ABSTRACT
The detection of exogenous 19-norandrosterone (19-NA) in urines was investigated by using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). 19-NA is, for the first time to our knowledge, isolated from urinary matrix by specific immunoaffinity chromatography (IAC) before analysis. The sample preparation consisted of a preliminary purification of urine by solid-phase extraction after hydrolysis by beta-glucuronidase. Unconjugated 19-NA was thus isolated by IAC and directly analysed by GC/C/IRMS. Optimisation of IAC purification was achieved and the reliability of the technique for anti-doping control is discussed.
Subject(s)
Estranes/urine , Acetylation , Chromatography, Affinity , Estranes/immunology , Gas Chromatography-Mass Spectrometry , Humans , Immunochemistry , Indicators and Reagents , SolventsABSTRACT
A new method of detection of perfluorocarbon molecules (PFCs) in blood sample has been established. After an extraction and pre-concentration step performed by headspace solid-phase microextraction (HS-SPME), the PFCs are detected by gas chromatography-mass spectrometry (GC/MS) with an ion trap mass spectrometer in MS and MS/MS modes. The influence of different parameters on the SPME process is discussed. The limit of detection and the linearity of the procedure have been determined for two PFCs.
Subject(s)
Fluorocarbons/blood , Gas Chromatography-Mass Spectrometry/methods , Gas Chromatography-Mass Spectrometry/instrumentation , Humans , Quality Control , Sensitivity and Specificity , TemperatureABSTRACT
Determination of whether the major metabolite of nandrolone in urine, 19-norandrosterone (19-NA), is exogenous or endogenous in origin is one of the most exciting challenges for antidoping laboratories. Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) can be used to differentiate these two origins by carbon isotopic ratio analysis. A complete method for purification of 19-NA in urine has been established. Acetylated ketosteroids, and in particular 19-NA, are isolated from the urine matrix before analysis after hydrolysis and purification of urine by reversed-phase and normal solid-phase extraction. The limit of detection for 19-NA was about 60 ng with recoveries of 54-60%. Evidence of exogenous administration of 19-NA may be established from isotope ratio determination from the 13C/12C ratios of several synthetic 19-norsteroids compared to those obtained for endogenous steroids.
Subject(s)
Estranes/urine , Gas Chromatography-Mass Spectrometry/methods , Doping in Sports , Humans , Reproducibility of Results , Sensitivity and SpecificityABSTRACT
A detailed procedure for the analysis of exogenous hydrocortisone and cortisone in urine by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) is proposed. As urinary levels of hydrocortisone are rather low for GC/C/IRMS analysis, the focus is on the main corticosteroid metabolites, tetrahydrocortisone (THE) and tetrahydrocortisol (THF). Following different solid phase extraction purifications, THE and THF are oxidized to 5beta-androstanetrione before analysis by GC/C/IRMS. Significant differences in delta(13)C per thousand values of synthetic natural corticosteroids and endogenous human corticosteroids have been observed. Therefore, a positive criterion, to detect exogenous administration of synthetic corticosteroids in anti-doping control, is proposed.
Subject(s)
Adrenal Cortex Hormones/administration & dosage , Adrenal Cortex Hormones/urine , Gas Chromatography-Mass Spectrometry/methods , Sports , Adrenal Cortex Hormones/chemistry , Adrenal Cortex Hormones/metabolism , Adult , Androstanes/chemistry , Androstanes/urine , Cortisone/administration & dosage , Cortisone/chemistry , Cortisone/metabolism , Cortisone/urine , Female , Humans , Hydrocortisone/administration & dosage , Hydrocortisone/chemistry , Hydrocortisone/metabolism , Hydrocortisone/urine , Male , Middle Aged , Molecular Structure , Tetrahydrocortisol/chemistry , Tetrahydrocortisol/urine , Tetrahydrocortisone/chemistry , Tetrahydrocortisone/urine , Time FactorsABSTRACT
This paper describes a GC-MS method (SIM mode) for the analysis of perfluorooctyl bromide (perflubron, I) in rat blood. The chromatographic separation was performed by injection in the split mode using a CP-select 624 CB capillary column. Following destruction of the emulsion by addition of ethanol, the analytical procedure involves a liquid-liquid extraction with 1,1,2-trichlorotrifluoroethane. The bis(F-butyl)ethene (II) was used as internal standard. Observed retention times were 3.22 min for I and 2.32 min for II. Two calibration curves were used; linear detection responses were obtained for concentrations ranging from 0.009 to 0.9 mg/ml and from 0.9 to 13.5 mg/ml. The extraction efficiency averaged 50% for I and 93% for II. Precision ranged from 0.7 to 14%, and accuracy was between 91 and 109%. The limit of quantification was 9 microg/ml. The method validation results indicate that the performance characteristics of the method fulfilled the requirements for assay method for use in pharmacokinetic studies.
