Sample Pretreatment for Confirmation of 19 – Norsteroids by GC – C – IRMS in Doping Control
Issued Date
2018
Resource Type
Language
eng
Rights
Mahidol University
Rights Holder(s)
National Doping Control Centre Mahidol University
Suggested Citation
Nimsoongnern S, Weewong C, Lohwithee S, Wiriyakosol N, Wilairat P, Kongpatanakul S (2018). Sample Pretreatment for Confirmation of 19 – Norsteroids by GC – C – IRMS in Doping Control. Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/44096
Title
Sample Pretreatment for Confirmation of 19 – Norsteroids by GC – C – IRMS in Doping Control
Other Contributor(s)
Abstract
Confirmation of the use of 19-norsteroids requires the identification of the exogenous origin of the main
metabolite, 19-norandrosterone (1g-NA), when found in the urine at concentrations between 2.5 ng/ml and
15 ng/ml. An effective pretreatment procedure is necessary prior to the IRMS measurement. Two HPLC clean
up steps were employed to isolate the fractions of 19-NA, '19-noretiocholanolone (19-NE) and two endogenous
reference compounds (ERCs), pregnandiol (PD) and androsterone (Andro). Validation followed the WADA
requirements as specified in TD2017NA and TD2016|RMS. Blank urine, 20-30 mL, spiked with 19-NA and 19-
NE at 2.5-15 ng/ml, were used for method validation-regarding intra and inter-assay precision. The accuracy
and isotopic fractionation were evaluated using standard 19-NA, 19-NE and certified standard USADA34-1
spiked in steroid stripfed urine. The results show no interference peak close to the target compounds. The
difference between the 613C (%d of pure certified standard and spiked steroid stripped urine of less than 0.5 %.
verified the accuracy of 613C (%.) measurement and the absence of isotopic fractionation during sample
prep.aratipn. This method is fit for the determination of 6l3C (%.) of 19-NA and 19-NE for anti-doping purposes.
Description
Recent Advances in Doping Analysis (25) Proceeding of the Manfred Donike Workshop 35th Cologne Workshop on Dope Analysis. 5th to 10th March 2017, page 136-139.