Liquid chromatography electrospray ionization tandem mass spectrometry for the detection of mesocarb abuse in horse doping.

A method is described for the determination of mesocarb abuse in equestrian sport by combining gradient liquid chromatography and electrospray ionization tandem mass spectrometry. Mesocarb was administrated orally to two horses at a dose of 50 µg/kg. Urine samples were collected up to 120 h post administration.

The potential use of complex derivatization procedures in comprehensive HPLC-MS/MS detection of anabolic steroids.

The use of two separate derivatization procedures with the formation of oxime (hydroxyl ammonium pretreatment) and picolinoyl (mixed anhydride method) derivates of anabolic steroids following HPLC-MS/MS analysis was proposed. The main product ions of obtained derivatives for 21 anabolic steroids were evaluated and fragmentation pathways were compared.The analysis of MS/MS spectra for underivatized steroids versus oxime or picolinoyl derivatives showed that in case of analytes containing conjugated double bonds in sterane core all of the observed MS/MS spectra contained abundant product ions of diagnostic value.

Possible indirect detection of rHuEPO administration in human urine by high-performance liquid chromatography tandem mass spectrometry.

The present study is based on the assumption that changes in an ADMA-DDAH-NOS (ADMA-asymmetrical dimethylarginine; DDAH-dimethyl-arginine dimethylaminohydrolase; NOS-nitric oxide synthase) system could be employed as indirect markers for recombinant human erythropoietin (rHuEPO) administration in doping control. We assessed a predictive value of four proposed new markers for rHuEPO abuse. Preliminary data showed that concentrations of ADMA, symmetrical dimethylarginine (SDMA), citrulline and arginine in human urine were increased after administration of a single intravenous erythropoietin injection (2000 U day(-1), Epocrine, St-Petersburg, Russia).