Topic on Rapid Detection Technology Empowering Multi-Scenario Applications in Forensic Toxicology SHI Yan
New psychoactive substances （NPS） have the characteristics of rapid turnover, wide varieties, and high abuse potential. It has become a major threat to global public safety. Currently, the forensic identification of NPS faces certain challenges in detection methods for effectiveness, sensitivity, accuracy and resistance to matrix interference. Novel functional materials （NFM）, with their high specific surface area, designability, specific recognition capability and signal amplification effects, provide a new path for advancing rapid detection techniques for NPS. This paper systematically reviews the innovative applications of NFM in the rapid detection of NPS over the past decade. By summarizing and analyzing the research and applications of NFM in laboratory detection and on-site rapid screening, it outlines the characteristics and advantages of different types of materials. Combined with the development trends of NFM in intelligent material design, interdisciplinary integration and portable integrated devices, it provides theoretical references for the development of rapid detection methods for NPS, which is conducive to improving the rapid detection ability of NPS in “anti-drug combat”.
Objective To construct an aptamer-functionalized carboxylated graphene oxide （CGO） fluorescent sensor to achieve highly sensitive and specific detection of ketamine （KET） and its metabolite norketamine （NK） using an aptamer capable of simultaneously recognizing KET and NK. Methods A specific aptamer for simultaneous recognition of KET and NK was screened using graphene oxide-systematic evolution of ligand by exponential enrichment （GO-SELEX） and molecular docking techniques. The aptamer, labeled with Cy5 fluorescence, was chemically conjugated to CGO to construct an aptamer-functionalized CGO fluorescent sensor. By optimizing detection conditions, including the mass concentration of CGO, aptamer concentration, reaction temperature, and incubation time, quantitative analysis of the target analytes was achieved using the ratio of fluorescence intensity changes before and after target addition. The stability of the sensor in biological matrices was evaluated by monitoring fluorescence intensity changes over incubation time in blank blood and urine, in comparison with the traditional physical adsorption-based CGO fluorescent sensor. Spiked recovery experiments in blank blood and urine were conducted to compare performance with that of HPLC-MS/MS. Results A specific aptamer A5 was selected and chemically conjugated with CGO to construct the aptamer-functionalized CGO fluorescent sensor. Under optimized conditions, the proposed fluorescent sensor exhibited a linear detection range of 1.0-5.0 ng/mL for KET, with a limit of detection （LOD） of 0.86 ng/mL; while for NK, the linear detection range was 1.0-5.0 ng/mL, with an LOD of 0.70 ng/mL. Compared with the CGO fluorescent sensor constructed via physical adsorption, this sensor demonstrated greater stability in blood and urine. The spiked recovery rates of KET and NK in blank blood and urine ranged from 81.50% to 110.03%, exhibiting detection performance comparable to that of HPLC-MS/MS. Conclusion The aptamer screening method offers a novel approach for selecting aptamers targeting drugs and their metabolites. The constructed aptamer-functionalized CGO fluorescent sensor provides an efficient and reliable strategy for the high-performance detection of KET and NK.
Objective To establish a rapid analysis method for cyanide based on a ratiometric fluorescent probe, providing a quantitative strategy for on-site visual and rapid detection of cyanide. Methods A dual-emission ratiometric fluorescent probe （AuNCs-FL） was constructed by using bovine serum albumin （BSA）-stabilized gold nanoclusters （AuNCs, fluorescence emission at 660 nm） as the responsive signal unit and fluorescein （FL, emission at 515 nm） as the internal reference. Results The etching effect of cyanide on AuNCs resulted in fluorescence quenching at 660 nm, while the fluorescence intensity of FL at 515 nm remained unchanged, enabling a rapid response analysis of cyanide shift from red to green fluorescence. The developed probe enabled rapid analysis of cyanide within 3 min, with a limit of detection （LOD） of 3.4 mg/L and a visual detection range of 10-100 mg/L. Conclusion The AuNCs-FL fluorescent probe is structurally simple, low-cost, and easy to operate, delivering rapid and accurate results. It also avoids the interference from sulfides encountered in commercial cyanide test kits, making it suitable for the on-site rapid detection of suspected powder samples in cyanide poisoning cases.
Objective To establish a rapid screening and analysis method for etomidate and its analogues using a portable mass spectrometer equipped with a thermal desorption-atmospheric pressure chemical ionization source-linear ion trap. Methods A 10 μL aliquot of a standard solution at a concentration of 1 μg/mL was taken, and after the solvent evaporated, the sample was inserted into the inlet of the portable mass spectrometer for detection. By adjusting the collision-induced dissociation parameters, the molecular ion peak and fragment ion peak information of the standard were obtained and used to establish a reference database. In addition, the method was applied to 29 seized liquid and plant samples. Results A screening system for etomidate and its analogues was established based on the portable mass spectrometer and the corresponding mass spectrometry library. The system enables qualitative screening analysis by identifying primary protonated molecular ions and secondary product ions of etomidate and its analogues. The limits of detection for etomidate and its 12 analogues ranged from 0.1 to 10 μg/mL. Etomidate and its analogues were detected in all 29 liquid and plant samples. However, this method could not distinguish between isomeric imidazole esters, such as isopropoxate and propoxate. Additionally, when testing 2-SH-etomidate, there was a false positive for the detection of etomidate. Conclusion This study established a rapid screening method for etomidate and its analogues using a portable mass spectrometer. The method combines the high sensitivity of mass spectrome-try with the on-site applicability of portable devices, significantly improving detection efficiency and meeting the on-site detection needs of etomidate and its analogues.
Objective To develop a rapid detection method for tiletamine that is easy to operate and low-cost under the premise of ensuring sensitivity and accuracy, to assist in carrying out rapid screening and drug control work on-site. Methods This study integrates dual-ligand copper nanozymes with molecular imprinting technology. Initially, copper nanozymes were synthesized using readily available raw materials at 120 ℃. Subsequently, specific cavities were imprinted on their surface at room temperature using a sol-gel method to construct a novel fluorescent sensing probe. This probe was characterized and methodologically validated, and then applied to the detection of actual samples. Results The developed probe exhibited stable fluorescence properties, strong anti-interference capability, and excellent specificity and sensitivity, with a detection limit of 5 ng/mL and a quantitative concentration range from 15 to 500 ng/mL. It enabled the rapid detection of tiletamine in real samples such as blood and e-cigarette oil. Conclusion This fluorescent probe can be used for rapid detection and on-site preliminary screening of tiletamine in various types of samples. It significantly improves the detection efficiency and reduces analysis costs, showing high research value and broad application prospects.
Objective To obtain differential spectral characteristics of etomidate and its structural analogues, and to establish a rapid identification method using surface-enhanced Raman spectroscopy （SERS） combined with machine learning algorithms for distinguishing etomidate and its analogues. Methods Silver nanoparticles （AgNPs） were used as the SERS substrate to collect SERS spectra of etomidate, metomidate, propoxate, and isopropoxate at two concentrations of 1×10-4 and 1×10-5 mol/L. SERS spectra were also obtained from blood and urine samples containing 1×10-5 mol/L of etomidate, metomidate, propoxate, and isopropoxate, as well as from confiscated e-cigarette oil containing etomidate. Uniform manifold approximation and projection （UMAP） was employed for nonlinear dimensiona-lity reduction and visualization, and a classification model based on the XGBoost algorithm was constructed to enable discriminant analysis of these four structurally highly similar compounds. Results Minor characteristic peak shifts （5-3 cm-1） were identified in the range of 1 398-811 cm-1. Qualitative identification of the compounds in serum, urine and e-cigarette oil samples was achieved without pretreatment. After UMAP dimensionality reduction, distinct clustering separation among different substances was observed. The XGBoost model achieved 100% classification accuracy on the test set. Feature weight analysis revealed that C-N stretching vibration （841 cm-1）, C=O stretching vibration （1 367 cm-1）, and C-O-C asymmetric vibration （1 049 cm-1） were the key spectral bands for discrimination. Conclusion The combination of SERS and machine learning can effectively amplify subtle differences in molecular structures, enabling rapid and accurate identification of etomidate and its analogues. This approach is suitable for on-site rapid screening in forensic toxicology.
Topic on Rapid Detection Technology Empowering Multi-Scenario Applications in Forensic Toxicology
