Abstract

To improve the screening of anabolic steroids and other prohibited substances, detection of which using GC-MS mass spectrometry does not allow in some cases to obtain the results satisfying MRPL requirements, a more sensitive method using the Agilent 7000 Series Triple Quad GC/MS in MS/MS mode was developed. The selected reaction monitoring mode (SRM) allows the detection of target compounds at trace levels in complex matrixes. Additionally, this method provides an opportunity to conduct the screening process, confirmation and quantification in one analysis. In the SRM mode, this method allows to test up to 30 analytes simultaneously. The developed method allows the identification of 27 anabolic steroids. Besides those anabolic steroids, this method was also used for the detection of other classes of substances such as aromatase inhibitors - formestane, letrozole and diuretics — camenone. To perform the process, we first selected the precursor ion obtained by electron ionization (EI), in the full scan mode (50-700 Da). Then, we generated the fragmentation of the selected ion in the product ion scan mode using different values of collision energy (from 20 to 60 CE) and selected its product ions for their further optimization. We carried out this process in the SRM mode for the selected pairs of precursor/product ions using CE values varying from 5 to 35 CE in the increments of 5. For each pair, the CE value with the maximal abundance was selected. Next, a general method for all pairs in the SRM mode was created and 10 different blank samples of urine were analyzed. Those ion pairs that showed a significant interference with the matrix were excluded from the method. The final verification of the method was carried out on urine samples spiked with the listed substances in concentrations corresponding to their MRPL levels and below. The obtained results confirmed that the new GC-QQQ instrument provides a higher level of confidence in the detection of banned substances. Einleitung