Browsing by Subject "dopinganalytiikka"

An ultra-high-pressure liquid chromatography method was used for simultaneous detection of 25 small peptide hormones and their metabolites in urine after solid-phase extraction. This method is first screening step in anti-doping analysis of urine samples. It should be fast, generic and able to detect any sample that may contain a prohibited substance while avoiding false negatives and reducing false positive results. Detection was achieved using quadrupole time-of-flight mass spectrometry coupled with electrospray ionization source in positive mode. Analytes included growth hormone secretagogues, gonadotropin releasing factors, anti-diuretic hormones and their metabolites which are all covered by the list of prohibited substances of the World Anti-Doping Agency (WADA). The practical part of investigation was done in United Medix Laboratories and the aim of study was to expand current screening method by adding new compounds. Optimal experimental conditions were stablished after investigation of different parameters concerning sample preparation and instrumental analysis. The extraction procedure was done by using weak cation exchange SPE with two washing steps (Milli-Q water and methanol), and elution with 5 % formic acid in methanol. The procedure was validated in terms of recovery, specificity, limits of detection, stability and robustness. Recovery was evaluated with 10 ng/ml concentration of analytes and the rest of validation procedures were done at half of minimum required performance level set by WADA (1 ng/ml). Recoveries ranged from 2,6 to 85 % with LODs from 0,01 to 1,76 ng/ml. The suitability of the method was assessed by analyzing different spiked urine specimens containing target substances.