Short term impact of Tribulus terrestris intake on doping control analysis of endogenous steroids

Tribulus terrestris is a nutritional supplement highly debated regarding its physiological and actual effects on the organism. The main claimed effect is an increase of testosterone anabolic and androgenic action through the activation of endogenous testosterone production. Even if this biological pathway is not entirely proven, T. terrestris is regularly used by athletes. Recently, the analysis of two female urine samples by GC/C/IRMS (gas chromatography/combustion/isotope-ratio-mass-spectrometry) conclusively revealed the administration of exogenous testosterone or its precursors, even if the testosterone glucuronide/epitestosterone glucuronide (T/E) ratio and steroid marker concentrations were below the cut-off values defined by World Anti-Doping Agency (WADA). To argue against this adverse analytical finding, the athletes recognized having used T. terrestris in their diet. In order to test this hypothesis, two female volunteers ingested 500 mg of T. terrestris, three times a day and for two consecutive days. All spot urines were collected during 48 h after the first intake. The (13)C/(12)C ratio of ketosteroids was determined by GC/C/IRMS, the T/E ratio and DHEA concentrations were measured by GC/MS and LH concentrations by radioimmunoassay. None of these parameters revealed a significant variation or increased above the WADA cut-off limits. Hence, the short-term treatment with T. terrestris showed no impact on the endogenous testosterone metabolism of the two subjects.     

A case study on the application of isotope ratio mass spectrometry (IRMS) in determining the provenance of a rock used in an alleged nickel switching incident

The application of isotope ratio mass spectrometry (IRMS) in forensic science to establish the provenance of a range of questioned substances including soils, drugs, explosives, currency, ivory and rhino horn has been widely documented. The present study wishes to highlight the applicability of IRMS and specifically stable carbon IRMS in determining the provenance of a carbonate rock that was switched for nickel metal exported from South Africa to Israel. The technique employed effectively argued against a South African origin for the rock whilst simultaneously supporting an Israeli origin, enabling investigators to focus their attention accordingly. The study represents the first documented instance known to the authors where IRMS has been employed in the forensic geo-location of a rock.