times and/or transitions; however, separation of some isomers has not been achieved. The validation was performed for 21 compounds. The limits of detection were in the range 0.01-0.20 ng/mL. The developed procedure enables simultaneous qualitative screening, detection and identification of 38 fentanyl analogues and five other new opioids. The method was implemented to analyze authentic samples (positive; n = 3) demonstrating its suitability for this application. The procedure can be easily expanded to include new emerging opioids, which is an indispensable advantage in the dynamically developing drug market. The developed protocol can be adopted for routine work in both forensic and clinical analytical laboratories worldwide.