Detection time comparison of non-hydrolysed sulphated metabolites of metenolone, mesterolone and 17α-methyltestosterone analysed by four different mass spectrometric techniques.

The frequent detection of anabolic androgenic steroids (AAS) indicates their popularity among rule-breaking athletes. The so called long-term metabolites play a crucial role in their detection, and non-hydrolysed sulphated metabolites have gained renewed interest, as research has demonstrated their extended detection time compared to the more conventional markers (e.g., for metenolone and mesterolone). Their potential has been investigated using liquid and gas chromatography-mass spectrometry (LC- and GC-MS). However, due to their complementary nature, chances are that the most promising metabolite on one technique does not necessarily exhibit the same behaviour on the other and vice versa. Therefore, a comparison was carried out where as a trial model, metenolone, mesterolone and 17α-methyltestosterone were selected and the most likely long-term sulphated metabolites identified on four mass spectrometric instruments. Additionally, using a modified sample preparation procedure, comparison between conventional and non-hydrolysed sulphated metabolites between different GC-MS instruments was also included. When focusing on each individual marker, no cases were observed where a single metabolite provided a superior detection time on all instruments. Furthermore, for each AAS, there were incidences where a metabolite provided the best detection time on one instrument but could only be detected for a shorter period or not at all on other instruments. This demonstrates that metabolite detection windows and hence their added-value as target substance are unique and dependent on the analytical technique and not only on their pharmacokinetic behaviour. Consequently, in each case, a metabolite versus instrument evaluation is needed to maximise the probabilities of detecting doping offences.

Evaluation of alternative gas chromatographic and mass spectrometric behaviour of trimethylsilyl-derivatives of non-hydrolysed sulfated anabolic steroids.

Sulfated metabolites have shown to have potential as long-term markers (LTMs) of anabolic-androgenic steroid (AAS) abuse. The compatibility of gas chromatography-mass spectrometry (GC-MS) with trimethylsilyl (TMS)-derivatives of non-hydrolysed sulfated steroids has been demonstrated, where, after derivatisation, generally, two closely eluting isomers are formed that both have the same molecular ion [M-H2 SO4 ]•+ . Sulfated reference standards are in limited commercial availability, and therefore, the current knowledge of the GC-MS behaviour of these compounds is mainly based on sulfating and analysing the available standard reference material. This procedure can unfortunately not cover all of the current known LTMs as these are often not available as pure substance. Therefore, in theory, some metabolites could be missed as they exhibit alternative behaviour. To investigate the matter, in-house sulfated reference materials that bear resemblance to known sulfated LTMs were analysed on GC-MS in their TMS-derivatised non-hydrolysed state. The (alternative) gas chromatographic and mass spectrometric behaviour was mapped, evaluated and linked to the corresponding steroid structures. Afterwards, using fraction collection, known sulfated LTMs were isolated from excretion urine to confirm the observed findings. The categories that were selected were mono-hydroxy-diones, 17-methyl-3,17-diols and 17-keto-3,16-diols as these are commonly encountered AAS conformations. The ability to predict the GC-MS behaviour of non-hydrolysed sulfated AAS metabolites is the corner stone of finding new metabolites. This knowledge is also essential, for example, for understanding AAS detection analyses, for the mass spectrometric characterization of metabolites of new designer steroids or when one needs to characterize an unknown steroid structure.

Investigation of the urinary excretion of prednisolone and metabolites after nasal administration: Relevance to doping control.

Glucocorticosteroid use in sport is restricted to non-systemic (nasal/ophtamological/dermatological/intra-articular) use. Systemic use is prohibited because of strong inflammatory suppressing effects. Prednisolone is a GC proven to be very effective in the treatment of nasal congestions and allergic rhinitis and its therapeutic use is allowed. To establish normal urinary concentration ranges for nasally administered prednisolone, an excretion study was performed with Sofrasolone® (nasal-inhaler). Six volunteers were administered a high dose (4.5 mg prednisolone in four gifts over a 9-h period). Samples were analysed using a validated LC-MS/MS method monitoring prednisolone (PRED) and the metabolites prednisone (PREDON), 20ß-dihydroprednisolone (20ßPRED) and 20α-dihydroprednisolone (20αPRED) in the total fraction (glucuroconjugated and free). Maximum concentrations were 266, 500, 350 and 140 ng/ml for PRED, PREDON, 20ßPRED and 20αPRED, respectively. These results show that the current reporting limit of 30 ng/ml in urine can be easily exceeded after therapeutic use. Hence, to avoid false-positive findings related to nasal application, this limit should be increased. To investigate the degree of glucuronidation of PRED and its metabolites also the free fraction was investigated. This shows that PREDON has the highest glucuroconjugation (50%). PRED, 20ßPRED and 20αPRED only show less than 20% conjugation.

Enabling the inclusion of non-hydrolysed sulfated long term anabolic steroid metabolites in a screening for doping substances by means of gas chromatography quadrupole time-of-flight mass spectrometry.

The World Anti-Doping Agency (WADA) publishes yearly their prohibited list, and sets a minimum required performance limit for each substance. To comply with these stringent requirements, the anti-doping laboratories have at least two complementary methods for their initial testing procedure (ITP), one using gas chromatography - mass spectrometry (GC-MS) and the other using liquid chromatography-MS (LC-MS). Anabolic androgenic steroids (AAS) have in previous years consistently been listed as the most frequently detected class of compounds. Over the last decade, evidence has emerged where a longer detection time is attained by focusing on sulfated metabolites of AAS instead of the conventional gluco-conjugated metabolites. Despite a decade of research on sulphated AAS using LC-MS, no LC-MS ITP has been developed that combines this class of compounds with the other mandatory targets. Such combination is essential for economical purposes. Recently, it was demonstrated that the direct injection of non-hydrolysed sulfates is compatible with GC-MS. Using this approach and by taking full use of the open screening capabilities of the quadrupole time of flight MS (QTOF-MS), this work describes for the first time a validated ITP that allows the detection of non-hydrolysed sulfated metabolites of AAS while, simultaneously, remaining capable of detecting a vast range of other classes of compounds, as well as the quantification of endogenous steroids, as required for an ITP compliant with the applicable WADA regulations. The method contains 263 compounds from 9 categories, including stimulants, narcotics, anabolic androgenic steroids and beta-blockers. Additionally, the advantages of the new method were illustrated by analysing excretion samples of drostanolone, mesterolone and metenolone. No negative effects were observed for the conventional markers and the detection time for mesterolone and metenolone increased by up to 150% and 144%, respectively compared to conventional markers.

Metabolism of testosterone during weight loss in men with obesity.

OBJECTIVE: Men with obesity often have low total and, with increasing adiposity, also low free testosterone (T) levels, which can partially restore during weight loss. Although this is partly explained by lower sex hormone binding globulin (SHBG) production and hypothalamic-pituitary downregulation, it is still not unravelled whether changes in androgen metabolism contribute to this phenomenon. Therefore, early changes in urinary excretion of T and its metabolites, during weight loss, in men with obesity are investigated. DESIGN: Longitudinal study. METHODS: Fourteen men with obesity (age 52(45-60)years, BMI 42.6(41.8-44.8)kg/m²) underwent gastric bypass surgery (GBS). Before surgery and 3 weeks, 6 weeks, 6 months and 1 year thereafter, 24 h urine and fasting serum samples were collected. Serum T and estradiol (E2) levels were analyzed using LC-MS/MS and urinary metabolites of T with GC-MS/MS. RESULTS: Already three weeks after GBS, serum SHBG and total T levels increased and remained increased as compared to baseline (all,p < 0.0125). Gonadotropins and (free) E2 levels were unchanged, serum E2/T ratio decreased (p < 0.0125). Total amount of urinary T increased non-significantly with mean increases of 53 % one year after GBS (p = 0.026). Urinary E2/T, estrone/T, 3α-androstanediol/T and androsterone/T ratios decreased after GBS (p < 0.0125). CONCLUSIONS: Restoration of circulating T levels during weight loss in this population is not only brought about by normalization of circulating SHBG levels, but increased production of and alterations in T metabolism also contribute. More specifically, relative decreases in aromatization and lower 5α-reductase activity might also be involved in restoring T levels in men with obesity.

Searching for new long-term urinary metabolites of metenolone and drostanolone using gas chromatography-mass spectrometry with a focus on non-hydrolysed sulfates.

Sulfated metabolites have been shown to have potential as long-term markers of anabolic-androgenic steroid (AAS) abuse. In 2019, the compatibility of gas chromatography-mass spectrometry (GC-MS) with non-hydrolysed sulfated steroids was demonstrated, and this approach allowed the incorporation of these compounds in a broad GC-MS initial testing procedure at a later stage. However, research is needed to identify which are beneficial. In this study, a search for new long-term metabolites of two popular AAS, metenolone and drostanolone, was undertaken through two excretion studies each. The excretion samples were analysed using GC-chemical ionization-triple quadrupole MS (GC-CI-MS/MS) after the application of three separate sample preparation methodologies (i.e. hydrolysis with Escherichia coli-derived ß-glucuronidase, Helix pomatia-derived ß-glucuronidase/arylsulfatase and non-hydrolysed sulfated steroids). For metenolone, a non-hydrolysed sulfated metabolite, 1ß-methyl-5α-androstan-17-one-3ζ-sulfate, was documented for the first time to provide the longest detection time of up to 17 days. This metabolite increased the detection time by nearly a factor of 2 in comparison with the currently monitored markers for metenolone in a routine doping control initial testing procedure. In the second excretion study, it prolonged the detection window by 25%. In the case of drostanolone, the non-hydrolysed sulfated metabolite with the longest detection time was the sulfated analogue of the main drostanolone metabolite (3α-hydroxy-2α-methyl-5α-androstan-17-one) with a detection time of up to 24 days. However, the currently monitored main drostanolone metabolite in routine doping control, after hydrolysis of the glucuronide with E.coli, remained superior in detection time (i.e. up to 29 days).

Validation of an ultra-sensitive detection method for steroid esters in plasma for doping analysis using positive chemical ionization GC-MS/MS.

The standard approach to detect misuse with testosterone in sport is based on the determination and evaluation of the urinary steroid profile followed by the confirmation of atypical profiles using isotope ratio mass spectrometry. The detection capacity of these methods can be attenuated by confounding factors or testosterone preparations with endogenous isotopic fingerprints. An alternative detection method for misuse of an endogenous steroid in sports is the direct detection of the administered steroid ester present in most preparations. Thus unambiguous proof for doping misuse can be delivered. In this work, the sensitivity of gas chromatography coupled to a triple quadrupole with chemical ionization (GC-CI-MS/MS) is applied to detect trace levels of 10 testosterone and 2 nandrolone esters in plasma for in human doping analysis. The detection method was developed employing a liquid-liquid extraction and HPLC cleanup step before analysis on the GC-CI-MS/MS. The quantitative method was validated in a linear range of 100-2000 pg/ml and proved to be selective, reproducible and very sensitive with limits of detection as low as to 10 pg/ml. A clinical study with the administration of testosterone undecanoate in 3 volunteers was carried out and the compound was detectable up to 86 days after administration.

Gas chromatography-mass spectrometry analysis of non-hydrolyzed sulfated steroids by degradation product formation.

Steroid detection and identification remain key issues in toxicology, drug testing, medical diagnostics, food safety control, and doping control. In this study, we evaluate the capabilities and usefulness of analyzing non-hydrolyzed sulfated steroids with gas chromatography-mass spectrometry (GC-MS) instead of the conventionally applied liquid chromatography-mass spectrometry (LC-MS) approach. Sulfates of 31 steroids were synthesized and their MS and chromatographic behavior studied by chemical ionization-GC-triple quadrupole MS (CI-GC-TQMS) and low energy-electron ionization-GC-quadrupole time-of-flight-MS (LE-EI-GC-QTOF-MS). The collected data shows that the sulfate group is cleaved off in the injection port of the GC-MS, forming two isomers. In CI, the dominant species (ie, [MH - H2 SO4 ]+ or [MH - H4 S2 O8 ]+ for bis-sulfates) is very abundant due to the limited amount of fragmentation, making it an ideal precursor ion for MS/MS. In LE-EI, [M - H2 SO4 ].+ and/or [M - H2 SO4 - CH3 ].+ are the dominant species in most cases. Based on the common GC-MS behavior of non-hydrolyzed sulfated steroids, two applications were evaluated and compared with the conventionally applied LC-MS approach; (a) discovery of (new) sulfated steroid metabolites of mesterolone and (b) expanding anabolic androgenic steroid abuse detection windows. GC-MS and LC-MS analysis of non-hydrolyzed sulfated steroids offered comparable sensitivities, superseding these of GC-MS after hydrolysis. For non-hydrolyzed sulfated steroids, GC-MS offers a higher structural elucidating power and a more straightforward inclusion in screening methods than LC-MS.

Development and validation of an open screening method for doping substances in urine by gas chromatography quadrupole time-of-flight mass spectrometry.

In anti-doping, a high number of classes of substances are prohibited and laboratories need to detect these at low urinary concentrations. Traditionally, testing is done using complimentary liquid chromatography mass spectrometry and gas chromatography mass spectrometry. High resolution mass spectrometric acquisition has some important advantages over triple quadrupole instruments (e.g., open screening due to full scan high resolution data acquisition with retrospectivity, compatibility with libraries and a straightforward and effortless addition and validation of new compounds in the future). Doping samples can be stored for 10 years and retrospective data analysis can be used to re-evaluate previously acquired data (e.g., searching for prohibited (designer) substances that were unknown at the initial moment of analysis). During the past decade, these advantages have led to the wide-scale transfer of liquid chromatography triple quadrupole mass spectrometry screening to liquid chromatography high resolution mass spectrometry screening for doping control purposes. Up to now, for gas chromatography a similar switch to high resolution screening has not yet occurred, because so far no method has been developed that combines sufficient sensitivity with wide-scale drug detection. In this work, the current gas chromatography triple quadrupole mass spectrometry screening method for human doping control purposes was successfully converted into an equivalent and complete gas chromatography high resolution acquisition screening method. This new screening method on a gas chromatography quadrupole time-of-flight mass spectrometer has been developed and validated. The method is compliant with the World Anti-Doping Agency requirements and allows the detection of 294 target compounds (and 14 internal standards), including diuretics, stimulants, narcotics, beta-2-agonists, beta-blockers, hormone modulators, anabolic agents and the quantification of 14 endogenous steroids in a single fast run (14.1 min).

Potential of saliva steroid profiling for the detection of endogenous steroid abuse: Reference thresholds for oral fluid steroid concentrations and ratios.

Urine and blood samples are the primary matrices for the detection of exogenous substances in doping control and toxicology. Although these matrices are, in general, very suitable for a wide range of substances, they do show some issues in particular cases. Here, alternative matrices may provide an answer. In this work, a quantitative method for steroid profiling (5 endogenous steroids and their ratios) in oral fluid was developed and validated. In total, 826 saliva samples were analyzed, and inter-individual reference population thresholds for saliva steroid profile parameters were set up. Alterations of this steroid profile after administration of naturally occurring anabolic androgenic steroids (e.g. testosterone (T) or dehydroepiandrosterone (DHEA)) were investigated. In addition, intra-individual short and long-term natural fluctuations were investigated. For longitudinal monitoring in oral fluid, steroid profile ratios (e.g., T/DHEA) were superior to absolute concentrations due to lower susceptibility towards the diurnal pattern. For the detection of a transdermal application of T, the salivary parameter T/DHEA proved to have the highest sensitivity. In contrast with the current screening procedures in urine, there is no need for an additional expensive and time-consuming isotope ratio mass spectrometry confirmation procedure to unequivocally attribute the elevated parameter to an exogenous origin.

Identification and characterization of novel long-term metabolites of oxymesterone and mesterolone in human urine by application of selected reaction monitoring GC-CI-MS/MS.

The search for metabolites with longer detection times remains an important task in, for example, toxicology and doping control. The impact of these long-term metabolites is highlighted by the high number of positive cases after reanalysis of samples that were stored for several years, e.g. samples of previous Olympic Games. A substantial number of previously alleged negative samples have now been declared positive due to the detection of various long-term steroid metabolites the existence of which was unknown during the Olympic Games of 2008 and 2012. In this work, the metabolism of oxymesterone and mesterolone, two anabolic androgenic steroids (AAS), was investigated by application of a selected reaction monitoring gas chromatography-chemical ionization-triple quadrupole mass spectrometry (GC-CI-MS/MS) protocol for metabolite detection and identification. Correlations between AAS structure and GC-CI-MS/MS fragmentation behaviour enabled the search for previously unknown but expected AAS metabolites by selection of theoretical transitions for expected metabolites. Use of different hydrolysis protocols allowed for evaluation of the detection window of both phase I and phase II metabolites. For oxymesterone, a new metabolite, 18-nor-17ß-hydroxymethyl-17α-methyl-4-hydroxy-androst-4,13-diene-3-one, was identified. It was detectable up to 46 days by using GC-CI-MS/MS, whereas with a traditional screening (detection of metabolite 17-epioxymesterone with electron ionization GC-MS/MS) oxymesterone administration was only detectable for 3.5 days. A new metabolite was also found for mesterolone. It was identified as 1α-methyl-5α-androstan-3,6,16-triol-17-one and its sulfate form after hydrolysis with Helix pomatia resulted in a prolonged detection time (up to 15 days) for mesterolone abuse. Copyright © 2017 John Wiley & Sons, Ltd.

Doping control container for urine stabilization: a pilot study.

Urine collection containers used in the doping control collection procedure do not provide a protective environment for urine, against degradation by microorganisms and proteolytic enzymes. An in-house chemical stabilization mixture was developed to tackle urine degradation problems encountered in human sport samples, in cases of microbial contamination or proteolytic activity. The mixture consists of antimicrobial substances and protease inhibitors for the simultaneous inactivation of a wide range of proteolytic enzymes. It has already been tested in lab-scale, as part of World Anti-Doping Agency's (WADA) funded research project, in terms of efficiency against microbial and proteolytic activity. The present work, funded also by WADA, is a follow-up study on the improvement of chemical stabilization mixture composition, application mode and limitation of interferences, using pilot urine collection containers, spray-coated in their internal surface with the chemical stabilization mixture. Urine in plastic stabilized collection containers have been gone through various incubation cycles to test for stabilization efficiency and analytical matrix interferences by three WADA accredited Laboratories (Athens, Ghent, and Rome). The spray-coated chemical stabilization mixture was tested against microorganism elimination and steroid glucuronide degradation, as well as enzymatic breakdown of proteins, such as intact hCG, recombinant erythropoietin and small peptides (GHRPs, ipamorelin), induced by proteolytic enzymes. Potential analytical interferences, observed in the presence of spray-coated chemical stabilization mixture, were recorded using routine screening procedures. The results of the current study support the application of the spray-coated plastic urine container, in the doping control collection procedure. Copyright © 2016 John Wiley & Sons, Ltd.

Efficient approach for the detection and identification of new androgenic metabolites by applying SRM GC-CI-MS/MS: a methandienone case study.

Identification of anabolic androgenic steroids (AAS) is a vital issue in doping control and toxicology, and searching for metabolites with longer detection times remains an important task. Recently, a gas chromatography chemical ionization triple quadrupole mass spectrometry (GC-CI-MS/MS) method was introduced, and CI, in comparison with electron ionization (EI), proved to be capable of increasing the sensitivity significantly. In addition, correlations between AAS structure and fragmentation behavior could be revealed. This enables the search for previously unknown but expected metabolites by selection of their predicted transitions. The combination of both factors allows the setup of an efficient approach to search for new metabolites. The approach uses selected reaction monitoring which is inherently more sensitive than full scan or precursor ion scan. Additionally, structural information obtained from the structure specific CI fragmentation pattern facilitates metabolite identification. The procedure was demonstrated by a methandienone case study. Its metabolites have been studied extensively in the past, and this allowed an adequate evaluation of the efficiency of the approach. Thirty three metabolites were detected, including all relevant previously discovered metabolites. In our study, the previously reported long-term metabolite (18-nor-17ß-hydroxymethyl,17α-methyl-androst-1,4,13-trien-3-one) could be detected up to 26 days by using GC-CI-MS/MS. The study proves the validity of the approach to search for metabolites of new synthetic AAS and new long-term metabolites of less studied AAS and illustrates the increase in sensitivity by using CI. Copyright © 2016 John Wiley & Sons, Ltd.

Gas chromatography/chemical ionization triple quadrupole mass spectrometry analysis of anabolic steroids: ionization and collision-induced dissociation behavior.

RATIONALE: The detection of new anabolic steroid metabolites and new designer steroids is a challenging task in doping analysis. Switching from electron ionization gas chromatography triple quadrupole mass spectrometry (GC/EI-MS/MS) to chemical ionization (CI) has proven to be an efficient way to increase the sensitivity of GC/MS/MS analyses and facilitate the detection of anabolic steroids. CI also extends the possibilities of GC/MS/MS analyses as the molecular ion is retained in its protonated form due to the softer ionization. In EI it can be difficult to find previously unknown but expected metabolites due to the low abundance or absence of the molecular ion and the extensive (and to a large extent unpredictable) fragmentation. The main aim of this work was to study the CI and collision-induced dissociation (CID) behavior of a large number of anabolic androgenic steroids (AAS) as their trimethylsilyl derivatives in order to determine correlations between structures and CID fragmentation. Clarification of these correlations is needed for the elucidation of structures of unknown steroids and new metabolites. METHODS: The ionization and CID behavior of 65 AAS have been studied using GC/CI-MS/MS with ammonia as the reagent gas. Glucuronidated AAS reference standards were first hydrolyzed to obtain their free forms. Afterwards, all the standards were derivatized to their trimethylsilyl forms. Full scan and product ion scan analyses were used to examine the ionization and CID behavior. RESULTS: Full scan and product ion scan analyses revealed clear correlations between AAS structure and the obtained mass spectra. These correlations were confirmed by analysis of multiple hydroxylated, methylated, chlorinated and deuterated analogs. CONCLUSIONS: AAS have been divided into three groups according to their ionization behavior and into seven groups according to their CID behavior. Correlations between fragmentation and structure were revealed and fragmentation pathways were postulated.

Improved sensitivity by use of gas chromatography-positive chemical ionization triple quadrupole mass spectrometry for the analysis of drug related substances.

In 2013, the World Anti-Doping Agency (WADA) drastically lowered the minimum required performance levels (MRPLs) of most doping substances, demanding a substantial increase in sensitivity of the existing methods. For a number of compounds, conventional electron impact ionization gas chromatography tandem mass spectrometry (GC-EI-MS/MS) is often no longer sufficient to reach these MRPLs and new strategies are required. In this study, the capabilities of positive ion chemical ionization (PICI) GC-MS/MS are investigated for a wide range of drug related compounds of various classes by injection of silylated reference standards. Ammonia as PICI reagent gas had superior characteristics for GC-MS/MS purposes than methane. Compared to GC-EI-MS/MS, PICI (with ammonia as reagent gas) provided more selective ion transitions and consequently, increased sensitivity by an average factor of 50. The maximum increase (by factor of 500-1000) was observed in the analysis of stimulants, namely chlorprenaline, furfenorex and phentermine. In total, improved sensitivity was obtained for 113 out of 120 compounds. A new GC-PICI-MS/MS method has been developed and evaluated for the detection of a wide variety of exogenous doping substances and the quantification of endogenous steroids in urine in compliance with the required MRPLs established by WADA in 2013. The method consists of a hydrolysis and extraction step, followed by derivatization and subsequent 1µL pulsed splitless injection on GC-PICI-MS/MS (16min run). The increased sensitivity allows the set up of a balanced screening method that meets the requirements for both quantitative and qualitative compounds: sufficient capacity and resolution in combination with high sensitivity and short analysis time. This resulted in calibration curves with a wide linear range (e.g., 48-9600ng/mL for androsterone and etiochanolone; all r(2)>0.99) without compromising the requirements for the qualitative compounds.

Studies on the minor metabolite 6a-hydroxy-androstenedione for doping control purposes and its contribution to the steroid profile.

Recent publications have shown that the concentrations of minor metabolites such as formestane and 6a-hydroxy-androstenedione (6aOHADION) are import parameters, capable of increasing the specificity and efficiency of steroid abuse screening. The importance of such minor metabolites has been recognized for some time, but setting up concentration thresholds is not that straightforward with a single quadrupole gas chromatograph mass spectrometer (GC-MS) because of the low concentrations; this is especially the case for 6aOH-ADION. The main aim of this study was to propose a concentration threshold above which the detected 6aOH-ADION is considered suspicious and isotope ratio mass spectrometry (IRMS) is recommended. Routine doping control samples (2128) from athletes that entered our lab and were not found suspicious for the intake of any doping substance were used to determine the baseline concentrations of 6a-OH-ADION. For this purpose, the more sensitive gas chromatography-tandem mass spectrometry (GC-MS/MS) was used, capable of quantifying these low concentrations with high reliability. A urinary concentration threshold of 5 ng/mL was set. Concentrations above this threshold are considered suspicious and are forwarded to IRMS for confirmation in routine practice. In addition, an IRMS method was developed, capable of determining the 13C value of 6aOH-ADION. If a urine sample has an elevated 6aOH-ADION concentration and normal 13C values for the traditional IRMS target compounds, we are still able to check the 13C value of 6aOH-ADION. Six excretion studies were executed to stress the applicability of the threshold by visualizing the concentration and δ13C value time profiles of 6aOH-ADION.

Profiling of urinary formestane and confirmation by isotope ratio mass spectrometry.

Formestane (F, androst-4-en-4-ol-3,17-dione) is an irreversible aromatase inhibitor with the ability to suppress the estrogen production from anabolic steroids. Consequently, F is mentioned on the World Anti-Doping Agency (WADA) prohibited list and because studies have shown that F is produced endogenously in small amounts, a threshold for urinary excreted F of 150 ng/mL was introduced. Lower concentrations could be due to endogenous production and need further investigation to prove the exact origin through determination of the carbon isotope ratio. However, because the current screening methods are a lot more sensitive, F is detected in practically every urine sample. A strict implementation of this WADA rule would imply that almost every urine sample needs additional investigation to verify an exogenous or endogenous origin. The main aim of this study was to propose and introduce a lower concentration limit of 25 ng/mL beneath which the detected F is considered as being endogenous and no further investigation is needed. The data presented in this paper suggests that this threshold provides a good balance between a sufficiently large detection window and not having to perform isotope ratio mass spectrometry (IRMS) analyses on negative urine samples.

Development of a sensitive GC-C-IRMS method for the analysis of androgens.

The administration of anabolic steroids is one of the most important issues in doping control and is detectable through a change in the carbon isotopic composition of testosterone and/or its metabolites. Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS), however, remains a very laborious and expensive technique and substantial amounts of urine are needed to meet the sensitivity requirements of the IRMS. This can be problematic because only a limited amount of urine is available for anti-doping analysis on a broad spectrum of substances. In this work we introduce a new type of injection that increases the sensitivity of GC-C-IRMS by a factor of 13 and reduces the limit of detection, simply by using solvent vent injections instead of splitless injection. This drastically reduces the amount of urine required. On top of that, by only changing the injection technique, the detection parameters of the IRMS are not affected and there is no loss in linearity.

Fast quantification of 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCA) using microwave-accelerated derivatisation and gas chromatography-triple quadrupole mass spectrometry.

A rapid and sensitive determination of cannabinoids in urine is important in many fields, from workplace drug testing over toxicology to the fight against doping. The detection of cannabis abuse is normally based on the quantification of the most important metabolite 11-nor-Δ9-tetrahydrocannabinol-9-carboxylic acid (THCA) in urine. In most fields THCA needs to be present at a concentration of exceeding 15ng/mL before a positive result can be reported. The method described in this paper, combines a 4min GC-MS/MS method with a fast sample preparation procedure using microwave assisted derivatisation in order to complete the quantification of THCA in urine in 30min, using only 1mL of urine. The method is selective, linear over the range 5-100ng/mL and shows excellent precision and trueness and hence, the estimated measurement uncertainty at the threshold level is small. The method also complies with applicable criteria for mass spectrometry and chromatography. Therefore the method can be used for rapid screening and confirmatory purposes.

Development of a GC/C/IRMS method--confirmation of a novel steroid profiling approach in doping control.

In doping control, an athlete can only be convicted with the misuse with endogenous steroids like testosterone (T), if abnormal values of steroid metabolites and steroid ratios are observed and if the subsequent analysis with isotope ratios mass spectrometry (IRMS) confirms the presence of exogenously administered androgens. In this work, we compare the results of a novel steroid profiling approach with the performance an in-house developed IRMS method. The developed IRMS has the advantage over other methods to be relatively short in time and with target compounds androsterone, etiocholanolone, 5ß-androstane 3α,17ß-diol and 5α-androstane 3α,17ß-diol. Pregnanediol was used as an endogenous reference compound (ERC). Reference limits for the IRMS values were established and applied as decision limits for the evaluation of excretion urine from administration with oral T, T-gel, dihydrotestosterone (DHT) - gel and dehydroepiandrosterone (DHEA). Results indicated the importance of both androstanediols as important IRMS markers where relative values compared to an ERC (Δδ(13)C) yielded better detection accuracy than absolute δ(13)C-values. The detection times of all administered endogenous steroids were evaluated using the proposed thresholds. The results of traditional steroid profiling and a new approach based upon minor steroid metabolites monitoring introduced in a longitudinal framework were evaluated with IRMS. With traditional steroid profiling methods, 95% of the atypical samples could be confirmed whereas an additional 74% of IRMS confirmed was provided by a new biomarkers strategy. These results prove that the other steroid profiling strategies can improve the efficiency in detection of misuse with endogenous steroids.