By: Christa Leste-Lasserre
Imagine a fair playing field where all competing horses could be tested for more than a hundred drugs at once from each of their urine samples, with results in a matter of minutes.
No more need to imagine it. Hong Kong researchers are already there. “The short run time (of our new method) enables a high throughput with minimal labor requirements and is especially useful in time-critical operations such as pre-race analysis,” said Terence S.M. Wan, PhD, EurChem, CSci, CChem, FRSC, FAORC, FCSFS, head of the racing laboratory and chief racing chemist at The Hong Kong Jockey Club.
This new system benefits from online solid phase extraction (SPE), as opposed to offline SPE. SPE is a popular sample preparation technique that essentially isolates dissolved target components (such as drugs) from the liquid they’re dissolved in (in this case, urine) as well as from the naturally occurring components. “Online,” despite what the name sounds like, doesn’t mean the analyses are carried out via the internet or wireless technology. Online SPE means the process from extraction to analysis is automated, with the samples being run automatically through the “line” of analytical equipment without human intervention.
Offline SPE, by contrast, works via extraction cartridges that laboratory technicians have to manipulate themselves (like cartridge conditioning, sample filling, elution, evaporation, and introducing the extract onto the equipment line). While offline SPE might have some advantages in other kinds of laboratory analyses, the system is labor-intensive and time-consuming. In horse racing and other equestrian events that involve testing and reporting prior to competition, time and simplicity matter—and online SPE appears to be the way to go.
Wan and his fellow researchers developed a drug-testing system for equine urine that runs the enzyme-treated samples through online SPE for sample preparation and then automatically introduces each resulting extract sequentially into the liquid-chromatograph/high-resolution mass spectrometer to check for the presence of more than 100 common doping substances. Unlike many current equine drug tests, each of which can require one to two days of waiting for results, Wan’s “over-100-drugs” test takes only 16 minutes per sample—including sample cleanup and machine resetting time. In other words, equine urine samples could be run back-to-back at 16-minute intervals, considered very fast in the equine doping control field.
What’s more, the over-100-drugs test is rather sensitive for each drug, despite being arranged to test a wide variety of drugs, Wan said. In their study, it revealed limits of detection (LoDs) of less than 5 ng/mL—largely sufficient for establishing positive cases—in 90% of the 118 tested drugs, and some of the LoDs even reached 0.05 ng/mL.
It’s important to note that the “over-100-drugs” test does not replace the “dilute-and-shoot” and other tests, he said. On the contrary, they complement each other.
“The dilute-and-shoot method is superior in the detection of very polar prohibited substances that are difficult to extract from urine or plasma samples,” Wan told The Horse. “While it offers a very simple sample preparation and broad drug coverage, it may not be sensitive enough to detect very low levels of certain potent doping agents. On the other hand, the present online SPE method is more sensitive for other types of drugs and can simultaneously detect more than 100 banned substances, most of which are not covered adequately by the dilute-and-shoot method in horse urine.”
Another benefit of the new test is its adaptability, even retrospectively, as new drugs are discovered. Because this mass spectrometry technique is high resolution and records each sample’s full-scan data, scientists can go back to that recorded data later and search for the possible evidence of new drugs (as they are discovered) within that data, without testing the original sample again, said Wan. In other words, stored urine samples might not need to be reanalyzed if authorities or scientists want to find out whether people have started using a new prohibited substance.
One final advantage, he adds: It’s cheaper than many of today’s drug tests. Because it checks so many drugs simultaneously and does so through automation with minimal expensive human labor involved, the direct costs would be lower, he explained. This test can be used immediately in laboratories worldwide, Wan said, provided they have access to “the appropriate instrumentation and reference materials.”
