Simultaneous detection and quantitation of organic impurities in methamphetamine by ultra‐high‐performance liquid chromatography–tandem mass spectrometry,a complementary technique for methamphetamine profiling

The analysis of organic impurities plays an important role in the impurity profiling of methamphetamine, which in turn provides valuable information about methamphetamine manufacturing, in particular its synthetic route, chemicals, and precursors used. Ultra‐high‐performance liquid chromatography – tandem mass spectrometry (UHPLC – MS/MS) is ideally suited for this purpose due to its excellent sensitivity, selectivity, and wide linear range in multiple reaction monitoring (MRM) mode. In this study, a dilute‐and‐shoot UHPLC – MS/MS method was developed for the simultaneous identification and quantitation of 23 organic manufacturing impurities in illicit methamphetamine. The developed method was validated in terms of stability, limit of detection (LOD), lower limit of quantification (LLOQ), accuracy, and precision. More than 100 illicitly prepared methamphetamine samples were analyzed. Due to its ability to detect ephedrine/pseudoephedrine and its high sensitivity for critical target markers (eg, chloro‐pseudoephedrine, N‐cyclohexylamphetamine, and compounds B and P), more impurities and precursor/pre‐precursors were identified and quantified versus the current procedure by gas chromatography – mass spectrometry (GC – MS). Consequently, more samples could be classified by their synthetic routes. However, the UHPLC – MS/MS method has difficulty in detecting neutral and untargeted emerging manufacturing impurities and can therefore only serve as a complement to the current method. Despite this deficiency, the quantitative information acquired by the presented UHPLC – MS/MS methodology increased the sample discrimination power, thereby enhancing the capacity of methamphetamine profiling program (MPP) to conduct sample‐sample comparisons.     

Solid‐phase extraction–liquid chromatography–tandem mass spectrometry method for the qualitative analysis of 61 synthetic cannabinoid metabolites in urine

This article comprises the development and validation of a protocol for the qualitative analysis of 61 phase I synthetic cannabinoid metabolites in urine originating from 29 synthetic cannabinoids, combining solid‐phase extraction (SPE) utilizing a reversed phase silica‐based sorbent (phenyl) with liquid chromatography–tandem mass spectrometry (LC?MS/MS). Validation was performed according to the guidelines of the German Society of Toxicological and Forensic Chemistry. Sufficient chromatographic separation was achieved within a total runtime of 12.3 minutes. Validation included specificity and selectivity, limit of detection (LOD), recovery and matrix effects, as well as auto‐sampler stability of processed urine samples. LOD ranged between 0.025 ng/mL and 0.5 ng/mL in urine. Recovery ranged between 43% and 97%, with only two analytes exhibiting recoveries below 50%. However, for those two analytes, the LODs were 0.05 ng/mL in urine. In addition, matrix effects between 81% and 185% were determined, whereby matrix effects over 125% were observed for 10 non‐first‐generation synthetic cannabinoid metabolites. The developed method enables the rapid and sensitive detection of synthetic cannabinoid metabolites in urine, complementing the spectrum of existing analytical tools in forensic case work. Finally, application to 61 urine samples from both routine and autopsy case work yielded one urine sample that tested positive for ADB‐PINACA N‐pentanoic acid.     

Analysis for higenamine in urine by means of ultra‐high‐performance liquid chromatography–tandem mass spectrometry: Interpretation of results

Higenamine (Norcoclaurine) is a very popular substance in Chinese medicine and is present in many plants. The substance may be also found in supplements or nutrients, consumption of which may result in violation of anti‐doping rules. Higenamine is prohibited in sport at all times and included in Class S3 (β‐2‐agonists) of the World Anti‐Doping Agency (WADA) 2017 Prohibited List. The presence of higenamine in urine samples at concentrations greater than or equal to 10 ng/mL constitutes an adverse analytical finding (AAF). This work presents a new metabolite of higenamine in urine sample which was identified by means of ultra performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). Samples were prepared according to 2 protocols – a Dilute and Shoot (DaS) approach and a method involving acid hydrolysis and double liquid‐liquid extraction (LLE). To meet the requirements typical for a confirmatory analysis, the screening procedure was further developed. In samples prepared by the DaS method, 2 peaks were observed; the earlier one was specific for higenamine and the later one unknown. MS scan analysis showed mass about 80 Da higher than that of higenamine. In turn, in samples prepared in accordance with the protocol involving hydrolysis, an increase in the area under peak for higenamine was observed, while the second peak was absent. It seems that the described strategy of detection of higenamine in urine avoids false negative results.     

Sensitive quantification of the somatostatin analog AP102 in plasma by ultra‐high pressure liquid chromatography–tandem mass spectrometry and application to a pharmacokinetic study in rats

AP102 is a di‐iodinated octapeptide somatostatin agonist (SSA) designed to treat acromegaly and neuroendocrine tumors. A sensitive and selective method was validated for the quantification of AP102 in plasma following the European Medicines Agency (EMA) and Food and Drug Administration (FDA) guidelines. Sample preparation was performed using solid‐phase extraction microplates. Chromatographic separation was achieved on an ultra‐high pressure liquid chromatography (UHPLC) C18 column in 6.0 minutes. The compounds were quantified using multiple reaction monitoring on a tandem quadrupole mass spectrometer with ¹³C,¹⁵N‐labeled AP102 as internal standard. Calibration ranged from 50 to 10000 pg/mL. The lower limit of quantification (LLOQ) was measured at 20 pg/mL, and robust analytical performances were obtained with trueness at 99.2%–100.0%, intra‐assay imprecision at 2.5%–4.4%, and inter‐assay imprecision at 8.9%–9.7%. The accuracy profiles (total error) built on the 3 concentrations levels showed accuracy within the 70%–130% range. AP102 is remarkably stable since no proteolytic fragments were detected on plasma samples analyzed by Orbitrap‐MS. Pharmacokinetic studies were conducted in rats, after single dose (1, 3, and 10 μg/kg, sc) and continuous subcutaneous administration (osmotic minipumps for 28 days, 3.0 or 10.0 μg/kg/h). AP102 showed a rapid absorption by the subcutaneous route (T_max: 15–30 minutes) and a fast elimination (t_1/2: 33–86 minutes). The PK profile of AP102 exhibited a mean clearance of 1.67 L/h and a mean distribution volume at steady state of 7.16 L/kg, about 10‐fold higher than those observed with other SSA or non‐ and mono‐iodinated AP102. LogD_7.4 determination confirmed the lipophilic properties of AP102 that might influence its distribution in tissues.     

Rapid determination of nine barbiturates in human whole blood by liquid chromatography‐tandem mass spectrometry

A rapid, simple and sensitive liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method was developed for the qualitative and quantitative analysis of nine barbiturates (barbital, phenobarbital, pentobarbital, amobarbital, secobarbital, thiopental, butalbital, butabarbital, and hexobarbital) in human whole blood. Barbiturates were extracted from 100 μL of human whole blood samples using a simple liquid‐liquid extraction (LLE) procedure, and detected by LC‐MS/MS. An UPLC C18 (2.1 mm × 100 mm, 1.7 µm) column was used at 40 °C for the separation and acetonitrile/water system was used as the mobile phase with gradient elution. This method showed excellent accuracy (86–111%) and precision (relative standard deviation <15%). The limits of detection (LODs) were 0.2 ng/mL for barbital and secobarbital and 0.5 ng/mL for the other barbiturates. The linearity ranged from 2 ng/mL to 2000 ng/mL, with r² > 0.99 over the range. This method achieved the separation and detection of pentobarbital and amobarbital at the same time in a convenient way. Moreover, it was both simple and sensitive for the determination of nine most commonly used barbiturate drugs, which was meaningful in the field of clinical and forensic toxicology. Copyright © 2016 John Wiley & Sons, Ltd.     

Detection of prohibited substances in equine hair by ultra‐high performance liquid chromatography–triple quadrupole mass spectrometry – application to doping control samples

The detection of drugs in human hair samples has been performed by laboratories around the world for many years and the matrix is popular in disciplines, such as workplace drug testing. To date, however, hair has not become a routinely utilised matrix in sports drug detection. The analysis of hair samples offers several potential advantages to doping control laboratories, not least of which are the greatly extended detection window and the ease of sample collection and storage. This article describes the development, validation, and utilisation of a sensitive ultra‐high performance liquid chromatography – triple quadrupole mass spectrometry (UHPLC – MS/MS) method for the detection of 50 compounds. This provides significantly improved coverage for those analytes which would be of particular interest if detected in hair, such as anabolic steroid esters and selective androgen receptor modulators (SARMs). Qualitative validation of the method resulted in estimated limits of detection as low as 0.1 pg/mg for the majority of compounds, with all being detected at 2 pg/mg or below. The suitability of the method for the detection of prohibited substances in incurred material was demonstrated by the successful detection of several compounds, such as stanozolol, boldenone undecylenate, clenbuterol, and GW‐501516, in genuine equine hair samples. Estimated concentrations of the detected substances ranged from 0.27 to 8.6 pg/mg. The method has been shown to be fit‐for‐purpose for routine screening of equine hair samples by the analysis of over 400 genuine hair samples.     

Rapid determination of quetiapine in blood by gas chromatography–mass spectrometry. Application to post‐mortem cases

A simple, fast and sensitive method for the determination of quetiapine in human blood has been developed and validated. The method involved a basic liquid–liquid extraction procedure and subsequent analysis by gas chromatography–mass spectrometry, previous derivatization with bis(trimethylsilyl)‐trifluoro‐acetamide and chorotrimethylsilane (99 : 1). The methods of validation included linearity with a correlation coefficient > 0.99 over the range 0.02–1 µg ml^–1, intra‐ and interday precision (always < 12%) and accuracy (mean relative error always < 12%) to meet the bioanalytical acceptance criteria. The limit of detection was 0.005 µg ml^–1. The procedure was further applied to post mortems from the Institute of Legal Medicine, University of Santiago de Compostela. Copyright © 2013 John Wiley & Sons, Ltd.     

Simultaneous quantification of THC‐COOH,OH‐THC,and further cannabinoids in human hair by gas chromatography–tandem mass spectrometry with electron ionization applying automated sample preparation

The detection of Δ⁹‐tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) in hair, for the purpose of identifying cannabis consumption, is conducted in many forensic laboratories. Since external contamination of hair with these cannabis components cannot be excluded, even after hair decontamination, only the detection of THC metabolites such as 11‐nor‐9‐carboxy‐Δ⁹‐tetrahydrocannabinol (THC‐COOH) or 11‐hydroxy‐Δ⁹‐tetrahydrocannabinol (OH‐THC), is considered to prove cannabis consumption. At present, testing for THC metabolites is not standard practice due to its analytical complexity. For these reasons, we developed a novel method for the detection of THC‐COOH and OH‐THC as well as THC, CBD, and CBN in one single analytical run using gas chromatography–tandem mass spectrometry (GC–MS/MS) with electron ionization. After manual hair washing and grinding, sample preparation was fully automated, by means of a robotic autosampler. The hair extraction took place by digestion with sodium hydroxide. A solid‐phase extraction (SPE) was chosen for sample clean‐up, using a mixed‐mode anion exchange sorbent. Derivatization of all analytes was by silylation. The method has been fully validated according to guidelines of the Society of Toxicological and Forensic Chemistry (GTFCh), with a limit of detection (LOD) of 0.2 pg/mg for THC‐COOH and OH‐THC and 2 pg/mg for THC, CBD and CBN, respectively, thus fulfilling the Society of Hair Testing (SoHT) recommendations. The validated method has been successfully applied to our routine forensic case work and a summary of data from authentic hair samples is given, as well as data from proficiency tests.     

Doping control analysis of four JWH‐250 metabolites in equine urine by liquid chromatography–tandem mass spectrometry

JWH‐250 is a synthetic cannabinoid. Its use is prohibited in equine sport according to the Association of Racing Commissioners International (ARCI) and the Fédération Équestre Internationale (FEI). A doping control method to confirm the presence of four JWH‐250 metabolites (JWH‐250 4‐OH‐pentyl, JWH‐250 5‐OH‐pentyl, JWH‐250 5‐OH‐indole, and JWH‐250 N‐pentanoic acid) in equine urine was developed and validated. Urine samples were treated with acetonitrile and evaporated to concentrate the analytes prior to the analysis by liquid chromatography–tandem mass spectrometry (LC–MS/MS). The chromatographic separation was carried out using a Phenomenex Lux^® 3 μm AMP column (150 x 3.0 mm). A triple quadrupole mass spectrometer was used for detection of the analytes in positive mode electrospray ionization using multiple reaction monitoring (MRM). The limits of detection, quantification, and confirmation for these metabolites were 25, 50, and 50 pg/mL, respectively. The linear dynamic range of quantification was 50–10000 pg/mL. Enzymatic hydrolysis indicated that JWH‐250 4‐OH‐pentyl, JWH‐250 5‐OH‐pentyl, and JWH‐250 5‐OH indole are highly conjugated whereas JWH‐250 N‐pentanoic acid is not conjugated. Relative retention time and product ion intensity ratios were employed as the criteria to confirm the presence of these metabolites in equine urine. The method was successfully applied to post‐race urine samples collected from horses suspected of being exposed to JWH‐250. All four JWH‐250 metabolites were confirmed in these samples, demonstrating the method applicability for equine doping control analysis.     

Optimization and validation of simultaneous analyses of ecgonine,cocaine, and seven metabolites in human urine by gas chromatography–mass spectrometry using a one‐step solid‐phase extraction

The presence of ecgonine in urine has been proposed as an appropriate marker of cocaine use. Only a few methods have been published for their determination along with cocaine and the rest of its metabolites. Due to their high polarity and consequent solubility in water, these have low recoveries, which is why it is necessary to increase the sensitivity, by the formation of hydrochloric salts or multiderivatization of the analytes or by performing two solid‐phase extractions (SPEs), considerably increasing the time and cost of the analysis. This work describes a fast and fully validated procedure for the simultaneous detection and quantification of ecgonine, ecgonine‐methyl‐ester, benzoylecgonine, nor‐benzoylecgonine, m‐hydroxybenzoylecgonine, cocaethylene, cocaine, norcocaine, and norcocaethylene in human urine (500 μL) using one SPE and simple derivatization. Separation and quantification were achieved by gas chromatography–electron ionization–mass spectrometry (GC–EI–MS) in selected‐ion monitoring mode. Quantification was performed by the addition of deuterated analogs as internal standards. Calibration curves were linear in the adopted ranges, with determination coefficients higher than 0.99. The lower limits of quantification ranged from 2.5 to 10 ng/mL. The intra‐ and inter‐day precision, calculated in terms of relative standard deviation, were 1.2%–14.9% and 1.8%–17.9%, respectively. The accuracy, in terms of relative error, was within a ± 16.4% interval. Extraction efficiency ranged from 84% to 103%. Compared with existing methods, the procedure described herein is fast, since only one SPE is required, and cost‐effective. In addition, this method provides a high recovery for ecgonine, resulting in a better alternative to the previously published methods.     

Enantiomeric separation and quantification of R/S‐amphetamine in serum using semi‐automated liquid‐liquid extraction and ultra‐high performance supercritical fluid chromatography‐tandem mass spectrometry

The amphetamine molecule contains a chiral center and its enantiomers exhibit differences in pharmacological effects, with the S‐enantiomer mediating most of the central nervous system stimulating activity. The majority of prescribed amphetamine consists of the pure S‐enantiomer, but therapeutic formulations containing the R‐enantiomer in various proportions are also available. Illegal amphetamine remains available mainly as a racemic mixture of the R‐ and S‐enantiomers. To distinguish between legal and illegal consumption of amphetamine a method for enantiomeric separation and quantification of R/S‐amphetamine in serum was developed and validated using ultra‐high performance supercritical fluid chromatography‐tandem mass spectrometry (UHPSFC‐MS/MS). Sample preparation prior to UHPSFC‐MS/MS analysis was performed by a semi‐automated liquid–liquid extraction method. The UHPSFC‐MS/MS method used a Chiralpak AD‐3 column with a mobile phase consisting of CO₂ and 0.1% ammonium hydroxide in 2‐propanol/methanol (50/50, v/v). The injection volume was 2 μL and run time was 4 minutes. MS/MS detection was performed with positive electrospray ionization and two multiple reaction monitoring transitions (m/z 136.1 > 119.0 and m/z 136.1 > 91.0). The calibration range was 12.5–1,000 nM for each analyte. The between‐assay relative standard deviations were in the range of 1.3–3.0%. Recovery was 73% and matrix effects ranged from 95 to 100% when corrected with internal standard. After development and validation, the method has been successfully implemented in our laboratory for both separation and quantification of R/S‐amphetamine and has proved to be a reliable and useful tool for distinguishing intake of R‐ and S‐amphetamine in authentic patient samples.     

Quantification of cocaine and cocaine metabolites in dried blood spots from a controlled administration study using liquid chromatography–tandem mass spectrometry

Cocaine is a common illicit stimulant and is mainly metabolized by hydrolysis to benzoylecgonine (BE) and ecgonine methyl ester (EME), but also to minor metabolites like norcocaine, or hydroxy‐BE. When ethanol is present, cocaethylene is formed. Dried blood spot (DBS) sampling is a minimally invasive microsampling technique with possible advantages for analyte stability and ease of storage, making it an attractive matrix in forensic and clinical settings. We developed a liquid chromatography–tandem mass spectrometry‐based (LC–MS/MS) method for quantifying cocaine, BE, EME, norcocaine, hydroxy‐BE, and cocaethylene in DBS. Six‐mm punches were extracted with aqueous buffer followed by protein precipitation, evaporation and reconstitution in mobile phase. Separation was achieved on a Polar‐RP column (Phenomenex) in a 6‐minute gradient including baseline‐separation of norcocaine and BE. For MS detection, a QTRAP 5500 (Sciex) was used in positive electrospray ionization (ESI) multiple reaction monitoring (MRM) mode. The method was validated for selectivity, sensitivity [lower limited of quantification (LLOQ) 1.0–5.0 ng/mL], imprecision (≤13.4%, ≤19.6% at LLOQ), accuracy (≤ ± 14.9%), matrix effects, extraction efficiency (≥20.9%), hematocrit effect, volume spotted, punch location, long‐term and autosampler stability. Concentrations in DBS from a controlled cocaine administration study in healthy volunteers were compared to whole blood and plasma. Although concentrations correlated moderately to strongly (Spearman's ρ 0.603–0.958), agreement between paired samples was poor, with overestimation of DBS concentrations and wide confidence intervals in Bland–Altman analysis. A possible cause are differences in capillary and venous blood concentrations, with the underlying mechanism requiring further research before DBS analysis for cocaine and its metabolites can be considered equivalent to whole blood or plasma analysis.     

The use of dried blood spots for quantification of 15 antipsychotics and 7 metabolites with ultra‐high performance liquid chromatography ‐ tandem mass spectrometry

Therapeutic drug monitoring of antipsychotics is important in optimizing individual therapy. In psychiatric populations, classical venous blood sampling is experienced as frightening. Interest in alternative techniques, like dried blood spots (DBS), has consequently increased. A fast and easy to perform DBS method for quantification of 16 antipsychotics (amisulpride, aripiprazole, asenapine, bromperidol, clozapine, haloperidol, iloperidone, levosulpiride, lurasidone, olanzapine, paliperidone, pipamperone, quetiapine, risperidone, sertindole and zuclopenthixol) and 8 metabolites was developed. DBS were prepared using 25 μL of whole blood and extraction of complete spots was performed using methanol: methyl‐t‐butyl‐ether (4:1). After evaporation, the extract was reconstituted in the mobile phase and 10 μL were injected on an ultra‐high performance liquid chromatography‐tandem mass spectrometry (UHPLC‐MS/MS). Separation using a C18 column and gradient elution with a flow rate of 0.5 mL/min resulted in a 6‐min run‐time. Ionization was performed in positive mode and a dynamic MRM method was applied. Median recovery was 66.4 % (range 28.7‐84.5%). Accuracy was within the acceptance criteria, except for pipamperone (LLOQ and low concentration) and lurasidone (low concentration). Imprecision was only aberrant for lurasidone at low and medium concentration. All compounds were stable during 1 month at room temperature, 4 °C and ?18 °C. Lurasidone was unstable when the extract was stored for 12 h on the autosampler. Absolute matrix effects (ME) (median 66.1%) were compensated by the use of deuterated IS (median 98.8%). The DBS method was successfully applied on 25‐μL capillary DBS from patients and proved to be a reliable alternative for quantification of all antipsychotics except for olanzapine and N‐desmethylolanzapine. Copyright © 2014 John Wiley & Sons, Ltd.     

Analysis of new psychoactive substances in oral fluids by means of microextraction by packed sorbent followed by ultra‐high‐performance liquid chromatography–tandem mass spectrometry

In recent years, new drugs, commonly known as new psychoactive substances (NPS), appeared on the market, which include, among others, synthetic cannabinoids, cathinones, and tryptamine analogs of psilocin. The aim of this work was to develop and validate a new method for simultaneous screening and quantification of 31 NPS in oral fluid by ultra‐high‐performance liquid chromatography‐tandem mass spectrometry (UHPLC–MS/MS). The chosen target analytes represented different chemical and toxicological NPS classes, such as synthetic cathinones, piperazines, phenethylamines, synthetic cannabinoids, and their metabolites. The procedure involved a rapid sample preparation based on protein precipitation followed by clean‐up utilizing microextraction by packed sorbent (MEPS); the quantitative analysis was performed by UHPLC–MS/MS. The MEPS clean‐up, regardless of non‐quantitative recoveries for some analytes, provided an effective removal of interfering compounds, as demonstrated by reduced matrix effects found at different concentrations for all the analytes. The validation protocol, based on SWGTOX guidelines, demonstrated the suitability of the proposed method for quantitative analysis: linearity range ranged over 3 or 4 orders of magnitude; precision and accuracy tests gave RSD% values below 25%, and accuracy ranged from 85.9% to 107%, accomplishing SWGTOX requirements. Limits of detection (LODs) ranged between 0.005 ng/mL and 0.850 ng/mL and limits of quantification (LOQs) from 0.015 to 2.600 ng/mL.     

Quantification of six cannabinoids and metabolites in oral fluid by liquid chromatography‐tandem mass spectrometry

Δ⁹‐Tetrahydrocannabinol (THC) is the most commonly analyzed cannabinoid in oral fluid (OF); however, its metabolite 11‐nor‐9‐carboxy‐THC (THCCOOH) offers the advantage of documenting active consumption, as it is not detected in cannabis smoke. Analytical challenges such as low (ng/L) THCCOOH OF concentrations hampered routine OF THCCOOH monitoring. Presence of minor cannabinoids like cannabidiol and cannabinol offer the advantage of identifying recent cannabis intake. Published OF cannabinoids methods have limitations, including few analytes and lengthy derivatization. We developed and validated a sensitive and specific liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) method for THC, its metabolites, 11‐hydroxy‐THC and THCCOOH quantification, and other natural cannabinoids including tetrahydrocannabivarin (THCV), cannabidiol (CBD), and cannabigerol (CBG) in 1 mL OF collected with the Quantisal device. After solid‐phase extraction, chromatography was performed on a Selectra PFPP column with a 0.15% formic acid in water and acetonitrile gradient with a 0.5 mL/min flow rate. All analytes were monitored in positive mode atmospheric pressure chemical ionization (APCI) with multiple reaction monitoring. Limits of quantification were 15 ng/L THCCOOH and 0.2 µg/L for all other analytes. Linear ranges extended to 3750 ng/L THCCOOH, 100 µg/L THC, and 50 µg/L for all other analytes. Inter‐day analytical recoveries (bias) and imprecision at low, mid, and high quality control (QC) concentrations were 88.7‐107.3% and 2.3‐6.7%, respectively (n = 20). Mean extraction efficiencies and matrix effects evaluated at low and high QC were 75.9–86.1% and 8.4–99.4%, respectively. This method will be highly useful for workplace, criminal justice, drug treatment and driving under the influence of cannabis OF testing. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.     

Determination of cannabinoid and synthetic cannabinoid metabolites in wastewater by liquid–liquid extraction and ultra‐high performance supercritical fluid chromatography‐tandem mass spectrometry

For the first time, ultra‐high performance supercritical fluid chromatography (UHPSFC) coupled to tandem mass spectrometry has been used to determine cannabinoid and synthetic cannabinoid residues in wastewater. Combined with a downscaled version of the classic liquid‐liquid extraction, the proposed method allows for the quantification of Δ9‐tetrahydrocannabinol, three of its major metabolites (the monohydroxylated, the dehydroxylated, and the carboxylated species) and four synthetic cannabinoid metabolites (from the JWH‐series) at low ng L⁻¹ levels. Limits of quantification are in the 1–59 ng L⁻¹ range, with recovery between 62 and 122% in ultrapure water and between 59 and 138% in wastewater. The applicability of the developed methodology was confirmed by the analysis of real wastewater, where cannabis metabolites could be positively quantified in all the samples analyzed. It is, therefore, a fast and simple alternative to common solid‐phase extraction‐liquid chromatography‐mass spectrometry procedures for the determination of these low polar substances in water. Copyright © 2017 John Wiley & Sons, Ltd.     

Separation of positional isomers of nine 2‐phenethylamine‐derived designer drugs by liquid chromatography–tandem mass spectrometry

The synthesis of positional isomers of designer drugs is a common way of bypassing legal restrictions. For forensic case work, and especially for the legal assessment of cases, there is a need for screening methods capable of the unequivocal identification of positional isomers. The presented liquid chromatography–electrospray ionization–tandem mass spectrometry (LC–ESI–MS/MS) method facilitates separation of positional isomers of 9 2‐phenethylamine‐derived designer drugs in different matrices including seized materials, hair, serum, and urine specimens. Chromatographic separation was achieved on a biphenyl phase using gradient elution with a total runtime of 26 minutes. The limit of detection was 25 pg/mg for hair samples and ranged from 0.1 ng/mL to 0.5 ng/mL for serum and from 0.2 ng/mL to 1.2 ng/mL for urine samples. The method proved to be selective and sensitive and showed good chromatographic resolution (R ≥ 1.2). The method was successfully applied to routine case samples.     

Development and validation of a liquid chromatography–tandem mass spectrometry method for the determination of nicotine and its metabolites in placenta and umbilical cord

Tobacco exposure during pregnancy is associated with obstetric and fetal complications. We developed and validated a liquid chromatography–tandem mass spectrometry (LC–MS/MS) method to determine nicotine, cotinine, and hydroxycotinine (OH‐cotinine) in placenta (PL) and umbilical cord (UC). Specimens were homogenized in water, followed by solid‐phase extraction. Chromatographic separation was performed using an Atlantis® HILIC Silica column. Detection was accomplished in electrospray in positive mode. Method validation included: linearity (5 to 1000 ng/g), accuracy (86.9 to 105.2% of target concentration in PL, and 89.1 to 105.0% in UC), imprecision (6.8 to 11.8% in PL, and 7.6 to 12.2% in UC), limits of detection (2 ng/g for cotinine and OH‐cotinine, and 5 ng/g for nicotine) and quantification (5 ng/g), selectivity (no endogenous or exogenous interferences), matrix effect (?34.1 to ?84.5% in PL, %CV = 9.1–24.0%; ?18.9 to ?84.7% in UC, %CV = 10.2–23.9%), extraction efficiency (60.7 to 131.5% in PL, and 64.1 to 134.2% in UC), and stability 72 h in the autosampler (<11.5% loss in PL, and < 13% loss in UC). The method was applied to 14 PL and UC specimens from tobacco users during pregnancy. Cotinine (6.8–312.2 ng/g in PL; 6.7–342.3 ng/g in UC) was the predominant analyte, followed by OH‐cotinine (相似文献