GC-MS Screening Research Articles

Non-Target Screening Method for the Identification of Persistent and Emerging Organic Contaminants in Seafood and Sediment from Jakarta Bay

Identification of persistent and emerging organic contaminants in green mussels (Perna viridis), various fishes, banana shrimp (Penaeus merguiensis) and sediment samples from Jakarta Bay has been employed. A non-target GC-MS screening approach has identified more than 60 individual organic compounds from the whole fractions either non-polar, semi-polar or acidic-polar compounds. The substances comprised as persistent organic pollutants (POPs) including DDT (dichlorodiphenyl trichloroethane) and its metabolites as well as high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs). Noteworthy, a number of emerging contaminants detected in the present study have never been reported previously either from the same location or from Asian waters. They include some priority contaminants of non-persistence halogens and emission of technical products, such as di-iso-propylnaphthalenes (DIPNs) dichlorobenzene (DCB), dichlorodiphenyl chloroethene (DDMU) and phenylmethoxynaphthalene (PMN). In general, the concentration order of the priority organic contaminants was sediment > green mussel > fishes > shrimp. Further analysis based on the spatial distribution, individual concentrations and bioavailability suggested that some contaminants are applicable as molecular marker for the assessment of anthropogenic emission in Jakarta Bay, i.e. DIPNs, linear alkylbenzenes (LABs), phenylmethoxynaphthalene (PMN), PAHs, dichlorobenzene, DDT and its metabolites.

A qualitative screening and quantitative measurement of organic contaminants on different types of marine plastic debris

Chemical compounds present on plastic were characterised on different types of plastic litter and beached pellets, using a general GC–MS screening method. A variety of plastic related compounds, such as building blocks, antioxidants, additives and degradation products, were identified next to diverse environmental pollutants and biofilm compounds. A validated method for the analysis of PAHs and PCBs on beached pellets at the Belgian Coast, showed concentrations of ∑ 16 EPA-PAHs of 1076–3007ngg−1 plastic, while the concentrations of ∑ 7 OSPAR-PCBs ranged from 31 to 236ngg−1 plastic. The wide variety of plastic compounds retrieved in the general screening showed the importance of plastic as a potential source of contaminants and their degradation products.

P44: Detection and determination of methadone in oral fluid from patients admitted to a drug-maintenance program

Introduction Oral fluid (OF) is a combination of gingival crevicular fluid (composition similar to serum) and fluid released from salivary glands (parotid, submandibular and sublingual). It is an alternative matrix that may have advantages over blood and urine for drug analysis among patients in treatment programs. OF can be collected painlessly, rapidly, non-invasively and the risk of adulteration is considered to be much lower. The aim of the present study is to investigate if OF can be used as alternative to urine and blood samples to monitor drug abuse in opioid-dependent patients in methadone (MTD) maintenance therapy. Methods Gas chromatography-mass spectrometry has been applied for screening of MTD presence in OF. The liquid chromatography with conventional UV detection has been used for quantitative determination of MTD. The results are compared to those obtained from urine sample (GC-MS screening) and blood samples (HPLC quantitation) taken at the same time. The quantitative determination of MTD in OF is performed by based liquidliquid extraction (ethyl acetate) and that in blood – by solidphase extraction on mixed mode sorbent. Resultats There is a good correlation in identified drugs by the screening performed as well as MTD presence. MTD in OF was measured in concentration range from 0.08 to 3,10 μg/mL following daily 150 mg/day intake depending on time of sampling. The result is not directly related to MTD blood concentration (c.a. 0,20 μg/mL), as the kinetic is different in both samples. Conclusion OF can be considered as a suitable non-invasive sample for screening of MTD in opioid-dependent patients subjective on substitutive therapy. Depending on time of sampling the concentration of MTD is highly variable while that in blood seems to be more stable in time.

P61: Implementation of a systematic toxicological screening method for post-mortem analysis using a UPLC-QToF MS system

Introduction General unknown screening (GUS) is the procedure used by toxicologists in order to unambiguously identify the xenobiotics involved in an intoxication case. Due to its high specificity, GC-MS was long considered the gold standard for GUS in clinical and forensic toxicology. Still, GC-MS is poorly suited for the detection of several xenobiotics and their more hydrophilic metabolites. Here we describe the optimization and implementation of a comprehensive high-resolution drug screen in biological matrices using a Waters UPLC XEVO G2 QToF MS system. We also examined the transferability of the high-resolution spectral lists established on mirror systems by comparing our data against two other instruments of the same model and manufacturer using the same chromatographic separation (Humbert et al., 2012; Rosano et al., 2013). Methods Drugs and metabolites were extracted from spiked matrices using SPE cartridges or liquid-liquid extraction. Extracts were sequentially injected into a UPLC coupled to a hybrid quadrupole- time of flight system (MSe) in positive and negative ESI mode. Data was collected using MSe acquisition which performs two sets of acquisition simultaneously and compared to a list containing the exact mass, the retention time and the exact mass fragments as previously described (Humbert et al., 2012; Rosano et al., 2013). In order to optimize the extraction procedure, we modeled different approaches (reverse phase SPE, mixed-mode cation exchange SPE and liquid-liquid extraction) using 18 different xenobiotics frequently encountered in toxicological investigations. Results The most efficient extraction process was chosen using the following criteria: ion suppression, recovery and the limit of detection. Based on our data, mixed-mode cation exchange SPE demonstrated the best overall performance and was selected to be compared to our reference GC-MS screening method. We then evaluated the recoveries, ion suppression and the limits of detections for 225 xenobiotics which are part of our GC-MS screen. Overall our transferability study showed few discrepancies in mass or fragments generated. Retention time reproducibility was 99% using a retention time tolerance of 0.4min and 96% using a 0.3 window. Finally, we performed a comparison between the test LC-QToF method and our reference GC-MS method on real samples to evaluate its performance; several cases will be presented. In summary, these cases demonstrated that the LC-QTOF method was able to identify more xenobiotics in the following categories: benzodiazepine and stimulant metabolites (7-amino-clonazepam, 4-methylamphetamine and desmethyl-diphenhydramine), anti hypertensive drugs metabolite (OH-propranolol), antiretroviral drugs (such as ritonavir and darunavir) and hydrophilic anticonvulsant pregabalin. Conclusion Overall, the LC-QToF method demonstrates increased sensitivity compared to GC-MS and should be more specific. Our evaluation of the transferability of lists between labs indicates that retention variability could be an issue for a small fraction of compounds. Also, in order to detect some families of xenobiotics, such as barbiturates and NSAIDS, the addition of a second injection (using negative ionization) was necessary.

Compliance work for food contact materials: feasibility of the legally required safety assessment of an epoxy/amine-based coating for domestic water pipe restoration

Options were explored for fulfilling the legally required safety assessment for a widely applied epoxy/amine coating used for restoring corroded domestic drinking water supply systems. The coating was made up of two components mixed shortly before application, the first mainly consisting of bisphenol A diglycidyl ether (BADGE), the second of various amines. The analytically identified starting substances were all authorised, but only constituted a small proportion of the low molecular mass material left after curing and potentially migrating into water. Reaction products synthesised from constituents of the starting components (expected oligomers) could not be eluted from GC even after derivatisation, indicating that standard GC-MS screening would miss most potential migrants. They were detectable by size exclusion chromatography (SEC) after acetylation. HPLC with MS or fluorescence detection was possible for constituents including a BADGE moiety, but phenalkamines could not be detected with adequate sensitivity. Possibilities for determining long-term migration relevant for chronic toxicity are discussed. Analysis in water shortly after application of the coating overestimates migration if migration decreases over time and requires detection limits far out of reach. Analysis of a solvent extract of the coating is easier and provides an upper estimate of what could migrate into the drinking water over the years. However, to satisfy the regulatory requirements, components of the complex mixture need to be identified at lower proportions than those accessible. In vitro testing of the whole mixture for genotoxicity is expected to fail because of the required sensitivity and the glycidyl functions probably wrongly resulting in positive tests. The difficulties in dealing with this situation are discussed.

Suicide Due to Cyclizine Overdose

Cyclizine is an antihistamine with sedative effect used to treat motion sickness. A few studies have reported on cyclizine abuse among teenagers, and cyclizine abuse has been reported among opioid dependants receiving methadone, with the combination having been reported to produce strong psychoactive effects. Few reports exist on the possible toxic effects of cyclizine, and it is regarded as a safe drug most often sold as a non-prescription/over-the-counter drug. Very few cases of fatalities resulting from cyclizine overdose can be found in the literature. We present a case where a 22-year-old female was found unconscious and intoxication with drugs and alcohol was suspected. Whole blood from the femoral vein, urine and stomach content were collected during autopsy and screened for drugs of abuse and medicinal drugs. GC-MS screening of the stomach contents revealed presence of cyclizine and meclozine. Cyclizine and meclozine concentrations in blood were determined using a UPLC-MS-MS method. Quantification of femoral blood revealed a high concentration of cyclizine (16 mg/L), a low concentration of meclozine (0.2 mg/L) and ethanol 0.16 g/dL. No other medicinal drugs or drugs of abuse were detected. We report on a case of suicide where cyclizine was found to be the principal drug and question the safety of this drug.

Rapid and simultaneous extraction of acidic and basic drugs from human whole blood for reliable semi-quantitative NAGINATA drug screening by GC–MS

We present a rapid procedure for simultaneous extraction of a wide range of acidic and basic drugs from whole blood samples for reliable semi-quantitative NAGINATA drug screening by gas chromatography–mass spectrometry (GC–MS). To extract a wide range of drugs, the partition/extraction procedure used for the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) method was employed as the initial step. Various procedures were tested as the second step for the removal of whole blood impurities, including the use of primary secondary amine and C18 for the dispersive solid-phase extraction of the QuEChERS method, four kinds of silica-based C18 columns, alumina columns, and protein–lipid removal filter cartridges (Captiva ND Lipids). Subsequent GC–MS screening used the NAGINATA software with a constructed calibration-locking database for detection of acidic and basic drugs; drug detection ability, accuracy of tentative concentrations, and drug recoveries were examined and compared. We also examined the applicability of our established method in an actual forensic case. Our results showed that the number of drugs detectable at low concentrations was greatly increased by the use of the partition/extraction procedure of the QuEChERS method as the initial step and the protein–lipid removal filter cartridge as the second step. These combined steps provided notably clean extracts. Recoveries carefully measured with each reference standard were largely more than 60 %, and tentative concentrations obtained by the established screening method without reference standards were in the range of 48–310 % of the expected values for 65 acidic and basic drugs. Therefore, relatively reliable semi-quantitative values were obtained at the screening step without the need for each reference standard. We also experienced significant time savings for the extraction and in obtaining tentative concentrations at the screening step in an actual forensic case, indicating that the method is useful for rapid diagnosis of drug intoxication. Our proposed method should prove useful for semi-quantitative screening of a wide range of drugs and poisons in whole blood samples in clinical and forensic cases.

The Abuse of 3,4- Methylenedioxypyrrolidinobutyrophenone(MDPBP). A Case Report

The Abuse of 3,4-Methylenedioxypyrrolidinobutyrophenone (MDPBP): A Case Report The abuse of new designer drugs available on the black marketis increasing worldwide. Their use has, in some cases, led to fatal overdoses in addition to other adverse social and health effects, yet revealing the cause of the potential intoxication has so far proven difficult on account of the absence of appropriate analytical data for the drug in question as well as the lack ofspecific knowledge of how it is metabolized. The case outlined here concerns abuse of an unspecified drug nicknamed “Funky”.Simultaneous general GC-MS screening and ultra-high resolution accurate mass liquid chromatography-mass spectrometry toxicological analysis of the subject’s urine confirmed the presence of 3,4 methylenedioxypyrrolidinobutyrophenone, one of the new synthetic cathinones. The parent drug in the urine sample was accompanied by a dominant metabolite, which was most likely one of the two possible stereoisomers produced by demethylenation and subsequent O-methylation of the hydroxy group. This was the first confirmation of MDPBP abuse in the Czech Republic supported by the toxicological identification of MDPBP and its dominant metabolite in human urine.

Physical Composition, Nutrients and Contaminants of Typical Waste Dumping Sites

Problem statement: The composition of wastes is quite variable depending upon the generating source and mode of collection. Most of the material from the domestic activities will be organic in nature and contains essential plant nutrients, whereas the dumping material of commercial and industrial wastes usually contains appreciable amounts of heavy and potentially toxic metals and organic pollutants. Approach: Objective of the present study was to characterize the physico-chemical properties of the waste material and the distribution and extent of toxic pollutants in three selected typical dumping sites in the state of Haryana, India. Results: 62-65% of the waste fine material consisted of mineral particles and biodegradable organic waste, 20-25% consisted of construction and demolition waste and the remaining 10-15% were other materials such as study, plastic, metals, glass and timber, with an amount of polyethene of 3.4-5.7%. The ratio of the plant available concentrations of P, K and S and their total amounts were 3-7% for P and 1-4% for S, whereas the macronutrient potassium reached values of 29-39%. Metals As, Ba, Cd, Cr, Cu, Ni, Pb and Zn were present in all samples (total concentration in aqua regia extract). As, Ba, Ni and Pb did not show clear differences between the three investigates sites. Cd, Cr and Zn concentrations were high but different at the different sites (Cu maximum: 1,964 mg kg−1, Zn maximum: 2,200 mg kg−1). The mobility of the metals was calculated as the ratio of DTPA/aqua regia extraction. Cd showed the highest ratio (18-22%), while the other calculated metals showed much lower ratios (Cu 6.7, Pb 7.9 Ni 2.1, Zn 3.6 and Cr 0.5%). In general, PAH and benzo(a)pyrene concentrations fell below the detection limit. Also the phenol index did not exceed the detection limit of 1.2 mg kg−1 (with two exceptions). In 14 out of 36 samples a GC-MS screening was conducted in order to get an overview of the organic pollutants usually present in the dumpsites. In all cases there was no relevant amount of organic pollutants that would be capable of measurement. Conclusion: The dumping sites are plant nutrient deposits, particularly for K, which could be used in future in a line with ideas of urban mining. The use of the waste material for fertilizing purposes may be restricted due to the metal contaminant concentrations. The analyzed organic pollutants did not indicate problematical concentrations.

Separation and structural characterization of a synthetic cannabinoid found in a herbal product using off-line LC-DAD-NMR

A herbal product confiscated by the Finnish Customs was analyzed. No illegal compounds were found in the preliminary GC-MS screening against the mass spectral library. The most prominent compounds in the sample, however, could not be identified. These compounds of interest were characterized using an off-line LC-DAD-NMR technique with a mass-sensitive microcoil probehead. The structural analysis, confirmed by GC-MS and LC-MS studies, revealed the presence of a CP 47,497-C8 type compound with a structural modification in the cyclohexyl part of the compound. The structural modification of this potentially psychoactive compound was presumably intended to elude routine screening.

Chemical Composition of Bioactive Compounds by GC-MS Screening and Anti-fungal Properties of the Crude Extracts of Cabbage Samples

Chemical Composition of Bioactive Compounds by GC-MS Screening and Anti-fungal Properties of the Crude Extracts of Cabbage Samples

Automated Mass Spectral Deconvolution and Identification System for GC-MS Screening for Drugs, Poisons, and Metabolites in Urine

The challenge in systematic toxicological analysis using gas chromatography and/or liquid chromatography coupled to mass spectrometry is to identify compounds of interest from background noise. The large amount of spectral information collected in one full-scan MS run demands the use of automated evaluation of recorded data files. We evaluated the applicability of the freeware deconvolution software AMDIS (Automated Mass Spectral Deconvolution and Identification System) for GC-MS-based systematic toxicological analysis in urine for increasing the speed of evaluation and automating the daily routine workload. We prepared a set of 111 urine samples for GC-MS analysis by acidic hydrolysis, liquid-liquid extraction, and acetylation. After analysis, the resulting data files were evaluated manually by an experienced toxicologist and automatically using AMDIS with deconvolution and identification settings previously optimized for this type of analysis. The results by manual and AMDIS evaluation were then compared. The deconvolution settings for the AMDIS evaluation were successfully optimized to obtain the highest possible number of components. Identification settings were evaluated and chosen for a compromise between most identified targets and general number of hits. With the use of these optimized settings, AMDIS-based data analysis was comparable or even superior to manual evaluation and reduced by half the overall analysis time. AMDIS proved to be a reliable and powerful tool for daily routine and emergency toxicology. Nevertheless, AMDIS can identify only targets present in the user-defined target library and may therefore not indicate unknown compounds that might be relevant in clinical and forensic toxicology.

New method for the study of Amaryllidaceae alkaloid biosynthesis using biotransformation of deuterium-labeled precursor in tissue cultures.

Biotransformation of deuterated-4'-O-methylnorbelladine into alkaloids galanthamine and lycorine in tissue cultures of Leucojum aestivum was demonstrated using HPLC coupled to mass spectrometry. GC-MS screening was also carried to investigate other native and deuterated alkaloids. A total of six labeled alkaloids were identified indicating that 4'-O-methyl-d(3)-norbelladine is incorporated into three different groups of Amaryllidaceae alkaloids that are biosynthesized by three modes of intramolecular oxidative phenol coupling.

Filter-based treatment of leachate from an industrial landfill containing shredder residues of end-of-life vehicles and white goods

A pilot plant was set up to treat leachate from an industrial landfill containing shredder residues of end-of-life vehicles and white goods. The treatment plant consisted of aeration and sedimentation steps for pre-treatment, and a filter. The plant was designed to simultaneously remove various types of pollutants. The efficiencies of pre-treatment and of the main treatment step were investigated over a period of 3 years at the landfill site. By continuous aeration of the leachate the concentrations of Fe and Mn were reduced by 55% and 49%, respectively. By prolonged sedimentation suspended solid content was noticeably reduced (72%). In the filter, consisting of a mixture of peat and carbon-containing ash as a treatment medium, very high reduction of polar organic compounds, e.g. phenol (74%), o-and p-cresol (91%), and 2,4-dimethylphenol (73%), high average reduction of metals, e.g. Pb (78%), Fe (74%), Cu (73%), Mn (56%), Sn (55%), and Zn (47%), and good average reduction of DOC (26%), Tot-N (23%) and NH4-N (46%) were achieved. Sixty non-polar compounds in the leachate, identified by GC-MS screening, occurred at trace level. Most of them were considerably reduced in the filter.

Influence of extraction techniques on GC–MS screening results

Gas chromatography coupled with mass spectrometry (GC-MS) is often used as a confirmatory technique for positive results obtained with immunoassay screening tests, but it can also be used as a screening method in clinical and forensic toxicology. Because of different reasons (amount of sample available, urgency, cost of analysis, etc.), laboratory is often in position to perform just one extraction and screening per sample. Influence of different extraction procedures on results is usually overlooked, but it can have great impact on obtained results, both quantitatively and qualitatively. We prepared four different levels of commercial urine toxicology control samples Liquichek (BIO-RAD), containing 12 drugs-ofabuse using three different extraction procedures: liquid– liquid extraction system TOXI-TUBES A (VARIAN), liquid–liquid extraction system Chem Elut (VARIAN) and solid phase extraction system based on Amberlite XAD2 polymeric adsorbent columns (Sigma–Aldrich). All extracts were analyzed with GC-MS (SHIMADZU GCMS-QP5050A). Obtained results are presented and influence of extraction procedure on GC-MS screening results is evaluated for every extraction procedure.

Estrogenicity profile and estrogenic compounds determined in river sediments by chemical analysis, ELISA and yeast assays

An effects-directed strategy was applied to bed sediments of a polluted tributary in order to isolate and identify the major estrogenic chemicals it discharges into the River Po, the principal Italian watercourse. Sediment extract was concentrated by solid phase extraction and then fractioned into 10 fractions by reversed phase high performance liquid chromatography (RP-HPLC). Estrogenic activity of whole extract and fractions were determined using a recombinant yeast assay containing the human estrogen receptor (YES). The 10 fractions and whole extract were analysed for target compounds, e.g. estrone (E1), 17β-estradiol (E2), estriol (E3), 4-nonylphenol (NP), 4- tert-octylphenol ( t-OP), bisphenol A (BPA), using both liquid chromatography–tandem mass spectrometry (LC–MS/MS) and non-competitive enzyme-linked immunosorbent assays (ELISA). The YES assay determined high estrogenic activity in whole sediment (15.6 ng/g EE2 equivalents), and positive results for fractions nr 1, 2, 6, 7 and 8. E1, E3 and NP were the main estrogenic chemicals, however, other unidentified compounds contributed to sediment estrogenicity, particularly for polar fractions nr 1 and 2. A GC–MS screening performed in scan mode identified other potential contributors such as phthalates (DBP, BBP), and OP isomers. A next sampling campaign extended to other tributaries and receiving stretches of the River Po confirmed E1, E3 and NP as major estrogenic chemicals potentially threatening other sites of the main river. In general, target compound ELISAs have been shown to be suitable tools for a rapid screening of wide areas or large numbers of environmental samples for estrogenic risk. The potential for interferences suggests however to use cautiously the concentration values obtained from some of the immunoassays.

Detection and identification of atypical quetiapine metabolite in urine

Abstract Quetiapine fumarate (Seroquel®) is an atypical antipsychotic dibenzothiazepine derivative. Due to its extensive hepatic metabolism and low level of unchanged excretion (< 1%) the routine toxicological drug-screening analyses of urine often leads to false negative results. In the present study, we report that a newly identified metabolite of quetiapine, N-desalkylquetiapine, can be used as an indicative marker of quetiapine-intake in urine using common GC-MS screening procedure. The structure of the mentioned metabolite was solved from the mass-spectrum obtained and the quetiapine presence was proved by consequent HPLC plasma analysis.

Application of LC–ESI–MS–MS for detection of synthetic adulterants in herbal remedies

Adulteration of allegedly “natural herbal medicines” with undeclared synthetic drugs is a common and dangerous phenomenon of alternative medicine. The purpose of the study was to develop a procedure for detection of most common synthetic adulterants in herbal remedies, using high-pressure liquid chromatography-electrospray tandem mass spectrometry (LC–ESI–MS–MS). Eighty drugs belonging to various pharmacological classes were included in the study. For most drugs two transitions were monitored, using protonated or deprotonated molecules as precursor ions. The drugs were isolated from herbal remedies using simple methanol extraction. Chromatographic separation was done in gradient of acetonitrile—10 mM ammonium formate buffer (pH 3.0). Drugs tested were grouped in suites, comprising analgesic drugs, antibiotics, antidiabetic drugs, antiepileptic drugs, aphrodisiacs, hormones and anabolic drugs, psychotropic drugs, and weight reducing compounds. These suites were used according to the declared benefits of examined preparations. Limits of detection ranged from 5 pg to 1 ng per injected sample. Drug-free herbal remedy spiked with eight various pharmaceuticals occurring in adulterated herbal preparations was used for internal proficiency testing. The recoveries of spiked drugs ranged from 63 to 100%. The procedure was applied in everyday casework. Several undeclared drugs were identified in “herbal” remedies, like e.g. sildenafil, tadalafil, testosterone, or glibenclamide. Pharmacological properties of detected drugs always corresponded with the claims of the “natural” remedies. The method presents a valuable extension of standard GC–MS screening used for this purpose.

Analysis for Identification in Amnesty Bin Samples from Dance Venues

The analysis of unknown substances discarded in amnesty bins, first described by Ramsey et al, from a large central London club and 7 smaller clubs in Manchester, UK are described. The contents of the bins were collected between July 2003 and March 2004. Solid dosage formulations were identified using the TICTAC database, chemical tests, and GC-MS screening. Drugs that could not be readily identified were subjected to other analytical techniques. The goal was to document the current range of drugs available on the dance scene and compare the findings between the London club, which had been the subject of a previous survey, and Manchester clubs. More than 1000 tablets, capsules, and powder doses were discarded in the amnesty bins. Tablets containing only MDMA (ecstasy) were found to be >94% and >84% of the total in London and Manchester, respectively. Although the quantities of tablets and powders recovered were different between London and Manchester, the proportions of the drugs were remarkably similar. The most common drugs found in powders in London and Manchester respectively were cocaine (29%, 40%), amphetamine (25%, 26%), ketamine (19%, 20%), and MDMA (19%, 11%).

Validation of a GC-MS Screening Method for Anabolizing Agents in Aqueous Nutritional Supplements

A sensitive and selective method for the screening of anabolizing agents in aqueous nutritional supplements is described and validated. A total of 28 different anabolizing agents are screened for, including testosterone and prohormones, nandrolone and prohormones, stanozolol, and metandienone. The different analytes are extracted from the aqueous nutritional supplements by liquid-liquid extraction with a mixture of pentane and freshly distilled diethylether (1:1) after the supplements have been made alkaline with a NaHCO3-K2CO3 (2:1) buffer. The anabolizing agents are derivatized with a mixture of MSTFA-NH4I-ethanethiol (320:1:2) as routinely used for the screening of anabolic steroids extracted from urine. The derivatives are analyzed by gas chromatography (GC)-mass spectrometry (MS) in the selective ion monitoring mode. The limits of detection range from 1 to 10 ng/mL. One aqueous nutritional supplement (creatine serum) was analyzed with this screening method and was found to contain dehydroepiandrosterone (DHEA) at very low concentrations. The presence of DHEA could be confirmed with GC-MS-MS. Results of the application of this method and a similar method for solid nutritional supplements previously described are given.