engleski

Analysis of opiates in horse feed by gas chromatography-mass spectrometry

Opiates such as morphine and codeine are substances often misused to improve the performance of racing horses during competitions and are therefore on the International Federation for Equestrian Sports' list of banned substances. However, a positive antidoping test may be due to the consumption of feed (mainly alfalfa or oats) contaminated by poppy seeds containing the alkaloids morphine and codeine. In order to determine whether a positive antidoping test is the result of an intentional abuse of opiates or ingestion of feed contaminated by poppy seeds, we optimised conditions for the extraction of morphine and codeine from dehydrated alfalfa and developed and validated a gas chromatographic-mass spectrometric method for the simultaneous determination of both analytes. The most efficient extraction of morphine and codeine from dehydrated alfalfa was achieved using a citrate buffer pH4 followed by solid phase extraction. The method showed good linearity (R2>0.9980) in the tested concentration range (50-1600 ng/g), as well as good precision (RSD<4 %), accuracy (95.5-97.7 %), and sensitivity (limit of detection=22 and 25 ng/g for morphine and codeine, respectively). The proposed method was used for analysing a sample of dehydrated alfalfa that contained 1510 ng/g morphine and 327 ng/g codeine. The literature data indicates that consumption of 10 g of poppy seeds containing 732 μg of morphine gives a detectable concentration of morphine in the serum and urine of horses up to 4 hours after consumption of poppy seeds. Since the 1 g of alfalfa we analysed contained 1.51 μg of morphine, for the amount of 732 μg of morphine, a horse needs to consume only 485 g of alfalfa for the positive results of serum and urine for morphine in an anti-doping test. The use of the proposed analytical method will enable the exclusion of horse feed as a cause of positive antidoping tests. Acknowledgements: This study was supported by the Ministry of Science and Education of the Republic of Croatia through Institutional Funding made available to the Institute for Medical Research and Occupational Health.

morphine ; codeine ; alfalfa ; gas chromatography-mass spectrometry ; antidoping test

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