Next-generation dried blood spot (DBS) microsampling coupled to LC-MS/MS in anti-doping testing

LC-MS/MS is widely recognized as the golden standard for anti-doping testing of most substances prohibited by the World Anti-Doping Agency (WADA). Despite its unparalleled sensitivity and selectivity, the reliability of final results is still heavily dependent on the specific sampling and sample preparation steps. Microsampling, in particular, has recently attracted much interest, and dried blood spotting (DBS) has been recently approved by WADA in its official analytical workflows. In the DBS strategy, after finger pricking, a small amount of blood is deposited on a card (Fig. 1a) and dried. Sample drying increases analyte stability, avoids the need for special transport conditions and simplifies sample preparation. DBS sampling is minimally invasive and feasible in most situations without the need for specialized personnel [1]. Since classical DBS can be affected by some variability of sample volume and limited reproducibility, innovative strategies are under development to enhance their quantitative performance. One of the most interesting new volumetric DBS technologies is the Capitainer qDBS, which allows the accurate sampling of 10 μL of blood from a single drop (Fig. 1b) [2]. Afterwards, the analytes can easily be extracted using minute amounts of solvents and analysed by LC-MS/MS. In this study, the Capitainer qDBS approach has been used for the determination in blood microsamples of anabolic androgen steroids (AASs), one of the prohibited substance classes most frequently involved in illicit administration to athletes.