15 February 2022, Volume 47 Issue 1
    

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    Topic: mixed STR analysis
  • SMART: an Analysis System for Mixed STR Profiles
    JI Xianchao, CHI Lianjiang, XU Zhen, PENG Zhu, YE Jian, TU Zheng, CHEN Hua
    Forensic Science And Technology. 2022, 47(1): 1-9. https://doi.org/10.16467/j.1008-3650.2021.0136
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    Objective Mixed STR profiles are difficult to analyze for forensic genetics. Most domestic forensic DNA laboratories rely on manual approaches to deconvolve the mixed STR profiles, leaving into a time-consuming and laborious task from which the more or less subjective opinions result in inability to meet the ever-growing demand for analysis of mixed STR profiles. A self-developed analysis system for mixed STR profiles, SMART (STR Mixture Analysis and Resolution Tools), was to introduce here, capable of realizing automatic analysis of mixed STR profiles into their constituents through splitting. Furthermore, SMART is functional of calculating likelihood ratio to unveil whether a suspect is a contributor of the relevant mixed STR profiles. Methods SMART adopts the probabilistic model of STR peak height, taking into account of such factors as stutter, degradation, locus specific amplification efficiency, peak height variation, drop-in and drop-out. With comparison of the likelihood of each assemblage of genotypes to fit the involving mixed STR profile, SMART is to infer the most likely combination of genotypes and uses the Markov Chain Monte Carlo (MCMC) algorithm to support its inference. Results SMART has achieved applications to the data generated from different kits and genetic analyzers. As an example of utilization of ABI-3500XL genetic analyzer and GlobalFiler kit, SMART has successfully split the mixed STR profiles composed of two to five individuals, outputting multiple resultant items including mixed proportion, mixed profile quality, STR genotyping of each individual contributor and likelihood ratio. Conclusions SMART, the self-developed analysis system for mixed STR profiles, can function to cover similar foreign software systems. Its technical performance indicates that it has reached onto the international advanced level, is eligible to meet the diversified needs of frontline forensic examiners to analyze mixed STR profiles which to have consequently their utilization rate improved.
  • Evolving Researches into Mixed STR Profiles for Their Analysis
    PENG Zhu, XU Zhen, TU Zheng, YANG Fan, LI Yongjiu, YAN Anxin, NIE Hao, ZHAO Hemiao, ZHAO Xingchun
    Forensic Science And Technology. 2022, 47(1): 10-17. https://doi.org/10.16467/j.1008-3650.2021.0114
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    Mixed STR profiles have always been a focus and obstacle for forensic genetics community with their difficulty to analyze and decipher. However, the ever-developing DNA detection technologies even make these mixed STR profiles resulted from less template amount yet more mingled components, having further brought forth such many handicaps to the decipherment that the traditional manual analytic methods are ineligible for the practical demand. Fortunately, the recent-emerging software-based automatic analysis approaches take the advantages of relevant statistical algorithms, gradually becoming the mainstream for mixed STR profiles to parse. Here, the mixed STR profiles were reviewed about their analysis into involving researches’ evolution, focused on the artificial ascription methods and the model-led ones of genotypic statistical probability. Finally, an envisioning was put about the mixed STR profiles for their trending analyses, with discussions being made on the prospect of artificial intelligence (AI) to be applied into analysis of mixed STR profiles.
  • Comparison and Application of Two Pieces of Software for Interpretation of Mixed STR Profiles
    LI Fu, XU Lei, LIN Chen, TU Zheng, JIN Xiaopan, XU Zhen
    Forensic Science And Technology. 2022, 47(1): 18-23. https://doi.org/10.16467/j.1008-3650.2021.0162
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    The ever-advancing DNA technology has been bringing the on-site biological evidential materials into more increasing attentions together with their collection and DNA testing, resulting in successful more detections of eligible STRs from mixed DNA evidential substances in recent years. Accordingly, more profiles of mixed STR are being encountered in forensic casework and waited for reasonal deconvolution and appropriate interpretation in routine task of DNA laboratory, leaving them becoming a hotspot and one of the greatest challenges for forensic DNA genotyping. STRmix and cloud-calculating GPM are presently the main-current two pieces of software to interpret mixed STRs of DNA, the most commonly used software worldwide, too. Discussions were here carried out on the two pieces of software about their similarities, differences, interpretation-dependent theories, analysis process and actual applications plus cases for exampling. References are intended to provide forensic DNA peers with the elucidated interpretation of mixed STR profiles and promotion of international exchange and cooperation.
    • Research Articles
  • Probabilistic Approach to Identifying Same Suspected Target from Multiple Cameras in Video Investigation
    LI Zhihui, XIE Lanchi, LÜ You, WANG Guiqiang
    Forensic Science And Technology. 2022, 47(1): 24-34. https://doi.org/10.16467/j.1008-3650.2021.0116
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    Objective The spatial-temporal track information is key to find the suspected target in video investigation for many cases, yet lacking a methodic basis on how to use such information in the stage of evidence preparation and court testimony. Thus, a probabilistic approach was here to try for the problem to solve with evidence transformation of the target’s track information in video investigation. Methods The characteristic features were specified for human body, clothes and transportation vehicle (motorcycle in this essay) to go past the surveillance cameras under typical process of video investigation so that the different features were estimated of their presence probability plus its upper limit. Accordingly, the probabilities were to express the course of suspect’s committing crime and escaping under multiple cameras, therewith having converted the probability-based track query from a graph-representing model to one Bayesian network whose characteristics were hence able to utilize to have the likelihood ratio estimated. Results The formula and approximate calculation method were given about the likelihood ratio for the concerned problem put under video investigation scene, along with 1) a feature-based spatial-temporal probability model plus analysis being established through decomposition of the proposed time segment/range and direction hypothesis; 2) one probabilistic analysis plus thought framework being proposed about the characteristics of clothes, human body and vehicle in video image; 3) the probability ratio (i.e., likelihood ratio) results being obtained with hypothetical conditions; and 4) the influence being given of hypothesis on probability calculation, meanwhile both the method of posterior ratio estimation and its limiting factors being discussed for practical application. With the condition of twelve commonly-seen features (body shape, coat color/texture/style, pants style/color, shoe style/color, hair length, motorcycle style/color/luggage style) observed under three consecutive cameras (fixed onto a simply non-divergent road), the same target appearing sequentially past the three cameras (all the 12 features showing identical) delivers such a likelihood ratio that equals to at least 8 exponential magnitudes of 10 (i.e., 108) than the target not same. Conclusions A quantitative reference model is unprecedentedly provided with the here-established theoretical analytic method for evidential applicability of video tracking. Why probability-based video tracking results can be used as evidence is explanatorily defined, therefore helpful to improve the evidential power of video tracking.
  • Defogging off Night-shot Image through Luminance-weighted Perception
    ZHANG Zhihao, SUN Peng
    Forensic Science And Technology. 2022, 47(1): 35-42. https://doi.org/10.16467/j.1008-3650.2021.0074
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    Objective To defog off the image/video shot with imaging equipment in foggy environment at night so as to enhance the visual effect with which the forensic image investigation could be carried out smoothly. Methods The underlit image was beforehand estimated of environmental transmittance from its areas of owning light source or none through the respective bright and dark channel by which the physical principle of night atmospheric scattering was abided so that a final mixed environmental transmittance was obtained from a luminance-weighted perception. Successively, the low pass filter was adopted to estimate the environmental illumination under the guide of channel difference. Finally, a night-atmospheric simulative formula was performed into calculation to achieve the fog removal from image. In addition, both CLAHE and SoG algorithms were selected to enhance the visual effect of image. Results With processing into a large number of actual cases and computer-generated images of foggy nights, the here-proposed approach was experimentally proved of its ability to defog and enhance the visual effect with the underlit image, demonstrating the color bias factor had debased by 65%, the average gradient increased by 233% and the information entropy lifted by 7%. Compared with other main choices, the method adopted here did have its significant advantages. Furthermore, the proposed method can simultaneously improve the image into its dynamic color scope, color bias and details of obscure zone. Conclusions Defogging off night-shot image through luminance-weighted perception can effectively highlight the obscure details of foggy images, improve the contrast and color bias, capable of providing more intuitive and effective information for forensic image investigation of public security.
  • Correlativity Determination and Origin Deduction about Heroin Drugs from “Golden Triangle”
    DUAN Zhengping, LIAN Jie, YANG Fazhen, LI Hong, LI Bin
    Forensic Science And Technology. 2022, 47(1): 43-48. https://doi.org/10.16467/j.1008-3650.2021.0081
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    Objective To establish a Pearson’s mathematical correlation model about heroin samples from “Golden Triangle” for differentiating the correlativity and deducing the original source of the heroin samples seized by the public departments of 6 border prefectures and cities in Yunnan province. Methods The seized 489 heroin samples (originated from “Golden Triangle”) were dissolved with acidic solvents and extracted through organic solvents, successively having them detected via ultra high performance liquid chromatography triple quadrupole tandem mass spectrometry (UPLC-TQ-MS/MS) under the electrospray-ionization positive ion source (ESI+) plus multi reaction monitoring (MRM) mode. 15 sorts of neutral/acidic impurity were selected as target analytes of the heroin samples. With processing into the data received from peak areas of relevant samples, both Pearson’s correlation coefficient calculation and principal component analysis (PCA) were undertaken to differentiate the correlativity among the heroin samples so that the heroin samples were one another to uncover their hidden information of origin. Results On the correlation threshold defined as 0.965, the heroin samples were sorted into correlativity-linked groups under Pearson correlation coefficient handling. There were 46 groups of strong correlation, with each group containing 2-22 samples. The relative standard deviation (RSD) of all the impurity-characteristic data in each group was less than 20%, indicating the small difference present with impurity-characteristic data among the samples of strong correlation, therewith having also verified the reliability of the approach adopted here. Principal component scoring and its consecutive mapping of heroin samples further had all the heroin samples divided into 3 categories: I, II and III. Thus, Dehong-seized heroin samples were mostly distributed in category I, with those of the Lincang-seized mainly in category II. Conclusions In coalescence of case information with threshold-based correlation grouping and principal component analysis, the 489 heroin samples from “Golden Triangle” were successfully analyzed. It was manifested that the heroin samples had both the same raw/processed materials and manufacturing process if they were from correlativity-same group, and the similarity was very high of the same batch. The approach adopted here should be of both strategic and tactical information references/services for law enforcement against drug abusing, assistant to establishment of drug-sample database.
  • Liquid Chromatography-triple Quadrupole Mass Spectrometry Simultaneously Detecting Paraquat and Metabolites in Biological Samples
    MENG Yuzhen, GONG Duo, LI Wenyue, WEN Yan, FAN Zheyu, ZHANG Chao, WANG Tao, FU Shanlin, WEI Zhiwen, YUN Keming
    Forensic Science And Technology. 2022, 47(1): 49-57. https://doi.org/10.16467/j.1008-3650.2021.0083
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    Objective To establish an LC-MS/MS method for determination of paraquat (PQ) and its main metabolites [monoquat, paraquat-monopyridone (MP), paraquat-dipyridone (DP) and 4-carboxy-1-methylpyridinium ion (MINA)] in biological samples. Methods The biological samples (blood and tissues for this assay) were added with Paraquat-d8 Dichloride (PQ-D8), the internal standard substance, successively having them adjusted of pH values and precipitated of proteins with acetonitrile so that their supernatants were cleansed with cyclohexane and consecutively centrifuged to receive the lower layer of acetonitrile. The received fluid was undergone with drying, re-dissolved into methanol, centrifuged and filtrated through membrane, thereafter having been brought to elution with different chromatographic columns of LC-MS/MS apparatus. For the analysis of mass spectrometry into the eluate from column separation, LC-MS/MS apparatus was set under multiple reaction monitoring (MRM) mode plus positive ionization. Results Linear ranges were present with PQ, monoquat, MP, DP and MINA at each individual’s 5-800ng/mL, 0.5-80ng/mL, 5-800ng/mL, 2.5-400ng/mL and 2-320ng/mL (all rendering an r higher than 0.993), with their intra- and inter-day precision (RSDs) being 5%~14%, 3%~13%, 3%~15%, 5%~13% and 2%~15% plus the accuracy (RE) being 91%~116%, 80%~100%, 80%~111%, 85%~114% and 91%~114%, respectively. Besides, if the processed samples were placed with the autosampler at room temperature for 72 hours, each analyte (in the order of PQ, monoquat, MP, DP and MINA) demonstrated its own accuracy of 90~119%, 56%~125%, 60%~110%, 78%~98%, 83%~117%, respectively. Conclusions This approach set up here is of simple pretreatment, good separation effect and high extraction efficiency, capable of detecting PQ and metabolites from suspected paraquat poisoning samples. As the optimized update from our team’s earlier attempt to detect paraquat, monoquat and MP in biological samples, this approach could also have detected the trace metabolites even if the PQ is greatly reduced of content lower than certain favorable conditions.
  • Applicability of Grid Features in Examination of Printed Documents
    XU Shiguo, WANG Hong, JIANG Feng
    Forensic Science And Technology. 2022, 47(1): 58-63. https://doi.org/10.16467/j.1008-3650.2021.0118
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    Objective It is difficult for forensic document examination to target second added printed and/or page-replaced documents from the model-identical and even same printer. The commonly-used printing devices (those types of needle, ink-jet or laser, all only able to process bitmap format files) cannot genuinely output the file of curving-glyph Chinese words. Alternatively, they adopt RIP (raster image processor) to handle the printed document, dividing every printed area further into certain numerous square zones (grid spaces) where to have the curving glyphs mapped so as to engender a printable bitmap format file. Here, grid features were to experimentally explore about their stability and change-caused factors with the printed documents, for purpose to provide a new reference regarding to identification of second added printed and/or page-replaced documents. Methods 500 frequently-used Chinese characters were taken as sample to print into their 9pt, 10.5pt, 12pt, 14pt, 15pt, 16pt and 18pt Simsun fonts with 26 laser printers of different brands or models at discrepant resolutions or quality modes. The laser printers were controlled under various print-driver programs from the same or different computers. With comparative analysis into the specifics of those printed words’ strokes, the involving grid features were to summarize their patterns and traits. Results There are 3 kinds of grid features: TFHS (Thickness Feature of Horizontal Strokes), WFVS (Width Feature of the Vertical Strokes) and LFOS (Ladder Feature of Oblique Strokes). The same-one printer delivered identical grid features when it printed one document to produce the words of same font and size from an undisturbed same-time printing. The grid features may change with the various printers, the computer-operation systems, the print-driver programs and/or the printing resolutions. Conclusions The grid features are stable within one document that is printed from a printer at one time, yet leaving a probability of changing once the printing configuration (hardware/software) has got any discrepancy.
  • Exploration into 5F-UR-144 about Its Thermal Instability
    LUO Xuan, ZENG Changguang, WANG Yanjun
    Forensic Science And Technology. 2022, 47(1): 64-68. https://doi.org/10.16467/j.1008-3650.2021.0151
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    Objective To explore the thermal instability of 5F-UR-144 by way of GC-MS, LC-Q-TOF/MS and NMR. Methods 5F-UR-144 was dissolved into ethanol, then analyzed with GC-MS and LC-Q-TOF/MS to have its thermal decomposition disclosed, with its operations of LC-Q-TOF/MS and NMR being carried out for confirmation of new substances generated after sealing for heating at room temperature and/or 280℃ meanwhile its thermal instability being explored through LC-Q-TOF/MS under the temperatures rising from room level to 300°C. Results 5F-UR-144 indeed generated new substances after heating to have its cyclic structure disrupted, demonstrating it starting to decompose from 130°C and completing decomposition up to 98% at 240°C, yet beginning to carbonize on the temperature exceeding over 260°C. Conclusions 5F-UR-144 is of thermal instability so that its ingestion is discrepant, resulting in the ingested substances involved being different, too. GC or GC-MS is not available for the quantitative examination of 5F-UR-144.
    • Reviews
  • Spatial-temporal Visualized Platform for Crime Scene Investigation: Development and Applicative Prospect
    SHI Yi, PENG Silu, XIE Pengda, MENG Xiangchao, LI Wenhai, ZHAO Qiansheng, WANG Mingzhi
    Forensic Science And Technology. 2022, 47(1): 69-75. https://doi.org/10.16467/j.1008-3650.2021.0058
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    Increasing information technologies and applications have been bringing in various correlating informative sources from different devices. It is very important and challenging about how to exploit the investigated findings from the social profile-high or impact-striking cases/events that are related to such information resources because they can provide key evidence to effectively support investigation deployment and the final juridical verdict. Through introduction of the relevant techniques of spatial-temporal visualization into scene investigation, a constructive design was here elaborated on one spatial-temporal visualized platform for crime scene investigation. The devising intention focused on setting up those visualized essential classifications and involving scrutiny-and-judging resorts so that the cases/events can be reasonably linked/connected with the pertinent evidential objects/findings. The platform was presented as a hierarchical framework, highlighting how to assemble those uniform geo-information sources and make them able to utilize. There are key features of the platform concerning with its whole buildup, functional modules, correlating modes and scheme implementation. The simulative and exampled applications were put forth about the platform to play its role in different scenarios. Finally, the prospect was analyzed on the platform’s systemic innovation and extending applicability into crime scene investigation.
  • Terrestrial 3D Laser Scanning and Its Application for Survey and Reconstruction into Traffic Accident Scenes
    GUAN Chuang, FENG Hao, HENG Weiwei, ZHANG Zhiyong, LI Wei, JIANG Zhenfei
    Forensic Science And Technology. 2022, 47(1): 76-82. https://doi.org/10.16467/j.1008-3650.2021.0113
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    Terrestrial 3D laser scanning (TLS) technology was here reviewed into its progressional development and application scenarios, with the relevant technical principles and operation procedures being briefly elucidated. Further, TLS technology was therewith divided into different applications so as for traffic accidents to be able to tackle adequately. Through the detailed looking-up about TLS latest researches and exampling implementations, an exploration was tried to carry out for traffic accidents to be surveyed and reconstructed under the on-going requirements, with the discussion being made about the current problems and future development directions, too.
  • Progress on Developing Reference Materials of Methamphetamine and Heroin
    YANG Hongxian, WEN Wu, ZHENG Hui
    Forensic Science And Technology. 2022, 47(1): 83-87. https://doi.org/10.16467/j.1008-3650.2021.0087
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    Methamphetamine and heroin are important targeting substances among the drugs that are fought against abuse and addiction. Routinely, drug testing laboratories must rely on the corresponding high-purity reference materials for the tested methamphetamine and heroin to get correct qualitative and quantitative analysis. At present, there are rare reports about the progress on developing reference materials of methamphetamine and heroin. Methamphetamine reference materials are currently available with their biological matrix-based ones and those certified versions home and abroad, having been applied into detection and identification of methamphetamine. The biological matrix-based reference materials include the products from frozen-dried urine, hair and frozen human serum. With addition of the certified ones, heroin reference materials have their 13C labeled preparations that excel in analytic precision to the deuterated derivative counterparts. The reference material should be confirmed of its structure with such approaches as gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, NMR and FTIR, together with its quantitative value being determined via different quantitative analysis choices, e.g., gas chromatography and liquid chromatography. Through the summarization made here about the related researches and publications, a fuller understanding would be thus achieved on developing reference materials of methamphetamine and heroin. Finally, prospects were also proposed for their future researches and developments.
  • Introduction to Automatic Fingerprint Identification Based on Deep Learning
    WU Chunsheng, LI Xiaojun, WU Hao
    Forensic Science And Technology. 2022, 47(1): 88-95. https://doi.org/10.16467/j.1008-3650.2021.0121
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    An introduction was here put forward about automatic fingerprint identification relating to deep learning. Starting from the brief review on automatic fingerprint identification technology (i.e., the automated fingerprint identification system, AFIS) and developing process, the computer-based innovations were further elucidated to focus on artificial intelligence (AI) technology and its application in recognition of images. Fingerprint identification is definitely a kind of image discrimination, hence having it brought into a new way of AI technology tackling. With the recognition algorithm about fingerprint pattern, AI is playing its role in fingerprint identification through improving image technology based on deep learning. AI’s fingerprint identification can be divided into three stages, leaving the second stage being here specifically described about the relevant developing trend. Forensic fingerprint recognition has since been changed with deep learning adopting image features other than traditional minutiae distinctions. The emphasis of this essay was put on the deep learning technology about its application mode and typical technology method in fingerprint identification, with the demonstrative technical scheme being illustrated. For the involving network model design in the technical scheme mentioned above, those important steps were explained one by one. Several key technical problems were also proposed about image processing, dimension reduction and the others related. The present available deep learning network models, eligible for fingerprint identification, were introduced with the examples of convolutional neural network and the auto-encoder one, too. Finally, the comparison was carried out on performance of AI’s fingerprint identification algorithm against the traditional one.
  • Qualitative Identification of PMK Methyl Glycidate, MDMA’s Precursor
    ZHAO Yang, HU Yupeng, CHANG Ying, GAO Lisheng
    Forensic Science And Technology. 2022, 47(1): 96-99. https://doi.org/10.16467/j.1008-3650.2021.0120
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    Objective To report the first-time emergence of PMK (piperonyl methyl ketone) methyl glycidate (a precursor substance of MDMA) in Chinese mainland through completion of establishing its gas chromatography-mass spectrometry (GC-MS) analytical method and confirming its structure with nuclear magnetic resonance (NMR) which to deliver the compound’s hydrogen and carbon spectrums. PMK methyl glycidate is able to synthesize MDMA (3,4- methylenedioxymethamphetamine, a controlled drug capable of seducing the eater into addiction) through transition of PMK. Methods The sample was extracted with methanol and DMSO-d6, successively subjected to detection of GC-MS and NMR. Results GC-MS rendered the characteristic mass-spectral fragments and retention time of the extracted compound with which NMR assigned the signal peaks of both hydrogen and carbon spectrums, having therewith determined the structure of the chemical substance. Conclusions At present, GC-MS technology, combined with mass spectrometric information database retrieval, is one of the most commonly used choices for analyzing drugs and their precursors in forensic laboratories. However, due to the difficulty in obtaining available reference substances against the combination of some drugs and their precursors, the absolute accuracy of retrieval results cannot be guaranteed. NMR approach is independently eligible to confirm the structures of compounds of the reference substances so as to ensure the accuracy of the identification results. In this study, PMK methyl glycidate was identified with GC-MS and NMR, having its 1H-NMR and 13C-NMR spectra analyzed, thus providing a reference for identification of other similar compounds. The method is simple, reliable, and suitable for qualitative analysis of PMK methyl glycidate.
    • Technology and Application
  • Forensic Next Generation Sequencing Technology Having Played Role into Solving a 19-year-long Cold Case
    ZHANG Chi, GUO Liliang, ZHOU Ke, SONG Zhen, KANG Kelai, WEI Meitian, GAO Yue, ZHUO Wenteng, JI Anquan, WANG Le
    Forensic Science And Technology. 2022, 47(1): 100-106. https://doi.org/10.16467/j.1008-3650.2021.0075
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    The male pedigree investigation technology, based on Y chromosomal STR (Y-STR) polymorphism, has helped to solve many cold cases. However, some cold cases cannot be resolved if the involving biological samples are significantly degraded, resulting in inability to carry out effective male pedigree tracing due to fewer number of Y- STR loci detected. STRSeqTyperY68 kit, purposed for forensic male pedigree screening on the basis of next generation sequencing, is competent of genotyping fifty-two single-copy Y-STR loci, six two-copy Y-STRs and one three-copy Y-STR plus a sex determinant locus in a single-tube reaction run with MiSeq FGx sequencing platform. Moreover, the kit supports length- and/or sequence-based STR polymorphism analyses simultaneously, having brought forth amplicons no longer than 350 bp for all the tested 68 loci among which 62 ones are shorter than 300 bp, as such making it suitable for detection of degraded samples. Here reported a 19-year-long unsolved rape homicidal case where only 24 Y-STRs were successfully genotyped with the traditional capillary electrophoresis, leaving some 300-plus-bp Y-STRs undetected. Adoption of STRSeqTyperY68 kit performed into next generation sequencing, had completely genotyped 67 Y-STRs and the sex determinant locus from the same samples, helping to fasten the suspect’s male family so that a key technical support was provided for the case to have been solved.
  • UPLC-HRMS Determining Metabolites of Difenidol from a Poisoning Case
    WANG Ling, HOU Jianping
    Forensic Science And Technology. 2022, 47(1): 107-110. https://doi.org/10.16467/j.1008-3650.2022.01.001
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    Objective To determine the metabolites of difenidol in blood of the dead from a poisoning case. Methods Ultra-performance liquid chromatography - high resolution mass spectrometry (UPLC-HRMS) was used to detect the sample from the poisoned dead’s blood that was previously treated with acetonitrile to have the proteins precipitated. The structures of compounds from the sample were to deduce with the information of high-resolution mass-spectral fragments and suitable analysis software. Results Three metabolites of difenidol were identified from UPLC-HRMS detection and relevant data analysis. Conclusion The method established here provides a new reference for detection of metabolites from difenidol and the poisoning cases of the kind.

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