Journal of Chromatography B (v.789, #1)
Editorial Board (iii).
Systematic toxicological analysis: computer-assisted identification of poisons in biological materials by Th. Stimpfl; W. Demuth; K. Varmuza; W. Vycudilik (3-7).
A new software was developed to improve the chances for identification of a “general unknown” in complex biological materials. To achieve this goal, the total ion current chromatogram was simplified by filtering the acquired mass spectra via an automated subtraction procedure, which removed mass spectra originating from the sample matrix, as well as interfering substances from the extraction procedure. It could be shown that this tool emphasizes mass spectra of exceptional compounds, and therefore provides the forensic toxicologist with further evidence—even in cases where mass spectral data of the unknown compound are not available in “standard” spectral libraries.
Comparison of a preliminary procedure for the general unknown screening of drugs and toxic compounds using a quadrupole-linear ion-trap mass spectrometer with a liquid chromatography–mass spectrometry reference technique by P. Marquet; F. Saint-Marcoux; T.N. Gamble; J.C.Y. Leblanc (9-18).
Liquid chromatography–tandem mass spectrometry (LC–MS–MS) might be a complement to GC–MS and HPLC–diode array detection for the general unknown screening (GUS) of drugs and toxic compounds, particularly when using information- or data-dependent acquisition (IDA or DDA), an auto-adaptive MS–MS product-ion scan mode where, at each unit time, the m/z ratios above a given intensity threshold are selected for fragmentation. A new quadrupole-linear ion-trap mass spectrometer (LC-QqQlinear ion-trap) was evaluated for GUS using IDA. For the first detection step (so-called “survey scan”) the single quadrupole “enhanced” MS mode (EMS), where ions are accumulated then filtered in the Q3-linear ion-trap, was used. The so-called “enhanced” parent ion scan mode (EPI) used at two alternated fragmentation energies gave the best signal intensity and the best mass spectral information when adding mass spectra obtained in low and high fragmentation conditions, respectively, both in the positive (+20 and +50 eV) and negative (−15 and −40 eV) modes. Solid-phase extracts of serum spiked with eight test compounds (chosen for their retention times distributed along the 30-min long chromatogram and for ionising in both the positive and negative modes) were analysed in parallel with this LC–MS–MS technique and with a reference LC–MS method run on a single-quadrupole instrument where low and high in-source fragmentation conditions in the positive and the negative ion modes are alternated. A C18, 5 μm (150×1 mm I.D.) column and a gradient elution of acetonitrile in pH 3, 2 mM ammonium formate, were used for both. Higher signal-to-noise ratios were obtained with the LC-QqQlinear ion-trap instrument than with the reference technique, resulting in mass spectra devoid of contaminant ions and at least as informative as the reconstructed single-MS spectra. After optimisation of the IDA intensity threshold for the detection of tiny chromatographic peaks in noise, five out of the eight compounds (milrinone, lorazepam, fluometuron, piretanide and warfarin) could be unambiguously identified at the concentration of 0.1 mg/l in serum, in the positive or negative modes, or in both, versus only two by LC–MS. All of them could be identified at 1 mg/l by both techniques. These preliminary results show that the sensitivity and mass structural information brought by this new LC-QqQlinear ion-trap instrument may help design an efficient toxicological GUS procedure.
Suitability testing of commercial solid-phase extraction sorbents for sample clean-up in systematic toxicological analysis using liquid chromatography–(tandem) mass spectrometry by Tineke N Decaestecker; Evelien M Coopman; Carlos H Van Peteghem; Jan F Van Bocxlaer (19-25).
An entire series of SPE sorbents, classified into three different categories (apolar, mixed-mode and polymeric) was evaluated for sample preparation of a data-dependent LC–MS–MS “general unknown” screening procedure. An extraction procedure was formulated for each individual column, in agreement with the enclosed instructions, according to the characteristics of each packing. For conciseness, only neutral and basic compounds were chosen for this sorbent suitability test. Thus, the goal of our research was to select the best sorbent with regard to extraction yield and cleanliness of the extracts, all with respect to data-dependent acquisition (DDA) mediated LC–MS–MS general unknown screening. We conclude that for that purpose an Isolute™ C8 sorbent performs best in terms of extraction yield and clean-up potential.
New designer drug p-methoxymethamphetamine: studies on its metabolism and toxicological detection in urine using gas chromatography–mass spectrometry by Roland F. Staack; Josef Fehn; Hans H. Maurer (27-41).
Studies are described on the metabolism and the toxicological analysis of the new designer drug rac-p-methoxymethamphetamine (PMMA) in rat urine using gas chromatography–mass spectrometry (GC–MS). The identified metabolites indicated that PMMA was extensively metabolized mainly by O-demethylation to pholedrine and to a minor extent to p-methoxyamphetamine (PMA), 1-hydroxypholedrine diastereomers (one being oxilofrine), 4′-hydroxy-3′-methoxymethamphetamine and 4′-hydroxy-3′-methoxyamphetamine. The authors’ systematic toxicological analysis (STA) procedure using full-scan GC–MS after acid hydrolysis, liquid–liquid extraction and microwave-assisted acetylation allowed the detection of the main metabolites of PMMA in rat urine after a dose corresponding to that of drug users. Therefore, this procedure should be suitable for detection of PMMA intake in human urine via its metabolites. However, it must be considered that pholedrine and oxilofrine are also in therapeutic use. Differentiation of PMMA, PMA and/or pholedrine intake is discussed.
Studies on the metabolism and toxicological detection of the Eschscholtzia californica alkaloids californine and protopine in urine using gas chromatography–mass spectrometry by Liane D. Paul; Hans H. Maurer (43-57).
Eschscholtzia californica preparations are in use as phytopharmaceuticals and as herbal drugs. Studies are described on the metabolism and the toxicological analysis of the Eschscholtzia californica alkaloids californine and protopine in rat urine using gas chromatography–mass spectrometry. The identified metabolites indicated that californine is extensively metabolized by N-demethylation and/or single or double demethylenation with consecutive catechol-O-methylation of one of the hydroxy groups. Protopine, however, only undergoes extensive demethylenation of the 2,3-methylenedioxy group followed by catechol-O-methylation. All phenolic hydroxy metabolites were found to be partly conjugated. The authors’ systematic toxicological analysis procedure using full-scan gas chromatography–mass spectrometry after acid hydrolysis, liquid–liquid extraction and microwave-assisted acetylation allowed the detection of the main metabolites of californine and protopine in rat urine after a dose which should correspond to that of drug users. Therefore, use of Eschscholtzia californica preparations should also be detectable in human urine by the authors’ systematic toxicological analysis procedure.
Keywords: Alkaloids; Californine; Protopine;
Determination of amphetamines in human urine by headspace solid-phase microextraction and gas chromatography by Nikolaos Raikos; Klio Christopoulou; Georgios Theodoridis; Heleni Tsoukali; Dimitrios Psaroulis (59-63).
Solid-phase microextraction (SPME) is under investigation for its usefulness in the determination of a widening variety of volatile and semivolatile analytes in biological fluids and materials. Semivolatiles are increasingly under study as analytical targets, and difficulties with small partition coefficients and long equilibration times have been identified. Amphetamines were selected as semivolatiles exhibiting these limitations and methods to optimize their determination were investigated. A 100-μm polydimethylsiloxane (PDMS)-coated SPME fiber was used for the extraction of the amphetamines from human urine. Amphetamine determination was made using gas chromatography (GC) with flame-ionization detection (FID). Temperature, time and salt saturation were optimized to obtain consistent extraction. A simple procedure for the analysis of amphetamine (AMP) and methamphetamine (MA) in urine was developed and another for 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxy-N-methamphetamine (MDMA) and 3,4-methylenedioxy-N-ethylamphetamine (MDEA) using headspace solid-phase microextraction (HS-SPME) and GC–FID. Higher recoveries were obtained for amphetamine (19.5–47%) and methamphetamine (20–38.1%) than MDA (5.1–6.6%), MDMA (7–9.6%) and MDEA (5.4–9.6%).
Routine analysis of amphetamine and methamphetamine in biological materials by gas chromatography–mass spectrometry and on-column derivatization by Manami Nishida; Akira Namera; Mikio Yashiki; Tohru Kojima (65-71).
A simple determination method of amphetamine (AP) and methamphetamine (MA) in biological materials was developed using on-column derivatization and gas chromatography–mass spectrometry (GC–MS). AP and MA in biological materials were adsorbed on the surface of Extrelut and then extracted and derivatized simultaneously on the Extrelut column. AP and MA were derivatized to the N-propoxycarbonyl derivatives using propylchloroformate. Pentadeuterated MA was used as an internal standard. The recoveries of AP and MA from urine were 88.2 and 92.5%, and those from blood were 89.7 and 90.3%, respectively. The calibration curves showed linearity in the range of 12.5–2000 ng/ml (ng/g) for AP and MA in urine and blood, and 0.25–20 ng/mg in hair. When urine samples containing two different concentrations (200 and 1000 ng/ml) of AP and MA, blood samples containing two different concentrations (200 and 1000 ng/g) of AP and MA, hair samples containing two different concentrations (0.5 and 5.0 ng/mg) of AP and MA, the coefficients of variation of intra-day and inter-day were 0.68–3.60% in urine, 0.42–4.58% in blood, and 1.20–13.1% in hair. Furthermore, this proposed method was applied to a medico-legal case of MA intoxication.
Keywords: Amphetamine; Methamphetamine;
Solid-phase micro-extraction–gas chromatography–mass spectrometry and headspace-gas chromatography of tetrahydrocannabinol, amphetamine, methamphetamine, cocaine and ethanol in saliva samples by Mauricio Yonamine; Nadia Tawil; Regina Lucia de Moraes Moreau; Ovandir Alves Silva (73-78).
In the present work, a method was developed aiming at the serial detection of tetrahydrocannabinol (THC), amphetamine, methamphetamine, cocaine and ethanol in saliva. Saliva samples were submitted to an initial headspace procedure for ethanol determination by gas chromatography/flame ionization detector (GC–FID). After this step, two consecutive solid-phase micro-extractions (SPME) were carried out: THC was extracted by submersing a polydimethylsiloxane fiber (100 μm) in the vial for 20 min; amphetamine, methamphetamine and cocaine were subsequently extracted after alkalinization. Derivatization of the amphetamines was carried out directly in the solution by adding 2 μl of butylchloroformate. Gas chromatography–mass spectrometry (GC–MS) was used to identify the analytes in selected ion monitoring (SIM) mode. Confidence parameters of validation of the method were: recovery, linearity, intra- and inter-assay precision as well as limits of detection and quantification of the analytes. The limits of quantification (LOQ) obtained were: ethanol (0.010 g/l); amphetamine (5.0 ng/ml); methamphetamine (0.5 ng/ml); cocaine (5 ng/ml) and THC (5 ng/ml). The method proved to be highly precise (coefficient of variation<8%) for all detected substances.
Keywords: Tetrahydrocannabinol; Amphetamine; Methamphetamine; Cocaine; Ethanol;
New designer drug 4′-methyl-α-pyrrolidinohexanophenone: studies on its metabolism and toxicological detection in urine using gas chromatography–mass spectrometry by Dietmar Springer; Frank T. Peters; Giselher Fritschi; Hans H. Maurer (79-91).
R,S-4′-Methyl-α-pyrrolidinohexanophenone (MPHP) is a new designer drug which has appeared on the illicit drug market. The aim of this study was to identify the MPHP metabolites using solid-phase extraction, ethylation or acetylation, as well as to develop a toxicological detection procedure in urine using solid-phase extraction, trimethylsilylation and GC–MS. Analysis of urine samples of rats treated with MPHP revealed that MPHP was completely metabolized by hydroxylation of the tolyl methyl group followed by dehydrogenation to the corresponding carboxylic acid, hydroxylation of the side chain, hydroxylation of the pyrrolidine ring with subsequent dehydrogenation to the corresponding lactam and/or reduction of the keto group. The carboxy and/or hydroxy groups were found to be only partly conjugated. Based on these data, MPHP could be detected in urine via its metabolites by GC–MS using mass chromatography for screening and library search for identification.
Hair analysis for opiates: evaluation of washing and incubation procedures by M.A Balı́ková; V Habrdová (93-100).
Hair analysis of drugs of abuse has been a subject of interest from a clinical, social and forensic perspective for years because of the broad time detection window after intake in comparison to urine or blood. However, the correct and reliable interpretation of opiates findings in an authentic hair sample requires optimalisation and standardisation of decontamination and incubation procedures. Comparing various published methods, we have found some variability in them and no unequivocal recommended procedure for starting with a method directly. Therefore, various combinations of solvents, of various polarity, as washing solvents were tested for removing opiates from the external surface of real hair samples. The yields of opiates from these washings were compared with the yields from the interior of the hair matrix after digestion with various procedures. The opiates after digestion were cleaned up from resulting solution on extraction columns with mixed solid-phase and analysed by GC–MS in standard EI mode after silylation. The efficiencies of neutral (Söerensen buffer, pH 7.4), acid (0.1 M HCl) and basic (1 M NaOH) digestion of the hair matrix were evaluated and the relative recoveries for morphine, codeine, dihydrocodeine and hydrocodone were compared. As it is very problematic to imitate the reference hair sample with a specific amount of analytes incorporated inside, which can be used for calibration to get a close estimate of the quantities of analytes inside the solid authentic sample, the total digestion of a hair sample in basic medium was considered to be a very important reference basis for quantitative determinations. The ratios of hydrolysis of labile 6-acetylmorphine or acetylcodeine were tested and evaluated in practical routine conditions of acid or neutral digestion of hair. Comparing the three methods of incubation of authentic hair samples, the methods using 1 M NaOH or 0.1 M HCl yielded higher recoveries of total equivalents of morphine or codeine, whereas the incubation in Söerensen buffer allowed the reflection of real ratios of labile metabolites and/or parent compounds in an original sample. This method has been shown to be capable of detecting hydrocodone in hair with other opiates concomitantly and to indicate the drug abuse pattern of a person at various time intervals in the past.
Rapid high-performance liquid chromatographic measurement of amisulpride in human plasma: application to manage acute intoxication by F. Péhourcq; S. Ouariki; B. Bégaud (101-105).
Amisulpride, a substituted benzamide derivative, is a second-generation (atypical) antipsychotic and is effective as maintenance therapy in patients with schizophrenia. For toxicological purpose, a rapid RP-HPLC assay was developed for the determination of amisulpride in human plasma. A linear response was observed over the concentration range 100–1000 ng/ml. A good accuracy (≤5%) was achieved for all quality controls, with intra- and inter-day variation coefficients equal or inferior to 4.9%. The lower limit of quantification was 20 ng/ml, without interferences of endogenous components. This rapid method (run time <5 min) was used to monitor eight intoxications involving amisulpride.
Screening procedure for eight quaternary nitrogen muscle relaxants in blood by high-performance liquid chromatography–electrospray ionization mass spectrometry by V Cirimele; M Villain; G Pépin; B Ludes; P Kintz (107-113).
A screening procedure was developed for the identification and the quantification of eight quaternary nitrogen muscle relaxants, including d-tubocurarine, alcuronium, pancuronium, vecuronium, atracurium, mivacurium, rocuronium and mebezonium, in blood samples. The procedure involves ion-pair extraction with methylene chloride at pH 5.4, reversed-phase HPLC separation and electrospray ionization mass spectrometry detection. The procedure was validated in terms of linearity (0.929<r<0.998 for concentrations ranging from 0.1 to 10 mg/l), repeatability (6.9<RSD<17.8% at 1 mg/l, n=8), relative extraction recovery (46.0 to 91.1% at 1 mg/l, n=8) and limit of detection (S/N ratio >5 for all the target compounds at 0.1 mg/l). The screening test was found satisfactory and applied in two fatal deaths. In the first case, toxicological investigations on biological fluids collected during the autopsy revealed the presence of vecuronium (1.2 and 0.6 mg/l in blood and urine, respectively) and its desacetylated metabolite, 3-hydroxy-vecuronium (4.4 and 0.7 mg vecuronium equivalent/l in blood and urine, respectively). In the second forensic case, blood analysis showed high levels of mebezonium (6.5 mg/l). The developed procedure was found suitable for forensic investigations.
Keywords: Quaternary nitrogen muscle relaxants;
Kinetics of kavain and its metabolites after oral application by F Tarbah; H Mahler; B Kardel; W Weinmann; D Hafner; Th Daldrup (115-130).
Kavain metabolism in humans was the target of this current investigation. In the present study a high-performance liquid chromatographic (HPLC–DAD) assay method for the simultaneous determination of kavain and its main metabolites (p-hydroxykavain, p-hydroxy-5,6-dehydrokavain and p-hydroxy-7,8-dihydrokavain) in serum and urine was developed and validated. The metabolites were mainly excreted in the form of their conjugates. All kavain metabolites were detectable in serum and urine, except for p-hydroxy-7,8-dihydrokavain, which was found in urine only. Confirmation of the results and identification of the metabolites were performed by LC–MS or LC–MS–MS. Kinetics of kavain and its metabolites in serum were investigated after administration of a single oral dose (800 mg kavain). Within 1 and 4 h after uptake, the serum concentrations ranged between 40 and 10 ng/ml for kavain, 300 and 125 ng/ml for p-hydroxykavain, 90 and 40 ng/ml for o-desmethyl-hydroxy-5,6-dehydrokavain, and 50 and 30 ng/ml for 5,6-dehydrokavain.
Determination of zaleplon and zolpidem by liquid chromatography–turbo-ionspray mass spectrometry: application to forensic cases by Christian Giroud; Marc Augsburger; Annick Menetrey; Patrice Mangin (131-138).
Zolpidem and zaleplon are two short-acting hypnotic agents used in Europe and in the USA. An atmospheric pressure ionisation liquid chromatography–mass spectrometry (Sciex API 150 EX) method was developed for the determination of zolpidem and zaleplon in whole blood. After single-step liquid–liquid extraction, the hypnotics were separated by gradient-elution with an ammonium formate buffer/acetonitrile eluent on an Inertsil ODS-3 column. Methaqualone was used as internal standard. The recovery was higher than 70% for both hypnotics and the internal standard. The best fit for the calibration curve was achieved, between 1 and 250 ng/ml, with 1/x quadratic regression. Coefficients of intra- and inter-assay variation calculated at 5, 25 and 100 ng/ml were less than 10%. The method was successfully applied to forensic cases.
Keywords: Zaleplon; Zolpidem;
Liquid chromatographic–atmospheric pressure chemical ionization mass spectrometric analysis of opiates and metabolites in rat urine after inhalation of opium by R Kikura-Hanajiri; N Kaniwa; M Ishibashi; Y Makino; S Kojima (139-150).
To examine the urinary excretion of opiates and their metabolites following inhalation exposure of rats to opium, analytical procedures for the simultaneous determination of the compounds in opium, the vapor derived by the volatilization of opium and the urine of rats exposed to the opium vapor were developed using liquid chromatography–atmospheric pressure chemical ionization mass spectrometry (LC–APCI-MS). Seven compounds were determined in the opium, namely morphine, codeine, thebaine, noscapine, papaverine, meconic acid and meconin. All seven were extracted with 2.5% acetic acid solution and subjected to LC–APCI-MS analysis. The separation was performed on an ODS column in acetonitrile–50 mM ammonium formate buffer (pH 3.0) using a linear gradient program and quantitative analysis was carried out in the selected ion monitoring mode ([M+H]+). For the analysis of the volatilization of opium, the opium (1 g) was added to a glass pipe, which was then heated at 300 °C for 20 min. Negative pressure (air flow-rate; 300 ml/min) was used to draw the vapor through a series of glass wool and methanol traps. The total amount of each compound in the vapor was estimated by measurement of the compounds trapped in the glass wool and methanol. Wister rats (n=3) were exposed to the vapor derived from the volatilization system and the urinary amounts (0–72 h) of the six opiates and metabolites including morphine-3-grucronide (M3G) and morphine-6-grucronide (M6G) were measured after solid-phase extraction. The calibration curves for those compounds in the rat urine were linear over the concentration range 10–500 ng/ml. The recoveries for each analyte from the rat urine sample spiked with standard solution were generally greater than 80%, and the relative standard deviation for the analytical procedure was less than 8% with the exception of meconin. After inhalation exposure of rats to opium, M3G (5.45–14.38 μg), morphine (2.27–4.65 μg), meconin (0.54–1.85 μg), codeine (0.54–1.85 μg), noscapine (0.34–0.40 μg) and papaverine (0.01–0.04 μg) were detected in the urine over 72 h. However, only trace levels of thebaine were observed despite it being one of the major alkaloids found in the opium. On the other hand, a relatively large amount of meconin was detected in the vapor and the urine as compared with the opium. It is suggested that the presence of meconin in biological fluids could be indicative of opium ingestion by inhalation.
Keywords: Opiates; Opium;
Evaluation of electrospray ionisation liquid chromatography–tandem mass spectrometry for rational determination of a number of neuroleptics and their major metabolites in human body fluids and tissues by M Josefsson; R Kronstrand; J Andersson; M Roman (151-167).
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.