Better Doping Detection
The Olympics and other sporting events are all about competition. Unfortunately, the desire to gain an edge can lead to doping — the use of performance-enhancing drugs. Because some of these chemicals are found naturally in varying amounts in athletes, detecting doping with certainty can be difficult. Now there’s a test method that is more sensitive, more capable and faster to perform than previous ones, report researchers from the Sports Medicine Research and Testing Laboratory at the University of Utah in Salt Lake City.
The hormone testosterone increases muscle size and strength, making the taking of it — or a chemical that the body turns into testosterone — a potential performance booster. Complicating the catching of cheaters is that testosterone levels vary considerably among people.
Fortunately, the natural steroid epitestosterone is found normally in about the same proportion as testosterone. It also is not synthesized from the testosterone precursors dehydroepiandrosterone and androstenedione, which dopers sometimes use. So an elevated ratio of testosterone to epitestosterone indicates possible doping. For that reason, the World Anti-Doping Agency has set a ratio between the two of 4.0 — more than twice the average for many athletes — as the limit.
One challenge has been quantitatively confirming ratio results, especially in dilute samples where the steroids are present in lower-than-normal concentrations. Correctly assessing the ratio in such cases requires testing with sufficient sensitivity, an issue for some previously used methods.
The Utah group developed a liquid chromatography-tandem mass spectrometry method using an Agilent liquid chromatography system and an Applied Biosystems quadrupole time-of-flight instrument. The technique can quantify concentrations as low as 1 ng/ml, better than required. The method also offers more diagnostic qualifier ions derived from testosterone and epitestosterone than previous techniques provided. It also is faster, requiring only 15 minutes instead of the 25 needed for other methods.
Finally, the researchers believe that the technique should transfer to any standard liquid chromatography-tandem mass spectrometry system found in drug screening laboratories.
Journal of Mass Spectrometry, July 2008, pp. 993-1000.
- The addition of impurities to another substance, usually solid, in a controlled manner that produces desired properties. Silicon doping with small amounts of other semimetallic elements increases the number of electrical carriers.
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