Doping control analysis of 121 prohibited substances in equine hair by liquid chromatography–tandem mass spectrometry

• Published in: Journal of pharmaceutical and biomedical analysis 2018-09, Vol.158, p.189-203
• Main Authors: Wong, J.K.Y., Choi, T.L.S., Kwok, K.Y., Lei, E.N.Y., Wan, T.S.M.
• Format: Article
• Language: English
• Subjects: Doping control; Hair; Horse; Liquid chromatography mass spectrometry; Prohibited substances
• ISSN: 0731-7085; 1873-264X
• DOI: 10.1016/j.jpba.2018.05.043

[Display omitted] •Mane hair is collected, pulverised and processed by solid-phase extraction.•The estimated limits of detection for the 121 drug analytes are in the range of 0.1 to 10 pg/mg.•The method has been validated for its specificity, precision and method recovery.•Soaked quality control samples are recommended to be prepared and analysed in parallel with each analysis.•Method applicability has been demonstrated by the detection of four drug analytes in genuine equine mane hair samples. Equine hair is becoming an increasingly popular biological matrix for doping control of horse sports; one of the reasons for this is the significantly longer detection window hair can offer. Hair analysis opens up the opportunity for longitudinal monitoring of drug exposure which would otherwise not be possible with the more traditional and common biological matrices, such as urine and blood. As such, there is a need for more multi-target screening methods covering a broad range of prohibited substances in equine hair at the required sensitivities for equine doping control. This paper describes a sensitive ultra-high performance liquid chromatography – tandem mass spectrometry (UHPLC–MS/MS) method for the detection of 121 drugs and/or their metabolites in equine hair covering ten classes of prohibited substances with estimated limits of detection between 0.1 and 10 pg/mg. To our knowledge, this is the first report of a screening method in equine hair which can cover such a broad range and well over one hundred prohibited substances in a single analytical run. This method has been validated for its specificity, precision and extraction recovery. Applicability of this method has been demonstrated by: (i) the successful identification of clenbuterol, 2-(1-hydroxyethyl) promazine sulfoxide, acepromazine and tetrahydrozoline in genuine equine mane samples; as well as (ii) the detection of drugs from artificially incurred mane hair samples which have been prepared by soaking blank hair samples in solutions of drug targets.