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Dive into the research topics where Alexandra Maas is active.

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Featured researches published by Alexandra Maas.


International Journal of Legal Medicine | 2015

Driving under the influence of synthetic phenethylamines: a case series

Alexandra Maas; Cornelia Wippich; Burkhard Madea; Cornelius Hess

New psychoactive drugs, so-called legal highs, have gained more and more popularity during the last years. One of the most important groups of these legal high substances are the synthetic phenethylamines that share a common phenethylamine moiety. Based on certain structural characteristics, these synthetic phenethylamines can be divided into further subclasses, among which the synthetic cathinones (‘bath salts’) are particularly noteworthy. Synthetic cathinones are characterized by an additional carbonyl group attached at the beta position on the amino alkyl chain. Consumption of synthetic phenethylamines can lead to impairments similar to those observed after the use of, for instance, amphetamine or 3,4-methylenedioxy-N-methylamphetamine (MDMA, ‘ecstasy’). These impairments include diverse neurological and psychological symptoms which can affect a safe driving behaviour. Although several reports on clinical symptoms and poisonings due to these substances have been published, most of these publications do not contain any analytical data. Additionally, there is still a lack of information concerning pharmacological and toxicological effects of these rather new psychoactive substances. In particular, the knowledge of the impact on the ability to drive following consumption of synthetic phenethylamines is relevant for the police as well as for forensic toxicologists. In this publication, several cases of individuals driving under the influence (DUI) of synthetic phenethylamines (4-fluoroamphetamine, mephedrone (4-methylmethcathinone, 4-MMC), 2-DPMP (desoxypipradol), methylenedioxypyrovalerone (MDPV), benzedrone, N-ethylamphetamine (etilamfetamine), 3-methylmethcathinone (3-MMC)) are presented, focusing on analytical results and signs of impairment.


Journal of Chromatography B | 2017

Separation of ortho, meta and para isomers of methylmethcathinone (MMC) and methylethcathinone (MEC) using LC-ESI-MS/MS: Application to forensic serum samples

Alexandra Maas; Konrad Sydow; Burkhard Madea; Cornelius Hess

Separation and identification of positional isomers is an important issue in forensic toxicology, particularly in the context of new psychoactive substances (NPS). Despite the structural similarity, positional isomers often show different pharmacological properties and thus can exhibit dramatic differences with respect to their toxicity. Additionally, besides these pharmacological and toxicological effects, the legal status is also of great importance. We present a sensitive and selective LC-MS/MS method to separate the ortho, meta and para isomers of methylmethcathinone (MMC) and methylethcathinone (MEC) using a core-shell biphenyl analytical column. Reliability of the method was confirmed under consideration of the validation parameters selectivity, linearity, accuracy and precision, analytical limits, processed sample stability, matrix effects and recovery. Linearity was demonstrated over the entire calibration range from 5 to 250ng/ml with the use of a 1/x2 weighting. Appropriate quantification and detection limits (LLOQ=5ng/ml, LOD<2ng/ml) could be achieved. Application of the method to real serum samples collected between June 2014 and August 2016 revealed the proof of a recent MMC or MEC consumption, respectively, in eight cases. Isomers of MMC could be detected in three of these eight cases, of which two were positive for 3-MMC and one was positive for 2-MMC. The other samples were tested positively for 3-MEC. In none of the samples 4-MMC, 2-MEC or 4-MEC could be detected. Only substances that were not governmentally controlled at that time could be detected, reflecting the rapid response of the recreational drug market to newly enacting drug laws.


Drug Testing and Analysis | 2017

Urinary excretion study following consumption of various poppy seed products and investigation of the new potential street heroin marker ATM4G

Alexandra Maas; Michael H. Kramer; Konrad Sydow; Pai-Shan Chen; Torsten Dame; Frank Musshoff; Bernd W.K. Diehl; Burkhard Madea; Cornelius Hess

Discrimination between street heroin consumption and poppy seed ingestion represents a major toxicological challenge in daily routine work. Several difficulties associated with conventional street heroin markers originate from their versatile occurrence in various poppy seed products and medications, respectively, as well as to small windows of detection. A novel opportunity to overcome these hindrances is represented by the new potential street heroin marker acetylated-thebaine-4-metabolite glucuronide (ATM4G), originating from thebaine during street heroin synthesis followed by metabolic reactions after administration. In this study, urine samples after consumption of different German poppy seed products and urine samples from subjects with suspicion of preceding heroin consumption were tested for ATM4G, 6-AC (6-acetylcodeine), papaverine, noscapine, 6-MAM (6-monoacetylmorphine), morphine, and codeine. Neither 6-AC and 6-MAM nor ATM4G but morphine and codeine could be detected in urine samples following poppy seed ingestion. As well, neither papaverine nor noscapine could be observed even after consumption of poppy seeds containing up to 37 µg noscapine and up to 9.8 µg papaverine, respectively. Concerning the urine samples with suspicion of preceding heroin consumption, ATM4G could be detected in 9 of 43 cases. By contrast, evidence of 6-AC and 6-MAM, respectively, could only be seen in 7 urine samples. In conclusion, ATM4G should be measured additionally in cases requiring discrimination of street heroin consumption from poppy seed intake. Copyright


Forensic Science International | 2018

Considerations regarding the validation of chromatographic mass spectrometric methods for the quantification of endogenous substances in forensics

Cornelius Hess; Konrad Sydow; Theresa Kueting; Michael Kraemer; Alexandra Maas

The requirement for correct evaluation of forensic toxicological results in daily routine work and scientific studies is reliable analytical data based on validated methods. Validation of a method gives the analyst tools to estimate the efficacy and reliability of the analytical method. Without validation, data might be contested in court and lead to unjustified legal consequences for a defendant. Therefore, new analytical methods to be used in forensic toxicology require careful method development and validation of the final method. Until now, there are no publications on the validation of chromatographic mass spectrometric methods for the detection of endogenous substances although endogenous analytes can be important in Forensic Toxicology (alcohol consumption marker, congener alcohols, gamma hydroxy butyric acid, human insulin and C-peptide, creatinine, postmortal clinical parameters). For these analytes, conventional validation instructions cannot be followed completely. In this paper, important practical considerations in analytical method validation for endogenous substances will be discussed which may be used as guidance for scientists wishing to develop and validate analytical methods for analytes produced naturally in the human body. Especially the validation parameters calibration model, analytical limits, accuracy (bias and precision) and matrix effects and recovery have to be approached differently. Highest attention should be paid to selectivity experiments.


Journal of Pharmaceutical and Biomedical Analysis | 2017

Simultaneous extraction of propofol and propofol glucuronide from hair followed by validated LC–MS/MS analyses

Alexandra Maas; Christoph Maier; Stefanie Iwersen-Bergmann; Burkhard Madea; Cornelius Hess

HIGHLIGHTSPropofol abuse is extremely dangerous with a high number of fatalities documented.Simple and fast methanolic hair extraction followed by highly sensitive LC–MS/MS analyses.Simultaneous extraction of propofol and its metabolite propofol glucuronide from hair.This method enables to detect non‐medical, particularly chronic propofol abuse. ABSTRACT Besides its clinical application, the anaesthetic agent propofol is being increasingly misused, mostly by healthcare professionals, and its abuse potential gained worldwide attention after the tragic death of Michael Jackson in 2009. Due to the short duration of its narcotic effects, propofol abuse is especially easy to hide compared with the use of other recreational drugs. However, propofol possesses a very narrow therapeutic window between the desired effect and potentially fatal toxicity, making abuse of the drug extremely dangerous even in experienced physicians. Consequently, it is important that forensic laboratories possess a sensitive and specific method for the detection of chronic propofol abuse. We present a simple, fast and reliable method to simultaneously extract propofol and its main metabolite propofol glucuronide from hair, followed by sensitive LC–MS/MS analyses, allowing to determine a chronic propofol abuse. Difficulties regarding the detection of propofol using LC–MS/MS were solved by using a derivatization reaction with 2‐fluoro‐1‐methylpyridinium‐p‐toluene‐sulfonate and triethylamine. Reliability of extraction method and subsequent LC–MS/MS analyses was confirmed under consideration of the validation parameters selectivity, linearity, accuracy and precision, analytical limits, processed sample stability, matrix effects and recovery. Appropriate quantification (LLOQ = 10 pg/mg hair) and detection limits (3.6 pg/mg hair for propofol and 7.8 pg/mg hair for propofol glucuronide) could be achieved, enabling to detect even small amounts of both analytes. Applicability of the method was confirmed by analysis of three human hair samples from deceased with suspicion of chronic propofol abuse.


Drug Metabolism and Personalized Therapy | 2017

Verification of propofol sulfate as a further human propofol metabolite using LC-ESI-QQQ-MS and LC-ESI-QTOF-MS analysis

Alexandra Maas; Christoph Maier; Beate Michel-Lauter; Sebastian Broecker; Burkhard Madea; Cornelius Hess

Abstract Background: Propofol (2,6-diisopropylphenol) is a water-insoluble, intravenous anesthetic that is widely used for the induction and maintenance of anesthesia as well as for endoscopic and pediatric sedation. After admission, propofol undergoes extensive hepatic and extrahepatic metabolism, including direct conjugation to propofol glucuronide and hydroxylation to 2,6-diisopropyl-1,4-quinol. The latter substance subsequently undergoes phase II metabolism, resulting in the formation of further metabolites (1quinolglucuronide, 4quinolglucuronide and 4quinol-sulfate). Further minor phase I propofol metabolites (2-(ω-propanol)-6-isopropylphenol and 2-(ω-propanol)-6-isopropyl-1,4-quinol)) are also described. Due to its chemical structure with the phenolic hydroxyl group, propofol is also an appropriate substrate for sulfation by sulfotransferases. Methods: The existence of propofol sulfate was investigated by liquid chromatography electrospray ionization triple quadrupole mass spectrometry (LCESIQQQ-MS) and liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LCESI-QTOF-MS). A propofol sulfate reference standard was used for identification and method development, yielding a precursor at m/z 257 (deprotonated propofol sulfate) and product ions at m/z 177 (deprotonated propofol) and m/z 80 ([SO3]−). Results: Propofol sulfate – a further phase II metabolite of propofol – was verified in urine samples by LC-ESI-QQQ-MS and LC-ESI-QTOF-MS. Analyses of urine samples from five volunteers collected before and after propofol-induced sedation verified the presence of propofol sulfate in urine following propofol administration, whereas ascertained concentrations of this metabolite were significantly lower compared with detected propofol glucuronide concentrations. Conclusions: The existence of propofol sulfate as a further phase II propofol metabolite in humans could be verified by two different detection techniques (LCESIQQQ-MS and LC-ESI-QTOFMS) on the basis of a propofol sulfate reference standard. Evaluation of the quantitative analyses of propofol sulfate imply that propofol sulfate represents a minor metabolite of propofol and is only slightly involved in human propofol clearance.


Forensic Toxicology | 2018

Propofol and propofol glucuronide concentrations in hair following medical propofol administration and in forensic death cases

Alexandra Maas; Christoph Maier; Stefanie Iwersen-Bergmann; Jennifer L. Pilgrim; Matthew Di Rago; Burkhard Madea; Cornelius Hess

PurposePropofol is the most preferred drug for general anesthesia as well as for analgosedation. However, the rate of abuse cases has increased in the past decade. Hair analysis is considered as the method of choice to determine chronic drug use, and propofol and propofol glucuronide have already been used to confirm previous propofol administration. However, given its frequent medical use, it is important that nonmedical propofol abuse can be distinguished from medical propofol application.MethodsNineteen hair samples collected from living subjects who received different doses of propofol in the setting of medical treatment and 31 hair samples from forensic death cases with indications of previous propofol administration were examined using our previously described method enabling the simultaneous extraction of propofol and propofol glucuronide from hair followed by validated liquid chromatography–tandem mass spectrometry analyses.ResultsRecent propofol administration was verified for eight of 19 living cases and 29 of 31 deceased cases. Of the living cases, propofol glucuronide could be detected in all eight cases, whereas propofol could only be detected in three of these cases. Propofol glucuronide could be detected more frequently and in higher concentrations than propofol following medical propofol administration and observed concentrations varied more widely.ConclusionsAlthough further research is still required to clarify the mechanisms involved in propofol incorporation into hair and to establish reliable cutoff concentrations for the differentiation of medical from nonmedical propofol use, it seems likely that relatively high concentrations of propofol found across multiple hair segments strongly suggest a nonmedical propofol abuse.


Forensic Science International | 2018

Chromatographic separation of R/S-enantiomers of amphetamine and methamphetamine: Pathways of methamphetamine synthesis and detection in blood samples by qualitative enantioselective LC–MS/MS analysis

Alexandra Maas; Moritz Losacker; Cornelius Hess

Methamphetamine can be synthesized either enantiopure or in its racemic form. We separated (R)- and (S)-enantiomers of methamphetamine and amphetamine by a fast LC-MS/MS-method using a Lux® 3μm AMP 150×3.0mm analytical column after simple protein precipitation with methanol. Sufficient resolution could be achieved. Method validation for qualitative detection showed limits of quantification <5ng/mL while only little (maximum 14.5%) ion suppression could be shown. Stability in the processed sample could be achieved using isotopically labelled internal standards. Plasma samples of police cases from the german regions of Franconia and Northrhine revealed that in the majority of 106 tested samples (>99%) only (S)-methamphetamine was detected which leads to the conclusion that, in Germany, predominantly enantiopure (S)-methamphetamine is consumed which is synthesized via (1R,2S)-ephedrine or (1S,2S)-pseudoephedrine. However, racemic methamphetamine seems also to be on the market.


Rechtsmedizin | 2014

„Legal highs“@@@Legal highs: Chemie, Pharmakologie, Toxikologie und forensische Bedeutung@@@Chemistry, pharmacology, toxicology and forensic importance

C. Hess; Alexandra Maas; Burkhard Madea

ZusammenfassungBei „legal highs“ handelt es sich um synthetische Verbindungen mit psychoaktiven Wirkungen, die sich in Bezug auf Struktur und Wirkungsweise oft nur geringfügig von den bekannten illegalen Drogen unterscheiden. Neben der Strukturklasse der Phenethylamine gehören verschiedene Tryptamin- und Piperazinderivate sowie synthetische Cannabinoide zu diesen neu auf dem Markt auftretenden Substanzen. Der Konsum von Legal highs ist mit erheblichen gesundheitlichen Risiken bis hin zum Tod verbunden. Der Nachweis der immer weiter modifizierten Substanzen stellt eine große Herausforderung für die forensische Toxikologie dar.AbstractA growing number of novel substances called legal highs continues to appear on the market and are abused as recreational drugs mostly by young people. Apart from the structural class of the phenethylamines, a variety of tryptamine and piperazine derivatives and synthetic cannabinoids have also entered the market as legal highs. These legal highs have psychotropic effects and are marketed for recreational use. Unfortunately substance legislation is inadequate in the light of the rapidly evolving market for legal highs. These substances mimic effects of more traditional drugs but have serious side effects and fatal cases have been described. As legal highs continue to inundate the market forensic toxicological analysis is confronted with great challenges.


Drug Testing and Analysis | 2018

Confirmation of recent heroin abuse: Accepting the challenge

Alexandra Maas; Burkhard Madea; Cornelius Hess

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Burkhard Madea

University Hospital Bonn

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