Appendix 1
Dopamine was confirmed with the highest degree of certainty since 4 SRM transitions were monitored instead of a single transition (Fig. A1). Each SRM transition denotes a characteristic fragmentation pathway of the target molecule. We considered a positive finding in the samples when all four SRMs demonstrated a positive signal in the expected retention time for dopamine. The control samples did not present any signal in any of the SRM transitions, denoting non-detectable concentrations.