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Objective To develop an approach of coupling liquid chromatography with Q-Exactive high resolution mass spectrometry (HRMS) for determination of 25 fentanyl-kind analogs and 2 precursors so that both the fragmentation pathways and characteristic ions of such fentanyl-kind analogs were to analyze for providing a reference into the identification of suspected fentanyl-kind chemicals without standards, meanwhile presenting a foundation for new psychoactive substances to be supervised timely or as early as possible. Methods The fentanyl-kind solid drugs were extracted with methanol under ultrasound, and those liquid ones were extracted with acetonitrile via liquid-liquid extraction and salting-out procedures. The extracts were separated through a Hypersil GOLD C18 column (150mm×2.1mm×1.8μm) where a gradient elution was performed with a mobile phase consisting of methanol and water (2mmol/L ammonium acetate solution containing 0.1% formic acid). The fragmentation ions were acquired by HRMS in positive ion mode under full-scan-data-dependent MS2 (Full MS/dd-MS2). Finally, a mass-spectral library of 27 fentanyl-kind chemicals was thus established for qualitative analysis. Results 27 fentanyl-kind analogs were effectively separated along with the isomers. All the tested substances showed a low detection limit ranging among 0.05~2ng/mL and the quantitative limits for the solid-/liquid-form fentanyl-kind chemicals were 0.5μg/kg and 0.5ng/mL, respectively. Recoveries were all between 77.03% and 115.07%. Out from the ESI mode, the fentanyl-kind analogs mainly underwent McLafferty rearrangement (McL) through γ-hydrogen of piperidinyl ring being rearranged onto carbonyl oxygen and the carbonyl β-bond cleaved, hence having afforded the product ion (m/z 188). Hydrogen-transfer reaction resulted in the product ion to render a double bond which to ignite the further retro-Diels-Alder reaction of yielding the product ions (m/z160, 146, 134, 132). Dissociation of piperidinyl ring and phenylethyl formed the fragment ions at m/z 84, 105. Conclusions The effort made here should be facilitating the identification of novel psychoactive substances with fentanyl as core (matrix) of the new synthetic chemicals, helpful to the qualitative and quantitative detection of seized chemical materials.
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Objective To establish a method for simultaneous determination of 12 fentanyl-kind drugs in blood through integral SPE-LC-MS/MS with purpose to provide reference for identification of relevant cases. Methods The blood samples (harboring the 12 fentanyl-kind drugs) were treated with acetonitrile for proteins to precipitate, successively centrifugated to collect the supernatant that was subjected to dilution and filtration. The filtrate was directly undergone into integral SPE-LC-MS/MS processing so that Agilent PLRP-S (15-20µm, 2.1mm×12.5mm) column had played its role to enrich and purify the injected filtrate and Agilent Poroshell 120 EC-C18 (3.0mm×150mm, 2.7µm) column to perform its chromatographic separation under the gradient elution of mobile phases of A (5mmol/L ammonium acetate plus 0.1% formic acid) and B (acetonitrile). The analytes were detected in multiple reaction monitoring (MRM) mode through the electrospray positive ionization (ESI+). Results Under the optimization of chromatographic condition, mass spectral setting, sampling flow, mobile phase, valve swithching programs and organic solvent ratio, the 12 fentanyl-kind drugs showed good linear relationship within the tested concentration ranges, revealing their coefficients of determination as R2>0.9990. The method was present of detection limits and quantification limits being 0.2-0.4ng/mL and 0.7-1.4ng/mL, demonstrating the recoveries at three levels being fallen into 83.1%-131.1%, intra-and inter-day RSDs being the respective 1.0%-25.6% and 2.1%-30.5% (n=6). Conclusions The method established here is simple and efficient, demonstrating its excellence of low quantity of required sample, high sensitivity and low detection limit, suitable for simultaneous determination of 12 fentanyl-kind drugs in blood.
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Objective To establish an HPLC-DAD method for simultaneously quantitative analysis of tramadol, fentanyl and diphenoxylate in seized drugs and/or illegally-added herbal medicines. Methods The sample was dissolved into methanol and extracted under ultrasonic, having the obtained analytes separated through an Agilent Zorbax SB-C18 (4.6×250mm, 5μm) column that was flowed with gradient-eluting of 12mM potassium dihydrogen phosphate buffer (pH=4 adjusted by 10% dilute phosphoric acid)/acetonitrile. The analysis was completed in 30 minutes and detected at the wavelength of 210nm. Results The three chemical substances were shown of their detection limits (S/N=3) and quantitation limits (S/N=10) among 0.2~0.5μg/mL and 0.5~1.0 μg/mL, respectively. The linear relationship was good in the range of 2~700μg/mL, with the correlation coefficients (R2) being all greater than 0.999, the three-concentration average recoveries (80%, 100%, 120%) in yellow and white powdery drugs among 99.6%~105.4%, the relative standard deviations (RSD%, n=6) being less than 1.4%, the inter-day precisions among 1.19%~2.11%, the repeatability within 0.31%~1.41%, and the stability being fallen into 0.29%~0.87%. Conclusions The method is simple, accurate, precise and stable, capable of quantitative analysis of tramadol, fentanyl and diphenoxylate in seized drugs and/or illegally-added herbal medicines.
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Objective To establish an HPLC-MS/MS method for simultaneous determination of sufentanil and its metabolite (norsufentanil) in human blood so as to achieve a detection of both high sensitivity, low detection limit and good reproducibility plus simple pretreatment of sample. Methods Deuterated isotopic sufentanil, the internal standard, was added into samples (blank blood, blood containing both sufentanil and its metabolite-norsufentanil) that were followed to precipitate of protein with acetonitrile, successively undergone into separation through HPLC and detection via ESI, positive ion scanning and MRM mode. Qualitative accuracy was measured with retention time and two pairs of characteristic ions while the quantitative accuracy was calculated with the curve derived from internal standard. Results The detection limit of sufentanil was 0.05ng/mL, with the limit of quantification being 0.1ng/mL, linear range as 0.1~20ng/mL, correlation coefficients being the respective 0.99984 and 0.99973, recoveries between 90% and 120%, intra-and inter-day precisions being less than 5%, and accuracy between 90% and 110%. Conclusions The method is no necessity of concentration or derivatization, hence avoiding errors caused from cumbersome operation, excelling in the advantages of rapidity, simplicity, accurateness and stableness, therefore capable of qualitative and quantitative determination of sufentanil and norsufentanil in blood.
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Objective To establish a novel amplification multiplex of 13 rapidly-mutating (RM) Y-STRs (the known and utilized thus far), and to assess its forensic applicability and capability. Methods A set of new 5-dye Y-STR multiplex system was tentatively developed to amplify 13 RM Y-STR loci (DYF387S1, DYF399S1, DYF403S1, DYF404S1, DYS526, DYS449, DYS518, DYS547, DYS570, DYS576, DYS612, DYS626, DYS627) through optimization of fluorescence labelling, primers designing, constituents concocting and amplification setup. One recommended nomenclature was concluded on the basis of reviewing into peers’ published normalizations and Sanger’s sequencing. The multiplex system was validated with determination of sensitivity, species specificity and stability plus its performance for detecting the mixed DNA samples. Results One novel RM Y-STR amplification multiplex was successfully constructed, demonstrating its optimal annealing temperature of 59°C and cycles of 28. A recommended nomenclature for the RM Y-STR loci was concluded from summarization. Full profiles of the selected Y-STR loci were still obtained down to a low level of template DNA (0.125ng). Besides, the multiplex system was of species-specific and robust to tolerate concentration-high PCR inhibitors (i.e., EDTA, hematin, humic acid and indigo with this assay). Furthermore, the system was able to detect complete male specific genotypic profiles in a male/female DNA mixture at a ratio of 1∶4000, and so was it for male/male ratio-various DNA mixtures to display mutually. Conclusions The RM Y-STR multiplex developed here is of forensic applicability, very suitable for both fine searching into male lineages and complementing to currently-used Y-STR kits.
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Objective To explore the operational principle of Cartesian-coordinate writing robot about its imitative signature handwriting and related characteristics on which how to consequently influence with the robot’s parameter setting. Methods The personal man-made signature handwritings and those of the writing robot were collected, having been observed into the characteristics of the robot’s imitative signature handwritings with the help of instruments (i.e., VSC8000 and RTI here). Results As the robot’s imitating signature handwriting is designed on Bezier curve and consecutively converted into G instructional code to control the robot to carry out writing, a highly consistency exists between the robot’s imitating signature handwriting and the one of personal man-made about their general features, local arrangements and writing-regulated features, yet the differences being present among their allocable proportion, repeated strokes, stroke order, pen’s running route and marks. Strokes’ jitter will result from the larger parameter setting of acceleration and speed. With the pen pressure-parameter augmenting, the pen marks maintain from gradual deepening to remaining unchanged. The pen’s closing stroke is to elongate along with the pen pressure/stroke parameters augmenting. Conclusions There are essential differences present in writing principle and handwriting characteristics between the robot imitative signature handwriting and the one of personal man-made, laying a feasibility for identification about such kind of signature handwriting.
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Compared with capillary electrophoresis (CE) technology, next generation sequencing (NGS) can accommodate more STR genetic loci within the relevant system, therefore emerging as a promising and potential technology for forensic practice. Illumina’s MiSeq FGxTM system is a sequencing platform dedicated to forensic services, with its supporting kit - Forenseq DNA Signature Prep kit having achieved higher sensitivity and accuracy. 41 pedigree samples were here reported of being sequenced with the kit mentioned above. The results showed that 26 of the tested 58 STR loci had come into being allelic subtypes, bringing forth the total number of alleles to increase by 79. There was one sample showing a dropout at the DYS392 locus against to its CE presentation, being speculated of correlativity with amplification efficiency of the kit’s primers. Besides, eight samples were found of inconsistency with CE results at the DXS7132 locus. Sanger sequencing was thus conducted and data were analyzed with other software to explore the causation. It was confirmed that the inconsistency resulted from irrelevant bioinformatics analysis. This study has proved that NGS owns many advantages over CE although it still awaits solutions about some issues in bioinformatics analysis. With the ever-coming continuous improvement of related technologies and standards, NGS is believed to be gradually applied into forensic practice.
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Objective To establish a novel method for determination of blood-harbored ketamine and F-ketamine through liquid chromatography-mass spectrometry (LC-MS/MS), with pretreatment choice being preferentially determined from the matrix effect and successively the blood-harbored ketamine and F-ketamine to be isolated and tested of their specificity, linearity, detection limit, precision and accuracy. Methods Sampling blood (1.00mL) was taken, added with 2.00mL acetonitrile, extracted under vibration, and centrifuged, having the supernatant filtered through 0.22μm membrane before analyzed into liquid chromatography-mass spectrometry (LC-MS/MS). With their retention time, characteristic ions and relative abundance ratio for qualitative determination plus their peak area of characteristic ions for quantification, the two chemical substances were to characterize. Results Acetonitrile precipitation showed no significant matrix effect yet good specificity. A good linearity was obtained with the concentration of ketamine and F-ketamine ranging from 1.50ng/mL to 150ng/mL in blood (R2˃0.999). The detection limit of the method was 0.30ng/mL, and the extraction efficiencies of samples spiked with concentration-different ketamine or F-ketamine were 82.1%~86.5%. The intra- and inter-day RSDs were less than 10%. Conclusions A new method was here successfully developed for determination of blood-harbored ketamine and F-ketamine using liquid chromatography-mass spectrometry (LC-MS/MS). The method is simple, quick, sensitive and stable, suitable for qualitative and quantitative determination of ketamine and F-ketamine in blood.
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Objective To develop a new derivatization method for GC-MS to rapidly determine fluoroacetate (salt) from food-poisoning samples and vomit. Methods The samples were extracted with pure water, then added of the organic solvent containing derivatization reagent (PFB-Br) into the aqueous phase so that the derivatization-synchronous extraction was achieved under the function of tetrabutylammonium hydrogen sulfate (also named as IPC-TBA-HS), a phase transfer catalyst (PTC). GC-MS, equipped with HP-5MS elastic quartz capillary column (30m×0.25mm×0.25mm), was adopted for analysis into the extractant. From the retention time of pentafluorobenzylmono-fluoroacetate (PFB-MFA) (the derivatized product), the relevant fragmented ions of m/z 181.0, 258.0, 61.0 and involving characteristic peak areas were selected as qualitative and quantitative benchmark. Results The method was showing linear among 0.1μg-10μg/ml (R2=0.9997, n=7), with its detection limit as 0.050ug/ml and recovery being more than 80%. Conclusions The developed method has been verified of time-saving, less workload, simplicity, easiness to operate and high sensitivity, suitable for frontline detection units to utilize, too.
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Objective To probe into near-infrared light about its detecting concentration-different trace bloodstains on various dark permeable objects. Methods The bloodstains were prepared on the patches of black, cyan and blue cloths, having the cloth-harboring bloodstain samples successfully made from dripping with concentration-differen blood fluid (the undiluted blood for all cloths; the blood dilutions of 1:1, 1:10, 1:20 and 1:50 for the black cloth, only). Onto each of the cloth patches harboring bloodstains was the detection from near-infrared light for discovering the bloodstains. Results Under the infrared light, the bloodstains became obscure while the dark cloth turning brighter, hence having brought forth a contrast against the dark cloths among which the black one was able to unveil the trace bloodstains made from up to the 20-fold-diluted blood fluid. Conclusions Near-infrared light is competent to detect trace bloodstains left from suspect at the crime scene, capable of quickening the detection of relevant case where the bloodstains on dark permeable objects are usually leaking out of discovery and difficult to detect, otherwise.
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The mixed stain of seminal and vaginal fluid is one of the important evidential materials in sexual assault cases, a crucial item in forensic biological examination, too. The vital role will be played when the sperm cell DNA is separated and extracted from the mixed stain and matched to the criminal suspect, resulting in the identification or exclusion of criminal suspects and successful unravelment of the involving case. Forensic scientists have until present established a variety of methods for separating sperm DNA from the mixed stains in their endeavor to meet the requirements of DNA detection and solve the specific problems and difficulties from actual cases. This review summarizes the relevant methods at the two levels of cell and DNA about their core gists, advantages, disadvantages and applicability, focusing on the new research progress home and abroad in recent years and carrying out overview and prospect with combination into the practical forensic applicability and developability.
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X-ray fluorescence spectrometry (XRF) is one approach commonly applied for element analysis, capable of distinguishing the types and contents of elements in the tested sample. XRF is therewith of wide forensic utilizations. This article reviewed the application of XRF into examining documents from the respective paper, writing/printing inks, banknotes and paper cultural relics, having summarized the XRF-based identification of document authenticity, concatenation, traceability and chronicling. Additionally, an introduction was carried out about the mathematical statistics adopted in quantitative analysis of elements, together with the qualitative analyses of various apigments. Finally, a prospect was envisioned on further application of XRF, with the concerned key issues and future trend being discussed, too.
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Paper-substrate photos were here elucidated about their traits and relevant domestic researches, together with common methods of forging photos. Pursuantly, the forged paper-substrate photos were thereby probed into their testing methods, standards, conclusions and enunciating specifications. For testing methods, the main procedure includes preliminary observation, digital scanning test, comparison and comprehensive evaluation. Accordingly, the paper-substrate photo’s authenticity was summarized with the focus being paid on the related difficulties and judicial practice. Logically, paper-substrate photo’s judicial authentication is necessary to establish its theoretical basis, and gradually explore different testing choices on uncovering the forging means through real cases.
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Objective To explore a method for aquatic decomposition scoring to estimate postmortem submersion interval (PMSI) and have its effect evaluated. Methods PMSI-known totaling 65 cases were collected from our past work in recent years, having each case obtained of its total aquatic decomposition score (TADS) with a new designed decomposition scoring algorithm. The relationship was explored between TADS and PMSI through statistical approach, rendering a regression equation. Results PMSI was positively correlated with TADS (R2=0.63, P<0.001). With log conversion of PMSI, the regression equation was established as lgPMSI=0.191+0.045TADS (R2=0.668, P<0.001). Conclusion Aquatic decomposition scoring is capable of effectively estimating PMSI.
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Arson, a typical violent crime anywhere, usually results in heavy casualties, severe economic losses and adverse social impact. Therefore, it is urgent and necessay to have an optimal investigation mechanism and method to determine the nature of a suspected fire case swiftly and accurately. Nevertheless, the highly destructive sites and easily destroyed evidence frequently have the fire investigators met with great challenges. As one of the countries of occurrence to frequent arson cases, the United States has developed advanced investigation technologies about arson and its investigators have thus accumulated rich experience through tackling with large number of arsons. In order to provide meaningful suggestions for arson investigors to optimize their investigating and handling mechanism and strengthen on-site investigation technologies in China, the essay herein introduced the means and technologies applied about arson investigations by the concerned departments in the United States in recent years and summarized the key points that can be referential for the investigations to handle those similar arson cases in China. For arson cases, whether they are involvement with ignitable liquid or not, this article is purposed of further improving the scientificity and accuracy for investigation of arson cases in China from the perspectives of response mechanism, information gathering and physical evidence collection.
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Objective To prepare a kind of sulfur-containing polymer for its exploratory utilization into fingerprint development. Methods The sulfur-containing polymer was prepared under a designed synthesis route, having been characterized of its chemical attribution with certain related physicochemical resorts. Latent sweat fingerprints were made on copper sheet surfaces in different states, successively sealed with the synthesized polymer into a reaction bottle for condition-various development. Observation was carried out about the development effect. Results The sulfur-containing polymer was successfully prepared, having achieved of developing the latent sweat fingerprints on copper sheets where whether those fingerprints were intact or undergone with water washing or detergent washing plus sponge wiping before development. Conclusions The sulfur-containing polymer is potential to develop latent sweat fingerprint on metal (e.g., copper) surface, capable of being utilized to develop difficult-to-handle fingerprints on copper sheet surface.
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iPhone furnishes the functional APPs of “Voice Memo”, “WeChat” and “File”, facilitating users to forward and dump audio files across them. Usually, either forwarding or dumping can remain the audio file unchanged of its size and recorded content, yet making it changed of the metadata information and electronic data. Therefore, the audio files stored in “Voice Memo” should be authenticated with not only the routine analyses of their metadata, signal, semantics and electronic data but also source-tracing into their systemic and applicative log files resulted throughout the entire course of generation and transformation from the audio files. With a real case, an introduction was here made on how to trace into the transferring process of audio files through iPhone-stored “WeChat” log files and accordingly judge the authenticity of the relevant audio recordings synthetically.
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Several typical cases were here reported about identification of tampered VIN (Vehicle Identification Number), thereby having the elaboration brought forward on how to apply the idea of systematic examination into VIN identification. Through discrimination and extraction of various information from the tested vehicles themselves, the correct identification opinions were finally delivered after comparison and comprehensive analysis against the identity information of the tested vehicles. In conclusion, a successful identification relies on the relevant details of case and other helping external information, avoidance of inertial thinking in identification process, adoption of varieties of scientific, technological and verifying means, striving to obtain valuable information as much as possible, and checking the obtained information from different angles. The cases and their successful identification reported here should provide certain reference for professionals engaging in such kind of forensic identification.