title: Optimization of an online heart-cutting multidimensional gas chromatography clean-up step for isotopic ratio mass spectrometry and simultaneous quadrupole mass spectrometry measurements of endogenous anabolic steroid in urine.
abstract: Measuring carbon isotope ratios (CIRs) of urinary analytes represents a cornerstone of doping control analysis and has been particularly optimized for the detection of the misuse of endogenous steroids. Isotope ratio mass spectrometry (IRMS) of appropriate quality, however, necessitates adequate purities of the investigated steroids, which requires extensive pre-analytical sample clean-up steps due to both the natural presence of the target analytes and the high complexity of the matrix. In order to accelerate the sample preparation and increase the automation of the process, the use of multidimensional gas chromatography (MDGC) prior to IRMS experiments, was investigated. A well-established instrumental configuration based on two independent GC ovens and one heart-cutting device was optimized. The first dimension (1D) separation was obtained by a non-polar column which assured high efficiency and good loading capacity, while the second dimension (2D), based on a mid-polar stationary phase, provided good selectivity. A flame ionization detector monitored the 1D, and the 2D was simultaneously recorded by isotope ratio and quadrupole mass spectrometry. The assembled MDGC set-up was applied for measuring testosterone, 5α- and 5β-androstanediol, androsterone, and etiocholanolone as target compounds and pregnanediol as endogenous reference compound. The urine sample were pretreated by conventional sample preparation steps comprising solid-phase extraction, hydrolysis, and liquid-liquid extraction. The extract obtained was acetylated and different aliquots were injected into the MDGC system. Two high performance liquid chromatography steps, conventionally adopted prior to CIR measurements, were replaced by the MDGC approach. The obtained values were consistent with the conventional ones. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Brazilian Laboratory Doping Control, LBCD-LADETEC/IQ-UFRJ, Rio de Janeiro, RJ, Brazil.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Casilli
authors.affiliation: German Sport University Cologne, Center for Preventive Doping Research - Institute of Biochemistry, Köln, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Piper
authors.affiliation: Brazilian Laboratory Doping Control, LBCD-LADETEC/IQ-UFRJ, Rio de Janeiro, RJ, Brazil.
authors.forename: Fábio Azamor
authors.initials: FA
authors.lastname: de Oliveira
authors.affiliation: Brazilian Laboratory Doping Control, LBCD-LADETEC/IQ-UFRJ, Rio de Janeiro, RJ, Brazil.
authors.forename: Monica Costa
authors.initials: MC
authors.lastname: Padilha
authors.affiliation: Brazilian Laboratory Doping Control, LBCD-LADETEC/IQ-UFRJ, Rio de Janeiro, RJ, Brazil.
authors.forename: Henrique Marcelo
authors.initials: HM
authors.lastname: Pereira
authors.affiliation: German Sport University Cologne, Center for Preventive Doping Research - Institute of Biochemistry, Köln, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Thevis
authors.affiliation: Brazilian Laboratory Doping Control, LBCD-LADETEC/IQ-UFRJ, Rio de Janeiro, RJ, Brazil.
authors.forename: Francisco Radler
authors.initials: FR
authors.lastname: de Aquino Neto
mesh_terms: D045930:Anabolic Agents / Q000737:chemistry / Q000652:urine*; D000738:Androsterone / Q000032:analysis / Q000737:chemistry / Q000652:urine*; D002247:Carbon Isotopes / Q000652:urine*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004300:Doping in Sports; D005043:Etiocholanolone / Q000032:analysis / Q000737:chemistry / Q000652:urine*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006801:Humans; D013058:Mass Spectrometry; D013256:Steroids / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D013739:Testosterone / Q000032:analysis / Q000652:urine*
chemical_list: D045930:Anabolic Agents; D002247:Carbon Isotopes; D013256:Steroids; D013739:Testosterone; D005043:Etiocholanolone; D000738:Androsterone
keywords: IRMS; MDGC; carbon isotope ratio; endogenous anabolic steroids