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Fitzgerald CCJ, Bowen C, Elbourne M, Cawley A, McLeod MD. Energy-Resolved Fragmentation Aiding the Structure Elucidation of Steroid Biomarkers. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1276-1281. [PMID: 35791638 DOI: 10.1021/jasms.2c00092] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The identification and confirmation of steroid sulfate metabolites in biological samples are essential to various fields, including anti-doping analysis and clinical sciences. Ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) is the leading method for the detection of intact steroid conjugates in biofluids, but because of the inherent complexity of biological samples and the low concentration of many targets of interest, metabolite identification based solely on mass spectrometry remains a major challenge. The confirmation of new metabolites typically depends on a comparison with synthetically derived reference materials that encompass a range of possible conjugation sites and stereochemistries. Herein, energy-resolved collision-induced dissociation (CID) is used as part of UHPLC-HRMS/MS analysis to distinguish between regio- and stereo-isomeric steroid sulfate compounds. This wholly MS-based approach was employed to guide the synthesis of reference materials to unambiguously confirm the identity of an equine steroid sulfate biomarker of testosterone propionate administration.
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Affiliation(s)
- Christopher C J Fitzgerald
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Christopher Bowen
- Mass Spectrometry Business Unit, Shimadzu Scientific Instruments (Australasia), Rydalmere, New South Wales 2116, Australia
| | - Madysen Elbourne
- Centre for Forensic Science, University of Technology Sydney, Broadway, New South Wales 2007, Australia
| | - Adam Cawley
- Australian Racing Forensic Laboratory, Racing NSW, Sydney, New South Wales 2000, Australia
| | - Malcolm D McLeod
- Research School of Chemistry, Australian National University, Canberra, Australian Capital Territory 2601, Australia
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2
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Alawi AI, Dhabbah AM, Morrison C, Ben-Jaber S, AlAngari WA, Bin Jassas M, Badjah‑Hadj‑Ahmed Y. Indirect chiral separation of crystal methamphetamine seized in Saudi Arabia using GC-MS. AUST J FORENSIC SCI 2022. [DOI: 10.1080/00450618.2022.2079720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ali I. Alawi
- Forensic Science Department, King Fahd Security College, Riyadh, Kingdom of Saudi Arabia
- School of Medicine, Dentistry and Nursing, College of Medical, Veterinary Life Sciences, University of Glasgow, Glasgow, UK
| | - Abdulrhman M. Dhabbah
- Forensic Science Department, King Fahd Security College, Riyadh, Kingdom of Saudi Arabia
| | - Calum Morrison
- School of Medicine, Dentistry and Nursing, College of Medical, Veterinary Life Sciences, University of Glasgow, Glasgow, UK
- Department of Applied Science, School of Computing, Engineering and Built Environment, Glasgow Caledonian University, Glasgow, UK
| | - Sultan Ben-Jaber
- Forensic Science Department, King Fahd Security College, Riyadh, Kingdom of Saudi Arabia
| | - Waleed A. AlAngari
- Poison Control and Forensic Medical Center, Riyadh, Kingdom of Saudi Arabia
| | - Meshal Bin Jassas
- Poison Control and Forensic Medical Center, Riyadh, Kingdom of Saudi Arabia
| | - Yacine Badjah‑Hadj‑Ahmed
- Department of Chemistry, College of Science, King Saud University, Riyadh, Kingdom of Saudi Arabia
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De Wilde L, Van Renterghem P, Van Eenoo P. Long-term stability study and evaluation of intact steroid conjugate ratios after the administration of endogenous steroids. Drug Test Anal 2021; 14:851-863. [PMID: 33982451 DOI: 10.1002/dta.3096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 12/26/2022]
Abstract
The most frequently detected substances prohibited by the World Anti-Doping Agency (WADA) belong to the anabolic steroids class. The most challenging compounds among this class are the endogenous anabolic steroids, which are detected by quantitative measurement of testosterone (T) and its metabolites with a so-called "steroid profiling" method. The current steroid profile is based on the concentrations and ratios of the sum of free and glucuronidated steroids. Recently, our group developed a steroid profiling method for the detection of three free steroids and 14 intact steroid conjugates, including both the glucuronic acid conjugated and sulfated fraction. The study aimed at evaluating the long-term stability of steroid conjugate concentrations and ratios, and the influence of different endogenous steroids on this extended steroid profile. A single dose of oral T undecanoate (TU), topical T gel, topical dihydrotestosterone (DHT) gel, and oral dehydroepiandrosterone (DHEA) was administered to six healthy male volunteers. One additional volunteer with a homozygote deletion of the UGT2B17 gene (del/del genotype) received a single topical dose of T gel. An intramuscular dose of TU was administered to another volunteer. To avoid fluctuation of steroid concentrations caused by variations in urinary flow rates, steroid ratios were calculated and evaluated as possible biomarkers for the detection of endogenous steroid abuse with low doses. Overall, sulfates do not have substantial additional value in prolonging detection times for the investigated endogenous steroids and administration doses. The already monitored glucuronides were overall the best markers and were sufficient to detect the administered steroids.
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Affiliation(s)
- Laurie De Wilde
- Department Diagnostic Sciences, Doping Control Laboratory (DoCoLab), Ghent University (UGent), Ghent, Belgium
| | - Pieter Van Renterghem
- Department Diagnostic Sciences, Doping Control Laboratory (DoCoLab), Ghent University (UGent), Ghent, Belgium
| | - Peter Van Eenoo
- Department Diagnostic Sciences, Doping Control Laboratory (DoCoLab), Ghent University (UGent), Ghent, Belgium
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4
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Development and application of analytical procedures for the GC–MS/MS analysis of the sulfates metabolites of anabolic androgenic steroids: The pivotal role of chemical hydrolysis. J Chromatogr B Analyt Technol Biomed Life Sci 2020; 1155:122280. [DOI: 10.1016/j.jchromb.2020.122280] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 11/17/2022]
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De Wilde L, Roels K, Van Renterghem P, Van Eenoo P, Deventer K. Steroid profiling in urine of intact glucuronidated and sulfated steroids using liquid chromatography-mass spectrometry. J Chromatogr A 2020; 1624:461231. [DOI: 10.1016/j.chroma.2020.461231] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 05/06/2020] [Accepted: 05/10/2020] [Indexed: 02/05/2023]
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Honour JW, Conway E, Hodkinson R, Lam F. The evolution of methods for urinary steroid metabolomics in clinical investigations particularly in childhood. J Steroid Biochem Mol Biol 2018; 181:28-51. [PMID: 29481855 DOI: 10.1016/j.jsbmb.2018.02.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 12/15/2022]
Abstract
The metabolites of cortisol, and the intermediates in the pathways from cholesterol to cortisol and the adrenal sex steroids can be analysed in a single separation of steroids by gas chromatography (GC) coupled to MS to give a urinary steroid profile (USP). Steroids individually and in profile are now commonly measured in plasma by liquid chromatography (LC) coupled with MS/MS. The steroid conjugates in urine can be determined after hydrolysis and derivative formation and for the first time without hydrolysis using GC-MS, GC-MS/MS and liquid chromatography with mass spectrometry (LC-MS/MS). The evolution of the technology, practicalities and clinical applications are examined in this review. The patterns and quantities of steroids changes through childhood. Information can be obtained on production rates, from which children with steroid excess and deficiency states can be recognised when presenting with obesity, adrenarche, adrenal suppression, hypertension, adrenal tumours, intersex condition and early puberty, as examples. Genetic defects in steroid production and action can be detected by abnormalities from the GC-MS of steroids in urine. New mechanisms of steroid synthesis and metabolism have been recognised through steroid profiling. GC with tandem mass spectrometry (GC-MS/MS) has been used for the tentative identification of unknown steroids in urine from newborn infants with congenital adrenal hyperplasia. Suggestions are made as to areas for future research and for future applications of steroid profiling. As routine hospital laboratories become more familiar with the problems of chromatographic and MS analysis they can consider steroid profiling in their test repertoire although with LC-MS/MS of urinary steroids this is unlikely to become a routine test because of the availability, cost and purity of the internal standards and the complexity of data interpretation. Steroid profiling with quantitative analysis by mass spectrometry (MS) after chromatography now provides the most versatile of tests of adrenal function in childhood.
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Affiliation(s)
- John W Honour
- Institute for Women's Health, University College London, 74 Huntley Street, London, WC1E 6AU, UK.
| | - E Conway
- Clinical Biochemistry, HSL Analytics LLP, Floor 2, 1 Mabledon Place, London, WC1H 9AX, UK
| | - R Hodkinson
- Clinical Biochemistry, HSL Analytics LLP, Floor 2, 1 Mabledon Place, London, WC1H 9AX, UK
| | - F Lam
- Clinical Biochemistry, HSL Analytics LLP, Floor 2, 1 Mabledon Place, London, WC1H 9AX, UK
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7
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High resolution full scan liquid chromatography mass spectrometry comprehensive screening in sports antidoping urine analysis. J Pharm Biomed Anal 2018; 151:10-24. [DOI: 10.1016/j.jpba.2017.12.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 12/10/2017] [Accepted: 12/11/2017] [Indexed: 12/11/2022]
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Pedersen M, Frandsen HL, Andersen JH. Optimised deconjugation of androgenic steroid conjugates in bovine urine. Food Addit Contam Part A Chem Anal Control Expo Risk Assess 2017; 34:482-488. [DOI: 10.1080/19440049.2016.1276637] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Mikael Pedersen
- National Food Institute, Technical University of Denmark, Søborg, Denmark
| | - Henrik L. Frandsen
- National Food Institute, Technical University of Denmark, Søborg, Denmark
| | - Jens H. Andersen
- National Food Institute, Technical University of Denmark, Søborg, Denmark
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Detection, production, and application of microbial arylsulfatases. Appl Microbiol Biotechnol 2016; 100:9053-9067. [PMID: 27654655 DOI: 10.1007/s00253-016-7838-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 08/24/2016] [Accepted: 08/26/2016] [Indexed: 10/21/2022]
Abstract
Arylsulfatases are enzymes which catalyze the hydrolysis of arylsulfate ester bonds to release a free sulfonate. They are widespread in nature and are found in microorganisms, most animal and human tissues, and plant seeds. However, this review focuses on arylsulfatases from microbial origin and gives an overview of different assays and substrates used to determine the arylsulfatase activity. Furthermore, the production of microbial arylsulfatases using wild-type organisms as well as the recombinant production using Escherichia coli and Kluyveromyces lactis as expression hosts is discussed. Finally, various potential applications of these enzymes are reviewed.
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Vichapong J, Burakham R, Srijaranai S. Determination of β-agonists in Porcine Meats by Ion-Pair Extraction and High Performance Liquid Chromatography. ANAL LETT 2015. [DOI: 10.1080/00032719.2015.1060602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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11
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Stevenson BJ, Waller CC, Ma P, Li K, Cawley AT, Ollis DL, McLeod MD. Pseudomonas aeruginosaarylsulfatase: a purified enzyme for the mild hydrolysis of steroid sulfates. Drug Test Anal 2015; 7:903-11. [DOI: 10.1002/dta.1782] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 02/04/2015] [Accepted: 02/04/2015] [Indexed: 01/09/2023]
Affiliation(s)
- Bradley J. Stevenson
- Research School of Chemistry; Australian National University; Canberra ACT 2601 Australia
| | - Christopher C. Waller
- Research School of Chemistry; Australian National University; Canberra ACT 2601 Australia
| | - Paul Ma
- Research School of Chemistry; Australian National University; Canberra ACT 2601 Australia
| | - Kunkun Li
- Research School of Chemistry; Australian National University; Canberra ACT 2601 Australia
| | - Adam T. Cawley
- Racing New South Wales - Australian Racing Forensic Laboratory; Sydney NSW 1465 Australia
| | - David L. Ollis
- Research School of Chemistry; Australian National University; Canberra ACT 2601 Australia
| | - Malcolm D. McLeod
- Research School of Chemistry; Australian National University; Canberra ACT 2601 Australia
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Pozo OJ, Gómez C, Marcos J, Segura J, Ventura R. Detection and characterization of urinary metabolites of boldione by LC-MS/MS. Part II: Conjugates with cysteine andN-acetylcysteine. Drug Test Anal 2012; 4:786-97. [DOI: 10.1002/dta.1431] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 09/14/2012] [Accepted: 09/25/2012] [Indexed: 11/12/2022]
Affiliation(s)
- Oscar J. Pozo
- Bioanalysis Research Group, IMIM, Hospital del Mar; Doctor Aiguader 88; 08003; Barcelona; Spain
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Cawley AT, George AV. Complementary stable carbon isotope ratio and amount of substance measurements in sports anti-doping. Drug Test Anal 2012; 4:897-911. [DOI: 10.1002/dta.1378] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 05/06/2012] [Accepted: 05/08/2012] [Indexed: 11/11/2022]
Affiliation(s)
| | - Adrian V. George
- School of Chemistry; University of Sydney; Sydney; NSW; 2006; Australia
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14
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Parr MK, Schänzer W. Detection of the misuse of steroids in doping control. J Steroid Biochem Mol Biol 2010; 121:528-37. [PMID: 20036329 DOI: 10.1016/j.jsbmb.2009.12.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 12/16/2009] [Accepted: 12/20/2009] [Indexed: 11/16/2022]
Abstract
The list of prohibited substances of the World Anti-Doping Agency (WADA) classifies the administration of several steroids in sports as doping. Their analysis is generally performed using urine specimen as matrix. Lots of the steroids are extensively metabolised in the human body. Thus, knowledge of urinary excretion is extremely important for the sensitive detection of steroid misuse in doping control. The methods routinely used in steroid screening mainly focus on substances, that are excreted unconjugated or as glucuronides. Common procedures include deconjugation using a beta-glucuronidase enzyme. Following extraction and concentration the analytes are submitted to LC-MS(/MS) analysis and/or GC-MS(/MS) analyses. Besides the classical steroids, more and more products appear on the market for "dietary supplements" containing steroids that have never been marketed as approved drugs, mostly without proper labelling of the contents. To cover the whole range of potential products comprehensive screening tools have to be utilised in addition to the classical methods. Endogenous steroids, e.g. testosterone, represent a special group of compounds. As classical chemical methodology is incapable of discriminating synthetic hormones from the biosynthesised congeners, the method of steroid profiling is used for screening purpose. Additionally, based on isotope signatures a discrimination of synthetic and natural hormones can be achieved.
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Affiliation(s)
- Maria Kristina Parr
- Institute of Biochemistry, German Sport University Cologne, Am Sportpark Muengersdorf 6, 50933 Cologne, Germany.
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Gomes RL, Meredith W, Snape CE, Sephton MA. Analysis of conjugated steroid androgens: deconjugation, derivatisation and associated issues. J Pharm Biomed Anal 2009; 49:1133-40. [PMID: 19304432 PMCID: PMC2684592 DOI: 10.1016/j.jpba.2009.01.027] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 12/31/2008] [Accepted: 01/22/2009] [Indexed: 11/22/2022]
Abstract
Gas chromatography/mass spectrometry (GC/MS) is the preferred technique for the detection of urinary steroid androgens for drug testing in athletics. Excreted in either the glucuronide or sulfated conjugated form, steroids must first undergo deconjugation followed by derivatisation to render them suitable for GC analysis. Discussed herein are the deconjugation and the derivatisation preparative options. The analytical challenges surrounding these preparatory approaches, in particular the inability to cleave the sulfate moiety have led to a focus on testing protocols that reply on glucuronide conjugates. Other approaches which alleviate the need for deconjugation and derivatisation are also highlighted.
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Key Words
- 13c/12c, stable carbon isotope ratio
- aps, adenosine-5′-phosphate
- atp, adenosine triphosphate
- bstfa, n,o-bis(trimethylsilyl)-trifluoroacetamide
- dhea, dehydroepiandrosterone
- es, external standard
- fid, flame ionisation detector
- fu, fishman unit
- g, glucuronide
- gc/c/irms, gas chromatography/combustion/isotopic ratio mass spectrometry
- gc/ms, gas chromatography/mass spectrometry
- is, internal standard
- iu, international unit
- lc/ms, liquid chromatography/mass spectrometry
- l–l, liquid–liquid
- mstfa, n-methyl-n-(trimethylsilyl)-trifluoroacetamide
- paps, 3′,5′-phosphoadenosine
- p-pi, pyrophosphate
- s, sulfate
- spe, solid phase extraction
- t/e ratio, testosterone to epitestosterone ratio
- tmcs, trimethylchlorosilane
- tmis, trimethyliodosilane
- tms, trimethylsilyating
- u, unit
- udpga, uridine diphosphoglucuronic acid
- ru, roy unit
- wada, world anti-doping agency
- conjugated steroids
- biological samples
- forensic drug testing
- deconjugation
- derivatisation
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Affiliation(s)
- Rachel L Gomes
- Department of Earth Science and Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK.
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Cawley AT, Trout GJ, Kazlauskas R, Howe CJ, George AV. Carbon isotope ratio (delta13C) values of urinary steroids for doping control in sport. Steroids 2009; 74:379-92. [PMID: 19056414 DOI: 10.1016/j.steroids.2008.11.004] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2008] [Revised: 10/19/2008] [Accepted: 11/05/2008] [Indexed: 10/21/2022]
Abstract
The detection of steroids originating from synthetic precursors in relation to their chemically identical natural analogues has proven to be a significant challenge for doping control laboratories accredited by the World Anti-Doping Agency (WADA). Endogenous steroid abuse may be confirmed by utilising the atomic specificity of gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) that enables the precise measurement of differences in stable isotope ratios that arise as a result of fractionation patterns inherent in the source of steroids. A comprehensive carbon isotope ratio (delta(13)C) profiling study (n=1262) of urinary ketosteroids is reported that demonstrates the inter-individual variation that can be expected from factors such as diet, ethnicity, gender and age within and between different populations (13 countries). This delta(13)C distribution is shown by principal component analysis (PCA) to provide a statistical comparison to delta(13)C values observed following administration of testosterone enanthate. A limited collection of steroid diol data (n=100; consisting of three countries) is also presented with comparison to delta(13)C values of excreted testosterone to validate criteria for WADA accredited laboratories to prove doping offences.
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Affiliation(s)
- Adam T Cawley
- Australian Sports Drug Testing Laboratory (ASDTL), National Measurement Institute (NMI), 1 Suakin Street, Pymble, NSW 2073, Australia
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Vissers B, Everaert J, Sekula J, Malak A, Bohets H, Bazylak G, Nagels LJ. Unique potentiometric detection systems for HPLC determination of some steroids in human urine. J Sep Sci 2009; 32:167-79. [DOI: 10.1002/jssc.200800489] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Cawley AT, Flenker U. The application of carbon isotope ratio mass spectrometry to doping control. JOURNAL OF MASS SPECTROMETRY : JMS 2008; 43:854-864. [PMID: 18523972 DOI: 10.1002/jms.1437] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The administration of synthetic steroid copies is one of the most important issues facing sports. Doping control laboratories accredited by the World Anti-Doping Agency (WADA) require methods of analysis that allow endogenous steroids to be distinguished from their synthetic analogs in urine. The ability to measure isotope distribution at natural abundance with high accuracy and precision has increased the application of Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry (GC-C-IRMS) to doping control in recent years. GC-C-IRMS is capable of measuring the carbon isotope ratio (delta(13)C) of urinary steroids and confirm their synthetic origin based on the abnormal (13)C content. This tutorial describes some of the complexities encountered by obtaining valid delta(13)C measurements from GC-C-IRMS and the need for careful interpretation of all relevant information concerning an individual's metabolism in order to make an informed decision with respect to a doping violation.
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Affiliation(s)
- Adam T Cawley
- Australian Sports Drug Testing Laboratory, National Measurement Institute, Pymble NSW 2073, Australia.
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Development and validation of a quantitative gas chromatography–mass spectrometry method for the detection of endogenous androgens in mouse urine. J Chromatogr A 2008; 1178:223-30. [DOI: 10.1016/j.chroma.2007.11.077] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2007] [Revised: 11/21/2007] [Accepted: 11/26/2007] [Indexed: 11/21/2022]
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20
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Chang MS, Ji Q, Zhang J, El-Shourbagy TA. Historical review of sample preparation for chromatographic bioanalysis: pros and cons. Drug Dev Res 2007. [DOI: 10.1002/ddr.20173] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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