So it's all well and good knowing what compounds are banned (part 1 is here for anyone who missed it), but how do the anti-doping agencies actually go about catching them? (Oh and if anyone would rather read about this in the literature, you'll find Chem. Soc. Rev. 2004, 33, p1-13 of interest, it's my main reference for the rest of this article)
Well firstly, cycling subjects athletes to more drug tests than any other sport. Drug tests are usually performed on urine and blood samples taken from athletes, either during events, or at random drug tests administered during breaks. Elite athletes have to constantly keep anti-doping agencies aware of their location at all times, so they can always be subjected to random drug tests. The first point worth making here is that the labs receiving the samples are given no indication as to who provided the sample. The samples are simply numbered, to ensure the integrity of the analysis. Also, when samples are collected, they are immediately split into 2 identical samples. The analysis is carried out on one vial, and only if there is significant evidence of a banned substance being used, is the second sample opened to confirm the result is genuine. As with forensic samples, there is a chain of paperwork associated with each sample, so that if suspicions are raised about tampering with the samples, everyone who has had contact with a sample is listed.
The labs themselves have to be up to an international standard. Wherever the Olympics are held, the IOC require that the host nation provide a dedicated drug testing facility, up to their exacting standards. For the 2012 Olympics, GlaxoSmithKline provided the state of the art facilities. By building a new facility every 4 years, a network of olympic-standard drug testing facilities is being established across the globe, providing testing facilities for other sporting events.
So once the samples are collected, and sent to the lab, what happens?
Well, urine samples allow detection of the majority of banned small to medium weight compounds, by fairly standard analytical chemistry techniques such as mass spectroscopy and gas chromatography. For larger molecules such as peptides and hormones (like growth hormones), a biological immuno-assay might be necessary.
Another complication is that to detect a molecule, and the amount at which it's present, an analysis has to take into account the effects the body has on the molecule. In some cases the molecule may be excreted intact, but others may be metabolised to smaller, or altered molecules, and of course some are between these two extremes. Once this is done, the work of an analytical chemist is to decide the best way to determine the quantity of each compound, and to accurately carry out the analysis. For most commonly detected performance enhancing drugs, standard operating procedures will exist to determine the amount present.
So how is the analysis itself carried out? Let's use stimulants as an example. Since taking stimulants can provide an instantaneous benefit in a race, they must be detected fairly quickly. Many stimulants are closely related structurally to amphetamine, giving them similar properties. By tailoring conditions to match these common properties, it is possible to extract most likely stimulants from a urine sample. In the standard protocol, this is achieved by extracting into a solution of ether at a pH above 9.5. This sample can be tested by GCMS (Gas Chromatography coupled to Mass Spectroscopy), to comfortably detect amphetamines at a concentration of 500 ng/mL.
What happens to athletes who test positive? Well, it depends on the sport. Currently, an athlete found guilty of doping by WADA receives a 2 year ban for a first major offence, with a life ban for a second offence. But WADA want to increase the ban for a first offence to 4 years. Different authorities however have different rulings and the recent events surrounding Lance Armstrong further complicate matters. Those who implicated Lance Armstrong in confessions to USADA appear to have been given significantly reduced bans, with some only receiving winter bans, which will have little effect on them competing. Whilst Armstrong himself was banned from professional cycling for life.
What about the future? Well the gains offered by doping will always appeal to some, but increasingly complicated doping programs will be necessary to outwit the authorities using the current drugs available. However, the idea of 'designer drugs' could make things very difficult for the testing agencies. A few years ago, Canadian customs officers seized bottles containing a drug called desoxy-methyl-testosterone (DMT). Analysis showed it to be a designer steroid, with similar effects to testosterone, but a drug which would never have shown up in a drugs test at the time. The spectre of this will always hang over elite sport. The development of new drugs can't be predicted, so testing agencies are reliant on obtaining samples of the new drug before they can begin to test for it. With enough money, it would be possible to both create a new drug, or obtain exclusive supply, and to rigorously keep it safe, so that drug testing will be kept in the dark, allowing those cheating to escape without detection.
So can we ever be sure sport is free of drugs? Well, the simple answer is no. The recent revelations about Lance Armstrong seem to have left a bad taste in the mouth of many elite athletes, such as Bradley Wiggins, and many teams too have come forward as being actively anti-doping, with hardline policies on it. But, whilst it is becoming increasingly difficult to dope, some will still keep trying.
Apologies for the delay in writing this, uni has kind of got in the way recently. As always, any comments/criticisms/corrections are greatly appreciated.