Two-dimensional gas chromatography with heart-cutting for isotope ratio mass spectrometry analysis of steroids in doping control

TY - JOUR

T1 - Two-dimensional gas chromatography with heart-cutting for isotope ratio mass spectrometry analysis of steroids in doping control

AU - Brailsford, Alan

AU - Gavrilovic, I.

AU - Ansell, R. J.

AU - Cowan, D. A.

AU - Kicman, A. T.

PY - 2012/12

Y1 - 2012/12

N2 - The accuracy and precision of gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) measurements are highly dependent on analyte purity. Reliable analysis of urinary steroids for doping control therefore requires extensive and time-consuming sample preparation (i.e. liquid chromatography fraction collection) prior to GC-C-IRMS analysis. The use of two-dimensional GC (GC-GC) with heart-cutting (Deans Switch) as a possible approach to reduce the sample purification required for IRMS analysis is described herein. The system uses a low thermal mass oven (LTM) incorporated into an existing GC-C-IRMS system. GC-GC allowed the use of a cyanopropyl/phenyl column in the first dimension to optimize the separation of underivatized steroids, while a phenyl-methylpolysiloxane column in the second dimension focuses the selectively cut analytes into narrower peaks for more sensitive and reliable MS analysis. In addition, to confirm analyte identity, eluent from the second GC was split, with 20 % entering a scanning MS, and 80 % flowing to the IRMS. As a proof concept, the developed method was then used to analyze a single spot urine (5?ml) from an individual receiving T therapy (2?x?50?mg sachets of Testogel (R)). The T delta value (-27.8 parts per thousand, [T]?=?38?ng/ml) was clearly distinct from 11-ketoetiocholanolone (-22.5 parts per thousand) (used as an endogenous reference compound (ERC)), indicating T as being of exogenous origin. The simultaneous analysis by the scanning MS yielded a full scan mass spectrum of the same chromatographic peak, thus confirming the peak to be T. Copyright (c) 2012 John Wiley & Sons, Ltd.

AB - The accuracy and precision of gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) measurements are highly dependent on analyte purity. Reliable analysis of urinary steroids for doping control therefore requires extensive and time-consuming sample preparation (i.e. liquid chromatography fraction collection) prior to GC-C-IRMS analysis. The use of two-dimensional GC (GC-GC) with heart-cutting (Deans Switch) as a possible approach to reduce the sample purification required for IRMS analysis is described herein. The system uses a low thermal mass oven (LTM) incorporated into an existing GC-C-IRMS system. GC-GC allowed the use of a cyanopropyl/phenyl column in the first dimension to optimize the separation of underivatized steroids, while a phenyl-methylpolysiloxane column in the second dimension focuses the selectively cut analytes into narrower peaks for more sensitive and reliable MS analysis. In addition, to confirm analyte identity, eluent from the second GC was split, with 20 % entering a scanning MS, and 80 % flowing to the IRMS. As a proof concept, the developed method was then used to analyze a single spot urine (5?ml) from an individual receiving T therapy (2?x?50?mg sachets of Testogel (R)). The T delta value (-27.8 parts per thousand, [T]?=?38?ng/ml) was clearly distinct from 11-ketoetiocholanolone (-22.5 parts per thousand) (used as an endogenous reference compound (ERC)), indicating T as being of exogenous origin. The simultaneous analysis by the scanning MS yielded a full scan mass spectrum of the same chromatographic peak, thus confirming the peak to be T. Copyright (c) 2012 John Wiley & Sons, Ltd.

KW - SPORT

KW - URINARY STEROIDS

KW - Multidimentional GC

KW - VALUES

KW - Testosterone

KW - MISUSE

KW - GC-GC

KW - MARKERS

KW - AUTHENTICATION

KW - Heart-cutting

KW - POPULATION

KW - IRMS

KW - ANDROSTANEDIOLS

KW - Steroids

KW - TESTOSTERONE ABUSE

U2 - 10.1002/dta.1379

DO - 10.1002/dta.1379

M3 - Article

SN - 1942-7603

VL - 4

SP - 962

EP - 969

JO - Drug Testing And Analysis

JF - Drug Testing And Analysis

IS - 12

ER -