Analysis of Drugs in Whole Blood by Paper Spray Mass Spectrometry with Integrated Solid-Phase Extraction

The continued rise in overdoses, driven by fentanyl and novel psychoactive substances (NPS), underscores the need for improved methods for drug screening. Traditional analytical techniques involving chromatography can be time-consuming and require sample preparation. Paper spray mass spectrometry (PS-MS) can rapidly detect analytes from complex matrices. However, challenges such as matrix effects can lead to higher detection limits, prompting improvements aimed at preconcentrating or cleaning up samples. While most methods focus on plasma analysis, there is a need to further simplify sample preparation, particularly for whole blood. Here, we report on three-dimensional (3D)-printed devices that preconcentrate drugs from whole blood for PS-MS analysis. An uncontrolled amount of blood was added to the blood reservoir part of the cartridge. The capillary fills and then rotates to sit on top of the SPE column. The blood wicks through the SPE to the waste pad, and the sample is left to dry until analysis. The dry SPE holder is "snapped" in the paper spray cartridge. A variety of parameters were optimized to improve manufacturing and the performance of the device, including waste pad substrates, SPE sorbents, and binders; the size of the SPE compartment; the amount of SPE; a water wash step; and blood volume. Performance was tested with 21 different drugs including opioids like fentanyl and isotonitazene, cathinones, designer and prescription benzodiazepines, cocaine, methamphetamine, and synthetic cannabinoids. Dried blood samples were found to be stable for at least 14 days. The detection limits were at single digit or subng/mL levels or lower for all analytes for 70 μL blood sample, with a median decrease of 9-fold compared to paper spray without SPE.