Cationic exchange SPE combined with triple quadrupole UHPLC-MS/MS for detection of GHRHs in urine samples.

The use of growth hormone-releasing hormones (GHRHs) is prohibited in sports according to the regulations of the World Anti-Doping Agency (WADA). Considering the complexity of urine samples and the low concentrations at which these analytes should be detected, analyzing GHRHs is a challenging task. In most of the studies, GHRHs are analyzed using UHPLC-HRMS with an orbitrap. The present developed and validated method for some GHRHs (tesamorelin, CJC-1295, sermorelin (GRF 1-29), sermorelin (3-29)-NH, somatorelin) is based on the triple quadrupole UHPLC/MS-MS method with solid phase extraction (SPE) with weak cation exchange and is able to detect concentrations as low as 0.2 ng/mL (LOD), a limit of quantification (LOQ) at 0.6 ng/mL, and linearity across the range of 0.1 ng/mL to 1.2 ng/mL. The present method developed by our doping control laboratory was validated according to WADA technical documents for selectivity, limit of detection (LOD), carryover, reliability of detection, stability and recovery. The results show that the method has adequate recoveries and sensitivity, hence, it can be employed for routine screening in anti-doping laboratories.