Doping control for metandienone using hair analyzed by gas chromatography-tandem mass spectrometry

A sensitive, specific and reproducible method for the quantitative determination of the anabolic metandienone in human hair has been developed. The preparation involved a decontamination step with methylene chloride. The hair sample (about 50 mg) was solubilised in 1 ml 1 M NaOH, 10 min at 95 degrees C, in presence of 2 ng of nandrolone-d(3) used as internal standard. The homogenate was neutralized and extracted using consecutively a solid-phase extraction (Isolute C(18) eluted with methanol) and a liquid-liquid extraction with pentane. The residue was derivatized by adding 5 microl MSTFA/NH(4)I/2-mercaptoethanol (250 microl; 5 mg; 15 microl) and 45 microl MSTFA, then incubated for 20 min at 60 degrees C. A 1 microl aliquot of derivatized extract was injected into the column (HP5-MS capillary column, 5% phenyl-95% methylsiloxane, 30 m x 0.32 mm i.d., 0.25 microm film thickness) of a Hewlett Packard (Palo Alto, CA, USA) gas chromatograph (6890 Series). Metandienone was identified using three transitions (its daughter ions at m/z 339 and 206 for the parent 444 and 191 for 206) using a Waters Quattro Micro MS-MS system. The transition m/z 444 to 206 has been used as quantification transition and the others as identification transitions. The assay was capable of detecting 2 pg/mg of metandienone when approximately 50 mg of hair material was processed. Linearity was observed for metandienone concentrations ranging from 2 to 500 pg/mg with a correlation coefficient of 0.9997. Intra-day and between-day precisions at 50 pg/mg were 13.4-16.5% and 22.0%, respectively, with an extraction recovery of 48%. The analysis of hair, cut into four segments, obtained from an athlete, revealed the presence of metandienone at the concentrations of 78, 7, 10 and 108 pg/mg in each segment of hair (0-1, 1-2, 2-3 and 3 cm to the tip).     

Doping control analysis of trenbolone and related compounds using liquid chromatography-tandem mass spectrometry

Trenbolone (17β-hydroxy-estra-4,9,11-trien-3-one) and its derivatives such as 17α-methyltrenbolone represent a class of highly potent anabolic-androgenic steroids, which are prohibited in sports according to the regulation of the World Anti-Doping Agency (WADA). Due to marginal gas chromatographic properties of these compounds but excellent proton affinities resulting from a large and conjugated π-electron system, liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been the method of choice for the detection of these analytes in sports drug testing. Recent findings of trenbolone and methyltrenbolone in doping control urine samples of elite athletes demonstrated the importance of a sensitive and robust analytical method, which was based on an enzymatic hydrolysis of target compounds, liquid-liquid extraction and subsequent LC-MS/MS measurement. Diagnostic product ions obtained after collision-induced dissociation of protonated molecules were found at m/z 227, 211, 199 and 198, which enabled targeted screening using multiple reaction monitoring. Using 7 model compounds (trenbolone, epitrenbolone, methyltrenbolone, ethyltrenbolone, propyltrenbolone, 17-ketotrenbolone and altrenogest), the established method was validated for specificity, lower limits of detection (0.3-3 ng/mL), recovery (72-105%), intraday and interday precision (≤20%).     

Testing for kavain in human hair using gas chromatography-tandem mass spectrometry

A sensitive, specific and reproducible method for the quantitative determination of kavain in human hair has been developed. The sample preparation involved a decontamination step of the hair with methylene chloride. The hair sample (about 50 mg) was incubated in 1 ml of methanol for 1 h, in an ultrasonic bath, in presence of 20 ng of methaqualone-d7 used as internal standard. The methanolic solution was evaporated to dryness, and the residue reconstituted by adding 30 microl of methanol. A 2 microl aliquot of the extract was injected onto the column (Optima5-MS capillary column, 5% phenyl-95% methylsiloxane, 30 m x 0.25 mm i.d. x 0.25 mm film thickness) of a Hewlett-Packard (Palo Alto, CA) gas chromatograph (5890). Kavain was detected by its parent ion at m/z 230 and daughter ions at m/z 111 and 202 through a Finnigan TSQ 700 MS/MS system. The assay was capable of detecting 30 pg/mg of kavain (limit of detection (LOD)). Linearity was observed for kavain concentrations ranging from 100 to 2000 pg/mg with a correlation coefficient of 0.998. Intra-day precision at 400 pg/mg was 13.7%. The analysis of a segment of hair, obtained from an occasional consumer, revealed the presence of kavain at the concentration of 418 pg/mg. A higher concentration (1708 pg/mg) was detected in the corresponding pubic hair.     

Analysis of corticosteroids in hair by liquid chromatography–electrospray ionization mass spectrometry

The present study describes a confirmatory method for the quantitative determination in hair of the most common corticosteroids illegaly used as doping agents by athletes. Corticosteroids are extracted from 50 mg of powdered hairs by methanolic extraction follows by a solid-phase extraction on C₁₈ cartridge. After extraction, the dried residue is reconstituted with 50 μl acetonitrile and injected in a liquid chromatograph. Liquid chromatography separation is performed on a reversed-phase C₁₈ column with a binary gradient of formiate buffer pH 3-acetonitrile as mobile phase. Detection is performed with an electrospray ionization mass spectrometer in negative ion and selected-ion monitoring mode. The limits of sensitivity achieved is 0.1 ng/mg in hair. Application to hair sample collected during an antidoping control and comparison to results obtain on urines, collected on the same athletes at the same time, shows the interest and the complementarity of both matrices. Hair analysis could allow the detection of corticosteroids on a large period preceding the control, and the detection of natural corticosteroids administered as pro-drug, like hydrocortisone acetate.     

Urinary analysis of 16(5alpha)-androsten-3alpha-ol by gas chromatography/combustion/isotope ratio mass spectrometry: implications in anti-doping analysis

We present a method for the analysis of urinary 16(5alpha)-androsten-3alpha-ol together with 5beta-pregnane-3alpha,20alpha-diol and four testosterone metabolites: androsterone (Andro), etiocholanolone (Etio), 5alpha-androstane-3alpha,17beta-diol (5alphaA), 5beta-androstane-3alpha,17beta-diol (5betaA) by means of gas chromatography/combustion/isotopic ratio mass spectrometry (GC/C/IRMS). The within-assay and between-assay precision S.D.s of the investigated steroids were lower than 0.3 and 0.6 per thousand, respectively. A comparative study on a population composed of 20 subjects has shown that the differences of the intra-individual delta(13)C-values for 16(5alpha)-androsten-3alpha-ol and 5beta-pregnane-3alpha,20alpha-diol are less than 0.9 per thousand. Thereafter, the method has been applied in the frame of an excretion study following oral ingestion of 50 mg DHEA initially and oral ingestion of 50mg pregnenolone 48 h later. Our findings show that administration of DHEA does not affect the isotopic ratio values of 16(5alpha)-androsten-3alpha-ol and 5beta-pregnane-3alpha,20alpha-diol, whereas the isotopic ratio values of 5beta-pregnane-3alpha,20alpha-diol vary by more 5 per thousand upon ingestion of pregnenolone. We have observed delta(13)C-value changes lower than 1 per thousand for 16(5alpha)-androsten-3alpha-ol, though pregnenolone is a precursor of the 16-ene steroids. In contrast to 5beta-pregnane-3alpha,20alpha-diol, the 16-ene steroid may be used as an endogenous reference compound when pregnenolone is administered.     

Enrichment of integral membrane proteins for proteomic analysis using liquid chromatography-tandem mass spectrometry

An increasing number of proteomic strategies rely on liquid chromatography-tandem mass spectrometry (LC-MS/MS) to detect and identify constituent peptides of enzymatically digested proteins obtained from various organisms and cell types. However, sample preparation methods for isolating membrane proteins typically involve the use of detergents and chaotropes that often interfere with chromatographic separation and/or electrospray ionization. To address this problem, a sample preparation method combining carbonate extraction, surfactant-free organic solvent-assisted solubilization, and proteolysis was developed and demonstrated to target the membrane subproteome of Deinococcus radiodurans. Out of 503 proteins identified, 135 were recognized as hydrophobic on the basis of their calculated hydropathy values (GRAVY index), corresponding to coverage of 15% of the predicted hydrophobic proteome. Using the PSORT algorithm, 53 of the proteins identified were classified as integral outer membrane proteins and 215 were classified as integral cytoplasmic membrane proteins. All identified integral cytoplasmic membrane proteins had from 1 to 16 mapped transmembrane domains (TMDs), and 65% of those containing four or more mapped TMDs were identified by at least one hydrophobic membrane spanning peptide. The extensive coverage of the membrane subproteome (24%) by identification of highly hydrophobic proteins containing multiple TMDs validates the efficacy of the described sample preparation technique to isolate and solubilize hydrophobic integral membrane proteins from complex protein mixtures.     

Sensitive determination of pethidine in body fluids by gas chromatography-tandem mass spectrometry

We have presented a simple and sensitive method for determining pethidine, a narcotic analgesic drug in body fluids by gas chromatography-tandem mass spectrometry (GC-MS/MS). Pethidine and 4'-piperidinoacetophenone (internal standard) were extracted from body fluids with Bond Elut C(18) columns; the recoveries were above 85% for both compounds. The calibration curves for blood and urine showed good linearities in the range of 1.25-40 ng/ml. Its detection limits (signal-to-noise ratio=3) were estimated to be approximately 0.5 ng/ml of whole blood and urine.     

Profiling of urinary formestane and confirmation by isotope ratio mass spectrometry

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

Software development to fermentation gas analysis using mass spectrometry

Summary Fermentation applications of mass spectrometer (Spectramass PC2000) hampered by interface and software difficulties have been successfully solved. A multiplexed exhaust gas analysis, data acquisition and estimation system was designed and implemented. An specific software was developed in C+ + language programming. This system was tested for lipase production by Candida rugosa in batch fermentation.     

Mediator lipidomics by liquid chromatography-tandem mass spectrometry

Comprehensive quantitative analysis of lipid mediators using liquid chromatography-tandem mass spectrometry is an effective strategy in the elucidation of disease mechanisms; but technically, it has been and is still a great challenge to achieve reliable datasets that cover variety of lipid metabolites contained at trace levels in complex biological matrices. In this opinion article, we introduce our experiences in developing lipid mediator profiling systems, and deliver some comments on limitations of current methodology.     

Automation of nanoflow liquid chromatography-tandem mass spectrometry for proteome analysis by using a strong cation exchange trap column

An approach was developed to automate sample introduction for nanoflow LC-MS/MS (microLC-MS/MS) analysis using a strong cation exchange (SCX) trap column. The system consisted of a 100 microm id x 2 cm SCX trap column and a 75 microm id x 12 cm C18 RP analytical column. During the sample loading step, the flow passing through the SCX trap column was directed to waste for loading a large volume of sample at high flow rate. Then the peptides bound on the SCX trap column were eluted onto the RP analytical column by a high salt buffer followed by RP chromatographic separation of the peptides at nanoliter flow rate. It was observed that higher performance of separation could be achieved with the system using SCX trap column than with the system using C18 trap column. The high proteomic coverage using this approach was demonstrated in the analysis of tryptic digest of BSA and yeast cell lysate. In addition, this system was also applied to two-dimensional separation of tryptic digest of human hepatocellular carcinoma cell line SMMC-7721 for large scale proteome analysis. This system was fully automated and required minimum changes on current microLC-MS/MS system. This system represented a promising platform for routine proteome analysis.     

Determination of protease inhibitors using liquid chromatography-tandem mass spectrometry

A method for the analysis of six protease inhibitors and one metabolite has been developed and validated. Amprenavir, ritonavir, saquinavir, lopinavir, indinavir, nelfinavir, and an active metabolite of nelfinavir (M8) are quantitated using reversed-phase liquid chromatography coupled to tandem mass spectrometry, equipped with an electrospray ionization source (ESI-LC-MS-MS). The validation data presented here shows that the method allows the rugged analysis of these species from one aliquot. The evolution of complex drug interactions assessments and the clinical use of therapeutic drug monitoring for these antiretrovirals will be a potential immediate application of this method.     

Simultaneous quantitative analysis of bioactive sphingolipids by high-performance liquid chromatography-tandem mass spectrometry

There has been a recent explosion in research concerning novel bioactive sphingolipids (SPLs) such as ceramide (Cer), sphingosine (Sph) and sphingosine 1-phosphate (Sph-1P) that necessitates development of accurate and user-friendly methodology for analyzing and quantitating the endogenous levels of these molecules. ESI/MS/MS methodology provides a universal tool used for detecting and monitoring changes in SPL levels and composition from biological materials. Simultaneous ESI/MS/MS analysis of sphingoid bases (SBs), sphingoid base 1-phosphates (SB-1Ps), Cers and sphingomyelins (SMs) is performed on a Thermo Finnigan TSQ 7000 triple quadrupole mass spectrometer operating in a multiple reaction monitoring (MRM) positive ionization mode. Biological materials (cells, tissues or physiological fluids) are fortified with internal standards (ISs), extracted into a one-phase neutral organic solvent system, and analyzed by a Surveyor/TSQ 7000 LC/MS system. Qualitative analysis of SPLs is performed by a Parent Ion scan of a common fragment ion characteristic for a particular class of SPLs. Quantitative analysis is based on calibration curves generated by spiking an artificial matrix with known amounts of target synthetic standards and an equal amount of IS. The calibration curves are constructed by plotting the peak area ratios of analyte to the respective IS against concentration using a linear regression model. This robust analytical procedure can determine the composition of endogenous sphingolipids (ESPLs) in varied biological materials and achieve a detection limit at 1 pmol or lower level. This and related methodology are already defining unexpected specialization and specificity in the metabolism and function of distinct subspecies of individual bioactive SPLs.     

Improved methodology for the detection and quantitation of urinary metabolites of sulphur mustard using gas chromatography-tandem mass spectrometry

Gas chromatography-tandem mass spectrometry (GC-MS-MS) with selected-reaction monitoring was applied to the analysis of urinary metabolites of sulphur mustard, derived from the β-lyase pathway and from hydrolysis. In the case of β-lyase metabolites, a limit of detection of 0.1 ng/ml was obtained, compared to 2–5 ng/ml using single stage GC-MS with selected-ion monitoring. GC-MS-MS methodology was less useful when applied to the analysis of thiodiglycol bis(pentafluorobenzoate) using negative-ion chemical ionisation although selected-reaction chromatograms were cleaner than selected-ion chromatograms. The advantage of using GC-MS-MS was demonstrated by the detection of low levels of β-lyase metabolites in the urine of casualties who had been exposed to sulphur mustard.     

Tryptic transpeptidation products observed in proteome analysis by liquid chromatography-tandem mass spectrometry

Commonly, prior to mass spectrometry based analysis of proteins or protein mixtures, the proteins are subjected to specific enzymatic proteolysis. For this purpose trypsin is most frequently used. However, the process of proteolysis is not unflawed. For example, some side activities of trypsin are known and have already been described in the literature (e.g., chymotryptic activity). Here, we describe the occurrence of transpeptidated peptides during standard proteome analysis using two-dimensional polyacrylamide gel electrophoresis followed by mass spectrometric protein identification. Different types of transpeptidated peptides have been detected. The most frequently observed transpeptidation reaction is N-terminal addition of arginine or lysine to peptides. Furthermore, addition of two amino acids to the N-terminus of a peptide has also been detected. Another transpeptidation that we observed, is combination of two peptides, which were originally located in different regions of the analyzed protein. Currently, the full amount of peptides generated by transpeptidation is not clear. However, it should be recognized that protein information is presently lost as these effects are not detectable with available database search software.     

Deciphering signaling control by phosphoproteome using mass spectrometry

Analysis of changes in genes and protein profiles provides invaluable information to understand the activities and functions of proteins. However, their activities are further regulated by post-translational modifications, such as glycosylation and phosphorylation. Cell growth and apoptotic pathways are good examples of demonstrating the roles of phosphorylation in activation of protein cascades upon stimulation.     

Method for analysis of polybrominated biphenyls by gas chromatography mass spectrometry

Gas chromatography using a short packed column (45 cm, 0.2 cm i.d., 2% OV-101 on Gas-Chrom Q) with mass spectrometric detection in the selected ion monitoring mode has been found satisfactory for the analysis of lower as well as higher polybrominated biphenyls. Acceptable sensitivity (< 1 ng) may be achieved for this method by focusing selectively at either the low (m/z 20-600) or the high m/z 600-1000) range of the quadrupole filter (low range for mono- through hexabromobiphenyl, high range for hexa- through decabromobiphenyl). A tuning technique has been developed for low range and high range polybrominated biphenyls using the ion abundances of perfluorotributylamine as a standard. Standard ions for the quantitation of mono- through decabromo-biphenyls were selected and validated. The technique was applied to the analysis of a variety of environmental samples.     

Molecular constituents of the postsynaptic density fraction revealed by proteomic analysis using multidimensional liquid chromatography-tandem mass spectrometry

Protein constituents of the postsynaptic density (PSD) fraction were analysed using an integrated liquid chromatography (LC)-based protein identification system, which was constructed by coupling microscale two-dimensional liquid chromatography (2DLC) with electrospray ionization (ESI) tandem mass spectrometry (MS/MS) and an automated data analysis system. The PSD fraction prepared from rat forebrain was solubilized in 6 m guanidium hydrochloride, and the proteins were digested with trypsin after S-carbamoylmethylation under reducing conditions. The tryptic peptide mixture was then analysed with the 2DLC-MS/MS system in a data-dependent mode, and the resultant spectral data were automatically processed to search a genome sequence database for protein identification. In triplicate analyses, the system allowed assignments of 5264 peptides, which could finally be attributed to 492 proteins. The PSD contained various proteins involved in signalling transduction, including receptors, ion channel proteins, protein kinases and phosphatases, G-protein and related proteins, scaffold proteins, and adaptor proteins. Structural proteins, including membrane proteins involved in cell adhesion and cell-cell interaction, proteins involved in endocytosis, motor proteins, and cytoskeletal proteins were also abundant. These results provide basic data on a major protein set associated with the PSD and a basis for future functional studies of this important neural machinery.     

Determination of clenbuterol residues in bovine hair by using diphasic dialysis and gas chromatography–mass spectrometry

A method for the determination of clenbuterol (4-amino-3,5-dichloro-α[(tert.-butylamino)methyl]-benzyl alcohol hydrochloride) in hair of living cows has been developed. Hair samples were digested in an alkaline medium. The diphasic dialysis technique is a semi-permeable membrane technology developed for the direct extraction of relatively low-molecular-mass analytes such as clenbuterol. In this case, we used sodium citrate buffer to homogenize the digested hair, dichloromethane was used as the extraction solvent at 37°C, and stirring was applied at 150 rpm for 4 h. The analysis was carried out using gas chromatography–mass spectrometry. The calibration curve for clenbuterol in hair was linear in the range from 12.5 to 400 ng g⁻¹. The detection limit of clenbuterol was 5 ng g⁻¹ and the quantification limit was 12.5 ng g⁻¹, in hair. A good inter-day reproducibility was obtained (R.S.D.=7.08%). The repeatability and intra-day reproducibility (50 ng g⁻¹ of hair, n=10) show R.S.D.s of 7.1 and 9.5%, respectively.     

Simultaneous analysis of THC and its metabolites in blood using liquid chromatography-tandem mass spectrometry

Cannabis is considered to be the most widely abused illicit drug in Europe. Consequently, sensitive and specific analytical methods are needed for forensic purposes and for cannabinoid pharmacokinetic and pharmacodynamic studies. A simple, rapid and highly sensitive and specific method for the extraction and quantification of Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy- Delta(9)-tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy- Delta(9)-tetrahydrocannabinol (THC-COOH) in blood is presented. The method was fully validated according to international guidelines and comprises simultaneous liquid-liquid extraction (LLE) of the three analytes with hexane:ethyl acetate (90:10, v/v) into a single eluant followed by separation and quantification using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chromatographic separation was achieved using a XBridge C(18) column eluted isocratically with methanol:0.1% formic acid (80:20, v/v). Selectivity of the method was achieved by a combination of retention time, and two precursor-product ion transitions. The use of the LLE was demonstrated to be highly effective and led to significant decreases in the interferences present in the matrix. Validation of the method was performed using 250 microL of blood. The method was linear over the range investigated (0.5-40 microg/L for THC, 1-40 microg/L for 11-OH-THC, and 2-160 microg/L for THC-COOH) with excellent intra-assay and inter-assay precision; relative standard deviations (RSDs) were <12% for THC and 11-OH-THC and <8% for THC-COOH for certified quality control samples. The lower limit of quantification was fixed at the lowest calibrator in the linearity experiments. No instability was observed after repeated freezing and thawing or in processed samples. The method was subsequently applied to 63 authentic blood samples obtained from toxicology cases. The validation and actual sample analysis results show that this method is rugged, precise, accurate, and well suited for routine analysis.