Detection of some anabolic steroid (testosterone) esters in blood samples of race horses by LC-MS/MS

It is known that anabolic steroids are frequently used in racing sports to increase muscle strength and provide superiority in performance. In this context, exogenous testosterone esters are used to provide the effect of an endogenous substance, testosterone. Testosterone esters are enzymatically hydrolyzed by blood esterases in the bloodstream and converted to testosterone. Therefore, ester amounts in the blood can be detected in plasma and serum samples. The aim of this thesis study is to detect testosterone esters in blood samples of race horses by using different liquid-liquid or solid phase extraction techniques by using liquid chromatography - tandem mass spectrometry (LC-MS/MS). After determining the appropriate extraction technique with different solvents and cartridge experiments, the developed method was validated in accordance with the directive no 2021/808 dated March 22, 2021 published by the European Union Publication Office. In the literature researches, it was seen that the studies in this field are very few and the derivatization process was carried out especially in the analyzes of testosterone esters. In this thesis study; in addition to making an important contribution to the literature with the new method developed by providing the detection of testosterone esters without derivatization process, it is also aimed to develop a method that can be used routinely in the detection of exogenous testosterone application in doping laboratories.