Forensic medicine serves as a vital branch of medical science dedicated to aiding national and societal functions.Its longstanding application in practice and the role it plays in national governance make it evident that forensic medicine principally serves judicial and administrative bodies,earning it the moniker"State medicine".As a first-class discipline within the realm of medical sciences,forensic medicine is also a crucial part of evidential law,embodying both natural and social scientific characteristics.Over nearly a century of development,modern forensic medicine has evolved into an independent technological science discipline.Its comprehensive system encompasses forensic medicine knowledge system,academic system,disciplinary system,as well as technological system.The science and technology system of forensic medicine is inherently open,continuously interacting with other domains such as the knowledge of medicine,information science,mathematics,physics,and chemistry,which fosters a continuous influx of new insights and the adoption of interdisciplinary methods,effectively broadening the scope and depth of forensic science.Moreover,this system is characterized by its dynamism,propelled forward by the unyielding research and practical engagement of all the forensic experts.

In recent years,the international drug control situation has become increasingly serious.According to the statistical data of the year 2021 from UNODC,in the past decade,the trafficking volume of traditional drug(such as methamphetamine,cannabis and cocaine)has continued to rise,new psychoactive substances(NPS)have emerged one after another,the drugs as well as their precursors and metabolites have become a new group of pollutants.They widely exist in environmental media such as water,air,sludge and soil,due to the manufacture and abuse of drugs,which endangers human and animal safety.Drug detection data from environmental samples can reflect the local drug use situation objectively,real-time,accurately and effectively,which is helpful to grasp the spatial distribution and time changes,monitor the development trends of drug abuse,assess the trend of drug abuse reasonably,and assist in combating related illegal and criminal activities through comprehensive data analysis.At present,sewage monitoring has become an important means of drug monitoring in countries around the world.Sewage testing can assess drug consumption in a place reasonably,and sewage network traceability technology can reduce the scope of regional investigation of drug manufacturing dens effectively,so as to combat accurately.Drug detection in the atmosphere,sludge and soil has been carried out in some foreign countries,but it has not been used as a long-term monitoring means.Long-term monitoring of drugs from the environment in a variety of ways not only helps to effectively update the drug situation in the region,but also to better understand local trends in drug use and identify new drugs of abuse.It will provide data support for more accurate monitoring and combating drug crimes in the future.This paper reviews the methods for detecting drugs and other related compounds in different environmental matrices including sewage,atmosphere and sludge in China and other countries,including the study on the sources and forms of related compounds in different environments,the preparation of different matrix samples and the quantitative analysis of drugs from environment,as well as the existing problems and shortcomings of various detection methods.Finally,the drug detection technology and comprehensive monitoring system in the environment are prospected.

In recent years,with the rapid development and widespread popularity of smartphones,analytical sensors based on different action principles have provided an effective solution for forensic real-time detection.In this paper,the recent progress of smartphone-based systems of analytical sensors in forensic real-time detection was reviewed.The analytical principle,the performance of different analytical sensing,and their future perspectives were discussed respectively.

Objective To establish a simultaneous detection approach for 34 emerging contaminants(ECs)in tap water by liquid chromatography-tandem mass spectrometry(HPLC-MS/MS).Human health risk assessment was performed according to the detection results from 43 tap water samples.Methods Tap water samples were concentrated and extracted by solid phase extraction,and then blown to near dry by nitrogen at 40℃.The sample extracts were dissolved in methanol-water solution(95:5,VN)to 0.5 mL for analyzing.Agilent Jet Stream Electrospray Ionization(AJS ESI)and the multiple reaction monitoring(MRM)mode were performed for MS to acquire the data of 34 ECs.A database including precursor ion,product ion and retention times was established accordingly.Results The average linear correlation coefficients(r)of 34 kinds of ECs was 0.995 9.The limits of detection were 0.01～0.60 ng/L and the recoveries were between 60.7％and 119.8％.The intra-group precisions were between 0.05％～9.89％and the intra-day precisions were between 0.20％～14.40％for the spiked samples.The method was applied to analyze 43 tap water samples and a total of 15 ECs were detected.According to the results,the detection rate of caffeine was the highest(84％),and the concentration range was ND～74.42 ng/L.Among all the ECs detected,1,2,3-benzotriazole had the highest concentration(ND～361.15 ng/L),where detection rate was 44％.Humans may be exposed to these ECs by drinking the tap water.The human health risk assessments of 12 kinds of ECs were carried out,however,the estimated risk was negligible(risk quotient＜0.01).Conclusion The method is simple,highly sensitive and selective,and could meet the detection needs of ECs at trace level in tap water.There was no human health risk posed for ECs identified in 43 tap water samples analyzed by this method.

Objective To analyze the metabolic changes of myocardial tissue in rats under acute exposure to macleaya cordata by gas chromatography mass spectrometry(GC-MS),explore forensic identifications of its characteristic metabolites,and verify its toxicological mechanism in poisoning cases.Methods The rats in the exposure group were given 382 mg/kg macleaya extract solution by gavage,and the rats in the control group were given the same dose of solvent.The myocardial samples were analyzed by GC-MS,and pattern recognition was conducted through partial least squares discriminant analysis(PLSDA).The differential metabolites with characteristic changes were identified by variable importance projection(VIP value＞1)and Student's t test(P＜0.01).Results Compared with the control group,21 potential characteristic metabolites were identified.Through KEGG pathway enrichment analysis,it was found that these metabolites were mainly involved in the pathways of glycine,serine and threonine metabolism;pyruvate metabolism and glycerolipid metabolism.Conclusion Through the study of myocardial metabolism in rats exposed to macleaya cordata,we found the information on metabolites closely related to poisoning,which provides new insight and reference for studies on the mechanisms of macleaya cordata poisoning in the field of forensic medicine.

Objective Synthetic cannabinoids(SCs)will be widely metabolized to phase I metabolites and glucuronide metabolites after entering human body.It is usually difficult to detect the parent drug of SCs in urine.Therefore,it is necessary to undergo de-glucuronidation in the preparation of urine samples.We aimed to optimize the enzymatic hydrolysis methods for SCs detection in urine.Methods We studied enzymatic hydrolysis for the determination of 11-demethyl-9-carboxyl-THC(Δ9-THC-COOH)in THC positive urine samples by liquid chromatography-tandem mass spectrometry(LC-MS/MS),and compared it with the alkaline digestion method.Meanwhile,we studied enzymatic hydrolysis for the determination of the related metabolites in MDMB-4en-PINACA and ADB-BUTINACA positive urine samples.Results The Δ9-THC-COOH glucuronic acid conjugate could be hydrolyzed by adding 3μL β-d-glucuronidase solution(＞100 000 units/mL)for 30 min at 55℃.The MDMB-4en-PINACA M and ADB-BUTINACA M glucuronide conjugates were hydrolyzed by adding 3μL β-d-glucuronidase solution(＞100 000 units/mL)for 30 min at 75℃.Conclusion This study can provide reference for the establishment of rapid,accurate and reliable enzymatic hydrolysis methods when detecting SCs in urine.

Objective To observe the effects of Levo-tetrahydropalmatine(l-THP)on the expression,regression and relapse of conditioned place preference(CPP)in ketamine induced rats,and to detect the content of dopamine(DA)in the striatum(caudate putamen,CPu)of the rat brain at different time points.Methods Ketamine addiction rat model was established by CPP.The effects of l-THP on the expression,regression and relapse of ketamine induced rat CPP were investigated using CPP score as the index.The content of DA in CPu of rats was determined by ultra-performance liquid chromatography coupled to tandem mass spectrometry(UPLC-MS/MS)after ketamine administration and l-THP intervention at 30 min,60 min,90 min,120 min and 150 min.Results It indicated that 1-THP could decrease the expression of CPP in ketamine induced rats,promote the process of CPP resolution and inhibit the process of relapse.In addition,l-THP combined with ketamine administration significantly inhibited the ketamine-induced increase in DA content in the CPu of the rats.Conclusion The mechanism of l-THP inhibiting the reward effect of ketamine may be related to blocking DA receptors and reducing the release of DA neurotransmitters.l-THP has potential implications for the treatment of ketamine addiction.

Objective To establish a method for determining hydrogen sulfide(H2S)in blood and apply it to practical cases.Methods A delute solution was achieved by adding 0.8 mL saturated borax solution into 0.2 mL blood sample was diluted with.1 mL acetonitrile solution containing 0.1％formic acid was then taken in a test tube,followed by adding 0.1 mL dilute solution and 0.1 mL thiozine aqueous solution(1％).After thorough mixing,the mixture was left to stand for 30 minutes.Subsequently,the sample was subjected to liquid chromatography-tandem mass spectrometry(LC-MS/MS)analysis after centrifugation and membrane filtration.Results The results showed that H2S exhibited good linearity within the concentration range of 10～2 000 ng/mL,with the R2 value of 0.998 5.The detection limit was 5 ng/mL,and the quantification limit was 10 ng/mL.In three cases of H2S poisoning,sulfur ions were detected in the blood of the deceased individuals,with concentrations ranging from 0.17 to 0.56 μg/mL.Conclusion For the first time,this study established a LC-MS/MS method for determining H2S in blood,which can meet the detection needs of H2S poisoning cases.

Objective To develop a method for the determination of ketamine analogues in hair samples by liquid chromatography quadrupole linear ion trap mass spectrometry(QTRAP LC-MS/MS).Methods 20 mg of washed and dried hair was added to 1 mL extracting solution and then prepared using an ultrasonic extraction with frozen pulverization method.After centrifugation and purification with membrane,the supernatant was separated in a ACQUITY UPLC? HSS T3 column with gradient elution,finally tested with multiple reaction monitoring for the detection of 10 ketamine analogues.The above method was applied for quantitative analysis of ethylfluamine,F-norketamine and tiletamine in 20 positive samples.Results When the concentration ranged from 0.01 to 2.00 ng/mg,there was good linearity for 10 ketamine analogues with the correlation coefficients over 0.99.The recoveries ranged from 89.1％to 106.1％,and the matrix effects were between 88.3％and 106.0％.Among the 20 positive samples,the contents of ethylfluamine,F-norketamine and tiletamine in hair ranged between 0.02～8.35 ng/mg,0.01～0.94 ng/mg and 0.02～10.93 ng/mg,respectively.Their mean values were 1.59 ng/mg,0.28 ng/mg and 2.69 ng/mg.Their medians were 0.40 ng/mg,0.19 ng/mg and 2.11 ng/mg.Conclusion The established method was simple,efficient,reliable and suitable for the determination of ketamine analogues in hair.The data provided reference for the drug control and forensic science practice.

Objective Corruption is the most common cadaver phenomenon in forensic practice and an important basis for inferring time of death(PMI),but the definition of corruption degree and the construction of model inference models have always been difficult in the practice of forensic science.Methods In this study,the late postmortem phenomena were observed.Meanwhile,the microbial flora structure of gut and gravesoil and the nature of gravesoil were detected,for analyzing the changes before and after the key moment of abdominal rupture which naturally happened during the cadaver decay.Results The results found that from the macroscopic and microscopic levels,there were significant differences in cadaver decay,including microbial flora structure and gravesoil properties before and after the key moment of the natural abdominal rupture during cadaver decay.The phenomena are highly observable and can be accurately judged by forensic examinations,as well as related means in the field of biology and physiochemistry.In this study,this critical event was called Rupture Point.Conclusion The Rupture Point can be used as an important node for the assessment of cadaver decay degree in the practice of forensic medicine.It can be utilized for a cut-off point as well when constructing PMI inference models based on microbial flora structure changes.The accuracy of PMI inference models can be improved when the models were constructed in segments.