Authentic Urine Samples Research Articles

In silico and in vitro metabolism studies support identification of designer drugs in human urine by liquid chromatography/quadrupole-time-of-flight mass spectrometry

Human phase I metabolism of four designer drugs, 2-desoxypipradrol (2-DPMP), 3,4-dimethylmethcathinone (3,4-DMMC), α-pyrrolidinovalerophenone (α-PVP), and methiopropamine (MPA), was studied using in silico and in vitro metabolite prediction. The metabolites were identified in drug abusers’ urine samples using liquid chromatography/quadrupole-time-of-flight mass spectrometry (LC/Q-TOF/MS). The aim of the study was to evaluate the ability of the in silico and in vitro methods to generate the main urinary metabolites found in vivo. Meteor 14.0.0 software (Lhasa Limited) was used for in silico metabolite prediction, and in vitro metabolites were produced in human liver microsomes (HLMs). 2-DPMP was metabolized by hydroxylation, dehydrogenation, and oxidation, resulting in six phase I metabolites. Six metabolites were identified for 3,4-DMMC formed via N-demethylation, reduction, hydroxylation, and oxidation reactions. α-PVP was found to undergo reduction, hydroxylation, dehydrogenation, and oxidation reactions, as well as degradation of the pyrrolidine ring, and seven phase I metabolites were identified. For MPA, the nor-MPA metabolite was detected. Meteor software predicted the main human urinary phase I metabolites of 3,4-DMMC, α-PVP, and MPA and two of the four main metabolites of 2-DPMP. It assisted in the identification of the previously unreported metabolic reactions for α-PVP. Eight of the 12 most abundant in vivo phase I metabolites were detected in the in vitro HLM experiments. In vitro tests serve as material for exploitation of in silico data when an authentic urine sample is not available. In silico and in vitro designer drug metabolism studies with LC/Q-TOF/MS produced sufficient metabolic information to support identification of the parent compound in vivo.

Simultaneous quantification of amphetamine, opiates, ketamine and relative metabolites in urine for confirmatory analysis by liquid chromatography tandem mass spectrometry

The rise in amphetamine, ketamine and opiates abuse in Taiwan has created a need for a reliable confirmatory assay. A method that combines superficially porous liquid chromatography tandem mass spectrometry (LC-MS/MS) with solid-phase extraction (SPE) was developed for the simultaneous quantification of amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), ketamine, opiates, and their corresponding metabolites in urine. The total run time of the method was 6.7min including equilibration time. The method was validated in accordance with the European Commission (EC) Decision 2002/642/EC. The within- and between-day precision was below 13.6% and the accuracy ranged from -17.1% to +9.9% for all analytes. Ion suppression was observed but compensated by using deuterated internal standards. No carryover was detected and the analytes were stable at room temperature for 16h, and for 72h at 4°C, and three-thaw cycles. The method was further validated by comparison with a reference gas chromatography-mass spectrometry (GC-MS) method, using 52 authentic urine samples. The results indicated that for the target analytes studied, the LC-MS/MS analysis was as precise, accurate, and specific as the GC-MS method. In conclusion, the present LC-MS/MS method is robust and reliable, and suitable for use as a confirmation assay in the simultaneous urine drug testing and quantification of amphetamines, ketamines, and opiates.

Rapid sample pre-treatment prior to GC–MS and GC–MS/MS urinary toxicological screening

Drug screening is an important issue in clinical and forensic toxicology. Gas chromatography coupled to mass spectrometry (GC–MS) remains the gold standard technique for the screening of unknown compounds in urine samples. However, this technique requires substantial sample preparation, which is time consuming. Moreover, some common drugs such as cannabis cannot be easily detected in urine using general procedures. In this work, a sample preparation protocol for treating 200μL of urine in less than 30min is described. The enzymatic hydrolysis of glucuro-conjugates was performed in 5min thanks to the use of microwaves. The use of a deconvolution software allowed reducing the GC–MS run to 10min, without impairing the quality of the compound identifications. Comparing the results from 139 authentic urine samples to those obtained using the current routine analysis indicated this method performed well. Moreover, additional 5-min GC–MS/MS programs are described, enabling a very sensitive target screening of 54 drugs, including THC–COOH or buprenorphine, without further sample preparation. These methods appeared as an interesting alternative to immuno-assays based screening. The analytical strategy presented in this article proved to be a promising approach for systematic toxicological analysis (STA) of drugs in urine.

Mass spectrometric detection of peginesatide in human urine in doping control analysis

Erythropoiesis-stimulating agents (ESAs) have frequently been confessed to be illicitly used in elite sports due to their endurance enhancing effects. Recently, peginesatide, the first representative of a new generation of ESAs, referred to as Erythropoietin (EPO)-mimetic peptides, obtained approval in the USA under the trade name Omontys(®) for the treatment of anaemic patients. Lacking sequence homology with EPO, it consists of a pegylated homodimeric peptide of approximately 45 kDa, and thus, specific approaches for the determination of peginesatide in blood were developed as conventional detection assays for EPO do not allow for the analysis of the EPO-mimetic peptides. However, as urine specimens are the most frequently provided doping control samples and pharmacokinetic studies conducted in rats and monkeys revealed the excretion of the pegylated peptide into urine, a detection method for peginesatide in urine would be desirable. A mass spectrometric assay in human urine was developed consisting of protein precipitation with acetonitrile followed by proteolytic digestion after the removal of the acetonitrile fraction under reduced pressure. Purification and concentration of the resulting proteotypic target peptide was accomplished by means of solid-phase extraction on strong cation-exchange resin prior to liquid chromatographic-tandem mass spectrometric analysis. Method validation was performed for qualitative purposes and demonstrated specificity, precision, linearity as well as sufficient sensitivity (limit of detection: 0.5 ng/ml) while proof-of-concept for the applicability of the assay for the determination of peginesatide in authentic urine samples was obtained by analyzing animal in vivo specimens collected after a single i.v. administration of peginesatide over a period of 4 days.

Synthesis and bioanalytical evaluation of morphine‐3‐O‐sulfate and morphine‐6‐O‐sulfate in human urine and plasma using LC‐MS/MS

The aim of this work was to synthesize morphine-3-O-sulfate and morphine-6-O-sulfate for use as reference substances, and to determine the sulfate conjugates as possible heroin and morphine metabolites in plasma and urine by a validated LC-MS/MS method. Morphine-6-O-sulfate and morphine-3-O-sulfate were prepared as dihydrates from morphine hydrochloride, in overall yields of 41 and 39% with product purities of >99.5% and >98%, respectively. For bioanalysis, the chromatographic system consisted of a reversed-phase column and gradient elution. The tandem mass spectrometer was operated in the positive electrospray mode using selected reaction monitoring, of transition m/z 366.15 to 286.40. The measuring range was 5-500 ng/mL for morphine-3-O-sulfate and 4.5-454 ng/mL for morphine-6-O-sulfate in plasma. In urine, the measuring range was 50-5000 ng/mL for morphine-3-O-sulfate and 45.4-4544 ng/mL for morphine-6-O-sulfate. The intra-assay and total imprecision (coefficient of variation) was below 11% for both analytes in urine and plasma. Quantifiable levels of morphine-3-O-sulfate in authentic urine and plasma samples were found. Only one authentic urine sample contained a detectable level of morphine-6-O-sulfate, while no detectable morphine-6-O-sulfate was found in plasma samples.

Liquid Chromatography-Tandem Mass Spectrometry Screening Method for the Simultaneous Detection of Stimulants and Diuretics in Urine

This study established a simultaneous screening method based on solid-phase extraction and liquid chromatography-tandem mass spectrometry (LC-MS-MS) for the detection of 23 stimulants and 23 diuretics in human urine. An electrospray ionization source and multiple reaction monitoring were used for data acquisition. All stimulants and diuretics were separated in less than 12.52 min. The limits of detection were in the range of 25-500 ng/mL for stimulants and 25-125 ng/mL for diuretics. To evaluate the performance of this method, urine samples were collected from 1627 athletes in Taiwan, and 7 positive samples were found. This LC-MS-MS method not only meets the minimum required performance limits set by the World Anti-Doping Agency but also provides a fast way to analyze the authentic urine samples in doping control laboratories.

An inter-laboratory comparison of urinary 3-hydroxypropylmercapturic acid measurement demonstrates good reproducibility between laboratories

BackgroundBiomarkers have been used extensively in clinical studies to assess toxicant exposure in smokers and non-smokers and have recently been used in the evaluation of novel tobacco products. The urinary metabolite 3-HPMA, a metabolite of the major tobacco smoke toxicity contributor acrolein, is one example of a biomarker used to measure exposure to tobacco smoke. A number of laboratories have developed liquid chromatography with tandem mass spectrometry (LC-MS/MS) based methods to measure urinary 3-HPMA; however, it is unclear to what extent the data obtained by these different laboratories are comparable.FindingsThis report describes an inter-laboratory comparison carried out to evaluate the comparability of 3-HPMA measurement between four laboratories. A common set of spiked and authentic smoker and non-smoker urine samples were used. Each laboratory used their in-house LC-MS/MS method and a common internal standard. A comparison of the repeatability ('r'), reproducibility ('R'), and coefficient of variation for 3-HPMA demonstrated that within-laboratory variation was consistently lower than between-laboratory variation. The average inter-laboratory coefficient of variation was 7% for fortified urine samples and 16.2% for authentic urine samples. Together, this represents an inter-laboratory variation of 12.2%.ConclusionThe results from this first inter-laboratory comparison for the measurement of 3-HPMA in urine demonstrate a reasonably good consensus between laboratories. However, some consistent measurement biases were still observed between laboratories, suggesting that additional work may be required to further reduce the inter-laboratory coefficient of variation.

Anion exchange SPE and liquid chromatography–tandem mass spectrometry in GHB analysis

In this study, the extraction of γ-hydroxybutyrate (GHB) from urine using solid-phase extraction (SPE) is described. SPE was performed on anion exchange columns after samples of urine had been diluted with de-ionized water. After application of the diluted samples containing GHB-d 6 as an internal standard, the sorbent was washed with deionized water and methanol and dried. The GHB was eluted from the SPE column with a solvent consisting of methanol containing 6% glacial acetic acid. The eluent was collected, evaporated to dryness, and dissolved in mobile phase (100 μL) for analysis by liquid chromatography–tandem mass spectrometry (LC–MS/MS) in negative multiple reaction monitoring (MRM) mode. Liquid chromatography was performed in gradient mode employing a biphenyl column and a mobile phase consisting of acetontitrile (containing 0.1% formic acid) and 0.1% aqueous formic acid. The total run time for each analysis was less than 5 min. The limits of detection/quantification for this method were determined to be 50 and 100 ng/mL, respectively. The method was found to be linear from 500 ng/mL to 10,000 ng/mL ( r 2 > 0.995). The recovery of GHB was found to be greater than 75%. In this report, results of authentic urine samples analyzed for GHB by this method are presented. GHB concentrations in these samples were found to be range from less than 500 ng/mL to 5110 ng/mL.

Structure characterisation of urinary metabolites of the cannabimimetic JWH-018 using chemically synthesised reference material for the support of LC-MS/MS-based drug testing

As recently reported, the synthetic cannabinoid JWH-018 is the subject of extensive phase I and II metabolic reactions in vivo. Since these studies were based on LC-MS/MS and/or GC-MS identification and characterisation of analytes, the explicit structural assignment of the metabolites was only of preliminary nature, if possible at all. Here, we report the chemical synthesis of five potential in vivo metabolites of JWH-018 derivatives featuring an alkylcarboxy (M1), a terminal alkylhydroxy (M2), a 5-indolehydroxy (M3), an N-dealkylated 5-indolehydroxy (M4) and a 2'-naphthylhydroxy (5) analogue, respectively, and their characterisation by nuclear magnetic resonance spectroscopy. The collision-induced dissociation (CID) patterns of the protonated compounds were studied by high-resolution/high-accuracy tandem mass spectrometry (MS( n )) applying an LTQ Orbitrap with direct infusion and electrospray ionisation of target analytes. An unusual dissociation behaviour including a reversible ion-molecule reaction between a naphthalene cation (m/z 127) and water in the gas phase of the MS was shown to be responsible for nominal neutral losses of 10u in the course of the CID pathway. LC-MS/MS-supported comparison of synthesised reference standards with an authentic urine sample using an API 4000 QTrap mass spectrometer identified the synthetic JWH-018 analogues M1-M4 as true in vivo metabolites, presuming a chromatographic separation of potentially present regioisomeric analogues. Existing doping control methods were expanded and validated according to international guidelines in order to allow for the detection of the carboxy and the alkylhydroxy metabolites, respectively, as urinary markers for the illegal intake of the synthetic cannabinoid JWH-018. Both metabolites were quantified in authentic doping control urine samples that had been suspicious of JWH-018 abuse after routine screening procedures, and a stable isotope-labelled (13)C(8)-(15)N-carboxy metabolite was synthesised for future analytical applications.

Rapid and sensitive drug metabolism studies by SU-8 microchip capillary electrophoresis-electrospray ionization mass spectrometry

Monolithically integrated, polymer (SU-8) microchips comprising an electrophoretic separation unit, a sheath flow interface, and an electrospray ionization (ESI) emitter were developed to improve the speed and throughput of metabolism research. Validation of the microchip method was performed using bufuralol 1-hydroxylation via CYP450 enzymes as the model reaction. The metabolite, 1-hydroxybufuralol, was easily separated from the substrate ( R s = 0.5) with very good detection sensitivity (LOD = 9.3 nM), linearity (range: 50–500 nM, r 2 = 0.9997), and repeatability (RSD Area = 10.3%, RSD Migration time = 2.5% at 80 nM concentration without internal standard). The kinetic parameters of bufuralol 1-hydroxylation determined by the microchip capillary electrophoresis (CE)-ESI/mass spectrometry (MS) method, were comparable to the values presented in literature as well as to the values determined by in-house liquid chromatography (LC)-UV. In addition to enzyme kinetics, metabolic profiling was demonstrated using authentic urine samples from healthy volunteers after intake of either tramadol or paracetamol. As a result, six metabolites of tramadol and four metabolites of paracetamol, including both phase I oxidation products and phase II conjugation products, were detected and separated from each other within 30–35 s. Before analysis, the urine samples were pre-treated with on-chip, on-line liquid-phase microextraction (LPME) and the results were compared to those obtained from urine samples pre-treated with conventional C18 solid-phase extraction (SPE, off-chip cartridges). On the basis of our results, the SU-8 CE-ESI/MS microchips incorporating on-chip sample pre-treatment, injection, separation, and ESI/MS detection were proven as efficient and versatile tools for drug metabolism research.

Rapid quantification of tilidine, nortilidine, and bisnortilidine in urine by automated online SPE-LC-MS/MS

The opioid tilidine is a prodrug which is hepatically metabolized to active nortilidine and bisnortilidine. Due to the increasing abuse of tilidine by drug users and the lack of a specific immunoassay, we developed an analytical method for the quantification of tilidine, nortilidine, and bisnortilidine in urine suitable for screening. In a following step, this method was used to establish data on excretion kinetics of the substances in order to evaluate the time window of detection after a single oral dose of tilidine/naloxone and also was applied to authentic urine samples from correctional facilities. Urine samples were mixed with internal standard solution and extracted on a weak cation exchanger at pH 6 using a Symbiosis Pico system. The chromatographic separation was achieved within a 3.5-min run time on a Phenylhexyl column (50 × 2.0 mm, 5 μm) via gradient elution (methanol and 0.2% formic acid) at a flow rate of 0.50 mL/min. The ESI-MS/MS was performed on a QTrap 3,200 in positive multiple reaction monitoring mode using two mass transitions per analyte. Validating the method resulted in a lower limit of quantification of 1.0 μg/L followed by a linear calibration range to 100 μg/L for each analyte (r(2) > 0.99). The analytical method allowed the detection of a single dose of a commercially available tilidine solution up to 7 days after administration. Using this highly sensitive method, 55 of 3,665 urine samples were tested positive.

Feasibility of gas chromatography–microchip atmospheric pressure photoionization-mass spectrometry in analysis of anabolic steroids

Mass spectrometers equipped with atmospheric pressure ion sources (API-MS) have been designed to be interfaced with liquid chromatographs (LC) and have rarely been connected to gas chromatographs (GC). Recently, we introduced a heated nebulizer microchip and showed its potential to interface liquid microseparation techniques and GC with API-MS. This study demonstrates the feasibility of GC–microchip atmospheric pressure photoionization-tandem mass spectrometry (GC–μAPPI-MS/MS) in the analysis of underivatized anabolic steroids in urine. The APPI microchip provides high ionization efficiency and produces abundant protonated molecules or molecular ions with minimal fragmentation. The feasibility of GC–μAPPI-MS/MS in the analysis of six selected anabolic steroids in urine samples was studied with respect to intra-batch repeatability, linearity, linear range, and limit of detection (LOD). The method showed good sensitivity (LODs 0.2–1 ng/mL), repeatability (relative standard deviation < 10%), and linearity (regression coefficient ≥ 0.9995) and, therefore, high potential for the analysis of anabolic steroids. Quantitative performance of the method was tested with two authentic urine samples, and the results were in good agreement with those obtained with conventional GC–electron ionization-MS after derivatization.

Hydrophilic interaction liquid chromatography and accurate mass measurement for quantification and confirmation of morphine, codeine and their glucuronide conjugates in human urine

A hydrophilic interaction liquid chromatography–time-of-flight mass spectrometry (HILIC–TOFMS) method for the quantification and confirmation of morphine (M), codeine (C), morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G) and codeine-6-glucuronide (C6G) is presented. The method was validated in terms of specificity, selectivity, extraction recovery, accuracy, repeatability, linearity and matrix effect. After a straightforward sample preparation by solid phase extraction (SPE) the compounds were analyzed directly without the need for hydrolysis, solvent transfer, evaporation or reconstitution. The HILIC technique provided good chromatographic separation which was critical for isomers M3G and M6G. The analytes were detected after electrospray ionization (ESI) in positive mode with mass accuracies below 2 mDa using a 5-mDa window. A measurement range of 50–5000 ng/ml was applied for calibration using deuterated analogs as internal standards. The precision of the method was 5.7% and 10.2% (RSD) within and between days, respectively. The applicability of the method was demonstrated with authentic urine samples known to contain codeine and/or morphine and their intact glucuronide conjugates. Identification of the analytes was based on in-source collision induced dissociation (ISCID), applying three diagnostic ions with accurate mass.

Estimation of the Measurement Uncertainty by the Bottom-Up Approach for the Determination of Methamphetamine and Amphetamine in Urine

The measurement uncertainty (MU) of methamphetamine (MA) and amphetamine (AP) was estimated in an authentic urine sample with a relatively low concentration of MA and AP using the bottom-up approach. A cause and effect diagram was deduced; the amount of MA or AP in the sample, the volume of the sample, method precision, and sample effect were considered uncertainty sources. The concentrations of MA and AP in the urine sample with their expanded uncertainties were 340.5 +/- 33.2 ng/mL and 113.4 +/- 15.4 ng/mL, respectively, which means 9.7% and 13.6% of the concentration gave an estimated expanded uncertainty, respectively. The largest uncertainty originated from sample effect and method precision in MA and AP, respectively, but the uncertainty of the volume of the sample was minimal in both. The MU needs to be determined during the method validation process to assess test reliability. Moreover, the identification of the largest and/or smallest uncertainty source can help improve experimental protocols.

Simultaneous screening for and determination of 128 date-rape drugs in urine by gas chromatography–electron ionization-mass spectrometry

Date-rape drugs (DRDs) are used for the purpose of “drugging” unsuspected victims and raping or robbing them while under the influence of the drug. The wide variety of substances used for criminal purposes, their low concentrations in body fluids and, often, a long time delay between the event and clinical examination make comprehensive screening analysis of biological materials collected from crime victims for the presence of these drugs very difficult. Detection of a drug used to facilitate sexual assault in biological fluids can be very important evidence of a committed crime. The purpose of this study was to develop a simple GC–EI-MS screening procedure for date-rape drugs in urine. Target analytes were isolated by solid-phase extraction. 2-mL urine samples were extracted and then derivatized by using BSTFA + 1%TMCS reagent. Detection of all compounds was based on full-scan mass spectra and for each compound one ion was chosen for further quantification. The method allowed the simultaneous screening, detection and quantification of 128 compounds from different groups (number of compounds): opioids (20), amphetamines (11), GHB and related products (3), hallucinogens (9), benzodiazepines (18), antihistamines (9), antidepressants (14), selective serotonin-reuptake inhibitors (4), antipsychotics (7), barbiturates (7), other sedatives (5), muscle relaxants (2) and other drugs (19). The procedure can easily be expanded to encompass more substances. The developed method appeared to be suitable for screening for the target DRDs. The procedure was successfully applied to the analysis of authentic urine samples collected from victims of rapes and other crimes in routine casework.

Survivin expression is an independent prognostic factor in rectal cancer patients with and without preoperative radiotherapy

A study of liquid chromatography-triple quadrupole mass spectrometry (LC-MS-MS) with positive electrospray ionisation (ESI) for the determination of selected drugs in human tissues and body fluids such as blood, urine and hair is described. The possibility to screen for and quantify the 19 most commonly prescribed neuroleptics on the Swedish market and determine the presence of their major metabolites within a single LC-MS-MS analysis was evaluated on a PE Sciex API2000 instrument. Chromatographic conditions were optimised and the best separation, with individual retention times for most of the analytes, was obtained on a Zorbax SB-CN column within a 9-min gradient run. The MS-MS fragmentation conditions were optimised for each compound in order to obtain both specific fragments and high signal intensity. Since neuroleptics are a heterogeneous group of compounds, a markedly difference in collision energy needed to achieve fragments of the selected parent ions was seen and the number of fragments achieved varied as well. For sensitive quantification the transition of the most intense fragment of the protonated molecular ion (M + 1)(+) was selected for multiple reaction monitoring analysis. More than 70 transitions were finally included in the assay. Detection levels down to the lower ng/ml level were achieved for all analytes, but between analytes more than a 10-fold difference in signal response was seen. By evaluation of extracted ion chromatograms from the analysis of authentic human blood, urine and hair sample the proposed concept for rational drug analysis was found to be both selective and sensitive for the neuroleptics included. A great number of metabolites could be determined in blood, urine and hair as well. A full method validation was not performed since the objective was to evaluate the method design rather than to validate a final method set-up.

Development of a Homogeneous Immunoassay for the Detection of Zolpidem in Urine

Sleep disorders are common conditions that affect about 40 million people in the U.S every year, the most common of which is insomnia, which is characterized by difficulty falling or staying asleep. Zolpidem (Ambien) is a non-benzodiazepine prescription drug that is used to treat insomnia and is often preferred over the commonly used benzodiazepines due to a lesser side effect profile. This is because the non-benzodiazepine binding is more selective to GABA-A receptors versus the non-selective binding of benzodiazepines. With the increasing popularity of non-benzodiazepines, drug abuse and driving-while-impaired cases involving sleep-inducing drugs have risen. Therefore, a highly sensitive and rapid homogeneous immunoassay (EMIT-type assay) has been developed for the detection of zolpidem in urine. The zolpidem antibody is highly specific and does not cross-react with other newer sleep aids such as zopiclone and zaleplon. This assay has a detection limit of 5 ng/mL for zolpidem in urine. Further evaluation of this assay using liquid chromatography-tandem mass spectrometry (LC-MS-MS) analysis of authentic urine samples demonstrated that the accuracy of the assay is greater than 90%. Because this assay is designed to measure the non-conjugated drug in urine, it resulted in simplification for gas chromatography-MS or LC-MS-MS confirmation methods that do not require urine hydrolysis before solid-phase extraction or liquid-liquid extraction.

Development of a broad toxicological screening technique for urine using ultra-performance liquid chromatography and time-of-flight mass spectrometry

Withdrawal of the support for the REMEDi HS drug profiling system has necessitated its replacement within our laboratories with an alternative broad toxicological screening technique. To this end, a novel method, based on ultra-performance liquid chromatography (UPLC) and time-of-flight (TOF) mass spectrometry, was developed for the routine analysis of urine samples. Identification was achieved by comparison of acquired data to libraries containing more than 300 common drugs and metabolites, and was based on a combination of retention time, exact mass and fragmentation patterns. Validation data for the method is presented and comprised an evaluation of the following parameters: precision; transferability of the methodology between the six collaborating laboratories; specificity; extraction recovery and stability of processed samples; matrix effects and sensitivity. This paper presents the benefits of supplementary fragmentation data with particular regard to increasing specificity and confidence of identification and its usefulness with overdosed samples. The utility of the method was assessed by the parallel analysis of 30 authentic urine samples using the REMEDi HS and UPLC–TOF. The latter provided enhanced detection, leading to the identification of twice as many drugs. Furthermore it did not miss any compounds that were identified by REMEDi HS. The UPLC–TOF findings were further verified by a combination of data from three other conventional screening techniques, i.e., GC–MS, HPLC-DAD and UPLC–MS/MS.

Rapid GC–MS confirmation of amphetamines in urine by extractive acylation

Amphetamine and related derivatives are widely abused central- and psychostimulants. Detection of certain derivatives, such as methcathinone, by commonly available immunoassay screening techniques is insufficient. Multi-analyte confirmations for amphetamine type stimulants are therefore required, but traditional gas chromatography–mass spectrometry methods necessitate lengthy analytical procedures with prolonged sample turn-around times. A validated rapid GC–MS assay for urinary confirmation of amphetamine, methamphetamine, methcathinone, ephedrine, norephedrine, methylenedioxyamphetamine, methylenedioxymethamphetamine, methylenedioxyethylamphetamine and N-methyl-1-(3,4 methylenedioxyphenyl)-2-butanamine is reported. The method entailed in situ derivatization of urine specimens by extractive acylation with pentafluoropropionic anhydride, followed by rapid chromatography on a microbore capillary column. Analytes were separated in less than 3 min and quantified simultaneously by selected-ion monitoring using stable isotope substituted internal standards. The total instrument cycle-time was 6 min per sample. The limits of detection were between 1.5 ng/mL and 6.25 ng/mL for the various analytes. Intermediate precision and accuracy were in the range of 6.3–13.8% and 90.5–107.3% for the respective analytes at the lower limit of quantitation, and between 5.8–12.6% and 95.4–103.1% for the high control. Long-term storage of methcathinone positive specimens at −20 °C proved insufficient stability of this analyte. The proposed assay is precise and accurate for confirmation of amphetamine and derivatives in urine. The complementary approach of extractive-derivatization and fast GC–MS analysis is especially applicable in routine clinical settings where reduced sample turn-around times are required. Further investigation of cathinone as a possible metabolite of methcathinone is warranted, based on results from analyzed authentic urine samples.

Liquid chromatographic–mass spectrometric analysis of glucuronide‐conjugated anabolic steroid metabolites: method validation and interlaboratory comparison

Liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) method for simultaneous and direct detection of 12 glucuronide-conjugated anabolic androgenic steroid (AAS) metabolites in human urine is described. The compounds selected were the main metabolites detected in human urine after dosing of the most widely abused AAS in sports, e.g. methandienone, methenolone, methyltestosterone, nandrolone and testosterone, and certain deuterium-labeled analogs of these metabolites. Sample preparation and the LC-ESI-MS/MS method were optimized, validated, and the overall process was implemented and the results between seven laboratories were compared. All the metabolites were extracted simultaneously by solid-phase extraction (SPE) and analyzed by LC-ESI-MS/MS with positive ionization mode and multiple reaction monitoring (MRM). Recovery of the SPE for the AAS glucuronides was 89-100% and ten out of twelve compounds had detection limits in the range of 1-10 ng/ml in urine. The results for inter/intraday repeatability were satisfactory and the interlaboratory comparison with authentic urine samples demonstrated the ease of method transfer from one instrument setup to another. When equivalent triple quadrupole analyzers were employed the overall performance was independent from instrument manufacturer, electrospray ionisation (ESI) or atmospheric pressure chemical ionization (APCI) and liquid chromatohraphic (LC) column, whereas major differences were encountered when changing from one analyzer type to another, especially in the analysis of those AAS glucuronides ionized mainly as adducts.