Analysis on dynamic changes of etizolam and its metabolites and exploration of its development prospect using UPLC-Q-exactive-MS.

As one of the most widely abused designer benzodiazepines in the world, etizolam has been found in many cases in many countries. In this study, UPLC-Q-Exactive-MS was used for the first time to establish a dynamic change model of etizolam and its metabolites in rats. Compared with previous studies, the detection sensitivity and reproducibility of the instrument were higher. In the experiment, we optimized the traditional pharmacokinetic model based on Gauss function. According to the significant difference of etizolam in the plasma elimination phase of rats, a new pharmacokinetic model based on Lorentz function was established to describe the dynamic changes of etizolam more rigorously, which made the error effects lower and the accuracy of the pharmacokinetic parameters was improved. At the same time, the pharmacokinetic parameters of etizolam were compared with four other designer benzodiazepines reported in previous studies in rats, and we found the direct reason for the popularity of etizolam in the NPS market and explored the future development of etizolam for the first time. In addition, 21 metabolites were found through rat experiments to effectively detect etizolam abuse for a long time, of which 4 metabolites had the longest detection window and could be used as long-acting metabolites for experiments, which greatly prolongs the detection window and extends the time range in which etizolam was detected in real cases. This study is the first to conduct a systematic and comprehensive study on the metabolism and pharmacokinetics of etizolam and find out the direct reason for the prevalence of etizolam abuse, and we also discuss the development trend of etizolam in the future market of new psychoactive substances, which is beneficial for forensic experts to assess the trend of drug abuse and can provide reference for relevant drug control and drug treatment.

Rapid detection of 10 benzodiazepines and metabolites in blood and urine using DART-MS/MS.

Benzodiazepines are essential screening targets for common sleeping and sedative drugs used in forensic toxicology. Direct analysis in real-time tandem mass spectrometry was used to rapidly identify 10 benzodiazepines and related metabolites in the blood and urine. The related direct analysis in real-time tandem mass spectrometry parameters were optimized. A liquid-liquid extraction method using ethyl acetate as the extraction solvent was used for sample preparation. The established method was validated and tested on case specimens. The limits of detection of this method ranged from 0.2 to 20 ng/mL and the limits of quantification from 1 to 50 ng/mL. The recoveries ranged from 78.8% to 114%, and the matrix effects were in the range of -21.2% to 17.9%. The precision and repeatability at high and medium concentrations did not exceed 14.6%, and the limit of quantification did not exceed 18.2%, indicating a desirable linear relationship. The established method was used to determine blood and urine specimens from authentic cases, and promising results were obtained.

Non-destructive recognition of copy paper based on advanced spectral fusion and feature optimization.

In order to provide more clues for ongoing investigations and case handling, as well as achieve fast, non-destructive, and accurate identification of copy paper found at crime scenes, this study aims to utilize advanced spectral fusion technology to characterize and identify the three-dimensional features of the "origin-manufacturer-brand" of copy paper. Confocal Raman Microscopic and Fourier transform infrared spectroscopy were employed to collect spectral data from 200 samples from four regions (Shandong, Henan, Shaanxi, Jiangsu). The effects of different preprocessing methods, such as Hilbert transformation and deconvolution, on the model's ability to distinguish were compared. Feature variables were extracted using principal component analysis, and Bayesian discriminant classification models were constructed based on single infrared spectroscopy, Raman spectroscopy, and three types of spectral fusion datasets. By comparing the classification accuracy of different models, the primary fusion based on the full spectrum dataset was selected as the optimal model for the three-dimensional feature classification of copy paper. The accuracy achieved for origin (96%), manufacturer (100%), and brand (100%) was satisfactory, and the classification results were highly accurate. This study provides valuable insights and serves as a reference for its application in forensic science research.

A novel aggregation-induced emission probe-linked phage sorbent assay for virulent bacteria strain imaging and on-site detection.

It was critically important to develop some sensitive, rapid, and specific imaging or detection methods for the virulent strain in food safety monitoring. In the study, a novel tetraphenyl mono-phenylboronic acid dye (TPE-PBA) with good aggregation-induced emission (AIE) features and high combining capacity towards bacteria was first synthesized. With TPE-PBA as a signal tag, a sandwich-type AIE probe-linked phage sorbent assay was developed for imaging and detecting virulent strains using Escherichia coli O157:H7 (E. coli O157:H7) as a representative. In the assay, phages for E. coli O157:H7 were firstly fixed on the bottom of a 96-well plate to specifically capture the strain, then the TPE-PBA signal tag was added and incubated with the captured strain to produce the phage/E. coli O157:H7/TPE-PBA complex. The complex could produce intensive AIE fluorescence being proportional to the amount of E. coli O157:H7 with a detection limit of 30 CFU mL-1 within 30 min. Simultaneously, the strain could be imaged in the plate with good anti-photobleaching and AIE effects. The results demonstrated the AIE-linked phage sorbent assay with a TPE-PBA signal tag could provide a suitable platform for rapid and specific detection and imaging of virulent strains. Therefore, it exhibited good application prospects in the on-site monitoring of food pathogens.