Reliable identification and quantification of anabolic androgenic steroids in dietary supplements by using gas chromatography coupled to triple quadrupole mass spectrometry.

The aim of the present research was the identification and quantification of specific anabolic androgenic steroids (AASs) and other sterane structured compounds in dietary supplements (DSs). The adulteration of DSs by these compounds is of a particular concern in athletes, because it might lead to a positive doping result. The research was focused on the optimization of a highly sensitive and selective GC-based analytical strategy using triple quadrupole MS as detector. Chromatographic method and multiple reaction monitoring (MRM) transitions of 28 target compounds were optimized. Sample clean-up was carried out by using a solid phase extraction (SPE) procedure, while the derivatization of AASs was performed by using N-methyl-N-(trimethylsilyl)-trifluoroacetamide (MSTFA). The method was validated, and the following parameters were investigated: linearity range, limit of detection, accuracy, and precision expressed in terms of intra-day precision. The calibration curves were evaluated by using regression model and resulting in a good determination coefficients (R ² ≥ 0.9912). The residuals were scattered randomly around zero. The limits of detection (LODs) were lower than 7.0 ng g ^-1 or ng ml ^-1 . The accuracy assessment was evaluated in different forms of DSs characterized by high sample-to-sample variability (liquid, powder, tablet, capsule, protein, and herbal-based). Intra-day assay precision was in all cases lower than 20%. The developed analytical method was successfully applied to the analysis of 67 commercially available dietary supplements. In five cases, one or more steroid-type compounds were found in the concentration of 5 ng g ^-1 -100 μg g ^-1 , which might result adverse analytical findings in athletes.
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