Per Ole M. Gundersena, Magnus Tvedteb and Yvette Dehnesa
a Norwegian doping control laboratory, Oslo University Hospital, Trondheimsveien 235, 0586 Oslo
b Anti-Doping Norway, Sognsveien 75 F, 0855 Oslo
Email: per.gundersen@dopinganalyse.no
This study describes an LC-MS/MS method for the detection and confirmation of 1,3-dimethylbutylamine (DMBA) in water, nutritional supplements, and crumb rubber, as part of a doping-related investigation. The prohibited substance DMBA had been detected in several urine samples taken after an indoor soccer match. Further analysis conducted as part of the investigation revealed DMBA contamination in water from a tap located directly by the indoor soccer field where the match had been played. The presence of DMBA was traced to black particulate matter in the water sample resembling crumb rubber fragments commonly used in artificial turf. DMBA was then identified and semi-quantified in samples of crumb rubber taken from under the tap and on the soccer field. The water samples were treated by evaporation while crumb rubber samples were extracted using methanol. All analysis was done on a liquid chromatography system coupled to a triple quadrupole mass spectrometer.
The crumb rubber used in the artificial turf of many soccer fields and in this specific case are made from used car tires. During the work with these samples, it became clear that the synthetic stimulant DMBA is also a breakdown product of the substance 6-PPD, a component used in car tires to improve robustness. Further studies are underway to understand which routes of exposure and other factors which result in these low levels of DMBA in urine.