Dried blood spots (DBS) for doping control analysis

Whole blood sample collection on cellulose paper has a more than 30-year-long tradition, especially in neonatal screening. The sampling is minimally invasive, fast, discreet, and robust against manipulation. The present approach highlights the potential to determine doping agents in dried blood spots (DBS) after extraction and subsequent analysis by liquid chromatography-mass spectrometry (LC-MS). The assay is focused on selected model compounds of which the circulating target concentration is of particular interest. Here, pre- or post-competition testing with DBS allows probing for the conditions (i.e. presence or absence of relevant drugs) in the athlete's circulation during competition, which complements earlier approaches towards the identification of urinary indicators for the temporal application of substances prohibited in-competition only. Precise (<20%), linear, and robust conditions with limits of detection in low ng/ml range were accomplished by means of LC coupled to high resolution/high accuracy mass spectrometry for the selected model compounds benzoylecgonine, cocaine, pseudoephedrine, amphetamine, salbutamol, and JWH-018. Deuterium-labelled internal standards were used to yield reliable quantitative results. In addition, the non-targeted screening approach (positive/negative switching combined with tandem mass spectrometry (MS/MS) experiments) enables the retrospective qualitative data evaluation for a comprehensive selection of known and unknown substances as exemplarily shown by the extraction of 20 target compounds (corticosteroids, aromatase inhibitors, anabolic steroids, beta-blockers, etc.) at 20 ng/ml. The simple and fast nature of the assay allows for an easy implementation into existing procedures and will potentially enhance the effectiveness of testing by reducing costs and effort of pre-analysis workload. Verf.-Referat