Metabolic profiles and screening tactics for MDMB-4en-PINACA in human urine and serum samples.

MDMB-4en-PINACA (Methyl 3,3-dimethyl-2-[1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido] butanoate) is a potent agonist of the CB1 receptor. In 2021, it was one of the most common synthetic cannabinoid receptor agonists (SCRAs) seized by the Beijing Drug Control Agency. MDMB-4en-PINACA can be hard to detect in biological specimens because of ester hydrolysis. In this work, a highly sensitive liquid chromatography-high-resolution mass spectrometry (LC-HRMS) method was developed for the detection of MDMB-4en-PINACA metabolites in urine, serum, and hair samples. Metabolites from authentic samples were compared with those from human liver microsomes (HLMs) in vitro and in zebrafish in vivo. A total of 75 metabolites, including 44 previously unreported metabolites, were identified from urine samples. We found that 11 metabolic pathways were involved in MDMB-4en-PINACA metabolism, including acetylation, a novel metabolic pathway for SCRAs. Our results revealed that ester hydrolysis and hydroxylation were to the major metabolic pathways involved in MDMB-4en-PINACA metabolism. Using serum samples, we detected 9 metabolites along with the parent drug. Only the parent drug was detected using hair samples. The existence of ADB-4en-PINACA makes the currently used biomarkers for MDMB-4enPINACA not very specific for the intake of MDMB-4en-PINACA. Therefore, based on the identified metabolites and their structural features, we propose more sensitive screening tactics for MDMB-4en-PINACA using urine and serum samples.

A retrospective analysis of data from illicit drug abuse cases in Beijing between 2018 and 2020.

The overall number of drug abuse cases has been on the rise around the world, causing it a disaster in many countries. In this retrospective study, we analyzed the characteristics of 11,903 drug abuse cases in Beijing, the capital of China, in the perspective of age, gender, nationality, region, season, type of specimens and various drugs, respectively. The case information was collected by the national-level forensic toxicology laboratory, which belongs to the China University of Political Science and Law. It was shown that the overall number of drug abuse cases had increased sharply from 2018 to 2019 and had a decrease of 25% in 2020. The incidence of drug abuse cases involving men was much higher than that of the cases involving women. The adolescents and young adults accounted for the largest share of drug abusers in our study. Haidian, as a national center of scientific and technological innovation with global influence, had the largest percentage of toxic substance-related cases, and the change was more pronounced than other districts during the 3-year-period. Chaoyang was second to Haidian in the number toxic substance-related cases. As a key window of economic, Chaoyang had the highest number of foreigner drug cases. June to August had the highest number of drug abuse cases, while amphetamines, opioids, cannabis and cocaine were the most common toxic substances involved in the cases we detected. To our knowledge, this is the first study to provide an overall analysis of drug abuse cases in Beijing, China. The study indicated the presence of a wide number of drug abuse cases in the capital city and confirmed the threat for the public safety and health. Such forensic information can assist the government to devise intelligence-based preventive and repressive measures and policies.

Polymer-based lab-on-a-molecule for the selective and sensitive recognition of fluoride and cyanide.

A polymer chemical sensor based on lab-on-a-molecule was synthesised by amine-aldehyde polymerisation for selective detection of fluorine ions (F-) and cyanide (CN-). The polymer chemical sensor shows significant absorption and fluorescence changes upon the addition of F- and CN-, which can be observed by the naked eye and optical reactions. The polymer has a higher fluorescence enhancement effect than its monomer and the distance of wavelength of each anion increased which could be applied to better distinguish the two anions.

Metabolic Profiles of 5F-MDMB-PICA in Human Urine, Serum and Hair Samples Using LC-Q Exactive HF-MS.

In 2020, 5F-MDMB-PICA (5F-MDMB-2201) was one of the most common synthetic cannabinoids (SCs) identified in drugs seized by the Beijing Drug Control Agency, and it was categorized as Schedule II by the United Nations Office on Drugs and Crime in March 2020. It is difficult to detect 5F-MDMB-PICA in biological matrices due to its fast metabolic rate in vivo. In this work, 5F-MDMB-PICA metabolic profiles were investigated by liquid chromatography--quadrupole exactive high field orbitrap mass spectrometer (LC-Q Exactive HF MS), with accurate mass measurements in human urine, serum and pubic hair. To obtain intact metabolites, solid-phase extraction for urine and serum and direct ultrasonic extraction for pubic hair were applied to clean the samples without enzymatic hydrolysis. The differences in 5F-MDMB-PICA metabolism in the three different matrices were compared for the first time to determine the best detection biomarkers for monitoring 5F-MDMB-PICA misuse. Urine samples were determined to be the preferred biological material for identifying 5F-MDMB-PICA abuse. Forty-seven intact metabolites were detected in human urine, the ester hydrolyzed with glucuronidated metabolite in urine samples can be used as the primary biomarker to identify drug misuse. Fifteen metabolites were found in serum samples. Ester hydrolysis was considered to be the major metabolic pathway, and a large number of metabolites were involved with it. Zero metabolites apart from the parent drug were detected in pubic hair samples. Twenty-eight new metabolites and their metabolic pathways were characterized and tentatively identified by LC-QE-HF-MS, and a new potential biomarker (M5 ester hydrolysis + propionic acid) was also identified.

Visualization of Literature Information on Postmortem Interval Estimation Indexed by CNKI Database from 1990 to 2020.

OBJECTIVES: To explore the development process of the postmortem interval (PMI) research in China from January 1990 to August 2020, research hotspots in different periods, authors and cooperation between institutions, and to provide a reference for the better development of PMI inference research through the visualization of the literature information of the PMI estimation research indexed in China National Knowledge Infrastructure (CNKI). METHODS: The information visualization analysis software CiteSpace 5.7.R1 was used to carry out big data analysis on hotspots, high-frequency keywords, authors, institutions and other information in the research literature on PMI inference from January 1990 to August 2020 indexed in CNKI. RESULTS: The peak time of publication of PMI was from 2006 to 2010 with 114 articles. In keyword co-occurrence network, the effective hot words were forensic entomology, DNA content analysis and some emerging words such as artificial intelligence and big data. In the cooperation network of institutions, the high-frequency institutions were mainly the scientific research institutions. The author cooperation network showed a trend of co-aggregation and multi-cooperation. CONCLUSIONS: With the development of science and technology, the research on PMI estimation based on traditional methods is mature and novel strategies are emerging. Big data and artificial intelligence combined with forensic science provide new research directions on PMI estimation.

Characterization and tentative identification of new flunitrazepam metabolites in authentic human urine specimens using liquid chromatography-Q exactive-HF hybrid quadrupole-Orbitrap-mass spectrometry (LC-QE-HF-MS).

Flunitrazepam (FNZ) is a potent hypnotic, sedative, and amnestic drug used to treat severe insomnia. In our recent study, FNZ metabolic profiles were investigated carefully. Six authentic human urine samples were purified using solid phase extraction (SPE) without enzymatic hydrolysis, and urine extracts were then analyzed by liquid chromatography-Q exactive-HF hybrid quadrupole-Orbitrap-mass spectrometry (LC-QE-HF-MS), using the full scan positive ion mode and targeted MS/MS (ddms2) technique to make accurate mass measurements. There were 25 metabolites, including 13 phase I and 12 phase II metabolites, which were detected and tentatively identified by LC-QE-HF-MS. In addition, nine previously unreported phase II glucuronide conjugates and four phase I metabolites are reported here for the first time. Eight metabolic pathways, including N-reduction and O-reduction, N-glucuronidation, O-glucuronidation, mono-hydroxylation and di-hydroxylation, demethylation, acetylation, and combinations, were implicated in this work, and 2-O-reduction together with dihydroxylation were two novel metabolic pathways for FNZ that were identified tentatively. Although 7-amino FNZ is widely considered to be the primary metabolite, a previously unreported metabolites (M12) can also serve as a potential biomarker for FNZ misuse.

A novel analytical method of TFMPP and mCPP in fluids of drug addicts using LLE-GC/NPD.

In recent years, drug-abuse problem is growing by leaps and bounds all over the world. The master minds spearheading its proliferation among the youth are difficult to identify, so drug-abuse case has become a hard nut to crack even with the help of best international experts in forensic science and criminology. Because most nations have tightened their controls on traditional drugs, the younger generation is now hooked onto new-type drugs: 1-(3- trifluoromethylphenyl) piperazine (TFMPP), 1-(3-chlorophenyl) piperazine (mCPP) and other new piperazine-drugs, acting as hallucinogens like 'ecstasy', are being consumed by vulnerable masses all over the world. However, only few research studies have focused on developing highly effective detection methods for TFMPP and mCPP in biological fluids; the number of detection methods for these new-type drugs is almost nil in China. Therefore, it is difficult to detect and prevent drug abuse cases related to piperazine drugs in China. There is an urgent need to develop some simple, fast, and reliable methods for detecting piperazine-drugs in vulnerable masses. Thus, the development of novel detection methods with high sensitivity and selectivity is a difficult task for the officials working in the department of forensic science in China. In this work, a new method was developed for the detection of piperazine derivatives: it was performed under the various specific conditions required for conducting chromatography and mass spectrometry analysis. With this novel method, TFMPP and mCPP was successfully detected with high accuracy in various biological samples. By comparing the purification effect of different solid-phase extraction columns for TFMPP and mCPP in biological fluids (urine and blood), we confirmed the validity of the novel method. In addition, this method has good linear relationship and a low detection line when GC/MS was performed for detecting TFMPP, mCPP in the biological fluids (urine and blood). It is a simple, reproducible method that is highly specific in the detection of piperazine-drugs. Thus, it is indeed a reliable method in forensic science.

[Determination of three phenoxyalkanoic acid herbicides in blood using gas chromatography coupled with solid-phase extraction and derivatization].

A method for the determination of three phenoxyalkanoic acid herbicides, 2,4-dichlorophenoxyacetic acid (2,4-D), 2-(2,4-dichlorophenoxy)-propanoic acid (2,4-DP), and 4-chloro-2-methylphenoxy-acetic acid (MCPA), in blood was developed. The blood sample was diluted with 0.1 mol/L hydrochloric acid, and extracted by solid-phase extraction using porous resin GDX401 as adsorbent and ethyl ether as eluent. The extract was esterified with dichloropropanol in the presence of sulfuric acid as catalyst. The derivatives were analysed by gas chromatography with electron-capture detection. The detection limits of 2,4-D, 2,4-DP and MCPA were 20, 8 and 40 ng/mL, respectively. In quantitative analysis, 2,4-dichlorophenylacetic acid was used as an internal standard. The linear relationships and recoveries were satisfactory. The derivatization of the three herbicides with methanol, ethanol, n-propanol, n-butanol, and trifluoroethanol were also studied, and the analytical methods of these derivatization were compared with that of dichloropropanol as esterifying agent. The method is sensitive enough for the examination of the poison samples in actual.