Advancing peptide analysis in dried blood spots: application potential and stability study of doping-relevant peptides (WADA 2020)

Current illicit doping practices include the use of peptide hormones and their peptide release factors, with different kinds of activity (gonadotrophic, corticotrophic, growth factor, etc.), with the common purpose of increasing sport performance. These substances are included in the WADA Prohibited List, section S2. One of the main analytical hurdles for the detection of peptides is their low stability in blood (and other biological fluids). This makes sample storage and shipping critical steps, possibly causing the decrease of peptide levels to amounts that are no longer detectable due to degradation. Dried microsampling provides logistic and analytical advantages over fluid samples: water loss can effectively stop most degradation and biotransformation reactions, leading to higher peptide stability and to more favourable, cheaper storage and transportation conditions. Among microsampling methods, dried blood spots (DBS) is the most well-known and widely applied one, but more innovative alternatives are also available (“smart DBS”), such as special cards and devices that obviate some drawbacks of “classical DBS”, like dependency of sampling volume on haematocrit and lack of sampling accuracy. Other dried microsampling approaches, such as volumetric absorption microsampling (VAMS), exist as well. Following the promising results obtained from stability studies on doping-relevant peptides in urine microsamples (Project funded within the 2017 Scientific Research Grants, successfully developed and concluded by this research team), aim of the present project is to carry out a systematic study on the stability of prohibited peptides in dried blood spots. The most important variables involved in the sampling process will be studied, such as humidity, temperature and light exposure, to determine the optimal sampling, storage and shipping conditions, and to evaluate the results obtained from microsamples. The project goal is to establish feasible and reliable workflows for dried blood microsample collection, which could be proposed as effective strategies for anti-doping testing.