Per- and poly-fluoroalkyl substances (PFAS) are a class of compounds with beneficial uses, harmful effects, and variable structures. Although the general conversation concerning PFAS is in regard to some of their negative effects e.g. “forever chemicals”, some possess beneficial uses in medical, cosmetic, and textile industries. In this study, certain PFAS used as synthetic blood substitutes due to their high efficiency of dissolving gases were analyzed for anti-doping purposes. These compounds are banned by numerous jurisdictions in many athletic events to promote a fair and balanced environment and continued safety of athletes. The method presented here utilized headspace gas chromatography-tandem mass spectrometry (GC-MS/MS) to detect these compounds in equine serum.
This methodology consisted of a screening analysis to identify a total of 12 total PFAS in equine serum. These compounds consisted of 11 oxygen-carrying PFAS and an internal standard, bromopentafluorobenzene. The 11 PFAS with potential for use as blood substitutes were: perfluorodecalin (PFD, two isomers: cis-PFD, trans-PFD), perfluorotripropylamine(PFTPA), perfluorooctylbromide (PFOB), perfluorodecylbromide (PFDB), perfluoroadamantane (PFA), perfluoromethyladamantane (PFMA), bis(perfluorobutylethene) (F-44E), perfluoro(tert-butylcyclohexane) (PFtBCH), perfluoro[1-(4-methylcyclohexyl)piperidine] (PFMCP), 1,8-dichloroperfluorooctane (DCPFO), and perfluoromethyldecalin/perfluoro-1-methyldecalin(PFMD/PF1MD) isomers. This method was able to separate both isomers of PFD, partially separate the isomers of PFMD, and was able to differentiate between all the PFAS listed above. Limits of detection for all compounds ranged from 10-250 ng/mL using a sample volume of 100 µL of serum. The rapid analysis time of 6 minutes allowed for high-throughput analysis of equine samples for the detection of these PFAS. This methodology was utilized to examine over 70 serum samples from racehorses.