A Book-Type Dried Plasma Spot Card for Automated Flow-Through Elution Coupled with Online SPE-LC-MS/MS Bioanalysis of Opioids and Stimulants in blood

Despite many benefits including simple point-of-care sample collection, reduced costs, and simplified shipping and storage, dried blood spot (DBS) techniques have faced adoption resistance due to factors such as the hematocrit (Hct) effects and the established preference for bioanalysis of plasma rather than whole blood. One way to potentially circumvent these challenges is to adopt the concept of dried plasma spot (DPS) techniques. One approach to accomplishing this is through an on-card red blood cell (RBC) filtration to generate plasma from whole blood without the need for centrifugation. In this report, a book-type DPS card has been developed and validated by employing fully automated flow-through elution coupled with online SPE-LC-ESI-MS/MS for the quantitative determination of four representative opioids (morphine, codeine, oxycodone, hydrocodone) and five stimulants (amphetamine, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA), phentermine, and mephedrone) in one method using their corresponding deuterium-labeled analogues as internal standards. Method validation results showed good linearity (R² ≥ 0.9963) ranging from 5 to 1000 ng/mL. Intraday and interday precision and accuracy were within the acceptable limits at four quality control (QC) levels. Extraction recovery was ≥87.9% at both the lower limit of quantitation (LLOQ) and the upper limit of quantitation (ULOQ) along with acceptable selectivity and sensitivity. DPS on-card short-term stability was compound-dependent and storage-dependent. The additional benefits of the validated book-type DPS card include a wider applicability range of Hct (30% to 60%), automated online analysis compatibility, and a higher plasma volume yield.