Recently, methods for detecting small peptides in dried blood spots have been published. These procedures typically involve multiple sample preparation steps, resulting in labor-intensive and costly workflows. In the present study, we report a fast, streamlined, and harmonized analytical workflow to detect 54 prohibited peptidic and non-peptidic compounds in dried blood spots, serum, and plasma. Sample preparation is based on a single microextraction step using 500 µL of a methanol/water (8 : 2, v/v) mixture. Detection was performed using liquid chromatography coupled with high-resolution mass spectrometry. The validation results showed satisfactory performance with respect to selectivity (no interferences were detected at the retention times of the analytes), detection limits (0.05-1.25 ng mL-1), carry-over (no signals in the negative sample injected after the positive sample), matrix effect (5-33%), extraction yield (15-80%), and extract stability (the target analytes were stable for at least 72 h in the autosampler at 10 °C). The method was successfully applied to samples containing sub-ng levels of ibutamoren, confirming that the analytical procedure presented in this study is fit for purpose within the doping-control framework. Stability studies showed that all compounds were stable (variation lower than 15%) for at least two months at -20 °C in all the blood matrices considered. At 4 and 22 °C, alexamorelin, AOD9604, buserelin, hGH 176-191, kisspeptin-10 and LHRH were extensively degraded after one week in serum and plasma, whereas BPC-157, TB500, vasopressin, lypressin, and terlipressin showed complete degradation only in serum. In contrast, in dried matrices all compounds remained detectable throughout the entire duration of the study, indicating that samples can be transported and stored under non-refrigerated conditions, thereby reducing costs.

A simple and sensitive microextraction protocol based on the use of unmodified cellulose was developed for the simultaneous extraction of 107 prohibited compounds and their metabolites from 20 µL of serum and plasma. Sample preparation consisted of spotting 20 µL of serum/plasma onto a cellulose card, followed by extraction of the analytes with 500 µL of a methanol/acetonitrile (1 : 1, v/v) mixture for 20 min. The extracts were analyzed by liquid chromatography coupled to high-resolution mass spectrometry. The entire workflow was validated in terms of selectivity (no interferences were detected at the retention times of the target analytes), sensitivity (limits of detection in the range of 0.08-7.50 ng mL-1) carry-over (no signals in the negative sample injected after the positive sample at high concentration), matrix effect (10-28%), extraction yield (42-89%), and extract stability (the analytes were stable for at least 72 h in the autosampler at 10 °C). The method was successfully applied to the analysis of samples containing the compounds at low nanogram per milliliter range, demonstrating its effectiveness for doping control purposes. Stability studies showed that the compounds were stable for at least 3 months at -20 and 4 °C in serum and plasma samples. In contrast, at 22 °C several thiazide-based compounds were completely degraded after 4 weeks; FG2216 was no longer detectable after 7 weeks; S6 and RAD140 were no longer detectable after 9 weeks, whereas trenbolone was completely degraded after 14 weeks. The other compounds were still visible for the entire study period, with variations in the range of 37-56%.

Salmeterol is a commonly used β2-agonist included on the List of Prohibited Substances and Methods published by the World Anti-Doping Agency (WADA). We developed a population pharmacokinetic (popPK) model to describe the PK of salmeterol including its major metabolite, α-hydroxysalmeterol, in plasma and urine after inhalation. The model was used to evaluate the ability of the current minimum reporting level (MRL) of 10 ng/mL for salmeterol to discriminate between permitted and prohibited use of salmeterol. Six studies on healthy participants, chronic asthmatics, or athletes were pooled and provided a total of 1175 concentrations (275 and 398 for salmeterol and 185 and 317 for α-hydroxysalmeterol in plasma and urine, respectively) from 92 individuals. A two-compartment model assuming intravenous-like bolus absorption best depicted plasma salmeterol PK, with a complete parent conversion into α-hydroxysalmeterol. Because urine volumes were only recorded in two studies, a separate urine compartment was defined to approximate physiologic micturition. Athletes had a 63% higher salmeterol plasma clearance and a 191% greater salmeterol urinary rate constant compared to other subjects, resulting in significantly higher salmeterol urine concentrations. Our popPK model suggests that salmeterol concentrations in urine at therapeutic doses (100 μg twice daily) are unlikely to be reported using the current MRL. However, to improve its sensitivity to detect cases of doping, an adjustment in the MRL and/or a different analytical target would be recommended.

Kisspeptin‐10 is a peptide hormone capable of increasing circulating follicle‐stimulating hormone, luteinizing hormone and testosterone levels in humans. Clinically, these effects suggest its use as a treatment for infertility. However, its testosterone‐increasing effect indicates potential misuse in sports. As such, it is included in the 2024 World Anti‐Doping Agency Prohibited List. This work describes the successful validation of an initial testing procedure (screening) and a confirmation procedure for kisspeptin‐10 in urine using liquid chromatography–mass spectrometry. Additionally, kisspeptin‐10 was incubated in human serum to mimic endogenous metabolism to improve method sensitivity, as previous research had demonstrated a rapid elimination time of only 30 min after injection (in rats). Four metabolites, corresponding to peptide fragments y9, y8, y7 and y5, were found and added to the ITP in full scan mode. A degradation product discovered during early experimentation was found to probably be caused by oxidation of the tryptophan residue into a kynurenine residue. Further research should elucidate the kinetic parameters of the reaction to improve product stability. Using the validated confirmation procedure, a black‐market vial of kisspeptin‐10 was analysed. The product contained no unexpected impurities, although it appeared to have undergone more degradation than the purchased reference standard.

This work presents an ultrafiltration-based, validated method for the screening and confirmation of prohibited growth hormone-releasing hormone (GHRH) analogues (sermorelin/CJC-1293, sermorelin metabolite, CJC-1295 and tesamorelin) in urine by nanoLC-HRMS/MS. Sample preparation avoids the use of laborious antibody-based extraction approaches and consists solely of preconcentration by ultrafiltration. Even in the absence of immunoaffinity purification steps, high sensitivity was still ensured as limits of detection between 5 and 25 pg/mL and limits of identification between 25 and 50 pg/mL were established. The robustness of the miniaturized chromatographic setup was evaluated through the injection of 200 + preconcentrated urinary extracts. In a comparison with immuno-affinity purification, enhanced recoveries (59 - 115%) and similar sensitivity were achieved, yet at lower operational costs. Stability experiments showed the importance of the proper handling of urine samples to avoid degradation of these peptide hormones, especially for sermorelin and its metabolite which were found to rapidly degrade at temperatures > 4 C and pH values < 7 in accordance with earlier studies. Without the need for specific antibodies, this method may be expanded to cover emerging peptide drugs (>= similar to 3 kDa), as well as their metabolites in the future to facilitate coverage for this class of prohibited substances.

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

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), 20β-dihydroprednisolone (20βPRED) and 20α-dihydroprednisolone (20αPRED) in the total fraction (glucuroconjugated and free). Maximum concentrations were 266, 500, 350 and 140 ng/ml for PRED, PREDON, 20βPRED 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, 20βPRED and 20αPRED only show less than 20% conjugation.

Nano-liquid chromatography (nanoLC) has proven itself as a powerful tool and its scope entails various applications in (bio)analytical fields. Operation at low (nL/min) flow rates in combination with reduced inner dimensions (ID < 100 mu m), leads to significantly enhanced sensitivity when coupled with electrospray ionizationmass spectrometry (ESI-MS). Challenges that remain for the routine implementation of such miniaturized setups are related to clogging of the system and robustness in general, and thus the application of tedious sample preparation steps. To improve ruggedness, a filter placed upstream in the LC prevents particles from entering and clogging the system. This so-called online automatic filtration and filter back-flush (AFFL) system was combined with nanoLC and the direct injection principle for the sensitive confirmatory analysis of fifty different dopingrelevant peptides in urine. The presented assay was fully validated for routine purposes according to selectivity and matrix interference, limit of identification (LOI), carryover, matrix effect, sample extract stability, analysis of educational external quality assessment (EQAS) samples, robustness of the online AFFL-setup and retention time stability. It was also fully compliant with the most recent minimum required performance levels (MRPL) and chromatographic/mass spectrometric identification criteria (IDCR), as imposed by the World Anti-Doping Agency (WADA). In the absence of labor-intensive sample preparation, the application of AFFL allowed for the injection of diluted urine samples without any noticeable pressure buildup in the nanoLC system. Contrary to earlier observations by our group and others, the addition of dimethylsulfoxide (DMSO) to the mobile phase did not enhance sensitivity in the presented nanoflow setup, yet was beneficial to reduce carry over. Although the robustness of the presented setup was evaluated only for the analysis of diluted urine samples, it is entirely conceivable that routine applications employing other matrices and currently running on analytical scale LC instruments could be transferred to micro/nanoLC scale systems to reach lower detection limits.

Small peptides are handled in the field of sports drug testing analysis as a separate group doping substances. It is a diverse group, which includes but is not limited to growth hormone releasing-factors and gonadotropin-releasing hormone analogues. Significant progress has been achieved during the past decade in the doping control analysis of these peptides. In this article, achievements in the application of liquid chromatography-mass spectrometry-based methodologies are reviewed. To meet the augmenting demands for analyzing an increasing number of samples for the presence of an increasing number of prohibited small peptides, testing methods have been drastically simplified, whilst their performance level remained constant. High-resolution mass spectrometers have been installed in routine laboratories and became the preferred detection technique. The discovery and implementation of metabolites/catabolites in testing methods led to extended detection windows of some peptides, thus, contributed to more efficient testing in the anti-doping community.

A challenge for the photodegradation of (organic) micro-pollutants in waste water treatment is the mechanistic and kinetic understanding beyond the degradation of the initial (parent) harmful product, e.g. the phenylurea herbicide isoproturon (IPU). By combining liquid chromatography-mass spectrometry and kinetic Monte Carlo modeling, we demonstrate that upon optimizing the dip-coating conditions (0.34 mol L (-1) TiO2 solution at a coating speed of 160 mm min( -1)) for the functionalization of a superhydrophilic electrospun silica nanofibrous membrane (i) hydroxylation is a dominant reaction pathway and (ii) once IPU reacts on the surface of the TiO(2 )nanoparticles, further hydroxylation occurs sufficiently fast, with complete IPU removal under the detection limit (5-10 mg Lsolution(-1)) as a result of UV irradiation within 8 h. As hydroxylation is dominant, degradation intermediates with a higher water solubility are formed and therefore a decreased toxicity is obtained upon reintroducing the treated solution into the environment. This is confirmed by respirometry, with an increase in the oxygen uptake rate of an activated sludge from 5.9 mg O(2 )g(activated) ( -1)(sludge) h (-1 )for an untreated 10 mg L-1 IPU solution to 8.2 mg O-2 g(activated sludge) (-1) h( -1) for a solution irradiated for 8 h, in line with a blank solution.

Quantification of IGF-I is relevant in both doping control as a biomarker of growth hormone (GH) misuse in sports, and in the clinical field for longitudinal follow-up of patients with disorders related to the GH axis. Currently, better standardization of IGF-I measurements using mass spectrometry is in our best interest as it would enable long-term monitoring of an athletes' IGF-I levels by its addition to the Athlete Biological Passport (ABP). Here, a simplified and rapid top-down LC-HRMS method for quantification of IGF-I in human serum is presented. A ten-minute precipitation-based offline sample preparation is combined with online sample clean-up and separation on a conventional LC, resulting in a total runtime of nine minutes in between injections. The method was validated in the relevant range of 50-1000 ng/mL for the following parameters: linearity, precision, bias, Limit Of Quantification (LOQ), carry-over, selectivity, recovery and ion suppression. As proof of concept, the presented LC-HRMS assay was compared with results from a previous inter-laboratory study on intact IGF-I quantification using four human GH administration samples. It was additionally compared with the IDS-iSYS immunoassay using 47 athlete serum samples, showing good overall agreement with a slight positive bias of 24.2 ng/mL for the LC-HRMS assay at a mean sample concentration of 234 ng/mL. Also, a discrepancy between commercially available IGF-I reference material for the calibration of quantitative assays is discussed. This is of importance if LC-MS assays for IGF-I are to be harmonized.

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.

Currently, quantification of IGF-I is relevant to doping control as a biomarker of growth hormone (GH) abuse, but also to the clinical field for longitudinal follow-up of patients with disorders related to the GH axis. In the past years, top-down liquid-chromatography coupled with high-resolution mass spectrometry (LC-HRMS) has gained popularity. Mainly because it is more straightforward than the bottom-up approach, which requires a trypsin digestion step. Hereby, a simple, validated top-down LC-HRMS method for rapid quantification of IGF-I in human serum is presented. The assay requires minimal sample preparation in combination with a short instrumental analysis and its performance is additionally compared with the IDS-iSYS immunoassay.

Human insulin and its synthetic analogs are considered as life-saving drugs for people suffering from diabetes mellitus. Next to the therapeutic use, scientific and non-scientific literature (e.g. bodybuilding forums; antidoping intelligence and investigation reports) indicate that these prohibited substances are used as performance enhancing agents. In the present report, the development and validation of a sensitive analytical strategy is described for the urinary detection of three rapid-acting insulin analogs (Lispro, Aspart, Glulisine). The method is based on sample purification by the combination of ultrafiltration and immunoaffinity purification and subsequent analysis by nano-flow liquid chromatography coupled to high resolution mass spectrometry. Next to the results on different validation parameters (LOD: 10 pg/mL; recovery: 25-48%; matrix effect: -3-(-8) %), data on urinary elimination times, which were obtained in the frame of an administration study with the participation of healthy volunteers, are presented. The determined detection windows (~9 hours) are expected to help to evaluate current routine analytical methods and aim to aid doping authorities to set appropriate target windows for efficient testing.

As hypoxia-inducible factor stabilizers (HIFs) can artificially enhance an athlete's erythropoiesis, the World Anti-Doping Agency prohibits their use at all times. Every urine sample for doping control analysis has to be evaluated for the presence of HIFs and therefore sensitive methods that allow high sample throughput are needed. Samples suspicious for the presence of HIFs need to be confirmed following the identification criteria established by the World Anti-Doping Agency. Previous work has shown the advantages of using turbulent flow online solid-phase extraction (SPE) procedures to reduce matrix effects and retention time shifts. Furthermore, the use of online SPE allows for automation and high sample throughput. Both an initial testing procedure (ITP) and a confirmation method were developed and validated, using online SPE liquid chromatography-tandem mass spectrometry (LC-MS/MS), with limits of detection between 0.1 ng/ml (or possibly lower) and 4 ng/ml (or higher for GSK360a) and limits of identification between 0.1 ng/ml (or possibly lower) and 1.17 ng/ml. The ITP only takes 6.5 min per sample. To the best of our knowledge, these are the first ITP and confirmation methods that include more than three HIFs without the need for manual sample preparation.

Stimulants are often used to treat attention deficit disorders and nasal congestion. As they can be misused and overdosed, the detection of stimulants is relevant in the toxicological field as well as in the doping control field. The effects of stimulants can indeed be beneficial for athletes. Therefore, their in-competition use is prohibited by the World Anti-Doping Agency (WADA). As stimulants represent one of the most detected categories of prohibited substances, automation of methods to detect and confirm their presence is desirable. Previous work has shown the advantages of using turbulent flow online solid-phase extraction liquid chromatography-tandem mass spectrometry (online SPE LC-MS-MS) for the detection and confirmation of diuretics and masking agents. Hence, a turbulent flow online SPE LC-MS-MS method, compliant with the WADA's identification criteria, was developed and validated for the detection and confirmation of 80 stimulants or metabolites with limits of identification varying between 10 (or possibly lower) and 100 ng/mL. As several metabolites are common metabolites for multiple administered stimulants, this means that with this method, misuse of well over 100 compounds can be detected. As the developed method uses the same columns and mobile phases as our turbulent flow online SPE LC-MS-MS method for the confirmation of diuretics and masking agents, there is no need to change the configuration of the instrument when switching between the diuretics method and the developed stimulants method.

Detection of endogenous anabolic androgenic steroids (EAAS) misuse is a major challenge in doping control analysis. Currently, a number of endogenous steroids, which constitute the steroid profile, are quantified using gas chromatography (GC). With this methodology, only the sum of the free and glucuronidated steroids is measured together. A dilute-and-shoot LC-MS method, which is compliant with the quality requirements for measuring EAAS established by the World Anti-Doping Agency (WADA), was developed and validated containing glucuronidated and sulfated steroids in order to gain some extra information and to expand the existing steroid profile. The developed method is, to the best of our knowledge, the first method to combine both steroid glucuronides and sulfates, which is compliant with the quality standards of the technical document on EAAS, established by WADA. The first advantage of this new steroid profile is the reduced sample preparation time, as it is a direct injection method of diluted urine. A second advantage is the ability of the used gradient to separate 5α-androstane-3α,17β-diol-3-glucuronide (5ααβdiol3G), 5α-androstane-3α,17β-diol-17-glucuronide (5ααβdiol17G), 5β-androstane-3α,17β-diol-3-glucuronide (5βαβdiol3G) and 5β-androstane-3α,17β-diol-17-glucuronide (5βαβdiol17G) allowing to gain specific information on these isomers, which cannot be accomplished in GC-MS screening due to hydrolysis. This steroid profile also contains free testosterone, 5α-androstane-3,17-dione and 5β-androstane-3,17-dione as markers of degradation. In total, 17 compounds and 10 isotopically labelled internal standards are included in this method.