Use of Clean Screen® DAU to Quantify and Confirm the Primary Fentanyl Metabolite in Equine Urine

July 21st, 2023 NewsSample Preparation News

The abuse of fentanyl, a synthetic opioid, is well known in humans. However, its misuse is becoming more popular in horseracing to enhance the performance of the racehorses. Fentanyl has both an analgesic and stimulatory effect on horses. The use of fentanyl in equine sports is prohibited by both the Association of Racing Commissioners International and the Fédération Équestre Internationale. Fentanyl is rapidly metabolized in horses, resulting in a detection window of less than 10 hours. The primary metabolite, N-[1-(2-Phenethy-4-Piperidinyl)] Maloanilinic Acid (PMA), was evaluated to determine if it could allow for a longer detection time.

Different sample preparation methods were evaluated, including dilute-and-shoot, LLE, and SPE with different cartridges. This study found that UCT’s Clean Screen® DAU cartridges resulted in the cleanest extract with the best sensitivity for PMA compared to other extraction protocols. The cartridges were conditioned, and 1 mL of urine was loaded directly onto the extraction cartridges without diluting. The final eluate was analyzed via LC-MS/MS.

Results indicated that fentanyl was rapidly metabolized and could not be confirmed at a concentration of 1 pg/mL in plasma or urine 10 hours or 3 hours past administration respectively. PMA was able to be detected in urine from 10 to 72 hours after administration. This validated method provides a useful tool to identify the exposure of horses to substances that compromise their well-being.


Citations: Youwen, You et al. Use of Liquid Chromatography-Tandem Mass Spectrometry to Quantify and Confirm the Fentanyl Metabolite N-[1-(2-Phenethy-4-Piperidinyl)] Maloanilinic Acid in Equine Urine for Doping Control, Journal of Analytical Toxicology, Volume 47, Issue 4, May 2023, Pages 393–402,

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