Ultra high performance liquid chromatography/tandem mass spectrometry based identification of steroid esters in serum and plasma: An efficient strategy to detect natural steroids abuse in breeding and racing animals

Anabolic steroids in livestock production: Background and implications for chemical food safety

The use of steroids in livestock animals is a source of concern for consumers because of the risks associated with the presence of their residues in foodstuffs of animal origin. Technological advances such as mass spectrometry have made it possible to play a fundamental role in controlling such practices, firstly for the discovery of marker metabolites but also for the monitoring of these compounds under the regulatory framework. Current control strategies rely on the monitoring of either the parent drug or its metabolites in various matrices of interest. As some of these steroids also have an endogenous status specific strategies have to be applied for control purposes. This review aims to provide a comprehensive and up-to-date knowledge of analytical strategies, whether targeted or non-targeted, and whether they focus on markers of exposure or effect in the specific context of chemical food safety regarding the use of anabolic steroids in livestock. The role of new approaches in data acquisition (e.g. ion mobility), processing and analysis, (e.g. molecular networking), is also discussed.

Detection of boldenone in the urine of female horses-ex vivo formation versus administration

Boldenone is an anabolic-androgenic steroid (AAS) that is prohibited in equine sports. However, in certain situations, it is endogenous, potentially formed by the microbes in urine. An approach to the differentiation based on the detection of the biomarkers Δ1-progesterone, 20(S)-hydroxy-Δ1-progesterone and 20(S)-hydroxyprogesterone was assessed, and their concentrations were monitored in the urine of untreated female horses (n = 291) alongside boldenone, boldienone, testosterone and androstenedione. Using an ultra-sensitive analytical method, boldenone (256 ± 236 pg/mL, n = 290) and the biomarkers (Δ1-progesterone up to 57.6 pg/mL, n = 8; 20(S)-hydroxy-Δ1-progesterone 85.3 ± 181 pg/mL, n = 130; 20(S)-hydroxyprogesterone 43.5 ± 92.1 pg/mL, n = 158) were detected at low concentrations. The ex vivo production of Δ1-steroids was artificially induced following the storage of urine samples at room temperature for 7 days in order to assess the concentrations and ratios of the monitored steroids. The administration of inappropriately stored feed source also resulted in an increase in 20(S)-hydroxy-Δ1-progesterone concentrations and the biomarker ratios. Using the results from different datasets, an approach to differentiation was developed. In situations where the presence of boldenone exceeds a proposed action limit of 5 ng/mL, the presence of the biomarkers would be investigated. If Δ1-progesterone is above 50 pg/mL or if 20(S)-hydroxy-Δ1-progesterone is above 100 pg/mL with the ratio of 20(S)-hydroxy-Δ1-progesterone:20(S)-hydroxyprogesterone greater than 5:1, then this would indicate ex vivo transformation or consumption of altered feed rather than steroid administration. There remains a (small) possibility of a false negative result, but the model increases confidence that adverse analytical findings reported in female horses are caused by AAS administrations.

Multiresidue Determination of Growth Promoters in Bovine Serum using QuEChERS and UHPLC-Q-ORBITRAP: Validation and In Vivo Study

A reliable method using a QuEChERS approach and liquid chromatography coupled to Q-Orbitrap mass spectrometry was optimized and validated for the quantification of 20 growth promoters in bovine serum. The recoveries ranged from 91.4-114.1%, relative standard deviations varied between 0.3-4.0%, and CCα values were between 0.023-0.350 μg L-1. The developed method was applied in an in vivo study using steers, which were intramuscularly treated with commercial injections containing stanozolol. A rapid metabolization was observed, with a detection window ranging from 3 to 10 days. The stability of incurred stanozolol was confirmed after 240 days at -20 °C and also after 5 freeze-thaw cycles. To the best of our knowledge, this is the first work in which an in vivo study was performed to support the monitoring of stanozolol in bovine serum. In addition, the use of Q-Orbitrap high-resolution mass spectrometry allows for retrospective analysis from a surveillance perspective.

Simplified screening approach of anabolic steroid esters using a compact atmospheric solid analysis probe mass spectrometric system

Due to the absence of chromatographic separation, ambient ionization mass spectrometry had the potential to improve the throughput of control laboratories in the last decades and will soon be an excellent approach for on-site use as well. In this study, an atmospheric solids analysis probe (ASAP) with a single quadrupole mass analyzer has been evaluated to identify anabolic steroid esters rapidly. Sample introduction, applied scan time, and probe temperature were optimized for sensitivity. The in-source fragmentations of seventeen selected steroid esters, commonly found in illicit samples, were determined by applying different cone voltages (12, 20, 30, and 40 V). A spectral library was created for these steroid esters based on the four stages of in-source fragmentation spectra. The applicability of this method was demonstrated for the rapid identification of steroid esters in oily injection solutions, providing test results in less than 2 min.

A novel strategy for the detection of boldenone undecylenate misuse in cattle using ultra-high performance liquid chromatography coupled to high resolution orbitrap mass spectrometry: From non-targeted to targeted

In this work multivariate strategies were employed in order to highlight new potential biomarkers of interest to detect the exogenous treatment of steers intramuscularly treated with boldenone undecylenate. Serum samples collected from treated (n = 4) and control (n = 8) crossbred animals of varying ages and weights were extracted using a simple sample preparation procedure based on salt assisted liquid-liquid extraction. Data acquisition was performed using liquid chromatography and Q-Exactive™ Orbitrap mass spectrometry. Data processing and treatment were performed using two non-targeted workflows: (1) Compound Discoverer software and (2) XCMS package on the open-source R software combined with MetaboAnalyst. Three potential biomarkers were highlighted taking into account the chromatographic shapes, the feature location on the generated s-plots, the fold change, the adjusted p values, the coefficient of variation in the QC samples and the area under the ROC curves. Predicted formulas based on mass accuracy, structural composition and spectra similarity were proposed. A robust statistical model to predict the boldenone treatment was further developed based on the weighted abundances of the selected biomarkers. The requirements for screening methods were successfully fulfilled, together with a wider detection window in comparison with the monitoring of the deconjugated metabolite boldenone, although biomarker identification studies are still ongoing.

Detection of testosterone microdosing in healthy females

The ready detectability of synthetic androgens by mass spectrometry (MS)-based antidoping tests has reoriented androgen doping to using testosterone (T), which must be distinguished from its endogenous counterpart making detection of exogenous T harder. We investigated urine and serum steroid and hematological profiling individually and combined to determine the optimal detection model for T administration in women. Twelve healthy females provided six paired blood and urine samples over 2 weeks prior to treatment consisting of 12.5-mg T in a topical transdermal gel applied daily for 7 days. Paired blood and urine samples were then obtained at the end of treatment and Days 1, 2, 4, 7, and 14 days later. Compliance with treatment and sampling was high, and no adverse effects were reported. T treatment significantly increased serum and urine T, serum dihydrotestosterone (DHT), urine 5α-androstane-3α,17β-diol (5α-diol) epitestosterone (E), and urine T/E ratio with a brief window of detection (2-4 days) as well as total and immature (medium and high fluorescence) reticulocytes that remained elevated over the full 14 posttreatment days. Carbon isotope ratio MS and the OFF score and Abnormal Blood Profile score (ABPS) were not discriminatory. The optimal multivariate model to identify T exposure combined serum T, urine T/E ratio with three hematological variables (% high fluorescence reticulocytes, mean corpuscular hemoglobin, and volume) with the five variables providing 93% correct classification (4% false positive, 10% false negatives). Hence, combining select serum and urine steroid MS variables with reticulocyte measures can achieve a high but imperfect detection of T administration to healthy females.

New approach to derivatisation for oestradiol esters detection in animal blood plasma using negative chemical ionisation GC-MS

In 1996, the EU prohibited the use of substances with anabolic action for food-producing animals (EU Directive 96/22/EC). In cases of illegal use of steroid hormones, these substances are usually applied to the animals in the form of esters. The reliable determination of intact steroid esters in animal tissues or body fluids is an unequivocal proof of illegal treatment of animals with EU prohibited anabolic substances. Previously our laboratory developed a sensitive method for determination of oestradiol benzoate and other steroid esters in blood plasma using LC-MS/MS, validated according to Commission Decision 2002/657/EC. This study describes a GC-MS method which has been developed for five oestradiol esters in blood plasma. The sample preparation procedure consisted of protein precipitation, phospholipids removal and cleaning on an alumina column. Oestradiol esters were derivatised with 2, 3, 4, 5, 6-pentafluorobenzoyl chloride (PFBCl) and pyridine in dichloromethane. The measurement of oestradiol esters was carried out by GC-MS/NCI with Cool On-Column injection. Methane was used as a negative chemical ionisation reagent gas. The method for determination of oestradiol esters in blood plasma has been validated according to Commission Decision 2002/657/EC. Decision limits for all analytes were observed below 0.05 ng mL^-1. The method is robust for bovine and porcine plasma analyses and can be applied both for screening and confirmatory determination in routine residue monitoring.

Quantification of 17 Endogenous and Exogenous Steroidal Hormones in Equine and Bovine Blood for Doping Control with UHPLC-MS/MS

A simple and fast analytical method able to simultaneously identify and quantify 17 endogenous and exogenous steroidal hormones was developed in bovine and equine blood using UHPLC-MS/MS. A total amount of 500 µL of sample was deproteinized with 500 µL of a mixture of methanol and zinc sulfate and evaporated. The mixture was reconstituted with 50 µL of a solution of 25% methanol and injected in the UHPLC-MS/MS triple quadrupole. The correlation coefficients of the calibration curves of the analyzed compounds were in the range of 0.9932–0.9999, and the limits of detection and quantification were in the range of 0.023–1.833 and 0.069–5.5 ppb, respectively. The developed method showed a high sensitivity and qualitative aspects allowing the detection and quantification of all steroids in equine and bovine blood. Moreover, the detection limit of testosterone (50 ppt) is half of the threshold admitted in plasma (100 ppt). Once validated, the method was used to quantify 17 steroid hormones in both bovine and equine blood samples. The primary endogenous compounds detected were corticosterone (range 0.28–0.60 ppb) and cortisol (range 0.44–10.00 ppb), followed by androstenedione, testosterone and 11-deoxycortisol.

Doping detection in animals: A review of analytical methodologies published from 1990 to 2019

Despite the impressive innate physical abilities of horses, camels, greyhounds, or pigeons, doping agents might be administered to these animals to improve their performance. To control these illegal practices, anti-doping analytical methodologies have been developed. This review compiles the analytical methods that have been published for the detection of prohibited substances administered to animals involved in sports over 30 years. Relevant papers meeting the search criteria that discussed analytical methods aiming to detect and/or quantify doping substances in animal biological matrices published from 1990 to 2019 were considered. A total of 317 studies were included, of which 298 were related to horses, demonstrating significant advances toward the development of doping detection methods for equine sports. However, analytical methods for the detection of doping agents in sports involving other species are lacking. Due to enhanced accuracy and specificity, chromatographic analysis coupled to mass spectrometry detection is preferred over immunoassays. Regarding biological matrices, blood and urine remain the first choice, although alternative biological matrices, such as hair and feces, have been considered. With the increasing number and type of drugs used as doping agents, the analytes addressed in the published papers are diverse. It is very important to continue to detect and quantify these drugs, recognizing those that are most frequently used, in order to punish the abusers, protect animals' health, and ensure a healthier and genuine competition.

Determination of selected testosterone esters in blood serum of slaughter animals by liquid chromatography with tandem mass spectrometry

Anabolic hormones, which cause muscle growth, have been banned for anabolic purposes in animal husbandry in Europe since the 1980s. Control of hormones from the list of Annex I to Directive 96/23/EC is mandatory in the European Union. The presence of hormones in samples of animal origin may be due to their endogeneous nature or illegal use. One way to distinguish their origin is to study hormones, particularly steroids in the form of ester derivatives. In the body synthetic hormone esters could be only exogenous therefore their detection in animal tissues is the undisputed evidence of illegal administration. The analytical procedure involves the extraction of esters from serum with organic solvents, derivatisation with methoxyamine and detection by liquid chromatography tandem mass spectrometry. The method was approved in accordance with the applicable legislative criteria and its effectiveness was verified in the proficiency test. The research material consisted of bovine serum samples officially taken. During the validation good apparent recovery, precision, decision limits and detection capabilities in the range 0.006-0.012 µg L^-1 and 0.010-0.020 µg L^-1 respectively were obtained. The developed method met the criteria for confirmation set out in Commission Decision 2002/657/EC. Since the inclusion of serum in 2018 for testing for testosterone esters in the National Residue Control Program, 130 samples have been examined. In none of the serum samples, esters above the decision limits were found. The control of animals and food of animal origin for hormone esters will be continued to ensure the health and safety of consumers.

Determination of Steroids in Bovine Serum: Validation of a Reliable LC-MS/MS Method and In Vivo Studies with Boldenone Undecylenate and Testosterone Propionate

Serum analysis has received much attention in regulatory analysis of food-producing animals, especially for anabolic steroids. The possibility of confirming the parent drugs with minimum metabolization enables the detection of intact steroid esters, whose identification represents unequivocal proof of drug administration. This work involved the development and validation of a quantitative LC-MS/MS method to determine 30 steroids and steroid esters in bovine serum. Sensitivity was improved using microwave-assisted chemical derivatization with methoxyamine hydrochloride. The validation was successfully conducted in accordance with the Decision 657/2002/EC guidelines. An in vivo experiment was performed on 12 crossbred steers in which two commercial formulations containing boldenone undecylenate and testosterone propionate were administrated via intramuscular injections. The samples were collected over a period of 120 days, in which both intact esters were identified within 11 days postadministration. 17β-Boldenone was observed after 92 days for 2 steers and 56 days for the other animals. The applicability of a cut-off level to the ratio between 17β-testosterone and epitestosterone was evaluated in an attempt to differentiate testosterone abuse from endogenous production. It could be observed that a calculated ratio above this level is strong evidence of drug administration, although a high false-negative rate was obtained.

Simultaneous quantitation of 9 anabolic and natural steroidal hormones in equine urine by UHPLC-MS/MS triple quadrupole

A new fast and easy analytical procedure for the simultaneous detection and quantification of 9 anabolic steroids (deslorelin, dexamethasone sodium phosphate, prednisolone, methylprednisolone, stanozolol, boldenone, nandrolone, dexamethasone isonicotinate and altrenogest) in horse urine for doping control have been developed by using the ultra-high-performance liquid chromatography coupled with tandem mass spectrometry technique (UHPLC-MS/MS). A total amount of 400 μl of sample was evaporated, restored and injected in the UHPLC-MS/MS. The proposed method was fully validated showing a recovery higher than 89.12% and a coefficient of variation lower than 6.02%. The correlation coefficients range of the analyzed compound's calibration curves was 0.9955-0.9997, and the limits of detection and quantification were in the range of 0.1 and 0.25 μg/l, respectively.

Determination of steroid hormones and their metabolite in several types of meat samples by ultra high performance liquid chromatography-Orbitrap high resolution mass spectrometry

A new analytical method based on ultra-high performance liquid chromatography (UHPLC) coupled to Orbitrap high resolution mass spectrometry (Orbitrap-HRMS) has been developed for the determination of steroid hormones (hydrocortisone, cortisone, progesterone, prednisone, prednisolone, testosterone, melengesterol acetate, hydrocortisone-21-acetate, cortisone-21-acetate, testosterone propionate, 17α-methyltestosterone, 6α-methylprednisolone and medroxyprogesterone) and their metabolite (17α-hydroxyprogesterone) in three meat samples (chicken, pork and beef). Two different extraction approaches were tested (QuEChERS "quick, easy, cheap, effective, rugged and safe" and "dilute and shoot"), observing that the QuEChERS method provided the best results in terms of recovery. A clean-up step was applied comparing several sorbents, obtaining the best results when florisil and aluminum oxide were used. The optimized method was validated, obtaining suitable results for all validation parameters in the three meat matrices evaluated. Recovery values ranged from 70% to 103% (except for prednisone in beef samples), meanwhile repeatability and reproducibility were obtained at values lower than 18% and 21%, respectively. The limit of quantification (LOQ) was established for most of the compounds at 1.0 μg/kg, except for testosterone in chicken and hydrocortisone-21-acetate and cortisone-21-acetate in pork at 2.0 μg/kg. Decision limit (CCα) and detection capability (CCβ) values ranged from 1.0-2.7 μg/kg and 1.9-5.5 μg/kg, respectively, in the three matrices. Finally, thirty one meat samples were analyzed and two hormones, progesterone and hydrocortisone, were detected in a beef and pork sample at 1.7 and 2.8 μg/kg respectively.

Olfactory stimulation or inhibition of sexual behavior of stallions in non-breeding season

Stallions show decreased sexual responses and activities during short days in winter. To evaluate the importance of sexual olfactory communication in horses, we tested whether sexual responses could be stimulated through various sexual olfactory stimulations in winter. To this end, we presented stallions with various olfactory stimulations (urine from mares at different stages of the reproductive cycle, urine from stallions or geldings, or chemically defined synthetic odorant) during the non-breeding season and measured their behavioral responses through (1) a test of olfactory investigation (olfactory investigation and flehmen behavior) and (2) a test of sexual activity in the context of semen collection for artificial insemination. It appears that the duration of olfactory investigation and flehmen behavior is longer after presentation of urine (stallion, gelding, anestrous, diestrous and estrous mare) than after presentation of water or synthetic odorant. By contrast, geldings showed reduced flehmen behavior that did not differ from that after water presentation. It is of interest that during the mounting test, mare estrous urine was associated with significantly reduced latency to ejaculation when spread in the nostril of the stallion, compared to anestrous mare urine or water. Anestrous mare urine seems to even inhibit stallion sexual motivation as measured through a longer latency to reach mounting and ejaculation. It appears therefore that during the season of sexual rest, stallion sexual motivation can be stimulated by mare estrous urine and inhibited by mare anestrous urine. These results also suggest that the physiological state of the mare influence the content of urinary chemosignals.

Carbon isotope ratios of endogenous steroids in Belgian Blue and Holstein cattle: Method development, reference population studies and application to steroid misuse control

RATIONALE

The misuse of growth promoters in livestock and breeding animals is prohibited according to the laws of the European Union. Among these growth promoters, the detection of endogenous steroids like testosterone, estradiol or progesterone remains especially challenging as concentration-based urinary thresholds may not provide conclusive results due to large inter-individual variations. In addition to the detection of intact steroid esters in blood or hair, carbon isotope ratio (CIR) determination of urinary steroids has commonly been the method of choice.

METHODS

A comprehensive sample clean-up procedure was developed and validated, which enables for the first time simultaneous CIR measurements of testosterone metabolites (17α-hydroxyandrost-4-en-3-one, 3α-hydroxy-5β-androstan-17-one and 5α-androstane-3β,17α-diol), the estradiol metabolite 17α-estradiol (ESTR) and the progesterone metabolite 5β-pregnane-3α,20α-diol (PD) from a single urine specimen. As endogenous reference compounds 3β-hydroxyandrost-5-en-17-one and 5-androstene-3β,17α-diol (5EN) were chosen. The method was validated by means of linear mixing models and a reference population encompassing n = 53 Belgian Blue and Holstein cattle was investigated to enable the calculation of population-based Δ¹³ C thresholds.

RESULTS

The combined measurement uncertainty determined for the Δ¹³ C-values of all steroids under investigation was found to be <0.8 ‰. Within the reference population studies, 5EN was demonstrated to be the most promising endogenous reference compound resulting in comparably low Δ-values and accompanying thresholds. For PD, a surprisingly high number of samples (n = 9) yielded significantly ¹³ C-depleted values and ESTR was only detectable in n = 13 samples. Proof-of-concept was accomplished by investigating two post-administration samples.

CONCLUSIONS

This first comprehensive investigation on the CIRs of endogenous urinary steroids demonstrated once more the potential of isotope ratios in aiding discrimination between endogenously produced and exogenously administered steroids. By means of the reference population-derived CIRs, it is possible to apply cattle-specific thresholds to differentiate between treated and non-treated animals.

Development and application of a UHPLC-MS/MS method for the simultaneous determination of 17 steroidal hormones in equine serum

A new, fast and simple analytical method that is able to identify and quantify simultaneously 17 steroid hormones and metabolites (pregnenolone, 17-OH-pregnenolone, progesterone, 17-OH-progesterone, androsterone, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, testosterone, cortisol, corticosterone, aldosterone, 11-deoxycortisol, 11-deoxycorticosterone, dihydrotestosterone, estrone and estradiol) has been developed in equine serum using the ultra-high-performance liquid chromatography-tandem mass spectrometry technique. A total of 400 µl of sample was deproteinized with 1000 µl of acetonitrile, evaporated, restored with 50 µl of a solution of 25% methanol and injected in ultra-high-performance liquid chromatography-tandem mass spectrometry triple quadrupole. The recovery percentage obtained by spiking the matrix at two different concentrations with a standard mixture of steroid hormones was in all cases higher than 85.60% and with the percentage of coefficient of variation lower than 8.37%. The range of the correlation coefficients of the calibration curves of the analyzed compounds was 0.9922-0.9986, and the limits of detection and limits of quantification were in the range of 0.002-2 and 0.0055-5.5 ng ml^-1 , respectively. The detected limit of quantification for testosterone (i.e. 50 pg ml^-1 ) is twofold lower with respect to its threshold admitted in geldings plasma (100 pg ml^-1 free testosterone). The high sensitivity and the quantitative aspect of the method permitted to detect most of the steroids in equine serum. Once validated, the method was used to quantify 17 steroid hormones in mare, stallion and gelding serum samples. The main steroids detected were corticosterone (range 37.25-51.26 ng ml^-1 ) and cortisol (range 32.57-52.24 ng ml^-1 ), followed by 17-OH-pregnenolone, dihydrotestosterone and pregnenolone. Copyright © 2016 John Wiley & Sons, Ltd.

The use of gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry to demonstrate progesterone treatment in bovines

Currently, no analytical method is available to demonstrate progesterone administration in biological samples collected in rearing animals, and therefore, tracking the abuse of this popular growth promoter is arduous. In this study, a method is presented to reveal progesterone (PG) treatment on the basis of carbon isotope measurement of 5β-pregnane-3α, 20α-diol (BAA-PD), a major PG metabolite excreted in bovine urine, by gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS). 5-Androstene-3β,17α-diol (AEdiol) is used as endogenous reference compound. Intermediate precisions (n=11) of 0.56‰ and 0.68‰ have been determined for AEdiol and BAA-PD, respectively. The analytical method was used for the very first time to successfully differentiate urine samples collected in treated and untreated animals.

Simultaneous Detection of Androgen and Estrogen Abuse in Breeding Animals by Gas Chromatography-Mass Spectrometry/Combustion/Isotope Ratio Mass Spectrometry (GC-MS/C/IRMS) Evaluated against Alternative Methods

The administration of synthetic homologues of naturally occurring steroids can be demonstrated by measuring (13)C/(12)C isotopic ratios of their urinary metabolites. Gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS) was used in this study to appraise in a global approach isotopic deviations of two 17β-testosterone metabolites (17α-testosterone and etiocholanolone) and one 17β-estradiol metabolite (17α-estradiol) together with those of 5-androstene-3β,17α-diol as endogenous reference compound (ERC). Intermediate precisions of 0.35‰, 1.05‰, 0.35‰, and 0.21‰, respectively, were observed (n = 8). To assess the performance of the analytical method, a bull and a heifer were treated with 17β-testosterone propionate and 17β-estradiol-3-benzoate. The sensitivity of the method permitted the demonstration of 17β-estradiol treatment up to 24 days. For 17β-testosterone treatment, the detection windows were 3 days and 24 days for the bull and the heifer, respectively. The capability of GC-MS/C/IRMS to demonstrate natural steroid abuse for urinary steroids was eventually compared to those of mass spectrometry (LC-MS/MS) when measuring intact steroid esters in blood and hair.

Collision induced dissociations of non-derivatized and trimethylsilyl-derivatized estradiols: similarities in fragmentation patterns

Fragmentation mechanisms of estradiol and trimethylsilyl (TMS)-derivatized estradiol were studied by triple quadrupole tandem mass spectrometry (MSMS) and density functional theory (DFT) at B3LYP/6-311G(d,p) level. Collision induced dissociations (CID) of estradiol give product ions that are associated with the cleavage of B, C and D rings. Characteristic fragments from the cleavage of the aromatic ring A were not identified, and this was confirmed with both labeled estradiol and trimethylsilyl (TMS)-derivatized estradiol. The mechanisms are based on charge-site directed, radical-directed and charge remote fragmentations that are consistent with previous studies of steroids. CID spectra show ion pairs at m/z: 145/146, 157/158, 185/186, 211/213 and 225/226 with significant intensities, suggesting that these pairs are not from isotopic contributions. The mechanisms show similarities with some minor differences in the fragmentation patterns between the non-derivatized and the TMS-derivatized estradiol.

Evaluation of the discriminative potential of a novel biomarker for estradiol treatments in bovine animals

The endogenous occurrence of natural hormones obstructs the application of classical targeted methods as confirmatory options. In the case of estradiol, the ultimate confirmation of its exogenous administration relies on gas chromatography coupled to combustion/isotope ratio mass spectrometry (GC-C/IRMS). A serum dipeptide composed of pyroglutamic acid and phenylalanine was identified as a potential biomarker of estradiol treatments in adult cows. To evaluate its potential to pinpoint suspicious samples, samples from prepubertal females under different estrogenic treatments have been analyzed. The results confirmed the up-regulation of the dipeptide in adult bovines. The 2-week-old females exhibited short-lasting responses only in a few animals. The 6-month-old female showed a delayed but clear increase on the biomarker level. The composition of the anabolic preparations, the dose, and/or the administration route are possible additional reasons for the reduced response in young animals. A comparison to previous results reported by various researchers is included.

High throughput quantification of prohibited substances in plasma using thin film solid phase microextraction

Simple, fast and efficient sample preparation approaches that allow high-throughput isolation of various compounds from complex matrices are highly desired in bioanalysis. Particularly sought are methods that can, without sacrificing time, easily remove matrix interferences capable of inducing ionization suppression/enhancement, or causing detrimental effects in instrumental performance. In this work, an automated high-throughput sample preparation method using thin film solid phase microextraction (SPME) for the analysis of multiple prohibited substances in plasma is proposed. A biocompatible SPME extraction phase made of hydrophilic-lipophilic balance particles immobilized with polyacrylonitrile (PAN) demonstrated satisfactory extraction capabilities for 25 compounds of a wide range of polarities (logP from -2 to 6.8). Due to the well-known biocompatible characteristics of PAN-based SPME coatings, minimum sample handling was required. Experimental conditions for pre-conditioning, extraction, wash and desorption were carefully optimized for the proposed method. By taking full advantage of the 96 thin film handling capability of the automated system, a preparation time of approximately 1.5min per sample can be achieved. Satisfactory results in terms of absolute matrix effects were found for the majority of the studied analytes, given that 24 out of 25 compounds exhibited values in the range of 100 and 120%. The method was validated in terms of linearity (R(2)>0.99), inter and intra-day accuracy (85-130%) and precision (<20%) and limits of quantitation (0.25-10ngmL(-1) for most compounds).

Monitoring the endogenous steroid profile disruption in urine and blood upon nandrolone administration: An efficient and innovative strategy to screen for nandrolone abuse in entire male horses

Nandrolone (17β-hydroxy-4-estren-3-one) is amongst the most misused endogenous steroid hormones in entire male horses. The detection of such a substance is challenging with regard to its endogenous presence. The current international threshold level for nandrolone misuse is based on the urinary concentration ratio of 5α-estrane-3β,17α-diol (EAD) to 5(10)-estrene-3β,17α-diol (EED). This ratio, however, can be influenced by a number of factors due to existing intra- and inter-variability standing, respectively, for the variation occurring in endogenous steroids concentration levels in a single subject and the variation in those same concentration levels observed between different subjects. Targeting an efficient detection of nandrolone misuse in entire male horses, an analytical strategy was set up in order to profile a group of endogenous steroids in nandrolone-treated and non-treated equines. Experiment plasma and urine samples were steadily collected over more than three months from a stallion administered with nandrolone laurate (1 mg/kg). Control plasma and urine samples were collected monthly from seven non-treated stallions over a one-year period. A large panel of steroids of interest (n = 23) were extracted from equine urine and plasma samples using a C18 cartridge. Following a methanolysis step, liquid-liquid and solid-phase extractions purifications were performed before derivatization and analysis on gas chromatography-tandem mass spectrometry (GC-MS/MS) for quantification. Statistical processing of the collected data permitted to establish statistical models capable of discriminating control samples from those collected during the three months following administration. Furthermore, these statistical models succeeded in predicting the compliance status of additional samples collected from racing horses.