Generic sample preparation and dual polarity liquid chromatography-time-of-flight mass spectrometry for high-throughput screening in doping analysis

Recent advances in mass spectrometry for the detection of doping

INTRODUCTION

The analysis of doping control samples is preferably performed by mass spectrometry, because obtained results meet the highest analytical standards and ensure an impressive degree of reliability. The advancement in mass spectrometry and all its associated technologies thus allow for continuous improvements in doping control analysis.

AREAS COVERED

Modern mass spectrometric systems have reached a status of increased sensitivity, robustness, and specificity within the last decade. The improved sensitivity in particular has, on the other hand, also led to the detection of drug residues that were attributable to scenarios where the prohibited substances were not administered consciously but rather by the unconscious ingestion of or exposure to contaminated products. These scenarios and their doubtless clarification represent a great challenge. Here, too, modern MS systems and their applications can provide good insights in the interpretation of dose-related metabolism of prohibited substances. In addition to the development of new instruments itself, software-assisted analysis of the sometimes highly complex data is playing an increasingly important role and facilitating the work of doping control laboratories.

EXPERT OPINION

The sensitive analysis and evaluation of a higher number of samples in a shorter time is made possible by the ongoing developments in mass spectrometry.

A comprehensive and high-throughput screening method for multiple prohibited substances by UPLC-QE Plus-HRMS and HPLC-QQQ-MS in human urine for doping control

Since the World Anti-Doping Agency's (WADA) Prohibited List is updated on an annual basis, screening methods must be continually adapted to align with these changes. In accordance with Technical Document-MRPL 2022, a newly combined, comprehensive, rapid and high-throughput doping control screening method has been developed for the analysis of 350 substances with different polarities in human urine using ultra-high performance liquid chromatography coupled with Q Exactive Plus Hybrid Quadrupole-Orbitrap mass spectrometer (UPLC-QE Plus-HRMS) and ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometer (UPLC-QQQ-MS). The limits of detection were in the range of 0.12-50 ng mL-1 for beta-2 agonists, hormone and metabolic modulators, narcotics, cannabinoids and glucocorticoids, 0.1-14 ng mL-1 for the manipulation of blood and blood components, beta blockers, anabolic agents and hypoxia-inducible factor (HIF) activating agents, and 2.5-100 000 ng mL-1 for substances of Appendix A, diuretics & masking agents and stimulants. The sample preparation consisted of two parts: one is the dilute & shoot part analyzed in UPLC-QQQ-MS, another is a mixture of the dilute & shoot part and a liquid-liquid extraction part of hydrolyzed human urine analyzed in UPLC-QE Plus-HRMS in full scan mode with polarity switching and parallel reaction monitoring (PRM) mode. The method has been fully validated for doping control purposes. All the substances were compliant with WADA's required 1/2 minimum requirement performance level (MRPL) or minimum reporting level (MRL), and this method was successfully used in the 2022 Beijing Winter Olympic Games and Winter Paralympic Games for anti-doping purpose.

Supramolecular solvents for making comprehensive liquid-liquid microextraction in multiclass screening methods for drugs of abuse in urine based on liquid chromatography-high resolution mass spectrometry

Multiclass screening methods involving hundreds of structurally unrelated compounds are becoming essential in many control labs and research areas. Accurate mass screening of a theoretically unlimited number of chemicals can be undertaken using liquid chromatography coupled to high resolution mass spectrometry (LCHRMS), but the lack of comprehensive sample treatments hinders this unlimited potential. In this research, the capability of supramolecular solvents (SUPRAS) for making comprehensive liquid-liquid microextraction (LLME) in multiclass screening methods based on LCHRMS was firstly explored. For this purpose, a SUPRAS made up of 1,2-hexanediol, sodium sulphate and water was synthesized directly in the urine and applied to compound extraction and interference removal in the screening of eighty prohibited substances in sports by LC-electrospray ionization-time of flight mass spectrometry. Selected substances included a wide range of polarities (log P from -2.4 to 9.2) and functionalities (e.g. alcohol, amine, amide, carboxyl, ether, ester, ketone, sulfonyl, etc.). No interfering peaks were observed for any of the 80 substances investigated. Around 84-93% of drugs were efficiently extracted (recoveries 70-120%) and 83-94% of the analytes did not show matrix effects (±20%) in the ten tested urines. Method detection limits for the drugs were in the interval 0.002-12.9 ng mL^-1, which are in accordance with the Minimum Required Performance Levels values established by the World Anti-Doping Agency. The applicability of the method was evaluated by the screening of thirty-six blinded and anonymized urine samples, previously analyzed by gas or liquid chromatography-triple quadrupole. Seven of the samples lead to an adverse analytical finding in line with the results obtained by the conventional methods. This research proves that LLME based on SUPRAS constitutes an efficient, economic, and simple sample treatment in multiclass screening methods, an application that is unaffordable for conventional organic solvents.

Performance- and image-enhancing drug use in the community: use prevalence, user demographics and the potential role of wastewater-based epidemiology

Performance- and image-enhancing drug (PIED) misuse is a significant public health issue. Currently, seizure data, surveys, anti-doping testing, and needle service provider data are used to estimate PIED use in populations. These methods are time consuming, single point-in-time measurements that often consist of small sample sizes and do not truly capture PIED prevalence. Wastewater-based epidemiology (WBE) has been used globally to assess and monitor licit and illicit drug consumption within the general community. This method can objectively cover large populations as well as specific subpopulations (gyms, music festivals, prisons), and has potential as a complementary monitoring method for PIED use. Information obtained through WBE could be used to aid public health authorities in developing targeted prevention and education programmes. Research on PIED analysis in wastewater is limited and presents a significant gap in the literature. The focus is on anabolic steroids, and one steroid alternative currently growing in popularity; selective androgenic receptor modulators. This encompasses medical uses, addiction, prevalence, user typology, and associated public health implications. An overview of WBE is described including its benefits, limitations and potential as a monitoring method for PIED use. A summary of previous work in this field is presented. Finally, we summarise gaps in the literature, future perspectives, and recommendations for monitoring PIEDs in wastewater.

A comprehensive study on the performance of different retention mechanisms in sport drug testing by liquid chromatography tandem mass spectrometry

Anti-doping substances listed by the World Anti-Doping Agency (WADA) include hundreds of compounds of very different physico-chemical properties. Anti-doping control laboratories need to screen all these substances in the so-called Initial Testing Procedures (ITPs) what is very challenging from an analytical point of view. ITPs are mostly based on reversed-phase (RP) liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) using C18 columns, which feature poor retention and peak tailing for polar and basic compounds, respectively. While studies on this field dealing with the comparison of stationary phases are focused on certain chemical classes, this research provides a wide multi-target approach. For this purpose, a representative group of 93 anti-doping agents (log P from -2.4 to 9.2) included in ten different classes of prohibited substances was selected. A comprehensive study on the performance of six columns and four eluents on different separation parameters (retention factors, asymmetry factors, co-elutions, total run times) and matrix effects (signal enhancement or suppression) was performed for LC-MS/MS-based ITPs. Columns working in both RP [C18, C8, phenyl hexyl (PH), pentafluorophenyl (PFP) and mixed-mode hydrophilic/RP (HILIC-RP)) and hydrophilic (HILIC)] modes were investigated. Eluents contained methanol or acetonitrile as organic modifiers, with or without the addition of ammonium acetate. The best column-mobile phase binomial for ITPs was PFP using water-methanol (0.1% formic acid) as eluent, while HILIC was the best option for highly polar non-aromatic anti-doping agents, which were poorly addressed by PFP. Excellent good peak shapes and relative acceptable matrix interferences were obtained for HILIC-RP, which was tested for the first time for the analysis of anti-doping agents, although the number of compounds eluting too fast was too high. On the whole, the alkyl phase C18 showed the worst performance and although C8 and PH were better, their performance did not surpass that of PFP. Possible retention mechanisms underlying separation in the different stationary phases were discussed. This research provides valuable information to anti-doping control labs for improving LC-MS/MS-based ITPs and it proposes PFP as a suitable alternative to the already established C18.

High-throughput liquid chromatography tandem mass spectrometry assay as initial testing procedure for analysis of total urinary fraction

In the recent years, a lot of effort was put into the development of multiclass initial testing procedures (ITP) to streamline analytical workflow in antidoping laboratories. Here, a high-throughput assay based on liquid chromatography-triple quadrupole mass spectrometry suitable for use as initial testing procedure covering multiple classes of compounds prohibited in sports is described. Employing a 96-well plate packed with 10 mg of weak cation exchange polymeric sorbent, up to 94 urine samples and their associated positive and negative controls can be processed in less than 3 h with minimal labor. The assay requires a 0.5-ml urine aliquot, which is subjected to enzymatic hydrolysis followed by solid phase extraction, evaporation, and reconstitution in a 96-well collection plate. With a 10-min run time, more than 100 analytes can be detected using electrospray ionization with polarity switching. The assay can be run nearly 24/7 with minimal downtime for instrument maintenance while detecting picogram amounts for the majority of analytes. Having analyzed approximately 28,000 samples, nearly 400 adverse analytical findings were found of which only one tenth were at or above 50% of the minimum required performance level established by the World Anti-Doping Agency. Compounds most often identified were stanozolol, GW1516, ostarine, LGD4033, and clomiphene, with median estimated concentrations in the range of 0.02-0.09 ng/ml (either as parent drug or a metabolite). Our data demonstrate the importance of using a highly sensitive ITP to ensure efficient antidoping testing.

Dual Polarity Ion Confinement and Mobility Separations

Here, we present simulations and describe the initial implementation of a device capable of performing simultaneous ion mobility (IM) separations of positive and negative ions based upon the structures for lossless ion manipulations (SLIM). To achieve dual polarity ion confinement, the DC fields used for lateral confinement in previous SLIM were replaced with RF fields. Concurrent ion transport and mobility separation in the SLIM device are shown possible due to the nature of the traveling wave (TW) voltage profile which has potential minima at opposite sides of the wave for each ion polarity. We explored the potential for performing simultaneous IM separations of cations and anions over the same SLIM path and the impacts on the achievable IM resolution and resolving power. Initial results suggest comparable IM performance with previous single-polarity SLIM separations can be achieved. We also used ion trajectory simulations to investigate the capability to manipulate the spatial distributions of ion populations based on their polarities by biasing the RF fields and TW potentials on each SLIM surface so as to limit the interactions between opposite polarity ions. Graphical Abstract.

Crystal structure of a host-guest complex between mephedrone hydro-chloride and a tetra-phospho-nate cavitand

A new supra-molecular complex (I) between the tetra-phospho-nate cavitand Tiiii[C3H7,CH3,C6H5] [systematic name: 2,8,14,20-tetra-propyl-5,11,17,23-tetra-methyl-6,10:12,16:18,22:24,4-tetra-kis-(phenyl-phospho-nato-O,O')resorcin[4]arene] and mephedrone hydro-choride {C11H16NO+·Cl-; systematic name: meth-yl[1-(4-methyl-phen-yl)-1-oxopropan-2-yl]aza-nium chloride} has been obtained and characterized both in solution and in the solid state. The complex of general formula (C11H16NO)@Tiiii[C3H7,CH3,C6H5]Cl·CH3OH or C11H16NO+·Cl-·C68H68O12P4·CH3OH, crystallizes in the monoclinic space group P21/c with one lattice methanol mol-ecule per cavitand, disordered over two positions with occupancy factors of 0.665 (6) and 0.335 (6). The mephedrone guest inter-acts with the P=O groups at the upper rim of the cavitand through two charge-assisted N-H⋯O hydrogen bonds, while the methyl group directly bound to the amino moiety is stabilized inside the π basic cavity via cation⋯π inter-actions. The chloride counter-anion is located between the alkyl legs of the cavitand, forming C-H⋯Cl inter-actions with the aromatic and methyl-enic H atoms of the lower rim. The chloride anion is also responsible for the formation of a supra-molecular chain along the b-axis direction through C-H⋯Cl inter-actions involving the phenyl substituent of one phospho-nate group. C-H⋯O and C-H⋯π inter-actions between the guest and adjacent cavitands contribute to the formation of the crystal structure.

Evaluation of two glucuronides resistant to enzymatic hydrolysis as markers of testosterone oral administration

Testosterone (T) has traditionally been the most commonly reported doping agent by doping control laboratories. The screening of T misuse is performed by the quantification of six endogenous androgenic steroids and the ratio T/E included in the Athlete Biological Passport (ABP). The inclusion of additional metabolites can improve the screening capabilities of ABP. In this study, the potential of 3α-glucuronide-6β-hydroxyandrosterone (6OH-Andros3G) and 3α-glucuronide-6β-hydroxyetiocholanolone (6OH-Etio3G) as markers of T oral administration was evaluated. These glucuronides have been shown to be resistant to enzymatic hydrolysis and their quantification by means of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was reported as the only way to obtain feasible results. Urine samples were collected from five volunteers before and after the oral administration of 40mg of T undecanoate and were analyzed by a LC-MS/MS method recently developed. Concentration of 6OH-Andros3G and 6OH-Etio3G compounds and those of the glucuronides of T (TG), epitestosterone (EG), androsterone and etiocholanolone were established and different concentration ratios were calculated. The detection windows (DWs) for the T administration obtained by each selected ratio were compared to the one of TG/EG. The results showed that four out of the nine tested markers presented DWs much larger for all volunteers than those obtained by the World Anti-Doping Agency established T/E marker or other alternative markers. The 6OH-Andros3G/EG, 6OH-Etio3G/EG, 6OH-Andros3G/TG and 6OH-Etio3G/TG markers were able to identify the T abuse up to 96h after the administration, extending our detection capability for the misuse up to 84h more than the classic marker. The importance of these markers was also highlighted by their prolonged capacity to detect the T misuse in the case of one volunteer whose TG/EG barely exceeded his individual threshold. As a consequence, the four markers presented in this study seem to have an exceptional potential as biomarkers of T oral administration.

Simplifying and expanding analytical capabilities for various classes of doping agents by means of direct urine injection high performance liquid chromatography high resolution/high accuracy mass spectrometry

So far, in sports drug testing compounds of different classes are processed and measured using different screening procedures. The constantly increasing number of samples in doping analysis, as well as the large number of substances with doping related, pharmacological effects require the development of even more powerful assays than those already employed in sports drug testing, indispensably with reduced sample preparation procedures. The analysis of native urine samples after direct injection provides a promising analytical approach, which thereby possesses a broad applicability to many different compounds and their metabolites, without a time-consuming sample preparation. In this study, a novel multi-target approach based on liquid chromatography and high resolution/high accuracy mass spectrometry is presented to screen for more than 200 analytes of various classes of doping agents far below the required detection limits in sports drug testing. Here, classic groups of drugs as diuretics, stimulants, β₂-agonists, narcotics and anabolic androgenic steroids as well as various newer target compounds like hypoxia-inducible factor (HIF) stabilizers, selective androgen receptor modulators (SARMs), selective estrogen receptor modulators (SERMs), plasma volume expanders and other doping related compounds, listed in the 2016 WADA prohibited list were implemented. As a main achievement, growth hormone releasing peptides could be implemented, which chemically belong to the group of small peptides (<2kDa) and are commonly determined by laborious and time-consuming stand-alone assays. The assay was fully validated for qualitative purposes considering the parameters specificity, robustness (rRT: <2%), intra- (CV: 1.7-18.4 %) and inter-day precision (CV: 2.3-18.3%) at three concentration levels, linearity (R²>0.99), limit of detection (0.1-25ng/mL; 3'OH-stanozolol glucuronide: 50pg/mL; dextran/HES: 10μg/mL) and matrix effects.

Untargeted profiling of urinary steroid metabolites after testosterone ingestion: opening new perspectives for antidoping testing

Aim: Antidoping procedures are expected to greatly benefit from untargeted metabolomic approaches through the discovery of new biomarkers of prohibited substances abuse. Results: Endogenous steroid metabolites were monitored in urine samples from a controlled elimination study of testosterone undecanoate after ingestion. A platform coupling ultra-high pressure LC with high-resolution quadrupole TOF MS was used and high between-subject metabolic variability was successfully handled using a multiblock data analysis strategy. Links between specific subsets of metabolites and influential genetic polymorphisms of the UGT2B17 enzyme were highlighted. Conclusion: This exploratory metabolomic strategy constitutes a first step toward a better understanding of the underlying patterns driving the high interindividual variability of steroid metabolism. Promising biomarkers were selected for further targeted study.

LC-QTOF-MS as a superior strategy to immunoassay for the comprehensive analysis of synthetic cannabinoids in urine

The objective of this study was to compare the performance of an immunoassay screening for synthetic cannabinoids with a newly developed confirmation method using liquid chromatography quadrupole time-of-flight mass spectrometry. The screening included metabolites from JWH-018, JWH-073, and AM-2201. The confirmation included metabolites from AM-2201, JWH-018, JWH-019, JWH-073, JWH-081, JWH-122, JWH-210, JWH-250, JWH-398, MAM-2201, RCS-4, and UR-144. The immunoassay was tested and found to have no cross-reactivity with UR-144 metabolites but considerable cross-reactivity with MAM-2201 and JWH-122 metabolites. Sensitivity and specificity for the immunoassay were evaluated with 87 authentic urine samples and found to be 87% and 82%, respectively. With a cutoff at 2 ng/ml, the confirmation showed 80 positive findings in 38 cases. The most common finding was JWH-122 5-OH-pentyl, followed by JWH-018 5-OH-pentyl. There were 9 findings of UR-144 metabolites and 3 of JWH-073 metabolites. In summary, the immunoassay performed well, presenting both high sensitivity and specificity for the synthetic cannabinoids present in the urine samples tested. The rapid exchange of one cannabinoid for another may pose problems for immunoassays as well as for confirmation methods. However, we consider time-of-flight mass spectrometry to be superior since new metabolites can be quickly included and identified.

Current status and bioanalytical challenges in the detection of unknown anabolic androgenic steroids in doping control analysis

Androgenic anabolic steroids (AAS) are prohibited in sports due to their anabolic effects. Doping control laboratories usually face the screening of AAS misuse by target methods based on MS detection. Although these methods allow for the sensitive and specific detection of targeted compounds and metabolites, the rest remain undetectable. This fact opens a door for cheaters, since different AAS can be synthesized in order to evade doping control tests. This situation was evidenced in 2003 with the discovery of the designer steroid tetrahydrogestrinone. One decade after this discovery, the detection of unknown AAS still remains one of the main analytical challenges in the doping control field. In this manuscript, the current situation in the detection of unknown AAS is reviewed. Although important steps have been made in order to minimize this analytical problem and different analytical strategies have been proposed, there are still some drawbacks related to each approach.

Screening and confirmation of 62 drugs of abuse and metabolites in urine by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry

An ultra-high-performance liquid chromatography--quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) method for the screening and confirmation of 62 drugs of abuse and their metabolites in urine was developed in this study. The most commonly abused drugs, including amphetamines, opioids, cocaine, benzodiazepines (BZDs) and barbiturates, and many other new and emerging abused drugs, were selected as the analytes for this study. Urine samples were diluted 5-fold with deionized water before analysis. Using a superficially porous micro-particulate column and an acetic acid-based mobile phase, 54 basic and 8 acidic analytes could be detected within 15 and 12 min in positive and negative ionization modes, respectively. The MS collision energies for the 62 analytes were optimized, and their respective fragmentation patterns were constructed in the in-house library for confirmatory analysis. The coefficients of variation of the intra- and inter-day precision of the analyte responses all were <17.39%. All analytes, except barbital, showed matrix effects of 77-121%. The limits of detection of the 62 analytes were between 2.8 and 187.5 ng/mL, which were lower than their respective cut-off concentrations (20-500 ng/mL). Ten urine samples from patients undergoing methadone treatment were analyzed by the developed UHPLC-QTOF-MS method, and the results were compared with the immunoassay method.

Validation of LC-TOF-MS screening for drugs, metabolites, and collateral compounds in forensic toxicology specimens

Liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) analysis provides an expansive technique for identifying many known and unknown analytes. This study developed a screening method that utilizes automated solid-phase extraction to purify a wide array of analytes involving stimulants, benzodiazepines, opiates, muscle relaxants, hypnotics, antihistamines, antidepressants and newer synthetic "Spice/K2" cannabinoids and cathinone "bath salt" designer drugs. The extract was applied to LC-TOF-MS analysis, implementing a 13 min chromatography gradient with mobile phases of ammonium formate and methanol using positive mode electrospray. Several common drugs and metabolites can share the same mass and chemical formula among unrelated compounds, but they are structurally different. In this method, the LC-TOF-MS was able to resolve many isobaric compounds by accurate mass correlation within 15 ppm mass units and a narrow retention time interval of less than 10 s of separation. Drug recovery yields varied among spiked compounds, but resulted in overall robust area counts to deliver an average match score of 86 when compared to the retention time and mass of authentic standards. In summary, this method represents a rapid, enhanced screen for blood and urine specimens in postmortem, driving under the influence, and drug facilitated sexual assault forensic toxicology casework.

Rapid screening for 67 drugs and metabolites in serum or plasma by accurate-mass LC-TOF-MS

Sixty-seven drugs and metabolites were detected in serum or plasma using a fast (7.5 min) liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) method. This method was developed as a blood drug screen, with emphasis on the detection of common drugs of abuse and drugs used to manage chronic pain. Qualitative drug detection may identify a drug exposure, assure patient adherence with prescribed therapy and document abstinence from non-prescribed medications. Compound identification is based on chromatographic retention time, mass, isotope spacing and isotope abundance. Data analysis software (Agilent) generates a compound score based on how well these observed criteria matched theoretical and empirical values. The method was validated using fortified samples and 299 residual patient specimens (920 positive results). All results were confirmed by gas chromatography-MS or LC-tandem MS. The accuracy of positive results (samples meeting all qualitative criteria for retention time, mass and compound score) was >90% for drugs and/or metabolites, except for two benzodiazepines. There were 35 false positive results (seven compounds, 3.8%) that could be distinguished by retention time and/or absence of metabolites. The most frequent was 6-acetylmorphine in the absence of morphine. The LC-TOF-MS targeted screening method presented represents a sensitive and specific technology for drug screening of serum or plasma.

Development and validation of a ultra high performance liquid chromatography-tandem mass spectrometric method for the direct detection of formoterol in human urine

Formoterol is a long acting β(2)-agonist and has proven to be a very effective bronchodilating agent. Hence it is frequently applied therapeutically for the treatment of asthma. Because β(2)-agonists might be misused in sports for the stimulatory effects and for growth-promoting action their use is restricted. Since January 2012, formoterol is prohibited in urinary concentrations higher than 30 ng/mL. The objective of this study was to develop and validate a simple and robust ultra high performance liquid chromatographic-tandem mass spectrometric (UHPLC-MS/MS) method for the direct quantification of formoterol in urine. Sample preparation was limited to an enzymatic hydrolysis step after which 2 μL was injected in the chromatographic system. Chromatography was performed on a C(8)-column using gradient conditions. The mobile phase consisted of water/methanol (H(2)O/MeOH) both containing 0.1% acetic acid (HOAc) and 1mM ammonium acetate (NH(4)OAc). Calibration curve were constructed between 15 and 60 ng/mL. Validation data showed bias of 1.3% and imprecision of 5.4% at the threshold. Ion suppression/enhancement never exceeded 7%. Calculating measurement uncertainty showed proof of applicability of the method. Stability of formoterol was also investigated at 56 °C (accelerated stability test) at pH 1.0/5.2/7.0 and 9.5. At the physiological pH values of 5.2 and 7.0, formoterol showed good stability. At pH 1.0 and 9.5 significant degradation was observed.

Impact of the emergence of designer drugs upon sports doping testing

Historically, dope-testing methods have been developed to target specific and known threats to the integrity of sport. Traditionally, the source of new analytical targets for which testing was required were derived almost exclusively from the pharmaceutical industry. More recently, the emergence of designer drugs, such as tetrahydrogestrinone that are specifically intended to evade detection, or novel chemicals intended to circumvent laws controlling the sale and distribution of recreational drugs, such as anabolic steroids, stimulants and cannabinoids, have become a significant issue. In this review, we shall consider the emergence of designer drugs and the response of dope-testing laboratories to these new threats, in particular developments in analytical methods, instrumentation and research intended to detect their abuse, and we consider the likely future impact of these approaches.

'Wrong-way-round ionization' and screening for doping substances in human urine by high-performance liquid chromatography/orbitrap mass spectrometry

To free analytical resources for new classes of doping substances, such as banned proteins, maximization of the number of compounds that can be determined with high sensitivity in a single run is highly urgent. This study demonstrates an application of 'wrong-way-round ionization' for the simultaneous detection of multiple classes of doping substances without the need to switch the polarity. A screening method for the detection of 137 compounds from various classes of prohibited substances (stimulants, diuretics, β(2)-agonists, β-blockers, antiestrogens, glucocorticosteroids and anabolic agents) has been developed. The method involves an enzymatic hydrolysis, liquid-liquid extraction and detection by liquid chromatography/orbitrap mass spectrometry with wrong-way-round ionization. Up to 64% of compounds had a 10-fold lower limit of detection (LOD) than the minimum required performance limit. To compare the efficiency of conventional ionization relative to wrong-way-round ionization of doping substances in + ESI, a fortified blank urine sample at the minimum required performance limit was analyzed using two ESI approaches. All compounds were detected with markedly better S/N in a high-pH mobile phase, with the exception of acetazolamide (minimal change in S/N, < 20%).The method was validated by spiking 10 different blank urine samples at five different concentrations. Validation parameters included the LOD, selectivity, ion suppression, extraction recovery and repeatability.

Development and validation of an open screening method for diuretics, stimulants and selected compounds in human urine by UHPLC-HRMS for doping control

A new doping control screening method for the analysis of diuretics and stimulants using ultra high pressure liquid chromatography-high resolution Orbitrap mass spectrometry has been developed. The screening was performed in full scan MS with scan-to-scan polarity switching which allowed to detect more than 120 target analytes. Sample preparation was limited to 10-fold dilution of the urine into the internal standard solution followed by injection. Total run time per sample was 10 min. Validation of the method yielded detection limits for diuretics between 25 and 250 ng mL(-1) and for stimulants between 5 and 500 ng mL(-1). The screening method has been implemented in routine doping control.

Zeranol: doping offence or mycotoxin? A case-related study

Zeranol ((7R,11S)-7,15,17-trihydroxy-11-methyl-12-oxabicyclo[12.4.0]octadeca-1(14),15,17-trien-13-one, also referred to as 7α-zearalanol, Ralone®, Frideron®, Ralgro®, etc.) is a semi-synthetic estrogenic veterinary drug with growth-promoting properties. Its use regarding animal husbandry has been prohibited in the European Union since 1981 and, due to its anabolic effects, it is further recognized as a banned substance in sport. Numerous studies were conducted concerning the identification of the illicit application of zeranol to domestic livestock. These studies also considered the natural occurrence of zeranol as a metabolite of the mycotoxin zearalenone and the issue of differentiating both scenarios, i.e. illegal use or unintended contamination. Human sports drug testing authorities are facing comparable challenges since the deliberate misuse of the (for human application non-approved) drug should be discriminated from adverse analytical findings resulting from the biotransformation of the mycotoxin zearalenone possibly ingested with contaminated food. The active drug (zeranol), its major human metabolites (zearalanone, 7β-zearalanol) and the mycotoxin (zearalenone) plus its major and unique metabolic products (α-zearalenol, β-zearalenol) have been monitored in routine doping controls by means of validated gas chromatography-(tandem) mass spectrometry (GC-(MS/)MS) methods since 1996, and between 2005 and 2010 four samples providing suspicious signals were detected. In agreement with literature data, in vitro metabolism studies demonstrated the metabolic pathway from zearalenone towards zeranol (and common metabolites). In contrast, an administration study urine sample (collected after oral application of 20 mg of zeranol) yielded only ultra-trace amounts of zearalenone and its characteristic metabolites, which supported the assumption that a mycotoxin contamination caused the finding of zeranol in the doping control specimens rather than a misuse of the anabolic agent.

Analytical aspects in doping control: challenges and perspectives

Since the first anti-doping tests in the 1960s, the analytical aspects of the testing remain challenging. The evolution of the analytical process in doping control is discussed in this paper with a particular emphasis on separation techniques, such as gas chromatography and liquid chromatography. These approaches are improving in parallel with the requirements of increasing sensitivity and selectivity for detecting prohibited substances in biological samples from athletes. Moreover, fast analyses are mandatory to deal with the growing number of doping control samples and the short response time required during particular sport events. Recent developments in mass spectrometry and the expansion of accurate mass determination has improved anti-doping strategies with the possibility of using elemental composition and isotope patterns for structural identification. These techniques must be able to distinguish equivocally between negative and suspicious samples with no false-negative or false-positive results. Therefore, high degree of reliability must be reached for the identification of major metabolites corresponding to suspected analytes. Along with current trends in pharmaceutical industry the analysis of proteins and peptides remains an important issue in doping control. Sophisticated analytical tools are still mandatory to improve their distinction from endogenous analogs. Finally, indirect approaches will be discussed in the context of anti-doping, in which recent advances are aimed to examine the biological response of a doping agent in a holistic way.

Applying in-silico retention index and mass spectra matching for identification of unknown metabolites in accurate mass GC-TOF mass spectrometry

One of the major obstacles in metabolomics is the identification of unknown metabolites. We tested constraints for reidentifying the correct structures of 29 known metabolite peaks from GCT premier accurate mass chemical ionization GC-TOF mass spectrometry data without any use of mass spectral libraries. Correct elemental formulas were retrieved within the top-3 hits for most molecular ion adducts using the "Seven Golden Rules" algorithm. An average of 514 potential structures per formula was downloaded from the PubChem chemical database and in-silico-derivatized using the ChemAxon software package. After chemical curation, Kovats retention indices (RI) were predicted for up to 747 potential structures per formula using the NIST MS group contribution algorithm and corrected for contribution of trimethylsilyl groups using the Fiehnlib RI library. When matching the range of predicted RI values against the experimentally determined peak retention, all but three incorrect formulas were excluded. For all remaining isomeric structures, accurate mass electron ionization spectra were predicted using the MassFrontier software and scored against experimental spectra. Using a mass error window of 10 ppm for fragment ions, 89% of all isomeric structures were removed and the correct structure was reported in 73% within the top-5 hits of the cases.

Fragmentation of toxicologically relevant drugs in positive-ion liquid chromatography-tandem mass spectrometry

The identification of drugs and related compounds by LC-MS-MS is an important analytical challenge in several application areas, including clinical and forensic toxicology, doping control analysis, and environmental analysis. Although target-compound based analytical strategies are most frequently applied, at some point the information content of the MS-MS spectra becomes relevant. In this article, the positive-ion MS-MS spectra of a wide variety of drugs and related substances are discussed. Starting point was an MS-MS mass spectral library of toxicologically relevant compounds, available on the internet. The positive-ion MS-MS spectra of ∼570 compounds were interpreted by chemical and therapeutic class, thus involving a wide variety of drug compound classes, such benzodiazepines, beta-blockers, angiotensin-converting enzyme inhibitors, phenothiazines, dihydropyridine calcium channel blockers, diuretics, local anesthetics, vasodilators, as well as various subclasses of anti-diabetic, antidepressant, analgesic, and antihistaminic drugs. In addition, the scientific literature was searched for available MS-MS data of these compound classes and the interpretation thereof. The results of this elaborate study are presented in this article. For each individual compound class, the emphasis is on class-specific fragmentation, as discussing fragmentation of all individual compounds would take far too much space. The recognition of class-specific fragmentation may be quite informative in determining the compound class of a specific unknown, which may further help in the identification. In addition, knowledge on (class-specific) fragmentation may further help in the optimization of the selectivity in targeted analytical approaches of compounds of one particular class.